Professor Annette Sterr

Research Interests

My research focuses on clinical neuroscience brain plasticity with particular emphasis on functional brain organization, neurological rehabilitation, and most recently sleep. A second strand of studies aims to understand the neuromodulatory effects of glucose and hormones on cognition.

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E-mail:
Phone: 01483 68 2883

Find me on campus
Room: 02 AC 04

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My office hours

Wednesday 12.00 - 14.00 or by appointment

Publications

Journal articles

  • Kidd T , Carey NJ, Mold F , Westwood SL, Miklaucich M , Konstantara E , Sterr AM, Cooke DD. (2017) 'A Systematic Review of the Effectiveness of Self-Management Interventions in People with Multiple Sclerosis at Improving Depression, Anxiety and Quality of Life.'. Public Library of Science PLoS ONE, 12 (10) Article number e0185931

    Abstract

    Background

    Self-management interventions have become increasingly popular in the management of long term health conditions; however, little is known about their impact on psychological well-being in people with Multiple Sclerosis (MS).

    Purpose

    To examine the effectiveness of self-management interventions on improving depression, anxiety and health related quality of life in people with MS.

    Method

    A structured literature search was conducted for the years 2000 to 2016. The review process followed the PRISMA guidelines, and is registered with PROSPERO (no. CRD42016033925).

    Results

    The review identified 10 RCT trials that fulfilled selection criteria and quality appraisal. Self-management interventions improved health-related quality of life in 6 out of 7 studies, with some evidence of improvement in depression and anxiety symptoms.

    Conclusion

    Although the results are promising more robust evaluation is required in order to determine the effectiveness of self-management interventions on depression, anxiety and quality of life in people with MS. Evaluation of the data was impeded by a number of methodological issues including incomplete content and delivery information for the intervention and the exclusion of participants representing the disease spectrum. Recommendations are made for service development and research quality improvement.

  • Parker WD, Gage HM, Sterr AM, Williams P . (2017) 'Holiday play for disabled children in England: access, choice and parents’ views about integration'. Taylor & Francis International Journal of Disability, Development and Education,

    Abstract

    Families with children with disabilities can feel isolated during school holidays and concerns exist that they face greater difficulties than families of children without disabilities in finding enriching activities for their child. In the context of national policies that encourage integrated play, local service commissioners in England require evidence on what sort of short breaks parents and children prefer. The parents of 99 children with disabilities and 43 children without disabilities attending various holiday play schemes in summer 2010 completed mailed questionnaires. Parents of children with disabilities reported more difficulty getting information, less choice of schemes and further distances to travel than parents of children without disabilities. Although 72% of parents of children without disabilities and 55.5% of parents of children with disabilities stated integrated schemes would be suitable for their child, open text comments provided weaker support. Variety of provision is required to meet all needs and preferences.

  • Dean PJA, Arikan G, Opitz B , Sterr AM. (2017) 'Potential for use of creatine supplementation following mild traumatic brain injury'. Future Medicine Concussion, 2 (2)

    Abstract

    There is significant overlap between the neuropathology of mild traumatic brain injury (mTBI) and the cellular role of creatine, as well as evidence of neural creatine alterations after mTBI. Creatine supplementation has not been researched in mTBI, but shows some potential as a neuroprotective when administered prior to or after TBI. Consistent with creatine’s cellular role, supplementation reduced neuronal damage, protected against the effects of cellular energy crisis and improved cognitive and somatic symptoms. A variety of factors influencing the efficacy of creatine supplementation are highlighted, as well as avenues for future research into the potential of supplementation as an intervention for mTBI. In particular, the slow neural uptake of creatine may mean that greater effects are achieved by pre-emptive supplementation in at-risk groups.

  • Kuhn M, Wolf E, Maier JG, Mainberger F, Feige B, Schmid H, Buerklin J, Maywald S, Mall V, Jung NH, Reis J, Spiegelhalder K, Kloeppel S, Sterr A, Eckert A, Riemann D, Normann C, Nissen C. (2016) 'Sleep recalibrates homeostatic and associative synaptic plasticity in the human cortex'. Nature Publishing Group Nature Communications, 7 Article number 12455
  • Frase L, Piosczyk H, Zittel S, Jahn F, Selhausen P, Krone L, Feige B, Mainberger F, Maier J, Kuhn M, Kloppel S, Normann C, Sterr AM, Spiegelhalder K, Riemann D, Nitsche M, Nissen C. (2016) 'Modulation of total sleep time by transcranial direct current stimulation (tDCS)'. Nature Publishing Group Neuropsychopharmacology., 41 (10), pp. pp. 2577-2586.

    Abstract

    Arousal and sleep are fundamental physiological processes, and their modulation is of high clinical significance. This study tested the hypothesis that total sleep time in humans can be modulated by the non-invasive brain stimulation technique transcranial direct current stimulation (tDCS) targeting a ‘top-down’ cortico-thalamic pathway of sleep-wake regulation. Nineteen healthy participants underwent a within-subject, repeated-measures protocol across five nights in the sleep laboratory with polysomnographic monitoring (adaptation, baseline, three experimental nights). tDCS was delivered via bi-frontal target electrodes and bi-parietal return electrodes prior to sleep (anodal ‘activation’, cathodal ‘deactivation’ and sham stimulation). Bi-frontal anodal stimulation significantly decreased total sleep time, compared to cathodal and sham stimulation. This effect was location specific. Bi-frontal cathodal stimulation did not significantly increase total sleep time, potentially due to ceiling effects in good sleepers. Exploratory resting-state EEG analyses prior to and after the tDCS protocols were consistent with the notion of increased cortical arousal after anodal stimulation and decreased cortical arousal after cathodal stimulation. The study provides proof-of-concept that total sleep time can be decreased by non-invasive bi-frontal anodal tDCS in healthy humans. Further elucidating the ‘top-down’ pathway of sleep-wake regulation is expected to increase knowledge on the fundamentals of sleep-wake regulation and to contribute to the development of novel treatments for clinical conditions of disturbed arousal and sleep.

  • Krone L, Frase L, Piosczyk H, Selhausen P, Zittel S, Jahn F, Kuhn M, Feige B, Mainberger F, Klöppel S, Riemann D, Spiegelhalder K, Baglioni C, Sterr A, Nissen C. (2016) 'Top-down control of arousal and sleep: Fundamentals and clinical implications.'. Elsevier Sleep medicine reviews,

    Abstract

    Mammalian sleep emerges from attenuated activity in the ascending reticular arousal system (ARAS), the main arousal network of the brain. This system originates in the brainstem and activates the thalamus and cortex during wakefulness via a well-characterized 'bottom-up' pathway. Recent studies propose that a less investigated cortico-thalamic 'top-down' pathway also regulates sleep. The present work integrates the current evidence on sleep regulation with a focus on the 'top-down' pathway and explores the potential to translate this information into clinically relevant interventions. Specifically, we elaborate the concept that arousal and sleep continuity in humans can be modulated by non-invasive brain stimulation (NIBS) techniques that increase or decrease cortical excitability. Based on preclinical studies, the modulatory effects of the stimulation are thought to extend to subcortical arousal networks. Further exploration of the 'top-down' regulation of sleep and its modulation through non-invasive brain stimulation techniques may contribute to the development of novel treatments for clinical conditions of disrupted arousal and sleep, which are among the major health problems worldwide.

  • Furlan L, Conforto AB, Cohen LG, Sterr A. (2016) 'Upper Limb Immobilisation: A Neural Plasticity Model with Relevance to Poststroke Motor Rehabilitation'. HINDAWI PUBLISHING CORP NEURAL PLASTICITY, Article number ARTN 8176217
  • Baglioni C, Nissen C, Schweinoch A, Riemann D, Spiegelhalder K, Berger M, Weiller C, Sterr A. (2016) 'Polysomnographic Characteristics of Sleep in Stroke: A Systematic Review and Meta-Analysis'. PUBLIC LIBRARY SCIENCE PLOS ONE, 11 (3) Article number ARTN e0148496
  • Plow EB, Sankarasubramanian V, Cunningham DA, Potter-Baker K, Varnerin N, Cohen LG, Sterr A, Conforto AB, Machado AG. (2016) 'Models to Tailor Brain Stimulation Therapies in Stroke'. HINDAWI PUBLISHING CORP NEURAL PLASTICITY, Article number ARTN 4071620
  • Wolf E, Kuhn M, Norman C, Mainberger F, Maier JG, Maywald S, Bredl A, Klöppel S, Biber K, van Calker D, Riemann D, Sterr A, Nissen C. (2015) 'Synaptic plasticity model of therapeutic sleep deprivation in major depression.'. Sleep medicine reviews, 30, pp. 53-62.
  • Magalhaes SC, Kaelin-Lang A, Sterr A, do Prado GF, Eckeli AL, Conforto AB. (2015) 'Transcranial magnetic stimulation for evaluation of motor cortical excitability in restless legs syndrome/Willis-Ekbom disease'. ELSEVIER SCIENCE BV SLEEP MEDICINE, 16 (10), pp. 1265-1273.
  • Landmann N, Kuhn M, Maier JG, Spiegelhalder K, Baglioni C, Frase L, Riemann D, Sterr A, Nissen C. (2015) 'REM sleep and memory reorganization: Potential relevance for psychiatry and psychotherapy'. Neurobiology of Learning and Memory, 122, pp. 28-40.
  • Dean PJ, Sato JR, Vieira G, McNamara A, Sterr A. (2015) 'Long-term structural changes after mTBI and their relation to post-concussion symptoms.'. Brain Inj, , pp. 1-8.

    Abstract

    PRIMARY OBJECTIVE: To investigate sustained structural changes in the long-term (>1 year) after mild traumatic brain injury (mTBI) and their relationship to ongoing post-concussion syndrome (PCS). RESEARCH DESIGN: Morphological and structural connectivity magnetic resonance imaging (MRI) data were acquired from 16 participants with mTBI and nine participants without previous head injury. MAIN OUTCOMES AND RESULTS: Participants with mTBI had less prefrontal grey matter and lower fractional anisotropy (FA) in the anterior corona radiata and internal capsule. Furthermore, PCS severity was associated with less parietal lobe grey matter and lower FA in the corpus callosum. CONCLUSIONS: There is evidence for both white and grey matter damage in participants with mTBI over 1 year after injury. Furthermore, these structural changes are greater in those that report more PCS symptoms, suggesting a neurophysiological basis for these persistent symptoms.

  • Conti J, Sterr A, Brucki SM, Conforto AB. (2015) 'Diversity of approaches in assessment of executive functions in stroke: limited evidence?'. eNeurologicalSci, 1 (1), pp. 12-20.
  • Landmann N, Kuhn M, Maier JG, Spiegelhalder K, Baglioni C, Frase L, Riemann D, Sterr A, Nissen C. (2015) 'REM sleep and memory reorganization: Potential relevance for psychiatry and psychotherapy.'. Neurobiol Learn Mem, United States: 122, pp. 28-40.
  • Sterr A, Furlan L. (2015) 'A case to be made: theoretical and empirical arguments for the need to consider fatigue in post-stroke motor rehabilitation'. MEDKNOW PUBLICATIONS & MEDIA PVT LTD NEURAL REGENERATION RESEARCH, 10 (8), pp. 1195-1197.
  • Minarik T, Sauseng P, Dunne L, Berger B, Sterr A. (2015) 'Effects of anodal transcranial direct current stimulation on visually guided learning of grip force control.'. Biology (Basel), Switzerland: 4 (1), pp. 173-186.
  • Lukoschek C, Sterr A, Claros-Salinas D, Gütler R, Dettmers C. (2015) 'Fatigue in Multiple Sclerosis Compared to Stroke.'. Front Neurol, Switzerland: 6
  • Dean PJA, Sato J, Vieira G, McNamara A, Sterr AM. (2014) 'Multimodal imaging of mild traumatic brain injury and persistent postconcussion syndrome'. Brain and Behavior,

    Abstract

    Background: Persistent postconcussion syndrome (PCS) occurs in around 5– 10% of individuals after mild traumatic brain injury (mTBI), but research into the underlying biology of these ongoing symptoms is limited and inconsistent. One reason for this could be the heterogeneity inherent to mTBI, with individualized injury mechanisms and psychological factors. A multimodal imaging study may be able to characterize the injury better. Aim: To look at the relationship between functional (fMRI), structural (diffusion tensor imaging), and metabolic (magnetic resonance spectroscopy) data in the same participants in the long term (>1 year) after injury. It was hypothesized that only those mTBI participants with persistent PCS would show functional changes, and that these changes would be related to reduced structural integrity and altered metabolite concentrations. Methods: Functional changes associated with persistent PCS after mTBI (>1 year postinjury) were investigated in participants with and without PCS (both n = 8) and non-head injured participants (n = 9) during performance of working memory and attention/processing speed tasks. Correlation analyses were performed to look at the relationship between the functional data and structural and metabolic alterations in the same participants. Results: There were no behavioral differences between the groups, but participants with greater PCS symptoms exhibited greater activation in attention-related areas (anterior cingulate), along with reduced activation in temporal, default mode network, and working memory areas (left prefrontal) as cognitive load was increased from the easiest to the most difficult task. Functional changes in these areas correlated with reduced structural integrity in corpus callosum and anterior white matter, and reduced creatine concentration in right dorsolateral prefrontal cortex. Conclusion: These data suggest that the top-down attentional regulation and deactivation of task-irrelevant areas may be compensating for the reduction in working memory capacity and variation in white matter transmission caused by the structural and metabolic changes after injury. This may in turn be contributing to secondary PCS symptoms such as fatigue and headache. Further research is required using multimodal data to investigate the mechanisms of injury after mTBI, but also to aid individualized diagnosis and prognosis.

  • Sterr A, O'Neill D, Dean PJA, Herron KA. (2014) 'CI therapy is beneficial to patients with chronic low-functioning hemiparesis after stroke'. Frontiers in Neurology, 5 Article number 205 , pp. 1-10.

    Abstract

    CI therapy is effective in patients with relatively good levels of residual arm function but its applicability to patients with low-functioning hemiparesis is not entirely clear. In the present study, we examined the feasibility and efficacy of the CI therapy concept in patients with very limited upper arm function prior to treatment, and further tested how the length of daily shaping training and constraining the good arm affects treatment outcome. In a baseline-controlled design, 65 chronic patients were treated with 2weeks of modified CI therapy. Patients were randomly allocated to four treatment groups receiving 90 or 180 min of daily shaping training applied with or without constraint, respectively. Outcome was measured through the Reliable Change Index, which was calculated for parameters of motor function, health, and psychological wellbeing. Follow-up data were collected at 6 and 12 months.Two analyses were conducted, a whole-group analysis across all 65 participants and a sub-group analysis contrasting the four treatment variants. The whole-group analysis showed a significant treatment effect, which was largely sustained after 1 year. The sub-group analysis revealed a mixed picture; while improvements against the baseline period were observed in all four subgroups, 180 min of daily shaping training coupled with the constraint yielded better outcome on the MAL but not the WMFT, while for 90 min of training the level of improvement was similar for those who wore the constraint and those who did not. Together these results suggest that, at least in those patients available for follow-up measures, modified CI therapy induces sustained improvements in motor function in patients with chronic low-functioning hemiparesis. The absence of clear differences between the four treatment variants points to a complex relationship between the length of daily shaping training and the constraint in this patient group, which is likely to be mediated by fatigue and/or compliance with the constraint.

  • Neumann M, Claros-Salinas D, Gütler R, Dettmers C, Sterr A, Ulrich R. (2014) 'Modulation of alertness by sustained cognitive demand in MS as surrogate measure of fatigue and fatigability'. Journal of the Neurological Sciences, 340 (1-2), pp. 178-182.
  • Herron K, Dijk D, Dean PJA, Seiss E, Sterr A. (2014) 'Quantitative Electroencephalography and Behavioural Correlates of Daytime Sleepiness in Chronic Stroke'. BioMed Research Internationl, 2014 Article number 794086

    Abstract

    Sleepiness is common after stroke, but in contrast to its importance for rehabilitation, existing studies focus primarily on the acute state and often use subjective sleepiness measures only. We used quantitative electroencephalography (qEEG) to extract physiological sleepiness, as well as subjective reports, in response to motor-cognitive demand in stroke patients and controls. We hypothesised that (a) slowing of the EEG is chronically sustained after stroke; (b) increased power in lower frequencies and increased sleepiness are associated; and (c) sleepiness is modulated by motor-cognitive demand. QEEGs were recorded in 32 chronic stroke patients and 20 controls using a Karolinska Drowsiness Test protocol administered before and after a motor priming task. Subjective sleepiness was measured using the Karolinska Sleepiness Scale.The findings showed that power density was significantly increased in delta and theta frequency bands over both hemispheres in patients which were not associated with subjective sleepiness ratings. This effect was not observed in controls.The motor priming task induced differential hemispheric effects with greater increase in low-frequency bands and presumably compensatory increases in higher frequency bands. The results indicate sustained slowing in the qEEG in chronic stroke, but in contrast to healthy controls, these changes are not related to perceived sleepiness.

  • Anjos SM, Cohen LG, Sterr A, De Andrade KNF, Conforto AB. (2014) 'Translational neurorehabilitation research in the third world: What barriers to trial participation can teach us'. Stroke, 45 (5), pp. 1495-1497.
  • Dean P, Perkins L, McNamara A, Sauseng P, Sterr A. (2014) 'A novel method for acquiring cognitive data after brain injury and during follow-up: The use of mobile technology in a visuo-spatial working memory task'. INFORMA HEALTHCARE BRAIN INJURY, 28 (5-6), pp. 656-656.
  • Dean P, Sato J, Vieira G, McNamara A, Sterr A. (2014) 'Correlation between functional, structural and metabolic changes after mild traumatic brain injury and it's relationship with persistent PCS and cognitive performance'. INFORMA HEALTHCARE BRAIN INJURY, 28 (5-6), pp. 656-656.
  • Anjos SM, Cohen LG, Sterr A, de Andrade KN, Conforto AB. (2014) 'Translational neurorehabilitation research in the third world: what barriers to trial participation can teach us.'. Stroke, United States: 45 (5), pp. 1495-1497.
  • Landmann N, Kuhn M, Piosczyk H, Feige B, Baglioni C, Spiegelhalder K, Frase L, Riemann D, Sterr A, Nissen C. (2014) 'The reorganisation of memory during sleep.'. Sleep Med Rev, England: 18 (6), pp. 531-541.
  • McNamara A, Moakes K, Aston P, Gavin C, Sterr A. (2014) 'The importance of the derivative in sex-hormone cycles: a reason why behavioural measures in sex-hormone studies are so mercurial.'. PLoS One, United States: 9 (11)
  • Berger B, Omer S, Minarik T, Sterr A, Sauseng P. (2014) 'Interacting memory systems-does EEG alpha activity respond to semantic long-term memory access in a working memory task?'. Biology (Basel), Switzerland: 4 (1), pp. 1-16.
  • Landmann N, Kuhn M, Piosczyk H, Feige B, Baglioni C, Spiegelhalder K, Frase L, Riemann D, Sterr A, Nissen C. (2014) 'The reorganisation of memory during sleep'. Sleep Medicine Reviews, 18 (6), pp. 531-541.
  • Kranczioch C, Zich C, Schierholz I, Sterr A. (2014) 'Mobile EEG and its potential to promote the theory and application of imagery-based motor rehabilitation'. International Journal of Psychophysiology, 91 (1), pp. 10-15.
  • Noone DM, Willis TA, Cox J, Harkness F, Ogilvie J, Forbes E, Sterr A, Gregory AM. (2014) 'Catastrophizing and Poor Sleep Quality in Early Adolescent Females'. Behavioral Sleep Medicine, 12 (1), pp. 41-52.
  • Sterr A, Dean PJ, Szameitat AJ, Conforto AB, Shen S. (2013) 'Corticospinal Tract Integrity and Lesion Volume Play Different Roles in Chronic Hemiparesis and Its Improvement Through Motor Practice.'. Neurorehabil Neural Repair,
  • Billows IJ, Khan S, Sterr A. (2013) 'Exploring sleep, sleepiness and fatigue in chronic stroke: A mixed methods study'. WILEY-BLACKWELL INTERNATIONAL JOURNAL OF STROKE, 8, pp. 73-73.
  • Kranczioch C, Zich C, Schierholz I, Sterr A. (2013) 'Mobile EEG and its potential to promote the theory and application of imagery-based motor rehabilitation.'. Int J Psychophysiol,
  • O'Sullivan M, Glorney E, Sterr A, Oddy M, Ramos SDS. (2013) 'Traumatic brain injury and violent behavior in females: A systematic review'. PERGAMON-ELSEVIER SCIENCE LTD AGGRESSION AND VIOLENT BEHAVIOR, 25, pp. 54-64.
  • Hope C, Seiss E, Dean PJA, Williams K, Sterr A. (2013) 'Consumption of glucose drinks slows sensorimotor processing: Double-blind placebo-controlled studies with the Eriksen flanker task'. Frontiers Frontiers in Human Neuroscience, 7 Article number 651
  • Dean PJ, Otaduy MC, Harris LM, McNamara A, Seiss E, Sterr A. (2013) 'Monitoring long-term effects of mild traumatic brain injury with magnetic resonance spectroscopy: a pilot study.'. Lippincott, Williams & Wilkins Neuroreport, England: 24 (12), pp. 677-681.

    Abstract

    This pilot study explores the metabolic changes associated with persistent postconcussion syndrome (PCS) after mild traumatic brain injury (mTBI; >12 months after injury) using magnetic resonance spectroscopy. We hypothesized that those mTBI participants with PCS will have larger metabolic differences than those without. Data were collected from mTBI participants with PCS, mTBI participants without PCS and non-head-injured participants (all groups: n=8). Magnetic resonance spectroscopy metabolite profiles within the dorsolateral prefrontal cortex showed a reduced creatine/choline ratio in mTBI patients compared with control participants. This data provides initial evidence for residual metabolic changes in chronic mTBI patients, but there was no conclusive relationship between these metabolic changes and PCS symptom report. Creatine is involved in maintaining energy levels in cells with high or fluctuating energy demand, suggesting that there may be some residual energy impairment in chronic mTBI.

  • Ellis JG, Thomson A, Gregory AM, Sterr A. (2013) 'Biased Processing of Sleep-Related Stimuli in Children of Parents With Insomnia'. Behavioral Sleep Medicine, 11 (2), pp. 108-119.
  • dos Santos-Fontes RL, Ferreiro de Andrade KN, Sterr A, Conforto AB. (2013) 'Home-Based Nerve Stimulation to Enhance Effects of Motor Training in Patients in the Chronic Phase After Stroke: A Proof-of-Principle Study'. SAGE PUBLICATIONS INC NEUROREHABILITATION AND NEURAL REPAIR, 27 (6), pp. 483-490.
  • Noone DM, Harkness F, Ogilvie J, Gregory AM, Willis TA, Cox J, Sterr A, Forbes E. (2013) 'Catastrophizing and Poor Sleep Quality in Early Adolescent Females'. Behavioral Sleep Medicine,
  • Dean PJA, Sterr AM. (2013) 'Long-term effects of mild traumatic brain injury on cognitive performance'. Frontiers Research Foundation Frontiers in Human Neuroscience, 7 Article number 30 , pp. 1-11.

    Abstract

    Although a proportion of individuals report chronic cognitive difficulties after mild traumatic brain injury (mTBI), results from behavioral testing have been inconsistent. In fact, the variability inherent to the mTBI population may be masking subtle cognitive deficits. We hypothesized that this variability could be reduced by accounting for post-concussion syndrome (PCS) in the sample. Thirty-six participants with mTBI (>1 year post-injury) and 36 non-head injured controls performed information processing speed (Paced Visual Serial Addition Task, PVSAT) and working memory (n-Back) tasks. Both groups were split by PCS diagnosis (4 groups, all n = 18), with categorization of controls based on symptom report. Participants with mTBI and persistent PCS had significantly greater error rates on both the n-Back and PVSAT, at every difficulty level except 0-Back (used as a test of performance validity). There was no difference between any of the other groups. Therefore, a cognitive deficit can be observed in mTBI participants, even 1 year after injury. Correlations between cognitive performance and symptoms were only observed for mTBI participants, with worse performance correlating with lower sleep quality, in addition to a medium effect size association (falling short of statistical significance) with higher PCS symptoms, post-traumatic stress disorder (PTSD), and anxiety. These results suggest that the reduction in cognitive performance is not due to greater symptom report itself, but is associated to some extent with the initial injury. Furthermore, the results validate the utility of our participant grouping, and demonstrate its potential to reduce the variability observed in previous studies.

  • Sterr A, Dean PJA, Sato JR, Vieira G, Conforto AB, Shen S. (2013) 'Cortical thickness changes in the non-lesioned hemisphere associated with non-paretic arm immobilization in modified CI therapy'. NeuroImage: Clinical, 2 (1), pp. 797-803.
  • Shen S, Sterr A. (2012) 'Is DARTEL-based voxel-based morphometry affected by width of smoothing kernel and group size? A study using simulated atrophy'. WILEY-BLACKWELL JOURNAL OF MAGNETIC RESONANCE IMAGING, 37 (6), pp. 1468-1475.
  • Szameitat A, McNamara A, Shen S, Sterr AM. (2012) 'Neural Activation and Functional Connectivity during Motor Imagery of Bimanual Everyday Actions'. Public Library of Science PLoS One, 7 (6)

    Abstract

    Bimanual actions impose intermanual coordination demands not present during unimanual actions. We investigated the functional neuroanatomical correlates of these coordination demands in motor imagery (MI) of everyday actions using functional magnetic resonance imaging (fMRI). For this, 17 participants imagined unimanual actions with the left and right hand as well as bimanual actions while undergoing fMRI. A univariate fMRI analysis showed no reliable cortical activations specific to bimanual MI, indicating that intermanual coordination demands in MI are not associated with increased neural processing. A functional connectivity analysis based on psychophysiological interactions (PPI), however, revealed marked increases in connectivity between parietal and premotor areas within and between hemispheres. We conclude that in MI of everyday actions intermanual coordination demands are primarily met by changes in connectivity between areas and only moderately, if at all, by changes in the amount of neural activity. These results are the first characterization of the neuroanatomical correlates of bimanual coordination demands in MI. Our findings support the assumed equivalence of overt and imagined actions and highlight the differences between uni- and bimanual actions. The findings extent our understanding of the motor system and may aid the development of clinical neurorehabilitation approaches based on mental practice.

  • Szameitat AJ, Shen S, Bastos Conforto A, Sterr A. (2012) 'Cortical activation during executed, imagined, observed, and passive wrist movements in healthy volunteers and stroke patients'. Elsevier Neuroimage, 62 (1), pp. 266-280.

    Abstract

    Motor imagery, passive movement, and movement observation have been suggested to activate the sensorimotor system without overt movement. The present study investigated these three covert movement modes together with overt movement in a within-subject design to allow for a fine-grained comparison of their abilities in activating the sensorimotor system, i.e. premotor, primary motor, and somatosensory cortices. For this, 21 healthy volunteers underwent functional magnetic resonance imaging (fMRI). In addition we explored the abilities of the different covert movement modes in activating the sensorimotor system in a pilot study of 5 stroke patients suffering from chronic severe hemiparesis. Results demonstrated that while all covert movement modes activated sensorimotor areas, there were profound differences between modes and between healthy volunteers and patients. In healthy volunteers, the pattern of neural activation in overt execution was best resembled by passive movement, followed by motor imagery, and lastly by movement observation. In patients, attempted overt execution was best resembled by motor imagery, followed by passive movement, and lastly by movement observation. Our results indicate that for severely hemiparetic stroke patients motor imagery may be the preferred way to activate the sensorimotor system without overt behavior. In addition, the clear differences between the covert movement modes point to the need for within-subject comparisons.

  • Sterr AM, Bastos Conforto A. (2012) 'Plasticity of Adult Sensorimotor System in Severe Brain Infarcts: Challenges and Opportunities'. Hindawi Publishing Corporation Neural Plasticity,

    Abstract

    Functional reorganization forms the critical mechanism for the recovery of function after brain damage. These processes are driven by inherent changes within the central nervous system (CNS) triggered by the insult and further depend on the neural input the recovering system is processing. Therefore these processes interact with not only the interventions a patient receives, but also the activities and behaviors a patient engages in. In recent years, a wide range of research programs has addressed the association between functional reorganization and the spontaneous and treatment-induced recovery. The bulk of this work has focused on upper-limb and hand function, and today there are new treatments available that capitalize on the neuroplasticity of the brain. However, this is only true for patients with mild to moderated impairments; for those with very limited hand function, the basic understanding is much poorer and directly translates into limited treatment opportunities for these patients. The present paper aims to highlight the knowledge gap on severe stroke with a brief summary of the literature followed by a discussion of the challenges involved in the study and treatment of severe stroke and poor long-term outcome.

  • Ellis J, Thomsom A, Gregory AM, Sterr AM. (2012) 'Biased Processing of Sleep-Related Stimuli in Children of Parents With Insomnia'. Routledge, Taylor & Francis Group Behavioral Sleep Medicine, 10

    Abstract

    Disorder-specific cognitive biases have been observed in children whose parents suffer from psychological disorders. Despite those same biases being observed in individuals with insomnia, they have yet to be explored as an index of vulnerability in children of parents with insomnia. It was hypothesized that potentially vulnerable children would demonstrate cognitive biases to sleep- related cues, relative to controls. Following a “tired-state induction,” a sleep-related Emotional Stroop was completed by 2 groups: 38 children of parents with insomnia and 51 controls. Children also reported their observations about the content of the Stroop words. Results showed an attention bias in children whose parents have insomnia, but no interpretive bias. The results are discussed in terms of a predispositional vulnerability to insomnia.

  • Dean PJ, Seiss E, Sterr A. (2012) 'Motor Planning in Chronic Upper-Limb Hemiparesis: Evidence from Movement-Related Potentials.'. Public Library of Science PLoS One, 7 (10)

    Abstract

    Background Chronic hemiplegia is a common long-term consequence of stroke, and subsequent motor recovery is often incomplete. Neurophysiological studies have focused on motor execution deficits in relatively high functioning patients. Much less is known about the influence exerted by processes related to motor preparation, particularly in patients with poor motor recovery. Methodology/Principal Findings The current study investigates motor preparation using a modified response-priming experiment in a large sample of patients (n = 50) with moderate-to-severe chronic hemiparesis. The behavioural results revealed that hemiparetic patients had an increased response-priming effect compared to controls, but that their response times were markedly slower for both hands. Patients also demonstrated significantly enhanced midline late contingent negative variation (CNV) during paretic hand preparation, despite the absence of overall group differences when compared to controls. Furthermore, increased amplitude of the midline CNV correlated with a greater response-priming effect. We propose that these changes might reflect greater anticipated effort to respond in patients, and consequently that advance cueing of motor responses may be of benefit in these individuals. We further observed significantly reduced CNV amplitudes over the lesioned hemisphere in hemiparetic patients compared to controls during non-paretic hand preparation, preparation of both hands and no hand preparation. Two potential explanations for these CNV reductions are discussed: alterations in anticipatory attention or state changes in motor processing, for example an imbalance in inter-hemispheric inhibition. Conclusions/Significance Overall, this study provides evidence that movement preparation could play a crucial role in hemiparetic motor deficits, and that advance motor cueing may be of benefit in future therapeutic interventions. In addition, it demonstrates the importance of monitoring both the non-paretic and paretic hand after stroke and during therapeutic intervention.

  • Dean PJ, O'Neill D, Sterr A. (2012) 'Post-concussion syndrome: Prevalence after mild traumatic brain injury in comparison with a sample without head injury.'. Informa Health Care Brain Injury, England: 26 (1), pp. 14-26.

    Abstract

    Primary objective: To compare the prevalence of persistent post-concussion syndrome (PCS; >1 year post-injury) in participants with mild traumatic brain injury (mTBI) and those without head injury. Research design: A cross-sectional sample of 119 participants with mTBI and 246 without previous head injury. Methods: Online questionnaires collected data about post-concussion symptoms, cognitive failures, anxiety, depression, sleep behaviour and post-traumatic stress disorder. Variability within the sample was addressed by splitting by PCS diagnosis to create four groups: mTBI + PCS, mTBI-PCS, Control + PCS and Control-PCS. PCS was diagnosed using ICD-10 criteria in all groups, with controls not requiring previous head injury. Main outcomes and results: PCS was present to a similar extent in participants with no head injury (34%) compared to those with mTBI (31%). Only report of headaches, which could be caused by expectation bias, distinguished between mTBI + PCS and Control + PCS groups. In addition, significantly higher cognitive problems were observed in participants with mTBI compared with the control group. Conclusions: Persistent PCS, as currently defined, is not specific to mTBI. These data suggest that somatic and cognitive symptoms are most likely to be able to distinguish PCS after mTBI from that present in the general population. Further research is necessary into these factors in order to create more specific PCS diagnostic criteria.

  • Szameitat AJ, McNamara A, Shen S, Sterr A. (2012) 'Neural Activation and Functional Connectivity during Motor Imagery of Bimanual Everyday Actions.'. Public Library of Science PLoS One, United States: 7 (6)
  • Szameitat DP , Darwin CJ, Szameitat AJ, Wildgruber D, Sterr AM, Dietrich S, Alter K. (2011) 'Format characteristics of human laughter'. Elsevier Journal of Voice, 25 (1), pp. 32-37.

    Abstract

    Although laughter is an important aspect of nonverbal vocalization, its acoustic properties are still not fully understood. Extreme articulation during laughter production, such as wide jaw opening, suggests that laughter can have very high first formant (F1) frequencies. We measured fundamental frequency and formant frequencies of the vowels produced in the vocalic segments of laughter. Vocalic segments showed higher average F1 frequencies than those previously reported and individual values could be as high as 1100 Hz for male speakers and 1500 Hz for female speakers. To our knowledge, these are the highest F1 frequencies reported to date for human vocalizations, exceeding even the F1 frequencies reported for trained soprano singers. These exceptionally high F1 values are likely to be based on the extreme positions adopted by the vocal tract during laughter in combination with physiological constraints accompanying the production of a “pressed” voice.

  • Szameitat DP, Kreifelts B, Alter K, Szameitat AJ, Sterr A, Grodd W, Wildgruber D. (2010) 'It is not always tickling: distinct cerebral responses during perception of different laughter types.'. Neuroimage, United States: 53 (4), pp. 1264-1271.
  • Shen S, Sterr A. (2010) 'Analyzing diffusion tensor images with ghosting artifacts: the effects of direct and indirect normalization.'. Magnetic Resonance Imaging, Netherlands: 28 (10), pp. 1507-1513.
  • Sterr A, Shen S, Szameitat AJ, Herron KA. (2010) 'The role of corticospinal tract damage in chronic motor recovery and neurorehabilitation: a pilot study.'. Sage Neurorehabilitation and Neural Repair, United States: 24 (5), pp. 413-419.
  • Shen S, Szameitat AJ, Sterr A. (2010) 'An improved lesion detection approach based on similarity measurement between fuzzy intensity segmentation and spatial probability maps.'. Magn Reson Imaging, Netherlands: 28 (2), pp. 245-254.
  • Kranczioch C, Mathews S, Dean PJA, Sterr A. (2010) 'Task complexity differentially affects executed and imagined movement preparation: evidence from movement-related potentials.'. Public Library of Science PLoS ONE, 5 (2)

    Abstract

    Background The neural simulation theory predicts similarity for the neural mechanisms subserving overt (motor execution) and covert (movement imagination) actions. Here we tested this prediction for movement preparation, a key characteristic of motor cognition. Methodology/Principal Findings High-density electroencephalogram (EEG) was recorded during covert and overt actions. Movement preparation was studied with a motor priming paradigm, which varied task complexity and amount of advance information. Participants performed simple or complex sequential finger movements either overtly or covertly. Advance information was either fully predictive or partially predictive. Stimulus-locked event-related potential (ERP) data showed the typical pattern of foreperiod activation for overt and covert movements. The foreperiod contingent negative variation (CNV) differed between simple and complex movements only in the execution task. ERP topographies differed between execution and imagination only when advance information was fully predictive. Conclusions/Significance Results suggest a differential contribution of the movement preparation network to action imagination and execution. Overt and covert actions seem to involve similar though not identical mechanisms, where overt actions engage a more fine-grained modulation of covert preparatory states.

  • Sterr AM, Shen S, Szameitat A, Herron K. (2010) 'The Role of Corticospinal Tract Damage in Chronic Motor Recovery and Neurorehabilitation: A Pilot Study'. SAGE Neurorehabilitation and Neural Repair, 24 (5), pp. pp. 413-419.

    Abstract

    Background. With diffusion-tensor imaging (DTi) it is possible to estimate the structural characteristics of fiber bundles in vivo. This study used DTi to infer damage to the corticospinal tract (CST) and relates this parameter to (a) the level of residual motor ability at least 1 year poststroke and (b) the outcome of intensive motor rehabilitation with constraintinduced movement therapy (CIMT). Objective. To explore the role of CST damage in recovery and CIMT efficacy. Methods. Ten patients with low-functioning hemiparesis were scanned and tested at baseline, before and after CIMT. Lesion overlap with the CST was indexed as reduced anisotropy compared with a CST variability map derived from 26 controls. Residual motor ability was measured through the Wolf Motor Function Test (WMFT) and the Motor Activity Log (MAL) acquired at baseline. CIMT benefit was assessed through the pre–post treatment comparison of WMFT and MAL performance. Results. Lesion overlap with the CST correlated with residual motor ability at baseline, with greater deficits observed in patients with more extended CST damage. Infarct volume showed no systematic association with residual motor ability. CIMT led to significant improvements in motor function but outcome was not associated with the extent of CST damage or infarct volume. Conclusion. The study gives in vivo support for the proposition that structural CST damage, not infarct volume, is a major predictor for residual functional ability in the chronic state. The results provide initial evidence for positive effects of CIMT in patients with varying, including more severe, CST damage. Keywords constraint-induced movement therapy, diffusion tensor imaging, chronic hemiplegia, upper limb, stroke rehabilitation, fractional anisotropy

  • Kranczioch C, Mathews S, Dean PJA, Sterr A. (2009) 'On the Equivalence of Executed and Imagined Movements: Evidence from Lateralized Motor and Nonmotor Potentials'. WILEY-BLACKWELL HUMAN BRAIN MAPPING, 30 (10), pp. 3275-3286.
  • Szameitat AJ, Shen S, Sterr AM. (2009) 'The functional magnetic resonance imaging (fMRI) procedure as experienced by healthy participants and stroke patients – A pilot study'. BioMed Central BMC Medical Imaging, 9

    Abstract

    Background: An important aspect in functional imaging research employing magnetic resonance imaging (MRI) is how participants perceive the MRI scanning itself. For instance, the knowledge of how (un)comfortable MRI scanning is perceived may help institutional review boards (IRBs) or ethics committees to decide on the approval of a study, or researchers to design their experiments. Methods: We provide empirical data from our lab gained from 70 neurologically healthy mainly student subjects and from 22 mainly elderly patients suffering from motor deficits after brain damage. All participants took part in various basic research fMRI studies using a 3T MRI scanner. Directly after the scanning, all participants completed a questionnaire assessing their experience with the fMRI procedure. Results: 87.2% of the healthy subjects and 77.3% of the patients rated the MRI procedure as acceptable to comfortable. In healthy subjects, males found the procedure more comfortable, while the opposite was true for patients. 12.1% of healthy subjects considered scanning durations between 30 and 60 min as too long, while no patient considered their 30 min scanning interval as too long. 93.4% of the healthy subjects would like to participate in an fMRI study again, with a significantly lower rate for the subjects who considered the scanning as too long. Further factors, such as inclusion of a diffusion tensor imaging (DTI) scan, age, and study duration had no effect on the questionnaire responses. Of the few negative comments, the main issues were noise, the restriction to keep still for the whole time, and occasional feelings of dizziness. Conclusion: MRI scanning in the basic research setting is an acceptable procedure for elderly and patient participants as well as young healthy subjects.

  • Sterr AM, Herron K, Dijk D , Ellis J. (2009) 'Time to wake-up: Sleep problems and daytime sleepiness in long-term stroke survivors'. Taylor & Francis Brain Injury, 22 (7-8), pp. 575-579.

    Abstract

    Background and purpose: In work with chronic stroke patients the authors observed that patients frequently appear sleepy and often comment on their poor sleep. Sleep difficulties are frequently reported and indeed clinically recognized in the acute phase post-stroke, but little is known about the sleep and daytime sleepiness of chronic stroke patients with sustained disabilities. The latter, however, deserves clarification because sleep is a critical modulator of health, daytime performance and wellbeing. The present study therefore explored the sleep and sleepiness in a chronic stroke population with sustained physical deficits. Methods: An opportunity sample of 20 patients with chronic low-functioning hemiplegia (12 months) completed the Epworth Sleepiness Scale, Pittsburgh Sleep Quality Index, Medical Outcome Study Short Form 36 and Hospital Anxiety and Depression Scale. Results: Compared to a normative healthy population, long-term stroke survivors reported poorer sleep and greater daytime sleepiness. Increased levels of sleepiness were associated with longer chronicity, whereas nocturnal sleep parameters were not. Conclusions: In line with clinical observations, stroke survivors with sustained physical disabilities report poorer sleep and experience greater levels of sleepiness. Further research in a larger cohort and including objective sleep measures is necessary to investigate the nature and scale of sleep difficulties and daytime sleepiness in more detail so that care and treatment strategies can be developed in due course.

  • Szameitat AJ, Rummel J, Szameltat DP, Sterr A. (2009) 'Behavioral and emotional consequences of brief delays in human-computer interaction'. ACADEMIC PRESS LTD- ELSEVIER SCIENCE LTD INTERNATIONAL JOURNAL OF HUMAN-COMPUTER STUDIES, 67 (7), pp. 561-570.
  • Szameitat DP, Alter K, Szameitat AJ, Wildgruber D, Sterr A, Darwin CJ. (2009) 'Acoustic profiles of distinct emotional expressions in laughter.'. J Acoust Soc Am, United States: 126 (1), pp. 354-366.
  • Sterr A, Shen S, Kranczioch C, Szameitat AJ, Hou W, Sorger B. (2009) 'fMRI effects of task demand and feedback accuracy on grip force tracking.'. Neurosci Lett, Ireland: 457 (2), pp. 61-65.
  • Szameitat DP, Alter K, Szameitat AJ, Darwin CJ, Wildgruber D, Dietrich S, Sterr A. (2009) 'Differentiation of emotions in laughter at the behavioral level.'. Emotion, United States: 9 (3), pp. 397-405.
  • Jehoel S, Sowden PT, Ungar S, Sterr A. (2009) 'Tactile elevation perception in blind and sighted participants and its implications for tactile map creation.'. SAGE journals Human Factors, United States: 51 (2), pp. 208-223.

    Abstract

    To determine the optimal elevation of tactile map symbols. Background: Tactile perception research predicts that symbol elevation (vertical height) and texture on tactile maps could influence their readability. However, while research has shown that elevation influences detection and discrimination thresholds for single tactile stimuli, and that the physiological response of fingertip receptors varies with texture, little is known about the influence of these parameters on the identification of stimuli in the context of multiple symbols as found on tactile maps. Method: Sighted and visually impaired participants performed tactile symbol identification tasks. In Experiment 1, we measured the effect of elevation on identification accuracy. In Experiment 2, we measured the effect of elevation and symbol texture on identification speed. Results: Symbol elevation influenced both speed and accuracy of identification with thresholds being higher than found in work on detection and discrimination but lower than on existing tactile maps. Further, as predicted from existing knowledge of tactile perception, rough features were identified more quickly than smooth ones. Finally, visually impaired participants performed better than sighted ones. Conclusion: The symbol elevations necessary for identification (0.040 to 0.080 mm) are considerably lower than would be expected on the basis of existing tactile maps (generally 0.5 mm or higher) and design guidelines (0.4 mm). Application: Tactile map production costs could be reduced and map durability increased by reducing symbol elevation. Further, legibility of maps could be improved by using rough features, which are read more easily, and smaller symbols, which reduces crowding of graphics.

  • Sterr AM, Shen S, Kranczioch C, Szameita A, Hou W, Sorger B. (2009) 'fMRI effects of task demand and feedback accuracy on grip force tracking'. Elsevier Neuroscience Letters, 457, pp. pp. 61-65.

    Abstract

    Previous research showed that force control in a visually guided continuous tracking task is influenced by feedback accuracy and force-varying rate. More specifically it was found that higher feedback accuracy and greater force-varying rate led to decreased task performance. Here we studied the neural signature of these effects using functional MRI. We hypothesised that performance costs were due to increased task demand and reflected by increased activations in the visuomotor network. Using the fMRI-BOLD response as an indirect measure of enhanced brain activity we found that the task induced activations in the visuomotor network. The different task conditions thereby modulated the BOLD response such that those conditions with poorest performance showed highest activation levels and vice versa. This indicates a parametric modulation of the BOLD response according to task difficulty and force production. The effects point towards the interdependent and parallel control of visual feedback information and force output rate, which is probably achieved through a joint neural network.

  • Szameitat AJ, Rummel J, Szameitat DP, Sterr AM. (2009) 'Detrimental Behavioral and Emotional Consequences of Brief Delays in Human-Computer Interaction'. International Journal of Human-Computer Studies, 67 (7), pp. 561-570.
  • Jehoel S, Sowden PT, Ungar S, Sterr AM. (2009) 'Tactile elevation perception in blind and sighted participants and its implications for tactile map creation'. Human Factors, 51, pp. 208-223.
  • Hou W, Shen S, Szameitat AJ, Jiang Y, Zheng J, van Loon M, Sterr A. (2009) 'A behaviour study of the effects of visual feedback on fluctuating isometric force production with force tracking tasks'. International Journal of Biomedical Engineering and Technology, 1 (4), pp. 367-381.
  • Sterr A, Herron K, Sanders J. (2009) 'Constraint-induced movement therapy (CIT) for restoration of upper-limb function. II: Hemipareses application'. , pp. 309-316.
  • Mou Z-X, Hou W-S, Zheng X-L, Wu X-Y, Shen S, Sterr AM, Peng C-L. (2009) 'fMRI observation of the effect of visual feedback gain on force production'. Chinese Journal of Medical Imaging Technology, 25 (5), pp. 749-752.
  • Sterr AM, Shen S, Kranczioch C, Hou W, Sorger B. (2009) 'Neural activities induced by tracking isometric grip force changes through visual feedback'. Neuroscience Letters, 457 (2), pp. 61-65.
  • Mou Z-X, Hou W-S, Zheng X-L, Wu X-Y, Shen S, Sterr AM, Peng C-L. (2008) 'An fMR1 based pilot study on the nerve excitability for force-regulating speed'. Chinese Journal of Medical Imaging Technology, 24 (3), pp. 341-345.
  • Herron K, Dijk D, Ellis J, Sanders J, Sterr AM. (2008) 'Sleep correlates of motor recovery in chronic stroke: a pilot study using sleep diaries and actigraphy.'. Journal of Sleep Research, 17, pp. 103-103.
  • Sterr A, Dean P. (2008) 'Neural correlates of movement preparation in healthy ageing'. European Journal of Neuroscience, 27 (1), pp. 254-260.
  • Herron K, Dijk D, Ellis J, Sanders J, Sterr AM. (2008) 'Sleep actigraphy in brain injured patients with chronic low functioning upper limb hemiparesis'. Journal of Sleep Research, 17, pp. 102-102.
  • Shen S, Szameitat AJ, Sterr A. (2008) 'Detection of infarct lesions from single MRI modality using inconsistency between voxel intensity and spatial location - A 3-D automatic approach'. Institute of Electrical and Electronics Engineers Ieee Transactions on Information Technology in Biomedicine, 12 (4), pp. 532-540.
  • Kranczioch C, Athanassiou S, Shen S, Gao G, Sterr AM. (2008) 'Short-term learning of a visually guided power-grip task is associated with dynamic changes in EEG oscillatory activity'. Elsevier Clinical Neurophysiology, 119 (6), pp. 1419-1430.

    Abstract

    Objective: Performing a motor task after a period of training has been associated with reduced cortical activity and changes in oscillatory brain activity. Little is known about whether learning also affects the neural network associated with motor preparation and post movement processes. Here we investigate how short-term motor learning affects oscillatory brain activity during the preparation, execution, and post-movement stage of a force-feedback task. Methods: Participants performed a visually guided power-grip tracking task. EEG was recorded from 64 scalp electrodes. Power and coherence data for the early and late stages of the task were compared. Results: Performance improved with practice. During the preparation for the task alpha power was reduced for late experimental blocks. A movement execution-related decrease in beta power was attenuated with increasing task practice. A post-movement increase in alpha and lower beta activity was observed that decreased with learning. Coherence analysis revealed changes in cortico-cortical coupling with regard to the stage of the visuomotor task and with regard to learning. Learning was variably associated with increased coherence between contralateral and/or ipsilateral frontal and parietal, fronto-central, and occipital brain regions. Conclusions: Practice of a visuomotor power-grip task is associated with various changes in the activity of a widespread cortical network. These changes might promote visuomotor learning. Significance: This study provides important new evidence for and sheds new light on the complex nature of the brain processes underlying visuomotor integration and short-term learning. (c) 2008 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  • Szameitat AJ, Shen S, Sterr A. (2007) 'Effector-dependent activity in the left dorsal premotor cortex in motor imagery'. Wiley European Journal of Neuroscience, 26 (11), pp. 3303-3308.
  • Shen S, Szameitat A, Sterr AM. (2007) 'VBM lesion detection depends on the normalization template: a study using simulated atrophy'. Elsevier Magnetic Resonance Imaging, 25 (10), pp. 1385-1396.

    Abstract

    Structural neuroimaging studies are of great interest for neuroscientists, which are reflected in the rising number of papers using voxel-based morphometry (VBM). One major step in VBM is the transformation of images to a standard template, a spatial normalization necessary to ensure that homologous regions are compared while interindividual characteristics are maintained. Templates can be created in different ways, and this may affect the likelihood that differences in gray/white matter density between groups are detected. However, studies investigating the interaction of normalization template and VBM accuracy are sparse. Existing work is based on patient control group comparisons, and the emerging results are inconclusive. The present paper therefore used simulated atrophy in a simplified one-lesion model to systematically study template effects of VBM analyses implemented in SPM. This allowed us to characterize template-specific biases in reference to a set of prespecified parameters of anatomical difference. The data suggest that the likelihood of correctly detecting the prespecified lesion is modulated by the normalization template. Thereby, the relationship between template-related VBM accuracy and specific group/study characteristics is complex, and there does not appear to be one `best template.' Our data show that template effects are critical and clearly suggest that the choice of template needs careful consideration in relation to the specific research question and study constraints. (c) 2007 Elsevier Inc. All rights reserved.

  • Sterr A, Shen S, Zaman A, Roberts N, Szameitat A. (2007) 'Activation of SI is modulated by attention: a random effects fMRI study using mechanical stimuli'. Neuroreport, 18 (6), pp. 607-611.
  • Szameitat AJ, Shen S, Sterr A. (2007) 'Motor imagery of complex everyday movements. An fMRI study'. ACADEMIC PRESS INC ELSEVIER SCIENCE NEUROIMAGE, 34 (2), pp. 702-713.
  • Mathews S, Dean P, Sterr AM. (2006) 'EEG dipole analysis of motor-priming foreperiod activity reveals separate sources for motor and spatial attention components.'. Elsevier Clinical Neurophysiology, 117 (12), pp. pp. 2675-2683.

    Abstract

    Objective: This study employed EEG source localisation procedures to study the contribution of motor preparatory and attentional 10 processing to foreperiod activity in an S1–S2 motor priming task. Methods: Behavioural and high-density event-related potential (ERP) data were recorded in an S1–S2 priming task where participants 12 responded to S2 with a left or right-hand button press. S1 either provided information about response hand (informative) or ambiguous information (uninformative). Results: Responses were significantly faster in informative trials compared with uninformative trials. Dipole source analysis of fore-period lateralized ERPs revealed sources of motor preparatory activity in the dorsolateral premotor cortex (PMd) in line with previous work. In addition, two spatial attention components (ADAN, LDAP) were identified with generators in the PMd and occipitotemporal visual areas in the middle temporal (MT) region, respectively. Separation of motor-related and attentional PMd source locations was reliable along the rostral–caudal axis. Conclusions: The presence of attentional components in a motor priming paradigm supports the premotor theory of attention which suggests a close link between attention and motor preparatory processes. Separation of components in the premotor cortex is in accord with a functional division of PMd into rostral (higher-order processing) and caudal (motor-related processing) areas as suggested by imaging work. Significance: A prime for response preparation is a trigger for separate, but closely linked, attention-related activity in premotor areas. copyright: Mathews2006 Published by Elsevier Ireland Ltd. on behalf of International Federation of Clinical Neurophysiology.

  • Mathews S, Dean PJA, Sterr A. (2006) 'EEG dipole analysis of motor-priming foreperiod activity reveals separate sources for motor and spatial attention components'. ELSEVIER IRELAND LTD CLINICAL NEUROPHYSIOLOGY, 117 (12), pp. 2675-2683.
  • Szameitat AJ, Lepsien J, von Cramon DY, Sterr A, Schubert T. (2006) 'Task-order coordination in dual-task performance and the lateral prefrontal cortex: an event-related fMRI study.'. Psychol Res, Germany: 70 (6), pp. 541-552.
  • Hou W, Zheng J, Jiang Y, Shen S, Sterr A, Szameitat AJ, van Loon M. (2006) 'A behavior study of the effects of visual feedback on motor output.'. Conf Proc IEEE Eng Med Biol Soc, United States: 1, pp. 1273-1276.
  • Sterr A, Szameitat A, Shen S, Freivogel S. (2006) 'Application of the CIT concept in the clinical environment - Hurdles, practicalities, and clinical benefits'. LIPPINCOTT WILLIAMS & WILKINS COGNITIVE AND BEHAVIORAL NEUROLOGY, 19 (1), pp. 48-54.
  • Sterr A. (2006) 'Preparing not to move: Does no-response priming affect advance movement preparation processes in a response priming task?'. Biological Psychology, 72 (2), pp. 154-159.
  • Sterr A, Herron KA, Hayward C, Montaldi D. (2006) 'Are mild head injuries as mild as we think? Neurobehavioral concomitants of chronic post-concussion syndrome'. Bmc Neurology, 6

    Abstract

    Background: Mild traumatic brain injury (MTBI) can sometimes lead to persistent postconcussion symptoms. One well accepted hypothesis claims that chronic PCS has a neural origin, and is related to neurobehavioral deficits. But the evidence is not conclusive. In the attempt to characterise chronic MTBI consequences, the present experiment used a group comparison design, which contrasted persons (a) with MTBI and PCS, (b) MTBI without PCS, and (c) matched controls. We predicted that participants who have experienced MTBI but show no signs of PCS would perform similar to controls. At the same time, a subgroup of MTBI participants would show PCS symptoms and only these volunteers would have poorer cognitive performance. Thereby, the performance deficits should be most noticeable in participants with highest PCS severity. Method: 38 patients with a single MTBI that had occurred at least 12 month prior to testing, and 38 matched controls, participated in the experiment. A combination of questionnaires and neuropsychological test batteries were used to assess the extent of PCS and related deficits in neurobehavioral performance. Results: 11 out of 38 MTBI participants (29%) were found to suffer from PCS. This subgroup of MTBI patients performed poorly on neuropsychological test batteries. Thereby, a correlation was found between PCS symptom severity and test performance suggesting that participants with more pronounced PCS symptoms performed worse in cognitive tasks. In contrast, MTBI patients with no PCS showed performed similar to matched control. We further found that loss of consciousness, a key criterion for PCS diagnosis, was not predictive of sustained PCS. Conclusion: The results support the idea that MTBI can have sustained consequences, and that the subjectively experienced symptoms and difficulties in everyday situations are related to objectively measurable parameters in neurocognitive function.

  • Hou W, Zheng J, Jiang Y, Shen S, Sterr A, Szameitat AJ, van Loon M. (2006) 'A behavior study of the effects of visual feedback on motor output.'. Conference proceedings : ... Annual International Conference of the IEEE Engineering in Medicine and Biology Society. IEEE Engineering in Medicine and Biology Society. Conference, , pp. 1273-1276.
  • Sterr A, Saunders A. (2006) 'CI therapy distribution: Theory, evidence and practice'. IOS PRESS NEUROREHABILITATION, 21 (2), pp. 97-105.
  • Szameitat AJ, Lepsien J, von Cramon DY, Sterr A, Schubert T. (2006) 'Task-order coordination in dual-task performance and the lateral prefrontal cortex: an event-related fMRI study'. Psychological Research-Psychologische Forschung, 70 (6), pp. 541-552.
  • Hou WS, Wu XY, Zheng XL, Shen S, Sterr AM. (2006) 'A behavior study on the effect of visual feedback gain to force production'. Chinese Journal of Biomedical Engineering, 25 (5), pp. 542-546.
  • Halder P, Sterr A, Brem S, Bucher K, Kollias S, Brandeis D. (2005) 'Electrophysiological evidence for cortical plasticity with movement repetition'. European Journal of Neuroscience, 21 (8), pp. 2271-2277.
  • Shen S, Sandham W, Granat M, Sterr A. (2005) 'MRI fuzzy segmentation of brain tissue using neighborhood attraction with neural-network optimization'. Ieee Transactions on Information Technology in Biomedicine, 9 (3), pp. 459-467.
  • Sterr AM. (2004) 'Training-based interventions in motor rehabilitation after stroke: theoretical and clinical considerations.'. Hindawi Behav Neurol, 15 (3-4), pp. 55-63.

    Abstract

    Basic neuroscience research on brain plasticity, motor learning and recovery has stimulated new concepts in neurological rehabilitation. Combined with the development of set methodological standards in clinical outcome research, these findings have led to a double-paradigm shift in motor rehabilitation: (a) the move towards evidence-based procedures for the assessment of clinical outcome & the employment of disablement models to anchor outcome parameters, and (b) the introduction of practice-based concepts that are derived from testable models that specify treatment mechanisms. In this context, constraint-induced movement therapy (CIT) has played a catalytic role in taking motor rehabilitation forward into the scientific arena. As a theoretically founded and hypothesis-driven intervention, CIT research focuses on two main issues. The first issue is the assessment of long-term clinical benefits in an increasing range of patient groups, and the second issue is the investigation of neuronal and behavioural treatment mechanisms and their interactive contribution to treatment success. These studies are mainly conducted in the research environment and will eventually lead to increased treatment benefits for patients in standard health care. However, gradual but presumably more immediate benefits for patients may be achieved by introducing and testing derivates of the CIT concept that are more compatible with current clinical practice. Here, we summarize the theoretical and empirical issues related to the translation of research-based CIT work into the clinical context of standard health care.

  • Sterr A. (2004) 'Training-based interventions in motor rehabilitation after stroke: Theoretical and clinical considerations'. Behavioural Neurology, 15 (3-4), pp. 55-63.
  • Sterr AM. (2004) 'Attention performance in young adults with learning disabilities'. Learning and Individual Differences, 14 (2), pp. 125-133.
  • Sterr A, Freivogel S. (2004) 'Intensive training in chronic upper limb hemiparesis does not increase spasticity or synergies'. Neurology, 63 (11), pp. 2176-2177.
  • Sterr A. (2004) 'Training-based interventions in motor rehabilitation after stroke: Theoretical and clinical considerations'. BEHAVIOURAL NEUROLOGY, 15 (3-4), pp. 55-63.
  • Sterr A, Green L, Elbert T. (2003) 'Blind Braille readers mislocate tactile stimuli'. Biological Psychology, 63 (2), pp. 117-127.
  • Sterr A, Freivogel S. (2003) 'Motor-improvement following intensive training in low-functioning chronic hemiparesis'. Neurology, 61 (6), pp. 842-844.
  • Sterr A, Freivogel S, Voss A. (2002) 'Exploring a repetitive training regime for upper limb hemiparesis in an in-patient setting: A report on three case studies'. Brain Injury, 16 (12), pp. 1093-1107.
  • Sterr A, Freivogel S, Schmalohr D. (2002) 'Neurobehavioral aspects of recovery: Assessment of the learned nonuse phenomenon in hemiparetic adolescents'. Archives of Physical Medicine and Rehabilitation, 83 (12), pp. 1726-1731.
  • Elbert T, Sterr AM, Rockstroh B, Pantev C, Muller M, Taub E. (2002) 'Expansion of the tonotopic area in the auditory cortex of the blind'. Journal of Neuroscience, 22 (22), pp. 9941-9944.

    Abstract

    A part of the core area of the auditory cortex was examined in nine blind and10 sighted individuals by magnetic source imaging and was found to be enlarged by a factor of 1.8 in the blind compared with the sighted humans. Moreover, the latency of the N1m component of the auditory-evoked magnetic response was significantly decreased in the blind. The development of use-dependent cortical reorganization may be a consequence of the absence of visual input in combination with enhanced auditory activity generated by the long-term concentration by blind individuals on nonvisual cues to interact appropriately with the environment. It is consistent with and well suited to mediate the demonstrated increased ability of the blind to accurately localize acoustic sources in peripheral auditory fields and to decode speech.

  • Sterr A, Elbert T, Berthold I, Kolbel S, Rockstroh B, Taub E. (2002) 'Longer versus shorter daily constraint-induced movement therapy of chronic hemiparesis: An exploratory study'. Archives of Physical Medicine and Rehabilitation, 83 (10), pp. 1374-1377.
  • Sterr A, Schmalohr D, Kolbel S, Freivogel S. (2001) 'Functional reorganization of motor areas following forced-use rehabilitation training in hemiparetic patients: A TMS study'. Biomedical Engineering, 46, pp. 102-108.
  • Sterr A, Schmalohr D, Kolbel S, Freivogel S. (2000) 'Transcranial magnetic stimulation-based investigation of motor cortex reorganization after repetitive training in brain-injured patients'. PSYCHOPHYSIOLOGY, 37, pp. S95-S95.
  • Grunze H, Amann B, Schafer M, Sterr A, Schaerer L, Wild E, Walden J. (2000) 'Efficacy, safety and practicability of valproate delayed release minitablets in bipolar affective disorders'. Fortschritte der Neurologie Psychiatrie, 68 (11), pp. 496-502.
  • Röder B, Teder-Sälejärvi W, Sterr A, Rösler F, Hillyard SA, Neville HJ. (1999) 'Improved auditory spatial tuning in blind humans.'. Nature, ENGLAND: 400 (6740), pp. 162-166.
  • Sterr A, Müller M, Elbert T, Rockstroh B, Taub E. (1999) 'Development of cortical reorganization in the somatosensory cortex of adult Braille students.'. Electroencephalogr Clin Neurophysiol Suppl, IRELAND: 49, pp. 292-298.
  • Rockstroh B, Clementz BA, Pantev C, Blumenfeld LD, Sterr A, Elbert T. (1998) 'Failure of dominant left-hemispheric activation to right-ear stimulation in schizophrenia.'. Neuroreport, ENGLAND: 9 (17), pp. 3819-3822.
  • Elbert T, Candia V, Altenmüller E, Rau H, Sterr A, Rockstroh B, Pantev C, Taub E. (1998) 'Alteration of digital representations in somatosensory cortex in focal hand dystonia.'. Neuroreport, ENGLAND: 9 (16), pp. 3571-3575.
  • Sterr AM, Müller M, Elbert T, Rockstroh B, Pantev C, Taub E. (1998) 'Perceptual Correlates of Changes in Cortical Representation of Fingers in Blind Multifinger Braille Readers'. The Journal of Neuroscience, The Journal of Neuroscience 18, pp. pp. 4417-4423.

    Abstract

    The mature mammalian nervous system alters its functional organization in a use-dependent manner. Enhanced stimulation of a body part enlarges its cortical representational zones and may change its topographic order. Little is known about the perceptual and behavioral relevance of these plastic alterations in cortical organization. We used blind Braille readers who use several fingers on each hand and who do so for many hours each day as a model to investigate this issue. Magnetic source imaging indicated that the cortical somatosensory representation of the fingers was frequently topographically disordered in these subjects; in addition, they frequently misperceived which of these fingers was being touched by a light tactile stimulus. In contrast, neither the disordered representation nor mislocalizations were observed in sighted controls. Blind non-teacher Braille readers who used only one finger for reading were not significantly different from the sighted controls. Thus, use-dependent cortical reorganization can be associated with functionally relevant changes in the perceptual and behavioral capacities of the individual.

  • Sterr A, Müller MM, Elbert T, Rockstroh B, Pantev C, Taub E. (1998) 'Perceptual correlates of changes in cortical representation of fingers in blind multifinger Braille readers.'. J Neurosci, UNITED STATES: 18 (11), pp. 4417-4423.
  • Sterr A, Müller MM, Elbert T, Rockstroh B, Pantev C, Taub E. (1998) 'Changed perceptions in Braille readers.'. Nature, ENGLAND: 391 (6663), pp. 134-135.
  • Kolbel S, Elbert T, Rockstroh B, Sterr A, Jahn T, Taub E. (1998) 'Constraint-induced (CI) movement therapy in patients treated according to German rehabilitation programs'. JOURNAL OF PSYCHOPHYSIOLOGY, 12 (2), pp. 206-206.
  • Sterr A, Muller MM, Elbert T, Rockstroh B, Taub E. (1998) 'Expansion of cortical hand representation and tactile sensory thresholds in blind Braille readers: A link between cortical organization and perception'. JOURNAL OF PSYCHOPHYSIOLOGY, 12 (2), pp. 193-194.
  • Rockstroh B, Watzl H, Kowalik ZJ, Cohen R, Sterr A, Müller M, Elbert T. (1997) 'Dynamical aspects of the EEG in different psychopathological states in an interview situation: a pilot study.'. Schizophr Res, NETHERLANDS: 28 (1), pp. 77-85.
  • Elbert T, Sterr A, Flor H, Rockstroh B, Knecht S, Pantev C, Wienbruch C, Taub E. (1997) 'Input-increase and input-decrease types of cortical reorganization after upper extremity amputation in humans.'. Exp Brain Res, GERMANY: 117 (1), pp. 161-164.

Conference papers

  • Wallace A, Dewar L, Pietrusz A, Dudziec M, Sterr A, Laura M, Skorupinska I, Skorupinska M, Hanna M, Trenell M, Baio G, Reilly M, Ramdharry G. (2015) 'Evaluating the benefits of community based aerobic training on the physical health and well-being of people with neuromuscular diseases: A pilot study'. PERGAMON-ELSEVIER SCIENCE LTD NEUROMUSCULAR DISORDERS, Brighton, ENGLAND: 20th International Congress of the World-Muscle-Society 25, pp. S273-S274.
  • Wallace A, Dewar L, Sterr A, Hanna M, Trenell M, Pietrusz A, Dudziec M, Hennis P, Stokes R, Reilly M, Ramdharry G. (2015) 'Normative aerobic exercise values in CMT'. PERGAMON-ELSEVIER SCIENCE LTD NEUROMUSCULAR DISORDERS, Brighton, ENGLAND: 20th International Congress of the World-Muscle-Society 25, pp. S285-S286.
  • Nissen C, Frase L, Piosczyk H, Feige B, Sterr A, Riemann D. (2014) 'The modulation of sleep continuity through transcranial direct current stimulation (TDCS)'. WILEY-BLACKWELL JOURNAL OF SLEEP RESEARCH, Tallinn, ESTONIA: 22nd Congress of the European-Sleep-Research-Society 23, pp. 39-39.
  • Seiss E, Hope C, Guinn A, Dean PJA, Sterr A. (2013) 'THE EFFECT OF ELEVATED BLOOD SUGAR LEVELS ON ENCODING AND RETRIEVAL IN A VERBAL MEMORY TASK'. WILEY-BLACKWELL PSYCHOPHYSIOLOGY, Florence, ITALY: 53rd Annual Meeting of the Society-for-Psychophysiological-Research 50, pp. S92-S93.
  • Encke M, Dean PJA, Seiss E, Sterr A. (2013) 'EFFECTS OF AGING ON MOTOR PREPARATION PROCESSES'. WILEY-BLACKWELL PSYCHOPHYSIOLOGY, Florence, ITALY: 53rd Annual Meeting of the Society-for-Psychophysiological-Research 50, pp. S87-S87.
  • Sterr A, Nissen C, Funk S, Ettine D, Unbehaun T, Kuemmerer D, Riemann D. (2013) 'CHANGES OF POLYSOMNOGRAPHIC SLEEP CHARACTERISTICS IN CHRONIC POST-STROKE HEMIPLEGIA'. WILEY-BLACKWELL PSYCHOPHYSIOLOGY, Florence, ITALY: 53rd Annual Meeting of the Society-for-Psychophysiological-Research 50, pp. S40-S40.
  • Dean PJA, McNamara A, Vieira G, Sato J, Sterr A. (2013) 'Structural and functional changes in mTBI and their relationship to persistent PCS: DTI, cortical thickness and fMRI analysis.'. British Neurosci. Assoc. Abstr., London: BNA2013: Festival Of Neuroscience 22, pp. 892-892.
  • Hope C, Sterr A, Elangovan P, Geades N, Windridge D, Young K, Wells K. (2013) 'High throughput screening for mammography using a human-computer interface with Rapid Serial Visual Presentation (RSVP)'. Proceedings of SPIE - The International Society for Optical Engineering, 8673

    Abstract

    The steady rise of the breast cancer screening population, coupled with data expansion produced by new digital screening technologies (tomosynthesis/CT) motivates the development of new, more efficient image screening processes. Rapid Serial Visual Presentation (RSVP) is a new fast-content recognition approach which uses electroencephalography to record brain activity elicited by fast bursts of image data. These brain responses are then subjected to machine classification methods to reveal the expert's 'reflex' response to classify images according to their presence or absence of particular targets. The benefit of this method is that images can be presented at high temporal rates (∼10 per second), faster than that required for fully conscious detection, facilitating a high throughput of image (screening) material. In the present paper we present the first application of RSVP to medical image data, and demonstrate how cortically coupled computer vision can be successfully applied to breast cancer screening. Whilst prior RSVP work has utilised multichannel approaches, we also present the first RSVP results demonstrating discriminatory response on a single electrode with a ROC area under the curve of 0.62-0.86 using a simple Fisher discriminator for classification. This increases to 0.75-0.94 when multiple electrodes are used in combination. © 2013 SPIE.

  • Dean P, Sato JR, Sterr A. (2012) 'The relationship between structural changes in mTBI and persistent PCS: DTI and cortical thickness analysis'. Informa Healthcare Brain Injury, Edinburgh, Scotland, UK: Ninth World Congress on Brain Injury 26 (4-5), pp. 509-509.
  • Pieridi C, Brown D, Sterr A. (2012) 'The experience of returning to work following a traumatic brain injury'. Informa Healthcare Brain Injury, Edinburgh, Scotland, UK: Ninth World Congress on Brain Injury 26 (4-5), pp. 625-625.
  • Dean P, Sterr A. (2012) 'Long-term effects of mild traumatic brain injury on cognitive performance'. Informa Healthcare Brain Injury, Edinburgh, Scotland, UK: Ninth World Congress on Brain Injury 26 (4-5), pp. 395-396.
  • Hope C, Seiss E, Dean PJA, Williams K, Guinn A, Sterr A. (2011) 'Response time slowing by glucose dependent on strength of stimulus response association: investigations with the flanker task'. Frontiers Frontiers in Human Neuroscience: ICON XI, Conference Abstracts, Palma, Mallorca, Spain: XI International Conference on Cognitive Neuroscience (ICON XI)
  • Dean PJA, Sterr A. (2010) 'Post concussion syndrome without head injury? A survey study'. Brain Injury, Washington DC: International Brain Injury Associations Eight World Congres on Brain Injury 3 (24), pp. 423-423.
  • Hope C, Seiss E, Dean P, Sterr A. (2009) 'An electrophysiological investigation of glucose administration effects on movement preparation and execution'. Wiley-Blackwell Psychophysiology. Special Issue: Society for Psychophysiological Research Abstracts for the Forty-Ninth Annual Meeting, Berliner Congress Center, Berlin, Germany: Society for Psychophysiological Research Annual Meeting 46 (Supplement s1)
  • Herron K, Dijk DJ, Dean P, Seiss E, Sterr A. (2009) 'EEG-Derived biomarkers for daytime sleepiness in patients with chronic stroke'. Wiley-Blackwell Special Issue: Society for Psychophysiological Research Abstracts for the Forty-Ninth Annual Meeting, Berliner Congress Center, Berlin, Germany: Society for Psychophysiological Research 49 Annual Meeting 46 (Supplement s1)

    Abstract

    Stroke patients with motor deficits often report daytime sleepiness. While slowing of the EEG during wakefulness has been shown after stroke, it is unknown if and how this is linked to their perception of sleepiness. Using waking EEG and a motor task (associated with mild sleepiness), we examined: 1) differences in the frequency composition and lateralisation of the EEG between stroke patients and controls, and 2) the relationship between the EEG and subjective sleepiness ratings. EEG and Karolinska Sleepiness Scale (KSS) data were collected from 15 right hemispheric stroke patients and 15 matched controls before and after a motor priming task. Frequency analysis was performed on C3 and C4 channels. Prior to the task, the stroke group revealed increased power density below 10 Hz compared to controls for both hemispheres, with more pronounced effects within the lesioned hemisphere. The motor task significantly increased KSS scores in both groups. Increased beta and alpha activity was observed after the task in the control group. The stroke group showed post task increases in beta activity for the non-affected hemisphere and bilateral increases in alpha and theta activity. An association between KSS and the EEG was observed post task in the stroke patients within the theta and alpha bands. Therefore, slowing of the EEG is related to perception of daytime sleepiness in stroke patients. This effect may not have been observed in the controls due to the way in which the motor task manipulates sleepiness within each group, as it is more challenging for those with motor deficits.

  • Dean PJA, Sterr A. (2008) 'Advance movement preparation is intact in hemiparetic patients: Validity effects seen in a response priming task with the affected arm'. Brain Injury, Lisbon: Seventh World Congress On Brain Injury Supplement 1 (22), pp. 168-169.
  • Grossheinrich N, Reinl M, Mulert C, Pogarell O, Fast K, Karch S, Sterr A, Padberg F. (2007) 'Modulation of event-related potentials by repetitive transcranial magnetic stimulation of the prefrontal cortex'. San Diego, CA : Elsevier Science Inc Psychology: 62nd Annual Scientific Meeting of the Society-of-Biological-Psychiatry
  • Sterr A, Dean PJA, Mathews S. (2006) 'Ageing in Motor Control: Behavioural and ERP correlates of Motor Priming in the Elderly.'. British Neuroscience Association Annual Meeting
  • Hou WS, Zheng J, Jiang YT, Shen S, Sterr A, Szatneitat AJ, van Loon M, Ieee . (2006) 'A behavior study of the effects of visual feedback on motor output'. New York, NY : Ieee Psychology: 28th Annual International Conference of the IEEE-Engineering-in-Medicine-and-Biology-Society, pp. 4777-4780.
  • Shen S, Sandham W, Granat M, Sterr AM. (2005) 'Intensity Non-uniformity Correction of Magnetic Resonance Images Using a Fuzzy Segmentation Algorithm'. 2005 IEEE Engineering in Medicine and Biology 27th Annual Conference, pp. pp. 1-4.

    Abstract

    Artifacts in magnetic resonance images can make conventional intensity-based segmentation methods very difficult, especially for the spatial intensity non-uniformity induced by the radio frequency (RF) coil. The non-uniformity introduces a slow-varying shading artifact across the images. Many advanced techniques, such as nonparametric, multi-channel methods, cannot solve the problem. In this paper, the extension of an improved fuzzy segmentation method, based on the traditional fuzzy c-means (FCM) algorithm and neighborhood attraction, is proposed to correct the intensity non-uniformity. Experimental results on both synthetic non-MR and MR images are given demonstrate the superiority of the algorithm.

  • Mathews S, Dean PJA, Harrison N, Williams N, Sterr A. (2005) 'Movement preparation and execution following a no-response pre-cue: A pilot study using behavioural and EEG data.'. Psychology Postgraduate Affairs Group Meeting
  • Elbert T, Sterr A, Rockstroh B, Charbonnier D, Flor H, Pantev C, Wienbruch C, Knecht S, Taub E. (2000) 'Cortical reorganization in arm amputees: Alterations of the somatosensory representation of the intact arm'. BIOMAG 96: PROCEEDINGS OF THE TENTH INTERNATIONAL CONFERENCE ON BIOMAGNETISM, VOLS I & II, , pp. 999-1002.

Book chapters

  • Sterr A, Herron K, Sanders JC. (2009) 'Constraint-induced movement therapy (CIT) for restoration of Upper-Limb function: Hemipareses Application'. in Soderback I (ed.) International Handbook of Occupational Therapy Interventions New York : Springer , pp. 309-316.
  • Sterr AM, Dean PJA, Mathews S. (2008) 'Preparing the unlikely event - when no-response priming activates the motor system'. in Conti G (ed.) Progress in Biological Psychology Research Hauppange, New York : Nova Science Publishers (Expert), pp. 13-10.

    Abstract

    Driven by considerations arising from studies in hemiplegic patients, we examined how the insertion of rare n-response trials affects motor preparation studied in S1-S2 paradigms. Results for the motor priming task (experiment 1) showed that for response-requiring conditions the 'validity effect' was conserved for behavioural and ERP indices. For the no-response condition, foreperiod activities were similar to neutral trials suggesting motor preparation in both conditions and hence preparation for the unlikely event. A second experiment with fully predictive primes showed no evidence for movement preparation processes in no-response trials. These findings suggest different strategies for the anticipation of likely responses compared to likely events that don't require a response.

  • Sterr A. (2007) 'Neuroplasticity'. in Gauggel S, Herrmann M (eds.) Handbook of Neurophysiology Berlin : Springer Verlag
  • Shen S, Sterr A, Szameitat A. (2005) 'A template effect study on voxel-based morphometry in Statistic Parametric Mapping'. in (ed.) 2005 27th Annual International Conference of the Ieee Engineering in Medicine and Biology Society, Vols 1-7 New York : IEEE , pp. 3051-3054.
  • Shen S, Sandham WA, Granat MH, Sterr A. (2005) 'Intensity non-uniformity correction of magnetic resonance images using a fuzzy segmentation algorithm'. in (ed.) 2005 27th Annual International Conference of the Ieee Engineering in Medicine and Biology Society, Vols 1-7 New York : IEEE , pp. 3035-3038.
  • Hou WS, Shen S, Sterr A. (2005) 'An MRI compatible visual force-feedback system for the study of force control mechanics'. in (ed.) 2005 27th Annual International Conference of the Ieee Engineering in Medicine and Biology Society, Vols 1-7 New York : IEEE , pp. 3687-3690.

    Abstract

    Motor task experiments play an essential role in exploring the brain mechanisms of movement control, and visual force-feedback is an important factor in these motor experiments. In this paper, the authors proposed a visual force-feedback system suitable for neuroscience experiment. With this system, the force output produced by participants can be detected and recorded in real time, while force output was visually displayed as a feedback cue to the participants simultaneously. Furthermore, this force feedback system is MRI compatible, and can be used both in fMRI and ERP experiments. The proposed system has been applied in hand-grip tasks and finger movement experiments, which were designed to explore the relationship between force output and brain activation mode in normal subject and stroke patient. The results demonstrated that various force levels were well detected and visual feedback signals enabled the accomplishment of experiments with both fixed and variable target force levels.

  • Sterr A, Elbert T, Rockstroh B. (2002) 'Functional reorganization of the human cerebral cortex and its perceptual concommitants'. in Fahle M, Poggio T (eds.) Perceptual Learning Cambridge, Massachusetts, USA : MIT Press , pp. 125-144.

Posters

  • Neumann M, Claros-Salinas D, Guetler R, Ulrich R, Sterr A, Dettmers C. (2013) Modulation of alertness by sustained cognitive demand in MS as surrogate measure of fatigue and fatigability. 2nd Conference of the International-MS-Cognition-Society (IMSCOGS )
  • Seiss E, Hope C, Dean PJA, Sterr A. (2010) An electrophysiological investigation of glucose effects in the Flanker task. Warwick Workshop on Motor Priming and Cognitive Control, 17-19 August, 2010. University of Warwick, Coventry , UK

    Abstract

    Behavioural studies have indicated that response times on complex reaction time tasks are faster if blood glucose concentrations are slightly elevated above normal (Donohoe & Benton, 2000). Such tasks involve several cognitive processing stages but it is not clear which of these stages are speeded after glucose administration. In order to investigate this problem we have used a double blind repeated measures design for the administration of glucose and placebo drinks. Participants performed a Flanker task while EEG was recorded as a physiological measure. More specifically, we used a Flanker task that required participants to respond to either left or right pointing central arrows by pressing a left or a right button, respectively. In addition on each trial there are extra arrows surrounding the central arrow which all either pointed in the same (congruent condition) or opposite (incongruent condition) direction as the central arrow or they were lines without an arrow head (neutral condition) All condition were presented equiprobably. No significant differences between the glucose and placebo condition were observed in mean reaction times and errors rates. However the ERP data showed that the N1 amplitude was significantly increased after glucose administration. This could indicate that stimulus identification is influenced by glucose administration, as previous researchers have found an increased N1 amplitude during discriminative feature processing compared to simple detection tasks (Hopf et al., 2002). In addition, mean reaction times and error rates were analysed separately for each of the 8 blocks. Differences between drink types were only found for the reaction times of the first block. Participants who had received glucose during their 1st session and placebo during the 2nd session, had longer reaction times after glucose administration compared to placebo. However this effect was not found for participants who received placebo before glucose drinks. These findings might be linked to task difficulty effects. Previous research has shown that high task difficulty is necessary to find glucose enhancement effects on the Hick task (sensorimotor function; Donohoe & Benton, 2000), working memory (Kennedy & Scholey, 2001) and episodic memory (Sünram-Lea et al., 2002). Our results conflict directly with Donohoe and Benton’s (2000), potentially caused by methodological or task differences. It might be also possible that separate cognitive processes might be d

  • Harris LM, Dean PJA, McNamara A, Sterr A. (2010) Using 3T Magnetic Resonance Spectroscopy to Assess The Long Term Effects of Mild Traumatic Brain Injury.. Joint Annual Meeting ISMRM-ESMRMB. 1-7 May, 2010. Stockholm, Sweden.

    Abstract

    The present study explores the link between brain metabolites, PCS symptoms and cognitive ability in participants who have experienced an mTBI. Lactate has been previously been shown to be elevated in acute mTBI (Son, Park et al. 2000), however, 2 month post-incidence lactate levels had returned to normal. The present study suggests that PCS symptoms as well as metabolite abnormalities may persist. More specifically the data provides initial evidence for a link between the elevation of lactate and with severity of long-term PCS following mTBI. Poster presented in Session: Other Spectroscopy Methodology Proceedings of the International Society for Magnetic Resonance in Medicine, 18 (2010); p. 937. ISSN 1545-4428. Available at: http://www.ismrm.org/meetings-workshops/2010-annual-meeting-3/

  • Dean PJA, Sterr A. (2010) Post-Concussion Syndrome without head injury? A Survey Study (Poster 0588).. Eight World Congress On Brain Injury. Washington, DC on March 10-14, 2010

    Abstract

    Objectives According to ICD-10 or DSM-IV criteria Post-Concussion Syndrome (PCS) requires a prior mild traumatic brain injury (mTBI). However, PCS symptoms are non-specific and can also affect non-mTBI populations. Symptoms further overlap with other diagnoses, such as depression. Consequently, the degree to which PCS is specific to or caused by mTBI is still debated. With the present study we aim to investigate the nature of PCS in greater detail by looking whether PCS is specific to mTBI, and the extent to which these symptoms and related factors (depression, anxiety, daytime sleepiness and cognitive failures) exist in the non-mTBI population. Method An online survey was sent to University staff and students. Included in this survey were the Rivermead Post Concussion Questionnaire (RPQ), Cognitive Failures Questionnaire (CFQ), Hospital Anxiety and Depression Scale (HADS), Epworth Sleepiness Scale (ESS), along with demographic questions and those related to the mTBI sustained. PCS was diagnosed as 3 or more symptoms within DSM-IV criteria. Results The survey created a database of 375 entries, 127 for mTBI and 248 controls (no history of mTBI). Within these groups the proportion of individuals experiencing PCS symptoms was not statistically different (39% for mTBI, 32% for control; Chi squared p=0.2), and there was no group difference for the RPQ, HADS or ESS. However, respondents with a history of mTBI showed significantly higher CFQ scores (p<0.001) than controls. In contrast, when split by PCS diagnosis, those with PCS revealed significantly greater scores for all questionnaires (p<0.001). When split into subgroups (mTBI+PCS, mTBI-PCS, Control+PCS, Control-PCS), a similar pattern was observed. The two groups with PCS both had greater scores for the RPQ, CFQ and HADS than both groups without PCS (p<0.005). There was only one difference when comparing the two groups with mTBI to those without (CFQ: mTBI+PCS greater than Control+PCS (p<0.05)). The ESS score for Control+PCS was greater when compared to both groups without PCS (mTBI-PCS (p<0.01); Control-PCS (p<0.005)). Conclusions The study suggests that PCS is equally common in a self-selected sample of persons with and without brain injury. Data on depression, anxiety, cognitive failures and daytime sleepiness scores show no increase in those with mTBI, but are significantly higher in those with PCS. Analysis of the four subgroups revealed no interaction between mTBI and PCS. This suggests that

  • Hope C, Seiss E, Dean P, Sterr A. (2009) AN ELECTROPHYSIOLOGICAL INVESTIGATION OF GLUCOSE ADMINISTRATION EFFECTS ON SENSORIMOTOR PROCESSING IN A MODIFIED ERIKSEN FLANKER TASK. 49th Annual Meeting of the Society-for-Psychophysiological-Research
  • Dean P, Seiss E, Sterr A. (2009) ADVANCE MOVEMENT PREPARATION IN HEMIPARETIC PATIENTS: ELECTROPHYSIOLOGICAL INDICE. 49th Annual Meeting of the Society-for-Psychophysiological-Research

    Abstract

    Descriptors: motor preparation, hemiparesis, CNV Movement preparation in patients with left hand hemiparesis (n 5 26) was investigated using a response priming paradigm, and in addition compared to age-matched controls (n 5 26). In this experiment, trials with valid, neutral and no response cues were presented 1300 ms before the imperative stimulus. Behavioral results showed validity effects for the control and the patient group’s affected and unaffected hand. In addition, patients responded slower with both the affected and the unaffected hand compared to the control group. Analysis of CNV amplitude within the patient group revealed validity effects over the contralateral left hemisphere for the unaffected hand. Interestingly, similar validity effects where found for both hemispheres for the affected hand. This additional usage of the ipsilateral left hemisphere might reflect a greater effort required for movement preparation. A comparison between conditions of patient and control groups showed reduced CNV amplitude over central and centro-parietal right hemisphere for validly prepared trials of the unaffected hand compared to the control group’s right hand. This might suggest a reduced usage of the lesioned ipsilateral cortex side possibly reflecting reduced innervation after the acute phase of the stroke. The competition for resources in the left hemisphere between the affected and unaffected hand and the reduced usage of the right ipsilateral hemisphere for the unaffected hand might explain why patients are generally slower than controls in the task.

  • Herron K, Dijk D, Ellis J, Sanders J, Sterr A. (2008) Sleep correlates of motor recovery in chronic stroke: a pilot study using sleep diaries and actigraphy. 19th Congress of the European-Sleep-Research-Society
  • Herron K, Dijk D, Ellis J, Sanders J, Sterr A. (2008) Sleep actigraphy in brain injured patients with chronic low functioning upper limb hemiparesis. 19th Congress of the European-Sleep-Research-Society
  • Dean PJA, Sterr A. (2008) Advance movement preparation in hemiparetic patients: validity effects seen in a response priming task with the affected arm.. Seventh World Congress On Brain Injury, 9-12 April, 2008.Lisbon, Portugal.

    Abstract

    Poster presented at the Seventh World Congress On Brain Injury, 9-12 April, 2008.Lisbon, Portugal. Organised by The International Brain Injury Association. www.internationalbrain.org

Theses and dissertations

  • Fielding J. (2016) Characterising amygdala activation during emotion processing in a sub-clinical anxiety cohort..
    [ Status: Approved ]

    Abstract

    Emotions play a pivotal role in guiding our behaviour within society and our environment. In particular, emotions enable interpersonal social interactions through non-verbal communication that may be below conscious awareness. However, when there is some disruption to normal emotional processing, such as in anxiety disorders, quality of life of the individual can be severely disrupted. Anxiety disorders account for nearly a quarter of all mental health diagnoses, however the aetiology and underpinning neural correlates of anxiety are still not fully understood. This thesis sought to investigate the neurobiological mechanisms of emotion processing, specifically in the amygdala, in a healthy sub-clinical cohort. Six different studies are presented using quantitative methodology to explore amygdala activation and connectivity during emotion processing, and structural differences, as modulated by gender and sub-clinical anxiety. Overall results reveal a modulating effect of sub-clinical anxiety on amygdala habituation, fronto-amygdala connectivity (at rest and during emotion processing) and neural structure. In addition, results presented in this thesis suggest that there may be an attentional component to characteristic hyper-responsivity of the amygdala during emotion processing seen in clinical anxiety patients that should be incorporated into future models of maladaptive emotion. Furthermore, various different chapters in this thesis present evidence that the left amygdala appears to be more specialised for responses to more socially salient stimuli and the right amygdala appears to be more responsive to threat related stimuli indicating that key theoretical models of emotion (the dual processing model, and the salience detection model) should be integrated into one cohesive model of emotion processing. In addition to these theoretical implications, results demonstrating the modulating effect of anxiety and gender presented in this thesis suggest that research on emotion should account for individual differences as a matter of standard practice. This thesis also supports the use of resting state -functional magnetic resonance imaging (fMRI) as a low cost, valid alternative, to task based fMRI within the study of anxiety. Finally, results suggest that investigation of structural differences in sub-clinical populations, and the use of analytical methods such machine learning classification techniques, could aid the development of diagnostic tools that can

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