Dr Debbie Gooch

Deficits in time perception (the ability to judge the duration of time intervals) have been found in children with both attention-deficit/hyperactivity disorder (ADHD) and dyslexia. This paper investigates time perception, phonological skills and executive functions in children with dyslexia and/or ADHD symptoms (AS).

Children with dyslexia-only (n = 17), AS-only (n = 17), comorbid dyslexia+AS (n = 25), and typically developing controls (n = 42), matched for age and non-verbal ability, were assessed on measures of phonological skills, executive function and time perception (duration discrimination and time reproduction).

Children with dyslexia were impaired on measures of phonological skill and duration discrimination compared to children without dyslexia (though problems on duration discrimination appeared to be attributable to mild symptoms of inattention in this group). In contrast, children with AS exhibited impairments on measures of both time perception and executive function compared to children without AS. Children with dyslexia+AS showed an additive combination of the deficits associated with dyslexia-only and AS-only.

Dyslexia and AS appear to be associated with distinct patterns of cognitive deficit, which are present in combination in children with dyslexia+AS.

The youngest children in an academic year are reported to be educationally disadvantaged and overrepresented in referrals to clinical services. In this study we investigate for the first time whether these disadvantages are indicative of a mismatch between language competence at school entry and the academic demands of the classroom.

We recruited a population sample of 7,267 children aged 4 years 9 months to 5 years 10 months attending state-maintained reception classrooms in Surrey, England. Teacher ratings on the Children's Communication Checklist-Short (CCC-S), a measure of language competence, the Strengths and Difficulties Questionnaire-Total Difficulties Score (SDQ), a measure of behavioural problems, and the Early Years Foundation Stage Profile (EYFSP), a measure of academic attainment, were obtained at the end of the reception year.

The youngest children were rated by teachers as having more language deficits, behaviour problems, and poorer academic progress at the end of the school year. Language deficits were highly associated with behaviour problems; adjusted odds ratio 8.70, 95% CI [7.25–10.45]. Only 4.8% of children with teacher-rated language deficits and 1.3% of those with co-occurring language and behaviour difficulties obtained a ‘Good Level of Development’ on the EYFSP. While age predicted unique variance in academic attainment (1%), language competence was the largest associate of academic achievement (19%).

The youngest children starting school have relatively immature language and behaviour skills and many are not yet ready to meet the academic and social demands of the classroom. At a population level, developing oral language skills and/or ensuring academic targets reflect developmental capacity could substantially reduce the numbers of children requiring specialist clinical services in later years.

Difficulty in controlling attention can lead to mental fatigue in the healthy population. We identified one trial reporting a benefit in patients’ attention using a homeopathic formula preparation. One component of the preparation was potassium phosphate, widely available off the shelf as Kali phos 6x for cognitive problems. The aim of this exploratory trial was to assess the effectiveness of Kali phos 6x for attention problems associated with mental fatigue.

We recruited student and staff volunteers (University of York) with self-reported mental fatigue, excluding any using homeopathy or prescribed stimulants, or with a diagnosis of chronic fatigue syndrome. In a triple blind, cross-over, placebo-controlled clinical trial, 86 volunteers were randomized to receive Kali phos 6x or identical placebo 10 minutes before taking a psychological test of attention (Stroop Colour-Word Test). One week later they were crossed over and took the other preparation before repeating the test.

We found no evidence of a treatment effect in a comparison of Kali phos 6x with placebo (Kali phos minus placebo = −1.1 (95% CI −3.0 to 0.9, P = 0.3) Stroop score units, Cohen effect size = −0.17) even when allowing for a weak period effect with accuracy scores in the second period being higher than those in the first (P = 0.05). We observed a ceiling effect in the Stroop test which undermined our ability to interpret this result.

Kali phos 6x was not found to be effective in reducing mental fatigue. A ceiling effect in our primary outcome measure meant that we could not rule out a type II error. Thorough piloting of an adequate outcome measure could have led to an unequivocal result.

The developmental relationships between executive functions (EF) and early language skills are unclear. This study explores the longitudinal relationships between children’s early EF and language skills in a sample of children with a wide range of language abilities including children at risk of dyslexia. In addition, we investigated whether these skills independently predict children’s attention/behaviour skills.

Data are presented from 243 children at four time points. Children were selected for being at risk of reading difficulties either because of a family history of dyslexia (FR; N = 90) or because of concerns regarding their language development (LI; N = 79) or as typically developing controls (TD; N = 74). The children completed tasks to assess their executive function and language skills at ages 4, 5 and 6 years. At 6 (T4) and 7 years (T5) parents and teachers rated the children’s attention/behaviour skills.

There was a strong concurrent relationship between language and EF at each assessment. Longitudinal analyses indicated a considerable degree of stability in children’s language and EF skills: the influence of language on later EF skills (and vice versa) was weak and not significant in the current sample. Children’s EF, but not language, skills at T3 predicted attention/behaviour ratings at T4/T5.

There is a strong concurrent association between language and EF skills during the preschool and early school years, when children with language impairment show persistent EF deficits. Latent variables measuring language and EF show high longitudinal stability with little evidence of significant or strong reciprocal influences between these constructs. EF, but not language, skills predict later ratings of children’s attention and behaviour.

Rating scales are often used to identify children with potential Attention-Deficit/Hyperactivity Disorder (ADHD), yet there are frequently discrepancies between informants which may be moderated by child characteristics. The current study asked whether correspondence between parent and teacher ratings on the Strengths and Weakness of ADHD symptoms and Normal behaviour scale (SWAN) varied systematically with child language ability.

Parent and teacher SWAN questionnaires were returned for 200 children (aged 61–81 months); 106 had low language ability (LL) and 94 had typically developing language (TL). After exploring informant correspondence (using Pearson correlation) and the discrepancy between raters, we report inter-class correlation coefficients, to assess inter-rater reliability, and Cohen’s kappa, to assess agreement regarding possible ADHD caseness.

Correlations between informant ratings on the SWAN were moderate. Children with LL were rated as having increased inattention and hyperactivity relative to children with TL; teachers, however, rated children with LL as having more inattention than parents. Inter-rater reliability of the SWAN was good and there were no systematic differences between the LL and TL groups. Case agreement between parent and teachers was fair; this varied by language group with poorer case agreement for children with LL.

Children’s language abilities affect the discrepancy between informant ratings of ADHD symptomatology and the agreement between parents and teachers regarding potential ADHD caseness. The assessment of children’s core language ability would be a beneficial addition to the ADHD diagnostic process.

Diagnosis of ‘specific’ language impairment traditionally required nonverbal IQ to be within normal limits, often resulting in restricted access to clinical services for children with lower NVIQ. Changes to DSM-5 criteria for language disorder removed this NVIQ requirement. This study sought to delineate the impact of varying NVIQ criteria on prevalence, clinical presentation and functional impact of language disorder in the first UK population study of language impairment at school entry.

A population-based survey design with sample weighting procedures was used to estimate population prevalence. We surveyed state-maintained reception classrooms(n = 161 or 61% of eligible schools) in Surrey, England. From a total population of 12,398 children (ages 4–5 years),7,267 (59%) were screened. A stratified subsample (n = 529) received comprehensive assessment of language, NVIQ,social, emotional and behavioural problems, and academic attainment.

The total population prevalence estimate of language disorder was 9.92% (95% CI 7.38, 13.20). The prevalence of language disorder of unknown origin was estimated to be 7.58% (95% CI 5.33, 10.66), while the prevalence of language impairment associated with intellectual disability and/or existing medical diagnosis was 2.34% (95% CI 1.40, 3.91). Children with language disorder displayed elevated symptoms of social, emotional and behavioural problems relative to peers, F(1,466) = 7.88, p = .05, and 88% did not make expected academic progress. There were no differences between those with average and low-average NVIQ scores in severity of language deficit, social, emotional and behavioural problems, or educational attainment. In contrast, children with language impairments associated with known medical diagnosis and/or intellectual disability displayed more severe deficits on multiple measures.

At school entry, approximately two children in every class of 30 pupils will experience language disorder severe enough to hinder academic progress. Access to specialist clinical services should not depend on NVIQ.

Causal theories of dyslexia suggest that it is a heritable disorder, which is the outcome of multiple risk factors. However, whether early screening for dyslexia is viable is not yet known.

The study followed children at high risk of dyslexia from preschool through the early primary years assessing them from age 3 years and 6 months (T1) at approximately annual intervals on tasks tapping cognitive, language, and executive-motor skills. The children were recruited to three groups: children at family risk of dyslexia, children with concerns regarding speech, and language development at 3;06 years and controls considered to be typically developing. At 8 years, children were classified as ‘dyslexic’ or not. Logistic regression models were used to predict the individual risk of dyslexia and to investigate how risk factors accumulate to predict poor literacy outcomes.

Family-risk status was a stronger predictor of dyslexia at 8 years than low language in preschool. Additional predictors in the preschool years include letter knowledge, phonological awareness, rapid automatized naming, and executive skills. At the time of school entry, language skills become significant predictors, and motor skills add a small but significant increase to the prediction probability. We present classification accuracy using different probability cutoffs for logistic regression models and ROC curves to highlight the accumulation of risk factors at the individual level.

Dyslexia is the outcome of multiple risk factors and children with language difficulties at school entry are at high risk. Family history of dyslexia is a predictor of literacy outcome from the preschool years. However, screening does not reach an acceptable clinical level until close to school entry when letter knowledge, phonological awareness, and RAN, rather than family risk, together provide good sensitivity and specificity as a screening battery.

Children at family risk of dyslexia have been reported to show phonological deficits as well as broader language delays in the preschool years.

The preschool language skills of 112 children at family risk of dyslexia (FR) at ages 3½ and 4½ were compared with those of children with SLI and typically developing (TD) controls.

Children at FR showed two different profiles: one third of the group resembled the children with SLI and scored poorly across multiple domains of language including phonology. As a group, the remaining children had difficulties on tasks tapping phonological skills at T1 and T2. At the individual level, we confirmed that some FR children had both phonological and broader oral language difficulties (compared with TD controls), some had only phonological difficulties and some appeared to be developing typically.

Background

Centile curves and standard scores are common in epidemiological research. However, standardised norms and centile growth curves for language disorder that reflect the entire UK local school population do not exist.

Methods

Scores on six language indices assessing receptive and expressive functioning of children were obtained from the SCALES population survey. Monolingual English speaking participants were aged between five and nine years. Children who attended special schools at study intake, or who were learning English as an additional language were excluded. We constructed language norms using the LMS method of standardisation which allows for skewed measurements. We made use of probability weights that were produced from a two-step logistic model. Distributions of estimated standard scores from an intensively assessed sub-population and from the full population were contrasted to demonstrate the role of weights.

Results

Non-overlapping centile curves and standardised scores at each age were obtained for the six language indices. The use of weights was essential at retrieving the target distribution of the scores. An online calculator that estimates standardised scores for the measures was constructed and made freely available.

Conclusions

The findings highlight the usefulness and flexibility of the LMS method at dealing with the standardisation of linguistic and educational measures that are sufficiently continuous. The paper adds to the existing literature by providing population norms for a number of language tests that were calculated from the same group of individuals.

Comorbidity among developmental disorders such as dyslexia, language impairment, attention deficit/ hyperactivity disorder and developmental coordination disorder is common. This study explores comorbid weaknesses in preschool children at family risk of dyslexia with and without language impairment and considers the role that comorbidity plays in determining children’s outcomes.

The preschool attention, executive function and motor skills of 112 children at family risk for dyslexia, 29 of whom also met criteria for language impairment, were assessed at ages 3½ and 4½ years. The performance of these children was compared to the performance of children with language impairment and typically developing controls.

Weaknesses in attention, executive function and motor skills were associated with language impairment rather than family risk status. Individual differences in language and executive function are strongly related during the preschool period, and preschool motor skills predicted unique variance (4%) in early reading skills over and above children’s language ability.

Comorbidity between developmental disorders can be observed in the preschool years: children with language impairment have significant and persistent weaknesses in motor skills and executive function compared to those without language impairment. Children’s early language and motor skills are predictors of children’s later reading skills.