ADHD and dysgraphia: underlying mechanisms

Multiple complaints in the domain of writing are common among children with Attention Deficit Hyperactivity Disorder (ADHD). In this work we sought to characterize the writing disorder by studying dysgraphia in twenty 6th grade boys with ADHD and normal reading skills matched to 20 healthy boys who served as a comparison group. Dysgraphia, defined as deficits in spelling and handwriting, was assessed according to neuropsychological explanatory processes within 3 primary domains: linguistic processing, motor programming and motor kinematics. Children with ADHD made significantly more spelling errors, but showed a unique pattern introducing letter insertions, substitutions, transpositions and omissions. This error type, also known as graphemic buffer errors, can be explained by impaired attention aspects needed for motor planning. Kinematic manifestations of writing deficits were fast, inaccurate and an inefficient written product accompanied by higher levels of axial pen pressure. These results suggest that the spelling errors and writing deficits seen in children with ADHD and normal reading skills stem primarily from non-linguistic deficits, while linguistic factors play a secondary role. Recommendations for remediation include educational interventions, use of word processing and judicious use of psychostimulants.     

Examining the link between working memory behaviour and academic attainment in children with ADHD

Aim The aim of the present study was to investigate whether behaviours typical of working memory problems are associated with poor academic attainment in those with attention‐deficit–hyperactivity disorder (ADHD), as well as a non‐clinical group identified on the basis of working memory difficulties. Method Children clinically diagnosed with ADHD‐combined (n=31; mean age 9y 7mo, SD 12mo; 27 males) were matched with 44 low working memory children (mean age 9y 4mo, SD 15mo; 32 males) and 10 healthy controls (mean age 10y, SD 12mo; 5 males). Working memory behaviour was measured using the Working Memory Rating Scale (WMRS) and academic attainment was assessed with standardized tests of literacy and numeracy. Results The majority of children considered by their teachers to have problematic behaviours performed poorly in literacy and numeracy. When the whole sample were split into two groups on the basis of their working memory behaviour (on the WMRS), the ‘At Risk’ group performed significantly worse in academic attainment. Interpretation As children with ADHD and a non‐clinical group exhibit classroom behaviour typical of working memory problems, early screening to prevent subsequent learning difficulties is important. The use of the WMRS allows educators to draw on their expertise in the classroom for early detection of children with working memory failures.     

Impaired working memory in children with attention deficit hyperactivity disorder and their siblings

Introduction: Impairment of working memory in children with attention deficit hyperactivity disorder (ADHD) has been well described. If similar impairment in working memory can be demonstrated among their siblings, this could suggest impaired working memory is a genetic component of ADHD. Methods: Fifty‐seven subjects were recruited: (1) ADHD group (n=21); (2) siblings of ADHD children group (n=15); and (3) non‐ADHD children with chronic medical condition as the control group (n=21). All subjects were aged between 6 and 15 years, and ADHD was diagnosed according to DSM‐IV‐TR. Those with other comorbidity or IQ<70 were excluded. Digit Recall was used for assessment of the phonological loop component, Maze Memory test for the visuospatial sketch pad component and Backward Digit Recall for the central executive component of working memory. Results: ADHD children and their siblings showed similar impairment and both differed from the control group on the Maze Memory test. ADHD children also showed impairment in the Digit Recall test; however, the sibling group did not differ from the control group on this test. The Backward Digit Recall score did not show any significant difference between the three groups. Discussion: Impairment of the visuospatial sketch pad component of working memory seems to cluster in ADHD children and their siblings. Thus, impairment of the visuospatial sketch pad component of working memory may point towards a genetic predisposition of ADHD.     

Impact of neurocognitive function on academic difficulties in pediatric bipolar disorder: A clinical translation.

BACKGROUND: Previous research has demonstrated that academic and neuropsychological functions are compromised in pediatric bipolar disorder (PBD). Investigation of the degree to which neuropsychological deficits might contribute to those academic problems is needed to aid in the recognition and intervention for school achievement difficulties in PBD. METHODS: A sample of 55 children and adolescents with PBD with and without attention-deficit/hyperactivity disorder (ADHD) (PBD group, n = 28; PBD+ADHD group, n = 27) were tested with a computerized neurocognitive battery and standardized neuropsychological tests. Age range of subjects was 7-17 years, with the mean age of 11.97 (3.18) years. Parents completed a structured questionnaire on school and academic functioning. RESULTS: Logistic regression analyses indicated that executive function, attention, working memory, and verbal memory scores were poorer in those with a history of reading/writing difficulties. A separate logistic regression analysis found that attentional dysfunction predicted math difficulties. These relationships between neuropsychological function and academic difficulties were not different in those with PBD+ADHD than in those with PBD alone. CONCLUSIONS: In PBD neuropsychological deficits in the areas of attention, working memory, and organization/problem solving skills all contribute to academic difficulties. Early identification and intervention for these difficulties might help prevent lower academic achievement in PBD.     

Increased Prefrontal Oxygenation Related to Distractor-Resistant Working Memory in Children with Attention-Deficit/Hyperactivity Disorder (ADHD)

This study aimed at investigating the effect of distraction on working memory and its underlying neural mechanisms in children with attention-deficit/hyperactivity disorder (ADHD). To this end, we studied hemodynamic activity in the prefrontal cortex using near-infrared spectroscopy while 16 children with ADHD and 10 typically developing (TD) children performed a working memory task. This task had two conditions: one involved a distraction during the memory delay interval, whereas the other had no systematic distraction. The ADHD patients showed significantly poorer behavioral performance compared with the TD group, particularly under the distraction. The ADHD group exhibited significantly higher level of prefrontal activation than did TD children. The activity level was positively correlated with the severity of ADHD symptoms. These results suggest that the impairment in the inhibition of distraction is responsible for the working memory deficits observed in ADHD children. Inefficient processing in the prefrontal cortex appears to underlie such deficits.     

Memory functioning and mental verbs acquisition in children with specific language impairment

Memory and language operate in synergy. Recent literature stresses the importance of memory functioning in interpreting language deficits. Two groups of 50 children each, ages 8-12 were studied. The first group included children with specific language impairment, while the participants in the second group were typically developing children. The two groups, which were matched on age, nonverbal intelligence and varied significantly in verbal ability were examined, using a test battery of four memory functioning (phonological, working and long-term memory) and five mental verb measures. The statistical analyses indicated that the two groups differed significantly in all language and memory measures; a logistic regression analysis revealed that within each main group existed nested subgroups of different developmental patterns with working and long-term memory measures as the most robust discriminate markers of classification. Language impaired children had more difficulties in the acquisition of mental verbs because they are less able to process and store phonological information in working memory and long-term lexicon.     

Coincidence of homophone spelling errors and attention problems in schoolchildren: a survey study

This article examines the relationship between writing and attention problems and hypothesizes that homophone spelling errors coincide with attention deficits. We analyze specific types of attention deficits, which may contribute to Attention Deficits Hyperactivity Disorder (ADHD); rather than studying ADHD, however, we focus on the inattention dimension of behavior. Our methodology was to develop a survey study for exploring the coincidence of homophone errors and attention problems in schoolchildren. Two sets of parent-questionnaires characterizing individually types of Chinese handwriting errors and behavioral problems in schoolchildren were developed by the research team. Our participants were 491 Taiwanese children from the first to fifth grades in an elementary school in Taipei; they all used traditional Chinese as their primary written language of communication. Based on the ratings of the parent-questionnaires, two groups with proficient and non-proficient homophonic writing were formed. One consisted of children known to have made heterographic homophone errors (words with correct pronunciation but different spellings). The other (control group) consisted of children known to be proficient in Chinese homophone spellings. In each group, there were 54 boy and girl pupils, matched by gender, age, school and grade. A significant correlation was found between attention deficits and homophone errors. This survey study confirms our hypothesis and strengthens a currently underdeveloped theory in the literature of handwriting that attention impairments play an important role in the production of homophone errors.     

Diagnostic profiles of children with developmental dyslexia in a transparent orthography

In the present study for 108 typical and 122 atypical Dutch readers in second grade, the accuracy and speed of decoding words and pseudowords, as well as the accuracy of spelling words were assessed along with four types of phonological precursor measures: rapid naming, verbal working memory, phoneme awareness and letter knowledge. The data show that the group being diagnosed as poor readers were significantly behind in all reading and spelling measures. It was also found that the criterion measures of reading and spelling explained already two third of the variance associated with the group distinction. Finally, we found word and pseudoword efficiency in the typical group to be explained by phonological awareness (spoonerism) and rapid naming of letters, word and pseudoword accuracy by phonological awareness, and spelling by phonological awareness and letter dictation. In the group of poor readers, a much greater variety of precursor measures was involved in explaining the variance in reading and spelling abilities.     

Delays in the reading and spelling of children with cerebral palsy: Associations with phonological and visual processes

BackgroundThis investigation addresses the question of whether there exists a significant discrepancy in the cognitive abilities of children with cerebral palsy (CP) who, despite the presence of age appropriate communication and language, have reading and spelling delays.AimsWe wanted to discover whether there was a relationship between the phonological and visual perceptual abilities of children with CP and their progress in reading and spelling.Methods and proceduresFifteen children with CP (aged between 6:9 years and 11:6 years) were assessed on reading and spelling; communication and language; non-verbal reasoning; phonological processing; and visual perception.Outcomes and resultsTen of the children had very weak reading and spelling skills. Five children had (mostly) age appropriate scores of reading and spelling. No differences were found between these two groups in non-verbal reasoning or communication and language. However, phonological abilities, visual sequential memory and perception of visuospatial relationships were found to be related to reading and spelling.Conclusions and implicationsThe findings suggest that children with CP are at risk for reading and spelling delays when they have poor phonological processing, visual sequential memory and perception of visuospatial relationships. The implications of the findings for classroom practice are discussed.     

Early reading and spelling abilities in children with severe speech and physical impairment: a cross-linguistic comparison

Early reading and spelling abilities in children from Ireland and Sweden with severe speech and physical impairment (SSPI) were studied and compared. The aim was to look for similarities as well as for differences that could be related to the different linguistic environments. Both group consisted of 15 children, and were matched on linguistic age. Reading and spelling as well as phonological awareness and memory were tested. Both groups performed fairly well on the phonological awareness tasks, but the Swedish children did not seem to manage to use this ability successfully for reading and spelling. Overall the Irish children showed a slightly stronger performance, and were significantly better at the reading tasks. There were some signs that children were affected by the structure of their individual languages. The Irish children revealed the greatest problems with pseudoword spelling which is in line with results from speaking children with English as their mother tongue and could be a result of using a strategy based on larger linguistic units. The Swedish children had particular problems with tasks presented without oral support, which may be an effect of memory problems due to their lack of articulatory ability.     

Spelling in oral deaf and hearing dyslexic children: A comparison of phonologically plausible errors

A written single word spelling to dictation test and a single word reading test were given to 68 severe-profoundly oral deaf 10–11-year-old children and 20 hearing children with a diagnosis of dyslexia. The literacy scores of the deaf children and the hearing children with dyslexia were lower than expected for children of their age and did not differ from each other. Three quarters of the spelling errors of hearing children with dyslexia compared with just over half the errors of the oral deaf group were phonologically plausible. Expressive vocabulary and speech intelligibility predicted the percentage of phonologically plausible errors in the deaf group only. Implications of findings for the phonological decoding self–teaching model and for supporting literacy development are discussed.     

Evidence that response inhibition is a primary deficit in ADHD

The present study examined response inhibition in children with attention deficit hyperactivity disorder (ADHD; n = 58) and controls (n = 84) using three go/no-go tests -- one with high working memory demand (cognitive), one with low working memory demand (simple), and one with rewards and response costs (motivation linked) in which emphasis was on reward for responding to "go" stimuli. Results of a repeated measure analysis of variance showed a significant effect of diagnosis for errors of commission for the simple, cognitive, and motivation-linked go/no-go tests, such that children with ADHD made significantly more errors than controls. Furthermore, a significant effect of test was noted across groups, such that both children in the ADHD and control groups performed worse on the cognitive and motivation-linked tests than they did on the simple test. The diagnosis by test interaction was not significant, suggesting that ADHD participants showed a similar degree of impairment to that of controls, regardless of the degree of working memory load or feedback provided in the test. In children with ADHD, response inhibition appears to be a primary deficit that is observed even when executive function demands of tasks are minimal. Although increasing working memory demand appears to impede response inhibition, this effect is similar in ADHD and typically developing children.     

Rolandic spikes increase impulsivity in ADHD - a neuropsychological pilot study

The present study was designed to examine the association of Rolandic spikes with the neuropsychological profile of children with ADHD. A total of 48 children (mean age 9.4 ± 1.6 years, range 6.7–14.9 years; 16 ADHD children with Rolandic spikes, 16 ADHD children without epileptiform discharges and 16 healthy controls) matched for age, gender, and IQ were examined with a neuropsychological assessment battery focussing on attentional processing, cognitive efficiency, response inhibition, visuospatial and auditory-verbal short-term memory and language function (CPT-AX, Stroop, digit span, Complex Figure of Rey, Heidelberg Language Development Test). ADHD children with Rolandic spikes performed worse than ADHD children without epileptiform discharges and healthy controls in a variety of CPT and Stroop test measures. In particular, they made significantly more commission errors, reflecting impaired inhibition of an ongoing response. In addition, they had pronounced difficulties in the color word condition of the Stroop test and exhibited lower interference scores, indicating poorer interference control. Results of this pilot study suggest that in some ADHD children Rolandic spikes or an associated dysfunction aggravate the course of ADHD and predispose to increased impulsivity, evidenced in deficient inhibition of an ongoing response, and decreased interference control.     

Serial order effects in spelling errors: evidence from two dysgraphic patients

This study reports data from two dysgraphic patients, TH and PB, whose errors in spelling most often occurred in the final part of words. The probability of making an error increased monotonically towards the end of words. Long words were affected more than short words, and performance was similar across different output modalities (writing, typing and oral spelling). This error performance was found despite the fact that both patients showed normal ability to repeat the same words orally and to access their full spelling in tasks that minimized the involvement of working memory. This pattern of performance locates their deficit to the mechanism that keeps graphemic representations active for further processing, and shows that the functioning of this mechanism is not controlled or "refreshed" by phonological (or articulatory) processes. Although the overall performance pattern is most consistent with a deficit to the graphemic buffer, the strong tendency for errors to occur at the ends of words is unlike many classic "graphemic buffer patients" whose errors predominantly occur at word-medial positions. The contrasting patterns are discussed in terms of different types of impairment to the graphemic buffer.     

Neuropsychological Functioning and Attachment Representations in Early School Age as Predictors of ADHD Symptoms in Late Adolescence

This study aimed to examine relations between parent and child attachment representations and neuropsychological functions at age 8, as well as relations between these constructs and ADHD symptoms over a 10-year period. A community-based sample of 105 children (52 boys) participated. Measures of attachment representations and a range of neuropsychological functions were collected at age 8. Parents rated emotion dysregulation and ADHD symptoms at age 8 and ADHD symptoms again at age 18. Significant, although modest, relations were found between disorganized attachment and some aspects of neuropsychological functioning in childhood. When studying outcomes in late adolescence and controlling for early ADHD symptom levels, spatial working memory and disorganized attachment remained significant in relation to both ADHD symptom domains, and one measure of inhibition remained significant for hyperactivity/impulsivity. When examining independent effects, spatial working memory and disorganized attachment were related to inattention, whereas spatial working memory and dysregulation of happiness/exuberance were related to hyperactivity/impulsivity. Our findings showing that disorganized attachment is longitudinally related to ADHD symptoms over and above the influence of both neuropsychological functioning and early ADHD symptom levels highlights the importance of including measures of attachment representations when trying to understand the development of ADHD symptoms. If replicated in more “at-risk” samples, these findings could also suggest that parent–child attachment should be taken into consideration when children are referred for assessment and treatment of ADHD.     

Attention-deficit/hyperactivity disorder in childhood epilepsy: a neuropsychological and functional imaging study

Purpose: Children with epilepsy have a significant risk for attention‐deficit/hyperactivity disorder (ADHD), which is often accompanied by deficits in working memory performance. However, it is not yet clear whether there are specific differences in the underlying mechanisms of working memory capability between children with epilepsy‐related ADHD and those with developmental ADHD. There is evidence that methylphenidate can improve the behavioral difficulties in children with developmental ADHD. Whether this medication has the same effect on ADHD symptoms in patients with epilepsy is not yet well understood. The aim of the present study is, therefore, to evaluate whether boys with epilepsy‐related ADHD and developmental ADHD share a common behavioral, pharmacoresponsive, and neurofunctional pathophysiology. Methods: Seventeen boys with diagnosed combined epilepsy/ADHD, 15 boys with developmental ADHD, and 15 healthy controls (aged 8–14 years) performed on working memory tasks (N‐back) while brain activation was recorded using functional magnetic resonance imaging. Each patient was tested twice: once after the intake of methylphenidate and once without in a counterbalanced order. Key Findings: On a behavioral level, we show that boys with epilepsy‐related ADHD as well as those with developmental ADHD performed similarly poorly on tasks with high cognitive load when compared to healthy controls, and that intake of methylphenidate improved performance almost to normal levels in both ADHD groups. On the functional level, both patient groups showed similar reductions of activation in all relevant parts of the functional network of working memory when compared to controls. Of interest, intake of methylphenidate did not significantly alter this activity pattern. Significance: Our data show strong similarities between epilepsy‐related and developmental ADHD on the behavioral, pharmacoresponsive, and neural level, favoring the view that ADHD with and without epilepsy shares a common underlying neurobehavioral pathophysiology.     

Lexical spelling in children and adolescents with specific language impairment: Variations with the writing situation

The goal of this study was to compare the lexical spelling performance of children and adolescents with specific language impairment (SLI) in two contrasting writing situations: a dictation of isolated words (a classic evaluative situation) and a narrative of a personal event (a communicative situation). Twenty-four children with SLI and 48 typically developing children participated in the study, split into two age groups: 7–11 and 12–18 years of age. Although participants with SLI made more spelling errors per word than typically developing participants of the same chronological age, there was a smaller difference between the two groups in the narratives than in the dictations. Two of the findings are particularly noteworthy: (1) Between 12 and 18 years of age, in communicative narration, the number of spelling errors of the SLI group was not different from that of the typically developing group. (2) In communicative narration, the participants with SLI did not make specific spelling errors (phonologically unacceptable), contrary to what was shown in the dictation. From an educational perspective or that of a remediation program, it must be stressed that the communicative narration provides children—and especially adolescents—with SLI an opportunity to demonstrate their improved lexical spelling abilities. Furthermore, the results encourage long-term lexical spelling education, as adolescents with SLI continue to show improvement between 12 and 18 years of age.     

Visual-perceptual and phonological factors in the acquisition of literacy among children with congenital developmental coordination disorder

Much research has shown that children with congenital developmental coordination disorder (CDCD) have marked impairments in the perception of visual-spatial information, a deficit which has been assumed to be causally related to difficulties that many CDCD children experience when learning to read and spell. However, current research in reading disability suggests that poor reading is mainly related to difficulties with the processing of phonological information or with metaphonological ability, not to visual-perceptual deficits. This study aimed to explore the relationship between reading achievement and the visual-perceptual, phonological and general cognitive ability of CDCD children. Twenty-eight children with a mean age of 8.3 years were tested on motor coordination, language, general ability, visual discrimination, visual-motor integration, phoneme awareness, phoneme discrimination, reading and spelling. Results showed that phoneme awareness was the most strongly related to reading and spelling performance, and that visual discrimination showed no relationship to reading ability, although it was related to spelling performance, phonological awareness, and motor coordination. These results suggest that CDCD children who have difficulty with the acquisition of literacy may suffer from visual-perceptual problems and metaphonological deficits, but these problems. are differentially related to reading and spelling.