Boys with reading disabilities and/or ADHD: distinctions in early childhood

We examined distinctions in the early childhood characteristics of boys with reading disabilities (RD) and/or attention-deficit/ hyperactivity disorder (ADHD). A four-group mixed design consisting of boys identified at age 11 with reading disabilities only (RD only; n = 46), reading disabilities and ADHD (RD/ADHD; n = 16), ADHD only (n = 20), and a comparison group (n = 281) was utilized. Differences on receptive and expressive language and temperament for ages 3 and 5 were investigated. Analyses indicated that the boys from the RD-only group performed worse on measures of receptive and expressive language. The results also indicated that boys from the RD/ADHD groups consistently performed worse on measures of receptive language and exhibited more behaviors indicative of an undercontrolled temperament. In summary, we suggest that reading disabilities and ADHD represent moderately unique disorders that frequently co-occur and are characterized by distinct developmental pathways.     

Longitudinal Study of Reading Disability and Attention-Deficit/Hyperactivity Disorder: Implications for Education

ABSTRACT— The majority of children who receive special education services meet criteria for reading disability (RD) or attention-deficit/hyperactivity disorder (ADHD), but additional research is needed to understand the long-term academic outcome of children in these groups. Individuals with RD only ( N = 71), ADHD only ( N = 66), both RD and ADHD ( N = 51), or neither disorder ( N = 118) were identified through the ongoing Colorado Learning Disabilities Research Center twin study and retested 5 years later. Results of the follow-up testing indicated that, in addition to ongoing reading difficulties, individuals with RD exhibited higher rates of academic difficulties, depression, and adolescent-onset conduct disorder. Initial ADHD status was associated with academic and social difficulties and elevated rates of nearly all comorbid disorders 5 years later. The group with comorbid RD and ADHD had more stable reading deficits than the group with RD without ADHD and exhibited greater impairment than groups with either disorder alone on outcome measures of academic functioning and social difficulties. These results suggest that individuals with both RD and ADHD are at increased risk for negative outcomes as adolescents and young adults and that when RD and ADHD co-occur, interventions should be provided for both disorders.     

Motor correlates of ADHD: contribution of reading disability and oppositional defiant disorder

This study investigated whether the likelihood of motor impairment in children with attention-deficit/hyperactivity disorder (ADHD) increases with the presence of other disorders, and whether the co-occurring diagnoses of reading disability (RD) and oppositional defiant disorder (ODD) account for the motor deficits seen in ADHD. A total of 291 children (218 boys, 73 girls) participated. Six groups of children were compared: ADHD only (n = 29); RD only (n = 63); ADHD and RD (n = 47); ADHD and ODD (n = 19); ADHD, RD, and ODD (n = 21); and typically developing control children (n = 112). Motor skills were assessed with the Bruininks-Oseretsky Test of Motor Proficiency and the Beery Test of Visual-Motor Integration. We found that the motor skills of the ADHD-only group did not differ from the typical control group. Furthermore, motor impairment in ADHD increased as a function of co-occurring disorders, and the presence of RD rather than ADHD predicted motor impairment.     

The IQs of children with ADHD are normally distributed

The purpose of this investigation was to determine whether or not attention-deficit/hyperactivity disorder (ADHD)-when there was an absence of reading problems-was associated with having a high IQ. The vocabulary and block design short forms of the Wechsler Intelligence Scale for Children-Third Edition were administered to 63 children with ADHD, 69 children with reading difficulties (RD), and 68 children with comorbid ADHD + RD. Results indicated that the distributions of estimated Full Scale IQs (FSIQ) for each of the three groups of children did not differ significantly from a normal distribution, with the majority of children (more than 50%) in each group scoring in the average range. The percentage of children with ADHD who scored in the above-average range for FSIQ was not significantly higher than the percentages of children in the other two groups. No significant group differences emerged for estimated FSIQ, vocabulary, or block design. It was concluded that children with ADHD are no more likely to have an above-average IQ than are other children.     

Reading motivational differences among groups: Reading disability (RD), attention deficit hyperactivity disorder (ADHD), RD + ADHD,and typical comparison

This study assessed the reading motivation of 133 students at individual grade levels (2nd–5th), who were divided in subgroups with and without reading disabilities/difficulties (RD) and with and without attention deficit hyperactivity disorder (ADHD). Major findings were that students in the RD subgroup had lower reading motivation (intrinsic, extrinsic, and self-efficacy) and read less for enjoyment than the nondisability (ND) group; students in the combined group (ADHD + RD) showed these motivational deficits in earlier grade levels. However, students with ADHD did not differ from the ND group in reading motivation, and children with RD (with and without ADHD) were equivalent to ND in social motivation up to the 5th grade. Implications of these findings were (a) social reading is an instructional pathway for both groups of students with RD, (b) assessments of reading motivation, in addition to reading skill, may be important in assessing responses to intervention, and (c) motivational interventions should be implemented early before motivational responses become a motivational style.     

ADHD and reading disability in male adults: is there a connection?

The present study examined the comorbidity between attention-deficit/hyperactivity disorder (ADHD) and reading disability (RD) in male adults. Participants were 120 men, of whom 24 were classified as having ADHD. The basis for the diagnosis was two self-report scales validated by interviews and background data. An extensive battery was used to assess phonological abilities and various aspects of reading skills. No differences were obtained between adults with and without ADHD on measures of either phonological processing skills or word decoding, indicating a low comorbidity with RD. This finding was valid even when different criteria were used to diagnose RD. However, the two groups differed in reading comprehension, with individuals with ADHD performing poorly in tests of reading comprehension. These results are compatible with the view that reading comprehension involves many of the higher cognitive control functions assumed to be impaired in ADHD. However, these attentional control functions are not critical to word recognition, which is determined by a more encapsulated phonological processing module. The pattern of associations between ADHD and RD observed in the present study is explained with reference to the differential attentional demands of the two aspects of reading.     

Cognitive profiling in Chinese developmental dyslexia with attention-deficit/hyperactivity disorders

The cognitive profiles of children with Developmental Reading Disorder (RD) and Attention-Deficit/Hyperactivity Disorders (ADHD) have been extensively studied in alphabetic language communities. Deficits in phonological processing and rapid naming have been implicated as core features of RD although whether the latter is a deficit specific to RD remains controversial. Similar research aiming to explore the cognitive profiles of children with both RD and ADHD in non-alphabetic language communities is limited. The specificity of rapid naming deficit to RD among Chinese has yet to be studied. In the first study, 43 Chinese children with confirmed diagnoses of RD + ADHD were assessed on their cognitive abilities in relating to reading. In the second study, the specificity deficit hypothesis of rapid naming to RD but not ADHD was examined. A digit naming test was administered to the RD + ADHD group (43 subjects) and an ADHD only group (49 subjects). In regard to cognitive profiling, rapid naming and orthographic knowledge were found to be the most common deficits among the Chinese RD + ADHD group. This co-morbid group was also found to have a significant deficit performance on the rapid naming task than the ADHD only group. The present findings support the double dissociation hypothesis in cognitive deficit between RD and ADHD. The results of both studies are discussed with reference to the findings of the Western counterparts.     

Reading difficulties and attention‐deficit/hyperactivity behaviours: evidence of an early association in a nonclinical sample

Attention‐deficit/hyperactivity disorder (ADHD) often co‐occurs with reading disability. A cross‐sectional study in an Italian‐speaking, nonclinical sample was conducted in an attempt to document the existence of an early association between reading difficulties (RD) and ADHD behaviours. We recruited a sample of 369 children in their first year at primary school. Of the sample, 8.4% displayed RD; 7.0% had ADHD; 3.5% presented both RD and ADHD behaviours; 50% of the children with ADHD displayed RD; 41.9% of those with RD displayed ADHD behaviours. Low socioeconomic status was associated with a fourfold increased probability of displaying RD (odds ratio = 3.98), but not ADHD behaviours. In this nonclinical sample, we detected an early association between ADHD behaviours and RD. A key role in this association may be played by inattention symptoms, which occurred with significantly increased frequency also in the group presenting only RD.     

Clinical importance of parent ratings of everyday cognitive abilities in children with learning and attention problems

This study addressed two issues: first, whether parental reports contribute information over and above a standardized psychometric assessment, and second, whether parental reports of everyday cognitive functioning might be useful in distinguishing between children with reading disabilities (RD), attention-deficit/hyperactivity disorder (ADHD), and combined ADHD + RD. Parent-reported information on 159 children with learning or attention problems was obtained using a questionnaire called the Parent Ratings of Everyday Cognitive and Academic Abilities (PRECAA). Psychometric information used for comparison included the Woodcock-Johnson Psychoeducational Battery-Revised, the Bruininks-Oseretsky Test of Motor Proficiency-Short Form, the Vocabulary and Block Design subtests of the Wechsler Intelligence Scale for Children, 3rd edition, and the Developmental Test of Visual-Motor Integration. The PRECAA was found to be sensitive to group differences between children with RD and children with ADHD and combined ADHD + RD. Its inclusion resulted in a significant increase in the number of children correctly classified compared to the use of psychometric measures alone. The PRECAA correctly classified more children (66%) than did the standard psychometric measures (50%). In fact, a very high percentage of children with ADHD (81%) were correctly classified using the PRECAA. These findings suggest that the PRECAA may be a useful aid to clinicians in the identification of children with learning and attention problems.     

Familial history of reading difficulty is associated with diffused bilateral brain activation during reading and greater association with visual attention abilities

Reading difficulty (RD; or dyslexia) is a heritable condition characterized by slow, inaccurate reading accompanied by executive dysfunction, specifically with respect to visual attention. The current study was designed to examine the effect of familial history of RD on the relationship between reading and visual attention abilities in children with RD using a functional MRI reading task. Seventy-one children with RD participated in the study. Based on parental reports of the existence of RD in one or both of each child’s parents, children with RD were divided into two groups: (1) those with a familial history of RD and (2) those without a familial history of RD. Reading and visual attention measures were collected from all participants. Functional MRI data during word reading was acquired in 30 participants of the entire cohort. Children with or without a familial history of RD demonstrated below-average reading and visual attention scores, with greater interaction between these measures in the group with a familial history of RD. Greater bilateral and diffused activation during word reading also were found in this group. We suggest that a familial history of RD is related to greater association between lower reading abilities and visual attention abilities. Parental history of RD therefore may be an important preschool screener (before reading age) to prompt early intervention focused on executive functions and reading-related skills.     

Comorbidity of reading disability and attention-deficit/hyperactivity disorder: differences by gender and subtype

This study used a community sample of 494 twins with a reading disability (223 girls, 271 boys) and 373 twins without a reading disability (189 girls, 184 boys) to assess the relation between reading disability (RD) and attention-deficit/hyperactivity disorder (ADHD). Symptoms of DSM-III and DSM-IV ADHD were classified into symptoms of inattention and symptoms of hyperactivity-impulsivity (H/I). Results indicated that individuals with RD were more likely than individuals without RD to meet criteria for ADHD and that the association between RD and ADHD was stronger for symptoms of inattention than for symptoms of H/I. Parents and teachers reported similar rates of ADHD, suggesting that ADHD symptoms were pervasive across settings and were not solely attributable to academic frustration. Analyses of possible gender differences revealed that RD was significantly associated with inattention in both girls and boys but associated with H/I only in boys. This difference may provide a partial explanation for the discrepancy between the gender ratio obtained in referred (approximately 4 boys to 1 girl) and nonreferred (1.2 to 1.5 boys to 1 girl) samples of individuals with RD. Specifically, the hyperactive and impulsive behaviors exhibited by boys with RD may be more disruptive than the inattentive behaviors exhibited by girls and may therefore precipitate more frequent referrals for clinical attention.     

Information processing deficits in children with attention-deficit/hyperactivity disorder, inattentive type, and children with reading disability

We examined the information processing capabilities of children diagnosed with the inattentive subtype of attention-deficit/hyperactivity disorder (ADHD) who had been characterized as having a sluggish cognitive tempo. Children referred for school-related problems (n = 81) and nonreferred community controls (n = 149) participated. Of the referred children, 24 met criteria for ADHD, 42 met criteria for reading disability (RD), and 9 of these were comorbid for RD and ADHD. Children with ADHD differed from those without ADHD on a visual search task but not on an auditory processing task; the reverse was true for children with RD. Decomposition of the visual search task into component operations demonstrated that children in the ADHD group had a slow processing rate that was not attributable to inattention. The children with ADHD were not globally poor at information processing or inattentive, but they demonstrated diminished speed of visual processing.     

Implications of Overlapping Difficulties in Mathematics and Reading on Self-Concept and Academic Achievement

In this study, the relationship between adolescents’ difficulty in mathematics and reading and the influence on academic self-concept and school grades was examined. The participants (N = 585; 299 girls, 286 boys) were one age group of ninth-graders whose mathematics and reading skills were assessed at the end of comprehensive school at age 16 years. Five student profile groups were found using cluster analysis: best achievers, normal achievers (NA), the reading difficulty (RD) group, the mathematical difficulty (MD) group, and the learning difficulty (LD) group. Post-hoc tests revealed that the RD group and the LD group had a higher academic self-concept than the MD group. In school grades history, surprisingly, the NA group and the RD group performed equally well across all school grades. Students in the MD group performed as poorly as the LD group. The results emphasise the prolonged and generalised effects of especially MD on students’ academic careers.     

Study on EEG power and coherence in patients with mild cognitive impairment during working memory task

To investigate the features of electroencephalography (EEG) power and coherence at rest and during a working memory task of patients with mild cognitive impairment (MCI). Thirty-five patients (17 males, 18 females; 52～71 years old) and 34 sex- and age-matched controls (17 males, 17 females; 51～63 years old) were recruited in the present study. Mini-Mental State Examination (MMSE) of 35 patients with MCI and 34 normal controls revealed that the scores of MCI patients did not differ significantly from those of normal controls (P＞0.05). Then, EEGs at rest and during working memory task with three levels of working memory load were recorded. The EEG power was computed over 10 channels: right and left frontal (F3, F4), central (C3,C4), parietal (P3, P4), temporal (TS, T6) and occipital (O1, O2); inter-hemispheric coherences were computed from five electrode pairs of F3-F4, C3-C4, P3-P4, T5-T6 and O1-O2 for delta (1.0～3.5 Hz), theta (4.0～7.5 Hz), alpha-1 (8.0～10.0 Hz), alpha-2 (10.5～13.0 Hz), beta-1 (13.5～18.0 Hz) and beta-2 (18.5～30.0 Hz) frequency bands. All values of the EEG power of MCI patients were found to be higher than those of normal controls at rest and during working memory tasks. Furthermore, the values of EEG power in the theta, alpha-1, alpha-2 and beta-1 bands of patients with MCI were significantly high (P＜0.05) in comparison with those of normal controls. Correlation analysis indicated a significant negative correlation between the EEG powers and MMSE scores. In addition, during working memory tasks, the EEG coherences in all bands were significantly higher in the MCI group in comparison with those in the control group (P＜0.05). However, there was no significant difference in EEG coherences between two groups at rest. These findings comprise evidence that MCI patients have higher EEG power at rest, and higher EEG power and coherence during working conditions. It suggests that MCI may be associated with compensatory processes at rest and during working memory tasks. Moreover, failure of normal cortical connections may be exist in MCI patients.     

Investigation of the Relationship of Attention Deficit Hyperactivity Disorder to the EKN1 Gene on Chromosome 15q21

Recently a gene, termed EKN1, has been identified because of a chromosomal breakpoint that occurred in this gene. This chromosomal breakpoint was found in 4 family members that had specific reading disabilities (RDs), indicating that disruption of this gene may be contributing to the risk of developing RDs. This gene was further supported as contributing to RD by association studies. Because of the evidence from twin studies for shared genetic factors contributing to RD and attention deficit hyperactivity disorder (ADHD), particularly inattention symptoms, we investigated the relationship of DNA markers in this gene to ADHD and ADHD symptoms in a sample of 186 nuclear families (probands, their parents, and affected siblings) collected through a proband with ADHD. We used 6 polymorphic DNA markers located across the gene, including the 2 markers previously reported to be associated with RD in a Finnish sample and a marker associated with RD in a sample of families collected in Toronto. We found a trend for association for several markers to the ADHD phenotype analyzed as a categorical trait using the transmission disequilibrium test and significant evidence for biased transmission of the haplotypes containing these markers, χ²(3) = 9.312, p =. 025. Using quantitative analysis, we observed evidence for association of one of the haplotypes to the inattention and hyperactive/impulsive symptom dimensions as reported by parents and to the inattention symptoms as reported by teachers, as well as a trend for association with the reading phenotypes of word identification and decoding. The results provide preliminary support for the role of the EKN1 chromosomal region in ADHD, suggesting that this region may contribute to ADHD symptoms in addition to RD.     

Time-frequency analysis of EEG signals evoked by voluntary,stimulated and imaginary motions

In order to investigate the characteristics of sensorimotor cortex during motor execution(ME), voluntary, stimulated and imaginary finger flexions were performed by ten volunteer subjects. Electroencephalogram(EEG) data were recorded according to the modified 10-20 International EEG System. The patterns were compared by the analysis of the motion-evoked EEG signals focusing on the contralateral(C3) and ipsilateral(C4) channels for hemispheric differences. The EEG energy distributions at alpha(8—13 Hz), beta(14—30 Hz) and gamma(30—50 Hz) bands were computed by wavelet transform(WT) and compared by the analysis of variance(ANOVA). The timefrequency(TF) analysis indicated that there existed a contralateral dominance of alpha post-movement event-related synchronization(ERS) pattern during the voluntary task, and that the energy of alpha band increased in the ipsilateral area during the stimulated(median nerve of wrist) task. Besides, the contralateral alpha and beta event-related desynchronization(ERD) patterns were observed in both stimulated and imaginary tasks. Another significant difference was found in the mean power values of gamma band(p0.01)between the imaginary and other tasks. The results show that significant hemispheric differences such as alpha and beta band EEG energy distributions and TF changing phenomena(ERS/ERD) were found between C3 and C4 areas during all of the three patterns. The largest energy distribution was always at the alpha band for each task.     

Phonological awareness and reading speed deficits in reading disabled Greek‐speaking children

There is evidence that phonological awareness skills secure decoding ability and that phonological deficits underlie failure to acquire adequate word recognition. Slow word‐reading rate may be an additional defining characteristic of reading disability. The present study aimed to investigate whether: (1) reading disabled (RD) Greek‐speaking children showed reading accuracy and reading speed deficits relative to chronological age‐matched controls (CAC) and reading age‐matched controls (RAC); (2) they showed phonological deficits relative to the two control groups who do not present reading difficulties; and (3) they showed reading comprehension deficits over and above any word reading deficits.

Results suggested that the reading accuracy of the RD group was predictably weaker than that of the CAC group but equivalent to that of the RAC group. However, the reading speed of the RD group was significantly slower than the RAC group, who showed the same single word reading speed as the CAC group.

Slow and laboured decoding was found to compromise the reading comprehension of the RD group, whose listening comprehension performance was as good as the two other groups. The RD children performed poorly on phonological awareness tasks and naming speed. Naming speed was not an independent core feature of reading difficulties in the Greek language but was associated with a general phonological deficit.

It is recommended that diagnostic assessments for children with reading difficulties in Greek should include phonological awareness, single word reading and pseudoword reading tasks that measure both accuracy and speed.     

Central auditory processing ability in children with ADHD with and without learning disabilities

A few studies have shown more central auditory processing deficits in children with attention-deficit/hyperactivity disorder (ADHD) than in nondisabled children. Because these studies failed to screen participants with ADHD for learning disabilities (LD), it is not clear whether these deficits are correlates of ADHD or LD or both. In the present study, the central auditory processing ability of children with ADHD, ADHD with LD, and no disabilities was examined. Results indicated lower central auditory processing ability, and significant correlations between reading and ADHD symptoms and reading and central auditory processing ability in the ADHD with LD group compared with the other two groups. These findings suggest that central auditory processing deficits are more likely to be associated with LD than ADHD.     

Word identification and reading disorders in the Spanish language

In this study, a reading-level-match design was used to test the hypothesis that children with reading disability (RD) are characterized by poor phonological skills, and that a developmental lag, as opposed to a specific deficit, will be found in transparent orthographies. Spanish has a transparent orthography and thus children with RD should not show severe difficulties in the use of the phonological route, as in the English language. A sample of 118 participants was selected and organized into three different groups: 40 with RD, 38 normal readers matched in age with the former, and 40 younger normal readers at the same reading level as those with RD. Two experiments were conducted to investigate the effects of lexicality, word frequency, word length, and positional frequency of syllables on lexical decision making and word-naming performance. While the participants were performing the naming task, we recorded what they read to subsequently analyze the form as well as the frequency of naming errors. The present study provides evidence for a deficit in phonological processing in a transparent orthography, particularly in nonword reading, because there were differences between the reading-level-matched groups.     

Is there an increased familial prevalence of psychopathology in children with nonverbal learning disorders?

The cognitive and behavioral symptoms of nonverbal learning disabilities (NLD) have been described by previous investigators. Nevertheless, we know far less about the potential genetic contributions that may predispose a child to have NLD. An endophenotype model was investigated in 5 samples of children ages 9 to 15 years: NLD (n = 32); reading disorders (RD; n = 59); participants with a psychiatric diagnosis but without a learning disability (n = 55); typically developing controls (n = 31); and children with velocardiofacial syndrome (VCFS), a chromosomal deletion syndrome that has been proposed as being an exemplar of NLD (VCFS + NLD; n = 20). Based on a family genetic interview, the authors' data suggest that children with NLD, RD, or a psychiatric diagnosis have a higher prevalence rate of attention-deficit/hyperactivity disorder (ADHD) and substance abuse/dependence. Psychiatric controls and children with NLD--but not children with RD-- showed higher prevalence rates of familial bipolar disorder.