Rapid naming deficits in children and adolescents with reading disabilities and attention deficit hyperactivity disorder.

Seventy-one children in three groups (reading disabilities, ADHD without reading disabilities, and normal controls) were compared on their ability to rapidly name colors, letters, numbers, and objects (RAN Tasks) and alternating letters/numbers and letters/numbers/colors (RAS tasks). Children with reading disabilities were found to be slower on letter- and number-naming tasks and made more errors on all tasks than controls or children with ADHD. There was an age effect for the RAN/RAS tasks, with younger children with reading disabilities performing more poorly on all tasks, while the older children with reading disabilities showed poorer performance only on the letter- and number-naming tasks.

Using MRI to examine brain-behavior relationships in males with attention deficit disorder with hyperactivity.

OBJECTIVE: The relationship between neuropsychological measures of inhibition and sustained attention and structural brain differences in the regions of the caudate and the frontal region was examined in males with attention deficit disorder with hyperactivity (ADD/H). METHOD: Ten males with ADD/H (aged 8-17) and 11 male controls (aged 9-18) participated in a neuropsychological evaluation and had a magnetic resonance imaging scan. RESULTS: As had been reported previously by these authors, the children with ADD/H were found to have reversed asymmetry of the head of the caudate, smaller volume of the left caudate head, and smaller volume of the white matter of the right frontal lobe. Children with ADD/H were found to score more poorly on measures of inhibition and sustained attention but not on measures of IQ, achievement, or motor speed. Comparison of neuropsychological measures and brain structure measures indicated a significant relationship between reversed caudate asymmetry and measures of inhibition and externalizing behavior; i.e., children with reversed caudate asymmetry performed more poorly on measures of inhibition regardless of group membership. Poorer performance on sustained attention tasks was related to smaller volume of the right-hemispheric white matter. CONCLUSIONS: There is emerging evidence that compromised brain morphology of selected regions is related to behavioral measures of inhibition and attention.

Components of attention in children with complex partial seizures with and without ADHD.

PURPOSE: To evaluate attentional difficulties in children with complex partial seizures, we reviewed the records of 12 children with complex partial seizures with attention deficient hyperactivity disorder (CPS/ADHD); 21 children with CPS without ADHD (CPS); 22 children with ADHD; and 15 control children. METHODS: Each child completed a computerized performance test (CPT), which evaluated sustained attention, inhibition of response, response time, and consistency of response. The ADHD groups also completed the CPT after a dose of methylphenidate. RESULTS: The results found poorest performance on the CPT by the CPS/ADHD group. Particular difficulty in attention was found for children with epilepsy regardless of the ADHD diagnosis. When methylphenidate was administered to the ADHD groups, both groups improved in performance on the CPT. CONCLUSIONS: Epilepsy may predispose children to attention problems that can significantly interfere with learning. Similar improvement for children with CPS/ADHD was found with methylphenidate compared with baseline as for children with ADHD but without CPS.

An intervention approach for children with teacher- and parent-identified attentional difficulties.

Using a multimodal and multi-informant method for diagnosis, we selected 33 children by teacher and parent nomination for attention and work completion problems that met DSM-IV criteria for attention-deficit/hyperactivity disorder (ADHD). Of the 33 children in this group, 21 participated in the initial intervention, and 12 were placed in an ADHD control group and received the intervention after pre- and posttesting. A similarly selected group of 21 children without difficulties in attention and work completion served as a control group. Each child was assessed on pre- and posttest measures of visual and auditory attention. After an 18-week intervention period that included attention and problem-solving training, all children in the intervention and control groups were retested on visual and auditory tasks. Children in both ADHD groups showed significantly poorer initial performance on the visual attention task. Whereas the ADHD intervention group showed commensurate performance to the nondisabled control group after training, the ADHD control group did not show significant improvement over the same period. Auditory attention was poorer compared to the control group for both ADHD groups initially and improved only for the ADHD intervention group. These findings are discussed as a possible intervention for children with difficulties in strategy selection in a classroom setting.

Evidence from imaging on the relationship between brain structure and developmental language disorders.

This article discusses findings using various imaging techniques regarding the neurological underpinnings of developmental language and learning disorders. Evidence from magnetic resonance imaging, functional magnetic resonance imaging, single photon emission spectroscopy, and positron emission tomography implicates the left perisylvian regions in the processing of phonemes and auditory information, as had been predicted from lesion data and from neurobiological theory. The areas of the planum temporale and angular gyrus have been found to be compromised in children and adults with dyslexia or language impairment. Emerging evidence suggests that these differences are also present in members of families with a history of developmental language disorders, which provides support for a transmittable, biological factor involved in such disorders. Dynamic imaging procedures are beginning to provide an understanding of the relationship between structure and function in normal and abnormal language acquisition.

Volumetric MRI analysis comparing subjects having attention-deficit hyperactivity disorder with normal controls.

OBJECTIVE: To test by MRI-based morphometry the a priori hypotheses that developmental anomalies exist in attention-deficit hyperactivity disorder (ADHD) in left caudate and right prefrontal/frontal/ and/or posterior parietal hemispheric regions, in accord with neurochemical, neuronal circuitry and attentional network hypotheses, and prior imaging studies. DESIGN: Case-control study. SETTING: Academic medical center. PARTICIPANTS: Fifteen male subjects with ADHD without comorbid diagnoses (aged 12.4 +/- 3.4 years) and 15 male normal controls (aged 14.4 +/- 3.4), group-matched for age, IQ, and handedness. MAIN OUTCOME MEASURES: Global and hemispheric regional volumes (in cm3) of cerebral hemispheres, cortex, white matter, ventricles, caudate, lenticulate, central gray nuclei, insula, amygdala, and hippocampus. RESULTS: Despite similar hemispheric volumes, ADHD subjects had smaller volumes of (1) left total caudate and caudate head (p < 0.04), with reversed asymmetry (p < 0.03); (2) right anterior-superior (frontal) region en bloc (p < 0.03) and white matter (p < 0.01); (3) bilateral anterior-inferior region en bloc (p < 0.04); and (4) bilateral retrocallosal (parietal-occipital) region white matter (p < 0.03). Possible structural correlates of ADHD response to stimulants were noted in an exploratory analysis, with the smallest and symmetric caudate, and smallest left anterior-superior cortex volumes found in the responders, but reversed caudate asymmetry and the smallest retrocallosal white matter volumes noted in the nonresponders. CONCLUSIONS: This study is the first to report localized hemispheric structural anomalies in ADHD, which are concordant with theoretical models of abnormal frontal-striatal and parietal function, and with possible differing morphologic substrates of response to stimulant medication.

Prediction of group membership in developmental dyslexia, attention deficit hyperactivity disorder, and normal controls using brain morphometric analysis of magnetic resonance imaging.

This study explored the utility of using selected brain morphometric indices for predicting group membership for children with developmental dyslexia (n = 10), attention deficit hyperactivity disorder: combined type (n = 10), and a control group (n = 10). Subjects ranged in age from 6.1 to 16 years (M = 10.5 years, SD = 2.8). None of the subjects were diagnosed with mental retardation, nor did any of the subjects have a history of seizure disorder, head trauma, or other neurodevelopmental disorders. WISC-R Full Scale IQ ranged from 87 to 149 (M = 114.4, SD = 13.3) with no significant differences noted between the clinical groups. Six brain regions, as defined by MRI scans, were selected a priori for inclusion in a discriminant function analysis. Reliability of the morphometric measures ranged from 0.94 to 0.97. One significant discriminant function was generated which accounted for about 61.4% of the variance between groups. The predictive discriminant analysis using the six morphometric MRI measurements classified subjects with an overall 60% accuracy with the best accuracy found for the developmental dyslexia and control groups. A predictive discriminant analysis incorporating these six morphometric measures as well as chronological age and FSIQ increased the overall classification accuracy to 87% with the misclassfied subjects assigned to one of the clinical groups. The findings support the presumed neurological basis for many neurodevelopmental disorders. They also underline the importance of including brain morphometric measures in predictive models.

Integrating neurobiological, psychosocial, and behavioral paradigms: a transactional model for the study of ADHD.

This article reviews neurobiological, psychological, behavioral, and social interactional paradigms for the study of attention deficit hyperactivity disorders (ADHD). An integrated model for the assessment, diagnosis, and treatment of ADHD will be explored. Because the controversy among these approaches remains vigorous today, a review of the literature provides a context for why these theories should be integrated. Whereas it will be argued that each paradigm offers unique information that adds significantly to advancing a science of childhood disorders, an integrated model provides a vehicle necessary for the study and understanding of ADHD.

Anomic aphasia in childhood.

Documented cases of anomic aphasia in childhood are rare, due to their low prevalence and relatively subtle clinical manifestations and because of probable referral bias. Such cases are important, however, because they may shed light on the nature of lesions that produce anomia in children and because they may contribute to our understanding of brain-behavior relations in children. This case involves a 10-year-old girl who experienced a left temporoparietal hematoma. Recovery over an 8-month period was good, with near normal verbal-expressive (Verbal IQ = 86) and normal perceptual-motor abilities (Performance IQ = 100). Reading, spelling, and repetition were preserved. Spontaneous speech was good, although initially circumlocutory and marked by obvious word-finding difficulty. Consistent with reports involving adults, there was significant disturbance in naming characterized by frequent literal and semantic paraphasias. Although she had significant difficulty on confrontational naming, she could accurately spell and read the name of the objects presented to her. This case is discussed relative to localization of lesions producing anomic aphasia and regarding the course of recovery in childhood.

Attention-deficit hyperactivity disorder: magnetic resonance imaging morphometric analysis of the corpus callosum.

OBJECTIVE: The following study seeks to document possible differences in corpus callosal area and shape between children with attention-deficit hyperactivity disorder (ADHD) and controls. METHODS: Fifteen carefully diagnosed right-handed male subjects with ADHD with overactivity symptomatology were compared to 15 right-handed male control subjects. The corpus callosum was divided into seven areas on the midsagittal slice of a magnetic resonance image with shape analysis also conducted. RESULTS: An exploratory shape analysis showed no significant differences in shape between the groups. No group differences were found in the area, length, or anterior regions of the corpus callosum. The ADHD subjects were found to have significantly smaller posterior corpus callosum regions than the control group, with the splenium accounting for most of the variance between the groups. CONCLUSIONS: The splenial area of the corpus callosum is smaller in children with ADHD than in a sample of normally developing children. These smaller areas may relate to commonly seen sustained attention deficits which in turn negatively impact on the development of more advanced levels of attention such as self-regulation. Further study of the regions surrounding the splenial area is suggested to determine whether they are correlated in size to the smaller corpus callosum.

Comorbidity between ADDH and learning disability: a review and report in a clinically referred sample.

A widely variable overlap ranging from 10 to 92% has been reported in the literature between attention deficit disorder with hyperactivity (ADDH) and learning disability (LD), most likely a result of inconsistencies in the criteria used to define LD in different studies. The following study seeks to more accurately determine rates of LD in clinically referred children. Using a psychometrically reliable methodological approach, it was expected that the rate of LD in ADDH children would be far more modest than previously reported. Subjects were referred children with ADDH (N = 60), children with academic problems (N = 30), and normal controls (N = 36) of both sexes with available psychological and achievement testing. Using a liberal definition of LD, significant differences were found between the groups (ADDH = 38% versus academic problems = 43% versus normals = 8%; p = 0.002). In contrast, more modest rates were found using two more stringent methods of assessment (23 and 17%; 10 and 3%; 2 and 0%, respectively; p = 0.02). Arithmetic-based LD appears to be equally identified by both stringent methods, whereas the liberal definition overidentified children in all three groups. These findings show that a liberal definition of LD overidentifies LD not only in ADDH children but also in normal children.

Corpus callosum morphology in attention deficit-hyperactivity disorder: morphometric analysis of MRI.

Although behavioral evidence provides support for the notion that attention deficit-hyperactivity disorder (ADHD) is related to central nervous system dysfunction, there is little direct evidence to reveal which neurometabolic systems or brain structures are involved. Recent magnetic resonance imaging (MRI) studies suggest that, compared to nondisabled controls, ADHD children may have a smaller right frontal region. Morphometric analysis of MRI scans was used in this exploratory study to determine whether correlated regional variation might exist in the corpus callosum of children with ADHD. While all MRI scans were judged to be clinically normal, morphometric analysis revealed that, compared to nondisabled controls, ADHD children had a smaller corpus callosum, particularly in the region of the genu and splenium, and in the area just anterior to the splenium. Interhemispheric fibers in these regions interconnect the left and right frontal, occipital, parietal, and posterior temporal regions. These results suggest that subtle differences may exist in the brains of children with ADHD and that deviations in normal corticogenesis may underlie the behavioral manifestations of this disorder.

Attention deficit disorder without hyperactivity: a distinct behavioral and neurocognitive syndrome.

This study examined the issue as to whether or not children carefully diagnosed as having either attention deficit disorder with hyperactivity (ADDH) or without hyperactivity (ADDnoH) could be distinguished on selected cognitive, academic, rapid naming, and behavioral measures. Employing a previously validated multimodal, multi-informant diagnostic process that results in reliable clinical diagnoses, 10 ADDH and 10 ADDnoH children were examined. While no significant differences in cognitive ability were noted between groups, significant underachievement was found in the children diagnosed as ADDnoH, particularly in mathematics achievement. The ADDnoH children were also significantly slower on rapid naming tasks than the ADDH children. Further, 60% of the ADDnoH children had a codiagnosis of a developmental reading or arithmetic disorder while none of the ADDH children received such a codiagnosis. Conversely, 40% of the ADDH children had a codiagnosis of conduct disorder and were rated by their parent as significantly more motorically active, impulsive, and deviant in the demonstration of age-appropriate social skills. These findings are discussed as they relate to the notion that children with attention deficit disorder may suffer from a right hemispheric syndrome.

Brain morphology in developmental dyslexia and attention deficit disorder/hyperactivity.

This study examined the specificity of deviations in patterns of normal brain asymmetry on the magnetic resonance imaging scans of 10 dyslexic, 10 attention deficit disorder/hyperactivity (ADD/H), and 10 normal age- and sex-matched control children. Reliabilities of region of interest measurements for left and right anterior and posterior width and area, length of the bilateral insular region, and length of the bilateral planum temporale were excellent. Both the dyslexic and ADD/H children had significantly smaller right anterior-width measurements than did normal subjects. The dyslexics also had a bilaterally smaller insular region and significantly smaller left planum temporale than did the normal subjects. Seventy percent of the normal and ADD/H children had the expected left greater than right pattern of plana asymmetry, while only 10% of the dyslexic children did. The very significant increase in the incidence of plana symmetry or reversed asymmetry seems unique to dyslexia and may be related to deviations in normal patterns of corticogenesis. Although significantly more dyslexic children were left-handed than were the normal and ADD/H children, no significant relationship emerged between left-handedness, incidence of allergies or familial autoimmune disease, and variability in indexes of brain morphologic findings.

Right hemispheric dysfunction in nonverbal learning disabilities: social, academic, and adaptive functioning in adults and children.

This review addresses recent research on social and nonverbal learning disabilities. Involvement of right hemispheric dysfunction in these disabilities has been hypothesized, as studies with adults have suggested that documented right hemisphere damage may lead to deficits in social skills, prosody, spatial orientation, problem solving, and recognition of nonverbal cues. Studies of children purported to evidence nonverbal learning disabilities are reviewed and compared with the results from studies of adults with right hemisphere damage. Specific subtypes of nonverbal learning disabilities are reviewed, including the nonverbal perceptual-organization-output subtype, Asperger's Syndrome, Developmental Gerstmann Syndrome, left hemisyndrome, right hemisphere syndrome, and right parietal lobe syndrome. Finally, implications and future research needs are addressed. The need for a diagnostic nosology and improved and validated intervention techniques is stressed as is early identification of these types of specific nonverbal learning disabilities.

Dyslexia and brain morphology.

Although the neurological basis of dyslexia has long been assumed, little direct evidence documents a relation between deviations in brain morphology and behavioral correlates of dyslexia. This article reviews two sources of evidence. Results of CT/MRI studies suggest that in the brains of dyslexics there is an increased incidence of symmetry in the region of the planum temporale and parietooccipital cortex that may be associated with language delay and handedness. Postmortem/cytoarchitectonic studies document symmetry of the plana, provide evidence of thalamic involvement, and chart widely distributed focal dysplasias preferentially involving the left frontal, left temporal, and right frontal regions. Methodological deficiencies characterize this literature, however, particularly regarding the diagnosis of dyslexia, appraisal of handedness and neurolinguistic deficits, and a failure to provide evidence that this pattern of involvement is unique to the dyslexic syndrome. These findings are discussed as they relate to neurobiological theory.

Dyslexia and neurodevelopmental pathology: relationships to cognition, intelligence, and reading skill acquisition.

This article addresses the neuroimaging (CT/MRI), electrophysiological (ERP/EEG), and postmortem evidence as to the neurological basis of dyslexia and discusses why these sources of evidence yield what appear to be inconsistent findings. It is concluded that what appear to be inconsistencies may relate in part to limitations of these investigative technologies. Then, important correlates of reading ability and disability are discussed in a developmental-neuropsychological context, and recommendations are made for research serving to further integrate cognitive and neurological paradigms. Of particular importance, inconsistencies between the results revealed through neuroimaging, electrophysiological, and postmortem studies, on the one hand, and neurolinguistic theory, on the other, must be addressed. Articulating the neurometabolic role-and particularly the nature of the behavioral correlates of the thalamus, supplementary motor area, and frontal cortex-in regard to bihemispheric mechanisms related to reading in developmental dyslexia should be a priority in future research.