The relationship between continuous performance tasks and neuropsychological tests in children with attention-deficit hyperactivity disorder

Relationships Between Continuous Performance Task Scores and Other Cognitive Measures: Causality or Commonality?

Relationships among continuous performance test, IQ, achievement, and memory/learning scores were explored in a clinical sample of 1,280 children ( M age = 9.4 years, M grade = 3.9). Intercorrelations among CPT measures were significant, but modest. Correlations between CPT measures and IQ, achievement, and memory/learning scores were also significant, but again generally weak. The CPT number correct scores were more strongly related to other cognitive measures than were commission (i.e., responding to incorrect stimuli) scores. The breadth and extent of associations among the CPT measures and the various cognitive/academic tasks suggest that all, to some extent, require attention and inhibition. The importance of routinely assessing attention and disinhibition in psychological testing is discussed.

A comparison of phenylketonuria with attention deficit hyperactivity disorder: do markedly different aetiologies deliver common phenotypes?

Phenylketonuria (PKU) is a well-defined metabolic disorder arising from a mutation that disrupts phenylalanine metabolism and so produces a variety of neural changes indirectly. Severe cognitive impairment can be prevented by dietary treatment; however, residual symptoms may be reported. These residual symptoms appear to overlap a more prevalent childhood disorder: Attention Deficit/Hyperactivity Disorder (ADHD). However, the aetiology of ADHD is a vast contrast to PKU: it seems to arise from a complex combination of genes; and it has a substantial environmental component. We ask whether these two disorders result from two vastly different genotypes that converge on a specific core phenotype that includes similar dysfunctions of Gray's (Gray, 1982) Behavioural Inhibition System (BIS), coupled with other disorder-specific dysfunctions. If so, we believe comparison of the commonalities will allow greater understanding of the neuropsychology of both disorders. We review in detail the aetiology, treatment, neural pathology, cognitive deficits and electrophysiological abnormalities of PKU; and compare this with selected directly matching aspects of ADHD. The biochemical and neural pathologies of PKU and ADHD are quite distinct in their causes and detail; but they result in the disorder in the brain of large amino acid levels, dopamine and white matter that are very similar and could explain the overlap of symptoms within and between the PKU and ADHD spectra. The common deficits affect visual function, motor function, attention, working memory, planning, and inhibition. For each of PKU and ADHD separately, a subset of deficits has been attributed to a primary dysfunction of behavioural inhibition. In the case of ADHD (excluding the inattentive subtype) this has been proposed to involve a specific failure of the BIS; and we suggest that this is also true of PKU. This accounts for a substantial proportion of the parallels in the superficial symptoms of both disorders and we see this as linked to prefrontal, rather than more general, dysfunction of the BIS.

Multivariate genomewide linkage scan of neurocognitive traits and ADHD symptoms: suggestive linkage to 3q13

Family and twin studies suggest that a range of neurocognitive traits index the inherited liability to ADHD; however, the utility of such measures as endophenotypes in molecular genetic studies remains largely untested. The current article examined whether the inclusion of neurocognitive measures in a genomewide linkage analysis of ADHD could aid in identifying QTL linked to the behavioral symptoms of the condition. Data were from an affected sibling pair linkage study of DSM-IV ADHD conducted at Massachusetts General Hospital. The sample included 1,212 individuals from 271 families. ADHD symptoms were assessed with the K-SADS-E. The neurocognitive battery included Wechsler Intelligence Scales subtests, the Stroop, the Wisconsin Card Sorting Test (WCST), the Rey-Osterreith Complex Figure, a working memory CPT, the CVLT and WRAT-III subscales. Evidence for linkage was assessed using a simulation-based method that combines information from univariate analyses into the equivalent of a multivariate test. After correction for multiple trait testing, a region on chromosome 3q13 showed suggestive linkage to all neurocognitive traits examined and inattention symptoms of ADHD. The second highest peak occurred on 22q12 but showed linkage to a single subscale of the WCST. In univariate analysis, this region retained criteria for suggestive linkage to this measure after correction for multiple trait testing. Our primary findings raise the possibility that one or more genes on 3q13 influence neurocognitive functions and behavioral symptoms of inattention. Overall, these data support the utility of neurocognitive traits as ADHD endophenotypes, but also highlight their limited genetic overlap with the disorder.

Characteristics of the sensory-motor, verbal and cognitive abilities of preschool boys with attention deficit/hyperactivity disorder combined type

The purpose of this study is to clarify the characteristics of sensory-motor, verbal and cognitive abilities of preschool boys with attention-deficit/hyperactivity disorder (ADHD) in order to provide information for their treatment and education at preschool age by teachers and professionals. For this purpose, 46 Japanese boys with ADHD-combined type (ADHD-C) whose ages ranged from 45 to 72 months were examined using the Japanese version of the Miller Assessment for Preschoolers (JMAP), and were compared with 46 Japanese boys matched for age and gender in the normative samples that served as the standardizations for the JMAP. The results showed that the ADHD-C group was significantly lower than the normative sample group both on the Total score and on each Index score (P < 0.01) with the exception of the Non-verbal Index. In particular, the number of boys with ADHD-C scoring below the 5th percentile on the Foundation Index (i.e. fundamental sensory-motor tests) was the highest among all index scores. The ADHD-C group had significantly lower scores than the normative sample group in equilibrium, postural control, fine motor of hand and tongue, motor praxis, articulation, memory related to the comprehension of long sentences, and visual construction. Because fundamental sensory-motor abilities were notably lower in the ADHD-C group than in the normative sample group, it is suggested that preschool boys with ADHD-C should be examined and treated for sensory-motor disabilities.

Study of attentional processes in children with idiopathic epilepsy by Conners' Continuous Performance Test

Before starting antiepilepsy therapy (T1) and after 1 year (T2), 19 children (7 female) affected by focal or generalized idiopathic epilepsy were considered with the aim of studying attention performance. All of the children received a neurological examination and clinical interview, electroencephalography (EEG) in wakefulness or sleep, and a standardized computerized measure of attention (Conners' Continuous Performance Test). At T1, 21% of the patients showed a specific attention disorder, and their percentage rose to 42% after 1 year, despite complete control of seizures. The prognosis was strongly correlated with (1) the presence of active seizures for a period of over 6 months, (2) the persistence of specific interictal abnormalities on an electroencephalogram at T2, and (3) the presence of emotional and behavioral disorders at the diagnosis of epilepsy. Our results confirm that attention disorders are frequent in children with idiopathic epilepsy. The Conners' Continuous Performance Test has proven useful both for diagnosis and follow-up over time.

Relations between visual and auditory continuous performance tests in a clinical population: a descriptive study

Increased interest in auditory continuous performance tests (CPTs) exists despite the absence of a clear understanding about this procedure. The relation between auditory and visual CPTs and associations with IQ, achievement, and memory are evaluated in a referred sample of 634 children, ages 5.5 to 17.9. Age effects are found with CPT performance, regardless of modality. Total number correct or number of commissions correlations across tasks were greater than within-task number correct-number of commissions relations. The mean visual minus auditory correct difference score was 7.01; the mean commission difference score was -.85. Difference scores decreased with age and were not consistently related to other measures. Those with the lowest number correct on both CPTs (<25th percentile) were younger and had weaker short-term auditory memory and verbal learning skills; those falling in the problem quartile on commissions (>75th percentile) were younger and had poorer reading, verbal memory, and verbal learning. Total error scores (omissions + commissions) were inversely related to age. The auditory CPT has clinical utility, but other factors must be considered.

The Gordon Diagnostic System and WISC-III Freedom from Distractibility Index: validity in identifying clinic-referred children with and without ADHD

Gordon Diagnostic System and WISC-III scores for clinic-referred 6- to 16-yr.-olds (184 with ADHD Combined Type and 46 without ADHD) were analyzed to evaluate the combination of scores and cutpoints that maximized diagnostic accuracy. Using an "ADHD cutpoint" of IQ minus the GDS Composite score > or = 13, 87.8% of the children were correctly identified as having or not having ADHD. IQ minus Freedom from Distractibility > 0 yielded 73.5% accuracy. When the two meaures were combined to create new criteria (IQ minus GDS Composite > or = 13 or IQ minus Freedom from Distractibility > or = 11), diagnostic accuracy increased to 90.9% and negative predictive power improved substantially. Diagnostic agreement between the Gordon Diagnostic System and Freedom from Distractibility was 70%, suggesting that the two tests measure both similar and unique traits.

Arm movement control: differences between children with and without attention deficit hyperactivity disorder

The purpose of this study was to examine performance differences in arm movement control (programmingvs. "on-line" control) between children with and without attention deficit hyperactivity disorder (ADHD). Twenty children (10 with ADHD and 10 without ADHD) from the ages of 8 to 13 years participated in the study. On the surface of a digitizer, each participant completed three types of aiming arm movements (10 trials for each) and 10 baseline trials (without accuracy requirement). Multivariate analyses of variance with repeated measures were used to analyze the variables of reaction time, movement time, normalized jerk, intersegment-interval (ISI), and movement timing. Children with ADHD appeared to use "on-line " monitoring during the arm movement and did not perform the entire movement sequence as afunctional unit. They executed the arm movements more slowly, had greater variability in movement timing, and demonstrated longer ISIs than their counterparts. Children with ADHD had multiple peaks in the velocity profiles. Children withoutADHD, however, appeared to program their entire arm movements and execute the sequence as a unit. Their velocity profiles were symmetrical with a single peak, and the movement segments were temporally coordinated. Thesefindings suggested that cognitive functions are important resources for controlling rapid aiming arm movements. Children with ADHD might rely more on visual feedback during the movements, which resulted in slower and more variant movement outcomes than children who did not have ADHD.

Diagnostic efficiency of neuropsychological test scores for discriminating boys with and without attention deficit-hyperactivity disorder

A growing literature has documented group differences between boys with and without attention deficit-hyperactivity disorder (ADHD) on neuropsychological tests; however, whether or not such tests can discriminate individuals with ADHD from non-ADHD controls remains unclear. This study used conditional probability and receiver operating characteristic analyses to examine the efficiency of test-based diagnostic discriminations in a large sample of referred boys with and without ADHD. Single neuropsychological tests had limited discriminating ability at various cutoff scores. When multiple tests were used together, prediction of ADHD status improved but overall diagnostic efficiency remained limited. Diagnostic efficiency did not differ when medicated and nonmedicated index children were considered separately. Results suggest that children with ADHD show variable deficits on neuropsychological tests of attention and executive functions. Impairments on multiple neuropsychological tests are predictive of ADHD, but normal scores do not rule out the diagnosis. The prognostic implications of variable neuropsychological deficits in children with ADHD require further investigation.

Central auditory processing disorder in school-aged children: a critical review

The rationale to evaluate for central auditory processing disorder (CAPD) in school-aged children is based on the assumption that an auditory-specific perceptual deficit underlies many learning problems including specific reading and language disabilities. A fundamental issue in this area is whether convincing empirical evidence exists to validate this proposition. Herein, we consider the issue of modality specificity by examining the extent to which reading, language, and attention disorders in school-aged children involve perceptual dysfunctions limited to a single sensory modality. Difficulty in validating CAPD as a diagnostic label is due in large part to use of the unimodal inclusive framework, which has biased the diagnosis to favor sensitivity of test results over documenting the specificity of the deficit. Indeed, empirical research documenting modality-specific auditory-perceptual dysfunction in this population is scarce. Therefore, the existing literature on this topic has not clarified the "true" nature of the problem, and has left many questions about this disorder unanswered. It is argued that demonstrating modality specificity is one way to rule out supramodal disorders as explanations for observed dysfunction. Multimodal perceptual testing is one logical approach to help clarify this area of investigation.

Right hemisphere dysfunction in subjects with attention-deficit disorder with and without hyperactivity

The attention-deficit disorder, with and without hyperactivity, is associated with defective attention, response inhibition and, in attention-deficit disorder with hyperactivity, with motor restlessness. In adults, inattention, defective response inhibition, and impersistence are more commonly seen in right hemisphere lesions. In the present study, we investigate possible right hemisphere dysfunctions in attention-deficit disorder with hyperactivity and attention-deficit disorder without hyperactivity. The right hemisphere performance of 60 teenagers, 16 having attention-deficit disorder with hyperactivity, 9 having attention-deficit disorder without hyperactivity, and 35 controls, selected clinically (DSM-III) and experimentally (through Continuous Performance Test and Paced Auditory Addition Task), with normal IQ was assessed using a wide-ranging battery of visuospatial, visuoperceptive, and visuoconstructive functions (Benton's Line Orientation, Benton's Visual Retention, Raven's Progressive Matrices, Wechsler Adult Intelligence Scale [WAIS] Block-Design, Rey's Complex Figure). Teenagers with attention-deficit disorder with and without hyperactivity performed significantly worse than controls. Greater differences were found between subjects with attention-deficit disorder without hyperactivity and control than between subjects with attention-deficit disorder with hyperactivity and control subjects. Our results seem to be consistent with right-hemisphere dysfunction, especially in subjects with attention-deficit disorder without hyperactivity. Additionally, WAIS Block-Design and Benton's Line Orientation are the visuospatial tests with the highest discriminant power to differentiate between controls, subjects with attention-deficit disorder without hyperactivity, and subjects with attention-deficit disorder with hyperactivity.

Use of a verbal fluency measure in understanding and evaluating ADHD as an executive function disorder

A primary characteristic of Attention Deficit Hyperactivity Disorder (ADHD) is an inability to establish and maintain sustained attention, which is speculated to reflect frontal lobe involvement. The Knight Verbal Fluency measure was administered to 19 ADHD inpatient boys and to a cohort group of 7 children who were matched for mean age, psychiatric diagnosis (depression), treatment facility, and examiner but were without the diagnosis of ADHD. Analysis indicated that ADHD children performed significantly lower than expected and lower than the similar non-ADHD children. These findings lend support to the hypothesis that frontal lobe dysfunction is involved in attentional process disorders and suggests the potential clinical usefulness in the diagnostic screening of ADHD children of a simply administered measure amenable to interpretation of frontal lobe function.