Differentiation of attention-deficit/hyperactivity disorder subtypes: application of a neuropsychological model of attention.

This study represents a neuropsychological attempt to differentiate subtypes of Attention Deficit/Hyperactivity Disorder (ADHD). Participants (N = 80) were grouped by gender and ADHD subtype-Predominantly Inattentive (ADHD-I) versus Combined (ADHD-C)-resulting in four age-matched groups. Statistical analysis revealed significant differences in performance on selective attention tasks for those with ADHD-I and those with ADHD-C. Relative to their counterparts without hyperactivity, participants with ADHD-C earned disproportionately lower scores on tasks associated with executive control. Both subgroups with ADHD-I and ADHD-C demonstrated significant difficulty on some tasks assessing complex mental operations relative to age-standardized normative data. Discriminant analysis revealed that a combination of five neuropsychological measures discriminated between the ADHD-I and ADHD-C subgroups with 80% accuracy. Results provide support for the notion of the Predominantly Inattentive and Combined subtype classifications as defined by the Diagnostic and Statistical Manual of Mental Disorders, 4th Edition (American Psychiatric Association, 1994). Further, findings from this study lend preliminary support for the utility of a neurophysiologically sensitive model of attention in the differentiation of these subtypes.

Parental report of sleep problems in children with attentional and learning disorders.

This study examined whether parents of children diagnosed with neurodevelopmental disorders (n = 79) report greater sleep-related problems in their offspring than do parents of normal community-based children (n = 86) on a research questionnaire developed to assess sleep and breathing problems, sleepiness, and behavioral problems. Clinical subgroups included: attention deficit/hyperactivity disorder (ADHD) (n = 43), learning disabilities (LD) (n = 11), and combined ADHD/LD (n = 25). Analyses revealed that parents of children with neurodevelopmental disorders report greater problems along all three dimensions than parents of normal control children. Sleep-related difficulties were reported at the same frequency across all three clinical subgroups. No significant difference between clinical and control groups was noted, however, in the reported length of sleep on weeknights. These preliminary findings suggest that sleep-related problems need to be routinely reviewed as part of the clinical evaluation of neurodevelopmental problems, because they may contribute to and/or exacerbate the behavioral manifestation of these disorders.

Psychosocial adjustment and educational outcome in adolescents with a childhood diagnosis of attention deficit disorder.

OBJECTIVE: To conduct a retrospective follow-up study of psychosocial adjustment and educational outcome in adolescents with a childhood diagnosis of attention deficit disorder (ADD) and a group of clinical controls. METHODS: Groups included male and female subjects aged 14 to 18 years at time of follow-up with childhood diagnosis of ADD (cases; n = 48) versus other neurodevelopmental disorders (clinical controls; n = 37). Cases were also subdivided based on the presence of conduct disorder (CD) at follow-up. All groups were compared on measures of academic performance, self-esteem, behavior, alcohol and substance use, and adaptive functioning. RESULTS: Cases had significantly lower academic performance and poorer social, emotional, and adaptive functioning than clinical controls. Cases with CD had significantly lower academic performance, greater externalizing behaviors and emotional difficulties, and lower adaptive functioning than cases without CD. Cases with CD fared worse than clinical controls on self-report measures of behavior, socialization skills, and alcohol and substance use. CONCLUSIONS: These academic and psychosocial problems in adolescents with a childhood diagnosis of ADD suggest potential long-term ramifications for vocational and psychological functioning into adulthood. In addition, the presence of CD in some of these cases during adolescence appears to further increase the risk for maladaptive outcome.

Antineuronal antibodies: tics and obsessive-compulsive symptoms.

Fluorescent serum antibody determinations were used to examine whether children with obsessive-compulsive disorder (OCD) or less pervasive obsessive-compulsive symptoms (OCS) would show evidence of caudate nucleus involvement. Recent studies of OCD have documented smaller caudate nucleus volumes in adults with childhood onset than in normal controls, but not smaller putamen volumes. Thirty-eight cases were recruited from an ongoing study of childhood neurodevelopmental disorders. Nineteen samples from clinical cases had existing or previously documented OCS and attention-deficit hyperactivity disorder (ADHD) with or without concomitant tics. Nineteen additional clinical controls with ADHD, but without tics or OCS, were identified. The sera from clinical cases showed antibodies directed against caudate [odds ratio (OR) 2.0; 95% confidence interval (CI) 1.0 to 4.1], putamen (OR 3.0; 95% CI 1.5 to 5.8), or both (OR 2.9; 95% CI 1.58 to 5.7) at a rate significantly higher than that of clinical controls, providing evidence of basal ganglia involvement in OCS. These preliminary data do not support a differential effect against caudate compared to putamen for these children, but suggest a more generalized central nervous system response.

Antineuronal antibodies in movement disorders.

OBJECTIVE: To determine whether children with recent onset of movement disorders (Tourette syndrome, motor and/or vocal tics, chorea, choreiform movements) show evidence of serological antibodies directed against the human central nervous system as previously documented in research on Sydenham's chorea. METHODS: Serum antibodies against previously frozen human caudate nucleus sections were analyzed using a blinded design and immunofluorescent staining methods. The sera of one group of 50 children referred for evaluation of attention deficit hyperactivity disorder, behavior disorders, and learning disabilities (24 with an associated movement disorder) seen between June 1989 and June 1990 were analyzed. The study was replicated in 33 children (21 with an associated movement disorder) seen between June 1990 and November 1990. RESULTS: In the original sample of 50 children, those with movement disorders were significantly more likely to have evidence of antineuronal antibodies than were those without movement disorders (odds ratio [OR] 4.80, 95% confidence interval [CI] 2.58 to 8.93). Results of the replication were similar (OR 6.00, 95% CI 2.56 to 14.03). For the total group, the OR was 5.50, (95% CI 3.54 to 8.99), which is highly significant. The percentage of children with a movement disorder whose sera were strongly positive for antineuronal antibodies (44%) was very similar to that previously found in children with Sydenham's chorea (46%). Children with movement disorders were also more likely than children without movement disorders to have at least one antistreptococcal titer elevated. CONCLUSIONS: The data strongly suggest an association between antecedent group A beta-hemolytic streptococcal infection as inferred from elevated antistreptococcal titers and the presence of serum antineuronal antibodies, which may, in turn, be linked to childhood movement disorders.

Speech lateralization in deaf populations: evidence for a developmental critical period.

Cerebral lateralization for speech in right-handed normal hearing and deaf adolescents was assessed using the dual-task paradigm. Subjects with normal hearing and deafness acquired after 3 years of age displayed left hemispheric dominance for speech production, whereas both congenitally deaf and those with an early acquired deafness (onset 6-36 months) showed atypical, anomalous cerebral representation. These results suggest the presence of a developmental critical period for cerebral lateralization during which exposure to adequate environmental stimulation may be needed to activate left hemispheric dominance for speech.

The effects of linguistic experience on cerebral lateralization for speech production in normal hearing and deaf adolescents.

The cerebral lateralization patterns for speech production in 57 normal hearing and deaf adolescents were studied using the dual-task paradigm. Normal hearing subjects showed left hemispheric dominance for speech production, whereas both the congenitally deaf and those with early acquired deafness showed atypical cerebral representation for speech production. Deaf subjects whose hearing loss occurred after 2 years of age displayed a pattern of mixed cerebral dominance related to complexity of speech production or task difficulty. These results are interpreted as evidence for a relationship between linguistic/cognitive stage of development and the ontogenesis of cerebral lateralization. A parallel lateralization hypothesis of left cerebral dominance for speech production is offered.

Cerebral lateralization for speech in deaf and normal children.

The cerebral lateralization pattern for speech production in normal hearing and congenitally deaf children was studied using the dual-task paradigm. Performance under the verbal task conditions showed predicted left hemispheric dominance for speech production in the normal hearing children. No developmental trends in asymmetry were found, suggesting that speech lateralization is present in normal 3-year-old children. These data support the developmental invariance hypothesis of cerebral organization. Deaf children showed more symmetrical patterns of cerebral control for speech production. No developmental trends in functional brain organization were observed among prepubescent deaf children.