Thomas L. Baumgardner

Corpus callosum morphology in children with Tourette syndrome and attention deficit hyperactivity disorder

The aim of this study was to investigate the morphology of the corpus callosum (CC) in Tourette syndrome (TS) and attention deficit hyperactivity disorder (ADHD) to determine whether these conditions affect distinct regional differences.Seventy-seven children and adolescents, aged 6 to 16 years, comprised the four research groups--16 patients with TS, 21 patients with TS plus ADHD, 13 patients with ADHD, and 27 unaffected control subjects. A semiautomated, computer-assisted procedure was used to measure the total area, five subregions, centerline length, perimeter, and bending angle of the CC. MRI data were analyzed using several statistical methods, primarily two-tailed analysis of variance to test the effects of TS and ADHD status, while controlling for the influence of age, gender, and total intracranial area (an estimate of brain size). TS was associated with significant increases in the area of four of five subdivisions, the total area, and the perimeter of the CC. ADHD was associated with a significant decrease in the area of the rostral body. There were no interactions between TS and ADHD factors. These findings suggest that the area of the CC is larger in children with TS, and that this difference is independent of age, handedness, intracranial area, and the diagnosis of ADHD. Our findings support hypotheses that the neurobiologic mechanisms in TS and ADHD involve frontal/subcortical circuits. NEUROLOGY 1996;47: 477-482

Neuropsychological status of children with Tourette's syndrome with and without attention deficit hyperactivity disorder

To determine the frequency of learning disabilities (LD) and describe the neuropsychological profile of children with Tourettes syndrome (TS) with and without attention deficit hyperactivity disorder (ADHD), we analyzed psychosocial, psychoeducational, and neuropsychological data from 65 children between the ages of 6 and 14 years selected from a larger study of LD.Three groups were formed: TS only, TS plus ADHD, and TS plus/minus ADHD. The third group was composed of children whose ADHD status was not as strongly confirmed by the three different instruments used for ADHD diagnosis. From other (non-TS) research projects in the Center, a comparison group of 27 unaffected siblings who had no diagnosis of ADHD was formed. All children were unmedicated at the time of assessment and had the full set of data available for analysis. LDs were present in 23% of the total TS sample, but LD was not present in the TS-only group. All TS groups had scores at or below 1 SD from the mean on measures of choice reaction time, but the TS-only group was significantly poorer on a measure of executive function (letter word fluency). We discuss the implication of the finding in the TS-only group in terms of a slowing of linguistic productivity. NEUROLOGY 1996;46: 958-965

Autistic Behaviors Among Girls with Fragile X Syndrome

Reports of autistic behaviors were examined for 30 school-age girls with fragile X (fraX) and 31 age- and IQ-matched controls through a structured interview administered to each girls parent(s). IQ scores were obtained for each participant; anxiety, neuroanatomical, and molecular-genetic data were derived for girls with fraX. Girls with fraX had significantly more autistic behaviors than controls. These behaviors were qualitatively similar to those reported for boys with fraX, but were not correlated with IQ. Anxiety in girls with fraX was positively correlated with abnormal social and communication behaviors; posterior cerebellar vermis area was negatively correlated with measures of communication and stereotypic/restricted behaviors. Severity of stereotypic/restricted behaviors was negatively correlated with the prevalence of active non-fraX chromosomes. Thus anxiety and posterior cerebellar area measures had distinct associations with subsets of autistic behaviors; these associations may have important implications for understanding the neurobiology of autism.

Social Functioning among Girls with Fragile X or Turner Syndrome and Their Sisters.

Social behaviors among two genetically homogeneous groups—girls with fragile X (fraX) or Turner syndrome (TS)—were examined to address the role of family environment versus biological determinants of social dysfunction in girls with these disorders. Using a sibling pair design, girls with fraX or TS were compared with their own sisters on measures of IQ and social functioning. The 8 girls with fraX and the 9 girls with TS had lower FSIQ scores and higher ratings of social and attention problems relative to their own sisters. Girls with fraX also had higher ratings of withdrawn behaviors, relative to their own sisters. The unaffected sisters were not rated as demonstrating any difficulties in these areas, relative to controls. Correlations between problem ratings and FSIQ were not statistically significant. Although these preliminary findings do not indicate a lack of familial impact on social development in girls with either disorder, the results provide preliminary evidence that social dysfunction reported for girls with fraX or TS cannot be attributed solely, nor primarily, to global aspects of the family environment.

Cognitive, behavioral, and neuroanatomical assessment of two unrelated male children expressing FRAXE

Standardized cognitive, behavioral, and neuroanatomical data are presented on 2 unrelated boys with the FRAXE (FMR2) GCC expansion mutation. In the context of normal IQ, both boys had a history of developmental delay, including significant problems with communication, attention, and overactivity. Additionally, one child was diagnosed with autistic disorder. Data from these 2 cases are compared to analogous information from previous reports about individuals with the FRAXE or FRAXA (FMR1) mutation. These comparisons support the idea that FRAXE is associated with nonspecific developmental delay and possibly high-functioning autism.

An Analysis of Two Discrepancy-based Models and a Processing-Deficit Approach in Identifying Learning Disabilities

The incidence of learning disabilities (LD) in a research center sample of 107 boys and 103 girls between 6 and 12 years of age was calculated using Wechsler IQ and Woodcock-Johnson cluster scores in a regression model (REG) and a reliability model (REL). The REL method identified LD three times more often than the REG method, and all those identified by REG were also identified by REL. When stratified by IQ, REG and REL identified similar percentages in the lowest IQ group; however, REG identified at a lower rate as IQ increased. All 87 children identified with reading disabilities (both REL-RD and REG-RD) were weak to a similar extent on phonemic awareness. Comorbid elevated attention ratings were found in 62% of children with RD; 26% had elevated attention ratings but no linguistic processing deficits, and 21% had at least one linguistic processing deficit but no attentionally suspect rating.

Reading proficiency affects the construct validity of the stroop test interference score

Abstract The Stroop Color and Word Test is used clinically to assess a specific aspect of executive function, that is, selective inhibition. It requires a subject to inhibit an automatized reading response in favor of a less well-rehearsed, competing color-naming response. Although it is necessary to the interpretation of the Stroop effect observed during the interference condition, the degree of automaticity of the reading response is usually assumed in an adult population rather than being defined by any standard reading measures. The present investigation demonstrated that, in a group of 306 parents of children with learning disabilities, the best indicator of reading automaticity was not simply a standard word-reading score within normal limits, but rather a score that was at least equal to the individuals Full Scale IQ. In those subjects who satisfied this reading criterion, the Stroop Interference score correlated significantly with other measures of response inhibition. No such correlation was obs...