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 Tourette's 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+ADHD, and TS +/- 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.

Relationship between T2-weighted hyperintensities (unidentified bright objects) and lower IQs in children with neurofibromatosis-1.

To address the controversy regarding the relationship between cognitive impairment (lowering of IQ) and magnetic resonance imaging (MRI) characteristics (T2-weighted hyperintensities or unidentified bright objects [UBOs]) in children with neurofibromatosis-1 (NF-1), we used a pairwise NF-1/ sibling design; we set out to predict the lowering of IQ in each child with NF-1 as a discrepancy from the IQ of an unaffected sibling (D-SIQ). Our multiple regression model included the age of the child with NF-1, familial or sporadic nature of the NF-1, number of locations in the child's brain occupied by T2-weighted hyperintensities (UBOs), and the volumetric percentage of brain tissue occupied by T2-weighted hyperintensities (UBOs). Only the number of locations occupied by UBOs accounted for IQ lowering (D-SIQ) in children with NF-1 (42% of the variance in D-SIQ). This is the first report to confirm that a continuum of lowered IQs in NF-1-affected children exists in relation to the distribution of UBOs (range 0-7), not just presence (vs. absence) of any UBOs.

Language-based cognitive functioning in parents of offspring with ADHD comorbid for Tourette syndrome or learning disabilities.

The parents of children diagnosed with attention deficit hyperactivity disorder (ADHD) were examined for characteristics symptomatic of 2 comorbidities (Co) within their offspring with ADHD: Tourette syndrome (TS) and language-based learning disabilities (LD). A 2 x 2 multivariate analysis of variance design was used; the parents were divided according to whether the offspring with ADHD had TS (Co-TS) or not (No Co-TS) and whether offspring had LD (Co-LD) or not (No Co-LD). Parents (86 mothers and 70 fathers) were administered the short form of the Wechsler Adult Intelligence Scale--Revised (WAIS-R; Wechsler, 1981), subtests of the Woodcock-Johnson Cognitive and Achievement Batteries (Woodcock & Johnson, 1989), and word fluency (semantic and letter; Benton & Hamsher, 1989; Wiig & Semel, 1987). The fathers of offspring with Co-TS were more likely to be diagnosed with LD and had lower WAIS-R Vocabulary, Arithmetic, and Picture Arrangement scores. In addition, when the WAIS-R full scale IQ was used as a covariate, these fathers had lower Woodcock-Johnson Oral Vocabulary, Spelling, and Reading scores (as measured by Letter-Word Identification). The mothers of children with Co-TS had lower WAIS-R Vocabulary scores. Parents of the children with No Co-TS showed a higher proportion of error patterns on the word fluency tasks involving repetitions and rule breaks. The findings show that it was the parents of the children with Co-TS, not the parents of the children with Co-LD, who showed language-based learning problems. In separate discriminant analyses for the fathers and mothers, when the aforementioned significant parental measures were used as predictors, 81% of offspring with Co-TS were correctly classified as having a diagnosis of TS, solely on the basis of characteristics in their parents.

Learning difficulties in children with Tourette syndrome.

Children with Tourette syndrome have been shown to have a variety of school difficulties. These difficulties, however, may be related to a single factor or to a combination of problems including tic severity, the use of tic-suppressing medication, executive dysfunction, a direct consequence of having a stigmatizing disorder, and coexisting attention deficit disorder, hyperactivity, obsessive-compulsive behaviors, or other psychopathologies. The goals for the treating health care team are to identify the presence of these factors, to clarify which are the major source of distress, and to develop an individualized multimodal treatment program. The prompt diagnosis of underlying problems and the prescription of appropriate therapy can play an important role in preventing school failure in children with Tourette syndrome.

Gender study of neuropsychological and neuromotor function in children with Tourette syndrome with and without attention-deficit hyperactivity disorder.

Neuropsychological and neuromotor functions were compared between boys and girls with Tourette syndrome (TS only), attention-deficit hyperactivity disorder (ADHD only), Tourette syndrome with ADHD (TS+ADHD), and a comparison group, in an age (mean = 10 years) and IQ (Wechsler Full-Scale mean = 111) matched sample (n = 116). There were no timed-task neuromotor differences among the groups. Analyses of variance revealed a group x gender interaction for Letter Word Fluency and the Rapid Automatized Naming test. Girls with ADHD only were faster than boys on both tasks. When data for girls only were analyzed, girls with Tourette syndrome with ADHD had the greatest variability of reaction time on the Test of Variables of Attention, and were slowest on Letter Word Fluency. Girls with TS only were slower than girls in the other three groups on Letter Word Fluency. Poor Letter Word Fluency is explained as a linguistic executive dysfunction involving speed and efficiency of memory search in this bright group of girls with Tourette syndrome, not otherwise at risk for linguistic difficulties.

Neuromotor functioning in children with Tourette syndrome with and without attention deficit hyperactivity disorder.

Neuromotor function was assessed in 94 children of normal intelligence with Tourette syndrome, Tourette syndrome and attention-deficit hyperactivity disorder (ADHD), or ADHD only, using the Physical and Neurological Examination of Subtle Signs (PANESS). Time to complete six motor movements was analyzed separately by side (left and right) and complexity (simple and patterned). All groups performed faster on their preferred, dominant side. Although all groups took longer to complete patterned versus simple movements, the group with ADHD had a larger discrepancy for complexity than the other two groups. The speed for simple and patterned tasks was at or faster than age expectations for 54% of tasks in the group with Tourette syndrome but only 15% of tasks in the other two groups. More children in the group with Tourette syndrome (76%) than the groups with Tourette syndrome with ADHD (54%) or ADHD (54%) or ADHD only (65%) performed movements within normal time limits for age. Findings suggest that Tourette syndrome is not associated with motor slowing.

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.

Executive function in children with Tourette syndrome and/or attention deficit hyperactivity disorder.

Tourette Syndrome (TS) in children is associated with various neurobehavioral disorders including attention deficit hyperactivity disorder (ADHD). Children with TS and ADHD show some difficulties with neuropsychological tasks, but we do not know if children with TS alone have neuropsychological deficits. To assess specific cognitive differences among children with TS and/or ADHD, we administered a battery of neuropsychological tests, including 10 tasks related to executive function (EF), to 10 children with TS-only, 48 with ADHD-only, and 32 with TS + ADHD. Children in all groups could not efficiently produce output on a timed continuous performance task [Test of Variables of Attention (TOVA) mean reaction time and reaction time variability]. Children with TS-only appeared to have fewer EF impairments and significantly higher perceptual organization scores than children with TS + ADHD or ADHD-only. These findings suggest that deficiencies in choice reaction time and consistency of timed responses are common to all three groups, but children with TS-only have relatively less EF impairment than children with TS + ADHD or ADHD-only.