Jeffrey H. Snow

Relationship of Head Circumference to Measures of School Performance

To study the possible relationship of head circumference (HC) to learning problems in children, a retrospective study was done, using records from 360 subjects who had been evaluated between the years 1976 and 1981. The data selected from the records included standardized academic test results, e.g., IQ scores and school achievement test results, as well as determinations of visual motor abilities. Statistical analyses demonstrated a positive correlation between full scale IQ (FSIQ) and HC (p < 0.005). The incidence of specific learning disabilities based on significant academic and achievement discrepancies was 54% in those with HC > 2 S.D., 39% for normocephalic, and 23% for those with HC < 2 S.D. Comparison of HC with results from the Wide Range Achievement Test (WRAT) demonstrated a tendency for those children with HC > 2 S.D. to have lower arithmetic scores when compared to results of children with normocephaly. Scores for spelling and reading ability did not demonstrate this tendency. The results of this study were found to be somewhat incongruous to those of previous studies of similar children. Further studies using large unselected populations are needed to better define the risks to learning that may be related to the extremes of head circumference.

Neuropsychological patterns of adolescents and young adults with spina bifida

The purpose of this study was to examine neuropsychological profiles for patients with spina bifida. The sample consisted of 37 subjects with spina bifida between the ages of 14 and 23. Each of the subjects was seen individually and administered the Halstead-Reitan Neuropsychological Test Battery as well as the appropriate Wechsler Intelligence Scale. Scores from the Halstead-Reitan were subjected to cluster analysis to formulate clinical subtypes. The results indicated a three group solution was most appropriate, which appeared to reflect a continuum of dysfunction. Implications for rehabilitation programming are discussed.

Learning Disability Subgroups Using Cluster Analysis of the WISC-R

The WISC-R was administered to a group of learning-disabled (LD) children and the results factor-analyzed. Factor scores were derived, and these variables were clustered using the hierarchical group procedure. The results indicated six distinct subgroups. The data are discussed in terms of cognitive patterns of subgroups of LD children.

Sex-specific association between infant diet and white matter integrity in 8-y-old children

Background:The American Academy of Pediatrics recommends breastfeeding, which is well known to promote cognitive and behavioral development. The evidence for why this occurs is not well understood.Methods:Fifty-six 7.5- to 8.5-y-old healthy children were breastfed (BF; n = 22, 10 males) or formula-fed (FF; n = 34, 16 males) as infants. All children were administered: the Reynolds Intellectual Assessment Scale (RIAS); the Clinical Evaluation of Language Fundamentals (CELF-4) tests; and magnetic resonance imaging of the brain. Diffusion tensor imaging (DTI) measured fractional anisotropy (FA) values were correlated with RIAS and CELF-4 scores.Results:DTI tract-based spatial statistics (TBSS) analyses showed multiple white matter regions in the left hemisphere with significantly higher FA (P < 0.05, corrected) values in BF than FF males, but no significant group differences in females. Males who were exclusively BF for at least 1 y appeared to have the greatest differences in FA. Mean FA values positively correlated with composite scores of RIAS (P = 0.03) and CELF-4 (P = 0.02).Conclusion:Breastfeeding during infancy was associated with better white matter development at 8 y of age in boys. A similar association was not observed in girls.

Mental Flexibility and Planning Skills in Children and Adolescents with Learning Disabilities

Mental flexibility (skill with shifting response set) and visual planning skills were examined with a group of 60 children and adolescents with learning disabilities. The sample consisted of 44 boys and 16 girls with an age range of 9 to 15. Scores from the Trail Making Test and the Wisconsin Card Sorting Test were cluster-analyzed and subgroups were formulated. The results of the cluster analysis indicated a two-group solution to be most appropriate. One subtype was clearly dysfunctional on the classifying variables, while the other subgroup approached average levels. The two subtypes were compared on measures of intellectual functions, academic skills, auditory memory, visual memory, visual-motor integration, motor speed, and tactile integration. Significance was found on several different tests. The results are discussed in terms of potential cortical dysfunction evidenced by the subgroups.

Visual-Spatial Orientation, Gaze Direction and Dichotic Listening Asymmetries

The effects of visual-spatial orientation on dichotic listening performance were investigated in a sample of right-handed male and female adults. The 30 pairs of dichotic stimuli (/ba/ka/da/ga/ta/pa) were presented under three conditions: eye gaze fixed toward center, eye gaze directed 20 degrees to the right, and eye gaze directed 20 degrees to the left of center. Although no effect for gender or order was evident, a significant right ear advantage was found under all conditions. However, over all dichotic listening accuracy was significantly increased when visual-spatial orientation was directed to the right or left side of space.

Differences between Mildly and more Severely Learning-Disabled Children on the Luria-Nebraska Neuropsychological Battery Children's Revision

The Luria-Nebraska Neuropsychological Battery (LNNB)-Childrens Revision was administered to 40 learning-disabled (LD) students. Twenty of the children were enrolled in self-contained classrooms (SC-LD) and 20 were in resource programs (R-LD). Significant differences (p < .01) were found between the groups on 4 of the 11 scales of LNNB-Children Revision, with the SC-LD group having more impaired performance. However, no significant differences were found between the groups on any scale when intelligence quotient and achievement scores were used as covariates. The results are discussed in terms of the utility of the battery with LD children.

A Multivariate Investigation of the Luria-Nebraska Neuropsychological Battery-Children's Revision with Learning-Disabled Children

This exploratory study examined the validity of the Luria-Nebraska Neuropsychological Battery-Childrens Revision with a group of 100 previously diagnosed learning-disabled children. All children were administered the Luria-Nebraska Neuropsychological Battery-Childrens Revision, Wechsler Intelligence Scale for Children-Revised (WISC-R), and Wide Range Achievement Test (WRAT). A Q-technique factor analysis using the subtests of the Luria-Nebraska-Childrens Revision as dependent measures yielded three distinct sub-groups. Follow-up MANOVAs between the three subgroups using the WISC-R IQ scores and WRAT subtest scores revealed that only two groups differed on one variable (WRAT Spelling). It was concluded that the subgroups identified by the Luria-Nebraska Neuropsychological Battery-Childrens Revision appear to be very similar and that the failure of this neuropsychological test battery to differentiate meaningful subgroups may relate to its poor construct validity.

Factor Structure of the Luria-Nebraska Neuropsychological Battery-Children's Revision with Learning-Disabled Children.

Abstract The factor structure of the Luria-Nebraska Neuropsychological Battery-Childrens Revision (LNNB-Childrens Revision) was examined in a population of learning-disabled children. The LNNB-Childrens Revision was administered to 100 learning-disabled children. Factor analysis and varimax rotation revealed three factors: a language-general intellectual factor, a reading-written expression factor, and a sensory-motor factor. The LNNB-Childrens Revision may be useful in differentiating learning-disabled children from normals. The three factors identified in this study provide some evidence for the factor validity of the LNNB-Childrens Revision and may be useful in clinical diagnosis.

Diffusion tensor imaging evaluation of white matter in adolescents with myelomeningocele and Chiari II malformation.

BackgroundMacrostructural abnormalities in cerebral white matter in patients with myelomeningocele are well known, but microstructural abnormalities are not as well studied.ObjectiveThe aim of this study was to evaluate cerebral white matter in adolescents with myelomeningocele using diffusion tensor imaging (DTI), and to investigate the effects of ventricular dilation and CSF shunt presence on white matter microstructure in these patients.Materials and methodsDTI and T1-weighted 3-D (T1-3-D) MRI were performed on nine adolescents with myelomeningocele and Chiari II malformation and nine age-matched controls. The fractional anisotropy (FA) and mean diffusivity (MD) values were measured and compared.ResultsSignificantly decreased FA and increased MD values were observed in most white matter regions and fibers in adolescents with myelomeningocele compared to controls. Further analysis in patients revealed significant changes in DTI parameters in hemispheres with enlarged lateral ventricles compared to those with normal ventricle size. In addition, a significant difference in FA values in the posterior limb of the internal capsule was found in the comparison of hemispheres in patients with or without CSF shunt catheters.ConclusionThis study revealed widespread microstructural abnormalities in white matter in adolescents with myelomeningocele and Chiari II malformation. Ventricular dilation may have additional effects on white matter microstructure in this patient population. CSF shunt diversion effects on white matter may be multifactorial and need further investigation.