Low cerebellar vermis volumes and impaired neuropsychologic performance in children treated for brain tumors and leukemia.

BACKGROUND AND PURPOSE: Injury of the cerebellar vermis may occur in children with brain malignancies. Because the vermis is involved in motor and cognitive functioning, the goal of this prospective longitudinal study was to evaluate treatment-related changes in vermal volumes and neuropsychologic performance in children receiving brain radiation of the cerebellum. MATERIALS AND METHODS: Ten patients (mean age, 11.6 years) and 10 healthy children (mean age, 12.1 years) were examined. Lobar vermal volumes and performance on neuropsychologic tests evaluating motor, visual, verbal, attention, memory, and executive functions were assessed at baseline and at 6-month follow-up visits. RESULTS: At baseline, lower mean vermal volumes and impaired performance on visual-spatial and fine-motor tasks were detected in patients. At 6-month follow-up, further decrease in vermal volumes was detected only in patients with medulloblastoma, who received the largest radiation doses to the entire vermis. The volume decrease was not associated with reduction in neuropsychologic performance compared with baseline. At 6-month follow-up, data from all subjects revealed an association between smaller vermal volumes and slower fine-motor speed and lower visual-spatial skills. CONCLUSIONS: Reduced brain-tissue volumes following radiation have been reported previously in pediatric patients. In this study, lower vermal volumes were detected even earlier, before radiation treatment was initiated or completed. Six months postradiation, vermal volume decreases detected in patients with medulloblastoma were not accompanied by declines in already poor neuropsychologic performance. In addition to radiation, the presence of brain malignancies and preradiation treatment may be important factors affecting cerebellar vermis tissue.

Proton MR spectroscopy correlates of frontal lobe function in healthy children.

BACKGROUND AND PURPOSE: Neuroimaging methods have been used to improve our understanding of the topographic organization of the brain. In our study, proton (1)H-MR spectroscopic imaging was used to evaluate frontal lobe function. The goal was to determine the relationship between neuropsychological measures of frontal lobe function and levels of a surrogate neuronal marker, N-acetylaspartate (NAA), in typically developing healthy children and adolescents. MATERIALS AND METHODS: Fifty-one healthy children (25 girls; 6.2-18.3 years of age; mean age, 12.3 +/- 3.6 years) were examined. All children completed a neuropsychological assessment including measures of attention, executive function, memory, language, and visual and motor skills. (1)H-MR spectroscopic imaging was performed by using a multisection spin-echo sequence at 1.5T. General linear model analysis of covariance was used to examine the relationship between the neuropsychological test scores and NAA/creatine (Cr) ratios, controlling for age and sex. RESULTS: A positive relationship between frontal lobe white matter NAA/Cr ratio and performance on 2 neuropsychological tests associated with frontal lobe function was detected. The Purdue Pegboard right-hand scores were higher with increasing NAA/Cr in the left frontal white matter (P = .047), and Stanford-Binet-IV "Bead Memory" scores improved with increasing NAA/Cr ratio in the right frontal white matter (P = .032). CONCLUSIONS: An association between frontal white matter NAA/Cr ratios and 1) measures of manual speed and dexterity, and 2) visual working memory was detected. Our data may provide a quantitative basis for assessment of frontal lobe impairments in disease states.

The effect of semantic cuing on CVLT performance in healthy participants. California Verbal Learning Test.

The California Verbal Learning Test (CVLT) is a widely used measure of verbal learning and memory; however, there is little empirical evidence about the effects of the administration procedure on the test results. The primary goal of this study was to examine the effect of the semantic cuing condition on subsequent free recall of the material. A secondary goal was to assess whether prior knowledge that the words on the list are drawn from four semantic categories would enhance recall. Participants were 154 young healthy adults. The results suggested that participants who received semantic cuing according to the standardized test instructions generated the same number of correct words on the delayed free recall of the list as did those who did not receive cuing. Cuing did, however, lead participants to use greater semantic clustering in their delayed recall of the list. Participants who were provided with information prior to learning about the semantic structure of the test did not show enhanced learning relative to those who did not receive this information. We conclude that semantic cuing on the CVLT does not substantially enhance delayed recall of the material in healthy participants, although it is quite possible that cuing would have a greater effect in patients who have poor semantic organizational skills.