ELECTROPHYSIOLOGICAL AND NEUROPSYCHOLOGICAL INDEXES OF COGNITIVE PROCESSING DEFICITS IN TURNER SYNDROME

Turner Syndrome (TS) is a naturally occurring genetic anomaly in which perinatal hormonal exposure is altered because of a missing X chromosome. In addition, TS females, as a group, have been shown to have significant deficits in visuospatial skills. Such skills have been purported to be largely a function of areas of the right cerebral cortex. In this study, electrophysiological measures were obtained along with measures of intellectual abilities and neuropsychological functioning in a group of TS girls between 8 and 14 years in order to explore the relationship between cortical organization and specific cognitive abilities in these subjects. Measures of psychosocial status were also obtained. Auditory evoked potentials (AEPs) to probe tones were used to detect differences in electrocortical activity between homologous left and right areas of the brain during the performance of visual-spatial tasks. Spatial and verbal abilities were measured using the Wechsler Intelligence Scale for Children-Revised, a subset of tests from the Halstead-Reitan Neuropsychological Battery and other tests of neurocognitive functioning. Although there was a heterogeneous pattern of neurocognitive test scores among subjects, they uniformly showed poor performance on measures specific to spatial skills. There was also a significant relationship between the pattern of evoked potential amplitude asymmetry obtained during visual-spatial task performance and the discrepancy between spatial and verbal abilities in each subject.