IMPROVEMENT IN SPECIFIC ASPECTS OF NEUROCOGNITIVE PERFORMANCE IN CHILDREN AFTER RENAL TRANSPLANTATION

Abstract

691 Uremia diminishes neurocognitive function in children, limiting development and educational attainment. We utilized an extensive battery of neuropsychological tests to measure mental processing speed, working memory, attention, verbal learning, visuospatial ability, motor dexterity and visual motor speed to determine which would be most sensitive to uremia and would improve after renal transplantation (Tx). Nine subjects (8-21 yrs) with full scale IQ of 92 ± 15 (mean±SD) were studied on chronic PD (n=6, Kt/V 2.3±.5), chronic HD (n=2, Kt/V 1.8±.9) or with advanced CRI, and restudied 1 year after successful renal Tx (Cr 1.3±.6 mg/dl) on stable doses of cyclosporine, prednisone and azathioprine. Comparisons were made within subjects, pre and post Tx, by paired t-test and Wilcoxon signed ranks test with p < .05 significant. Mental processing speed indices from the Cognitive Abilities Tests and the Conners Continuous Performance Test improved post-Tx. Working memory, measured by the Paced Auditory Serial Addition Test also improved post-Tx. In contrast, indices which depended upon motor speed, attention, visual motor speed, visuospatial ability and verbal learning did not change post-Tx. Increased renal function post-Tx resulted in enhanced performance on tests of mental processing speed and working memory. Intensive assessment and within subject comparisons allowed us to detect subtle, reversible effects on specific areas of cognitive function. These observations may provide insights into mechanisms of neuropsychological impairment in uremia and justify early Tx in children to permit cognitive development.