Neuropsychological profile of children with kidney transplants

Background. Varying results on the cognitive outcome of children who have undergone kidney transplantation (KTx) have raised concern for specific neurocognitive difficulties. Methods. Fifty children with KTx were assessed at a mean age of 11.1 (SD 3.2; range 6.3–16.4), on average 6.9 (SD 3.6; range 1.0–14.1) years post-operatively. A standardized test of intelligence [Wechsler Intelligence Scale for Children (WISC-III)] and neuropsychological tests from NEPSY-II were administered. The neuropsychological profile of KTx children was compared to that of a control group matched for gender, age and maternal education. Results. The KTx children had a lower intelligence quotient (83.9) than the test norms (100.0, P < 0.001). On neuropsychological assessment, the KTx group scored generally lower than the control group did (P < 0.001). The difference was evident in both the verbal and visuospatial domains, on a sub-test of complex auditory attention, verbal working memory and facial affect recognition. When children with neurological co-morbidity were excluded, the remaining group still scored lower than the controls did on Comprehension of Instructions (P ¼ 0.06), Design Copying (P ¼ 0.007) and Affect Recognition (P ¼ 0.018). A better cognitive outcome was mainly associated with the absence of neurological co-morbidity, younger age, shorter disease duration and sustained kidney function. Children with congenital nephrosis had a similar outcome to those with other diagnoses. Conclusions. KTx children exhibit a pattern of effects in their cognitive outcome in which both the visuospatial and language domains are affected, but visual memory and simple auditory attention remain intact. Patients without neurological co-morbidity exhibit impairment in receptive language, visuospatial functions and in recognizing emotional states.