Evaluation of Cognitive Functions in Children with Chronic Kidney Disease

Abstract

Objectives: The aim of our study is to evaluate the cognitive functions of the children with chronic kidney disease (CKD) and to identify the factors influencing on these cognitive functions. Fifty-seven children with various stages of CKD following up in three pediatric nephrology centers were enrolled in this multicentric study. Mean age was 12±2.57 years.Methods: Initial information about the patients was obtained from hospital records and their parents. WISC-R and CNS Vital Signs tests were performed by a certified psychologist to evaluate cognitive functions of the patients. Mental retardation (MR) was defined as Intelligence quotient (IQ) level lower than 70 according to WISC-R test. The patients who have IQ level between 71-84 were classified as “borderline mental capacity”. Statistical analyses were performed with SPSS 21 software. Results: IQ level was normal only in 14 (24.6%) children in our study group. Fourteen (24.6%) patients had a “borderline mental capacity”, 29 (50.8%) patients had mild and moderate MR. IQ level was not found to be related to the stage of CKD (p=0.085). MR was more frequent in the patients with anemia and also history of small for gestational age (p=0.029 and p=0.033; respectively). IQ level of the patients were positively correlated with education level of their mothers (r=0.330 p=0.012).All of special cognitive functions were affected negatively except verbal memory. The percentage of the affected patients was 76.8% in cognitive flexibility, 69.6% in composite memory, 69.6% in neurocognition index, 66% in executive function and 60.7% in psychomotor speed. The duration of CKD, history of small for gestational age and especially maternal education level were found to be related to poor cognitive functions (p<0.05). Conclusion: IQ level and other cognitive functions were affected in the children with CKD. Maternal education level is one of the most important factors influencing IQ level and cognitive functions of these children.