Evaluation of visual evoked potentials and brain-stem auditory evoked response in patients of chronic kidney disease.

Chronic kidney disease (CKD) is associated with functional changes in the central nervous system (CNS) which, in the initial stages do not manifest clinically. Early involvement of the CNS can be identified by the assessment of the electrocortical activity. Visual evoked potential (VEP) and brain-stem auditory evoked response (BAER) are useful tests for the early diagnosis of CNS involvement in CKD and are more sensitive compared to electroencephalography. One hundred adult CKD patients (stage 3-5 and 5D) and 50 controls were included in the study. Clinical and biochemical parameters were assessed and all the patients and controls underwent VEP and BAER evaluation. Evaluation of the VEP showed prolonged latencies of all the three peaks (N75, P100, and N145) compared to controls. Furthermore, all the absolute and interpeak BAER latencies for the CKD patients were similarly prolonged compared to controls. CNS dysfunction is common in CKD patients. The electrophysiological tests of VEP and BAER can be used for the early diagnosis of these disorders, even in the sub-clinical stages, thus allowing for their better management.