Contingent Negative Variation of Pre- and Post-Hemodialysis in Patient with End Stage Renal Disease

ABSTRACT

BACKGROUND: The contingent negative variation (CNV) reflects neuronal activities related to sensorimotor integration and motor planning or execution and is probably originated from the frontal-subcortical circuit. The aim of this study is to investigate the neurophysiologic changes in uremia and the effect of hemodialysis to them by utilizing the CNV test. METHODS: Fifteen right-handed healthy subjects and 12 patients with end stage renal disease (ESRD) were studied. CNV was recorded from Fz, Cz, and Pz referenced to linked ear lobes by using an S1 (click)-S2 (flashes)-key press paradigm. The amplitude of initial CNV (iCNV) was calculated as the average amplitude of 550~750 msec after S1. The amplitude of late CNV (lCNV) was calculated as the average amplitude between 200 msec before S1 and S2. The test was repeated for the patients group at the time of pre- and post-hemodialysis. Neuropsychological measurements, the trail making test (TMT) and mini-mental state score (MMSE), were conducted at the time of each test. RESULTS: Both the mean amplitudes of iCNV and lCNV at the vertex (Cz) were significantly lower in the patient group than those in the control group (p<0.05). The MMSE score and TMT were also significantly different between the patient and control group (p<0.05). There was no significant correlation between the values of neuropsychological tests and the parameters of CNV. Both iCNV and lCNV were not significantly different between the pre- and post-dialysis test. CONCLUSIONS: It appears that CNV negativity in uremia reflects dysfunctions in the frontal-subcortical circuit. In addition, hemodialysis seems to have no significant effect on it in patients with ESRD.