Effect of hemodialysis on cognitive function in ESRD patients

Background. Uremia is associated with impairment of different cognitive functions. However the pathogenesis of this cognitive dysfunction is unknown. Objective. In this study, long-latency event related potentials (ERPs) were used to assess changes in cortical function due to hemodialysis treatment. Methods. In this cross-sectional study, we measured event related potentials in 15 end stage renal disease (ESRD) patients maintained on hemodialysis, two hours before and two hours after they underwent hemodialysis and compared their data with a strictly age and sex matched healthy control group. The P3 was elicited by using standard auditory "odd-ball" paradigm and the data obtained was statistically analyzed (Wilcoxon signed ranks, Mann Whitney). Results. Before hemodialysis, the patients' P3 latency (347.73 +/- 39.47 ms) was significantly increased as compared with that of healthy control group (308.4 +/- 13.73 ms) (p = 0.001). After hemodialysis, P3 latency of the patients showed a significant decrease (347.73 +/- 39.47 ms to 325.20 +/- 37.15 ms, p = 0.001). P3 latency after dialysis was not significantly different from controls. No significant correlation was noted between various biochemical parameters (hemoglobin, blood urea, creatinine, uric acid and calcium) and P3 latency or amplitude. Conclusions. Removal of uremic toxins by hemodialysis leads to an improvement in cognitive processing.