Electrophysiological Studies on Uremic Patients - Comparison of Peritoneal Dialysis and Hemodialysis

1. Paired patients with end-stage renal disease were placed on either peritoneal (P) or hemodialysis (H); EEGs, visual evoked responses (VERs) and photic driving (PO) responses were recorded and computer analyzed. Both clinical groups were compared to control subjects given the same tests. 2. Compared to the controls, the renal patients showed more slow activity in the EEG, longer latencies in the VER and higher amplitudes in the PO responses at the slow subharmonics and lower amplitudes at the fast harmonics and fundamental frequency. 3. In comparison to the P patients, the H group showed more slow activity, not only in the resting EEG, but also in the photic driving responses in the form of slow subharmonic responses of higher amplitude. These data suggest that the major effect of hemodialysis may be on the brain-stem reticular formation. 4. The P patients showed longer latencies (and somewhat lower amplitudes) of the VER, suggesting that (of the three different tests used) the major effect of peritoneal dialysis may be on the visual system. 5. The BUN correlated well with the three electrophysiological tests; higher BUN values were associated with more slow activity in the EEG, more (slow) subharmonic responses in photic driving responses, but higher amplitudes of wavelets IV and V of the VER. Higher BUN values were also associated with harmonic (3F) photic driving responses of higher amplitde. 6. The BUN (or Cr) correlated best in the groups with less slowing in the EEG, less of an increased latency in the VER and less of an increased amplitude at subharmonic PO responses, suggesting that these serum values have a closer relationship to neurophysiological indices when the latter show more moderate, less extreme values.