EVOKED-POTENTIALS (VEPS AND BAEPS) IN A LARGE COHORT OF SHORT-TERM AND LONG-TERM HEMODIALYZED PATIENTS

To evaluate the presence and the severity of uraemic encephalopathy (UE) in regular dialysis treatment patients in relation to dialytic age, pattern reversal visual evoked potentials (PRVEPs) and brainstem auditory evoked potentials (BAEPs) were respectively performed in 86 and 98 patients on haemodialysis for 1-194 months, divided into three subgroups according to dialytic age (group 1, < 5 years of regular dialysis; group 2, 5-10 years; group 3, > 10 years). VEPs in the whole group of 86 patients and in each subgroup with different dialytic age differed significantly from controls for both eyes, 41.7% of whom had pathological P100; no differences were observed between the three subgroups. BAEPs were pathological in 9.7% of the ears and 18.4% of patients. On the right ear the three subgroups were significantly different from controls in the latencies of peaks III and V; subgroup 2 and 3 differed from controls in the I-V interpeak, while the interpeak I-III was different from controls only in subgroup 3. On the left ear the three subgroups differed significantly from controls in the latencies of peak V; subgroup 2 and 3 were significantly different from controls in the latency of peak 1; subgroup 3 was different in the peak III latency; subgroup 1 and 3 were different from controls in the interpeak I-V; no differences were observed in BAEPs between the three subgroups with increasing dialytic age. No significant correlations were found between the neurophysiological parameters and some biochemical parameters (urea, creatinine, PTH). In summary, regular dialysis does not prevent the persistence of mild signs of uraemic encephalopathy, but these signs do not appear to worsen with increasing dialytic age.