Evaluation of visual evoked potentials in chronic renal failure patients with different treatment modalities

Uremia causes central nervous system (CNS) dysfunction. Modern diagnostic methods are useful for the recognition of CNS complications in uremic patients. Data concerning visual evoked potentials (VEPs) of chronic renal failure (CRF) patients is limited.

In this study, we aimed to assess and compare VEPs abnormalities in CRF patients managed by only medical therapy (pre-dialysis) or medical therapy plus renal replacement therapy (continuous ambulatory peritoneal dialysis (CAPD) or hemodialysis (HD)).

Fifty-nine patients diagnosed with CRF of various etiologies were divided into 3 groups according to the treatment modalities used to manage CRF; pre-dialysis group, HD group and CAPD group. For the comparison of VEPs parameters, an age matched control group was formed with 10 healthy subjects.

Bilateral N2 latency (p<0.001), bilateral P2 latency (p=0.003), right N2 latency (p=0.006) and left VEP N2 latency (p=0.002) in the HD group was significantly higher than the control group. The CAPD group had significantly increased bilateral N2 latency (p<0.001), right eye VEP N2 latency (p=0.004), right eye P2 latency (p=0.001), left eye N2 latency (p=0.005) and left eye P2 latency (p=0.001) levels than the control group. There was no significant difference between VEPs of the CAPD and HD groups.

The renal replacement treatments that we evaluated have similar effects on VEPs. Diminished VEPs indicating visual neuronal system damage were observed, when CRF progresses. CNS dysfunctions can be diagnosed and additional therapeutic approaches could be followed using VEPs during the treatment of CRF.