Early acute changes in brainstem auditory-evoked responses - A diagnostic parameter for uremic encephalopathy

The brainstem auditory evoked responses (BAERs) of 87 patients with chronic renal failure (average age 51 years) were examined according to serum creatinine levels, the nature of the chronic renal disease present and the effect of dialysis. Changes recorded were followed over a period of 3 years. Altogether BAERs of 272 ears were evaluated. Results demonstrated changes in wave morphology and abnormal prolongations of all wave latencies and interpeak intervals. Wave V latencies and the interpeak interval for waves I-V showed a correlation to serum creatinine levels. The direct positive effect of dialysis was reflected in shortening of all wave latencies. The nature of the chronic renal disease and the existence of coexistence diseases were not important for changes in central BAER responses. The recording of the intra-individual course of a BAER permitted documentation of worsened cerebral function even in patients with constant uremic conditions.