Audiometry in chronic renal failure before and after intermittent haemodialysis.

In seven cases, audiometric studies were carried out immediately before and after haemodialysis. Hearing was found to be affected in all cases, and the impairment was particularly significant in higher frequency ranges. Following haemodialysis an average improvement of 20 dB was found for the highest frequencies, and in most cases a narrowing of the bone-air gap was also observed. As the improvement was reflected mainly in serum osmolality, BUN and fluid retention in the post-dialysis stage, it was thought that the mechanism reversing the hearing impairment might be due to these parameters.