[Effects of glycine on auditory evoked potentials among diabetic patients with auditory pathway neuropathy].

BACKGROUND Glycine inhibits the formation of advanced glycation end products that may cause central and peripheral neuronal damage, affecting also the auditory nerve. AIM To evaluate the effect of glycine on auditory nerve conduction and hearing level among patients with type 2 diabetes mellitus and auditory neuropathy. MATERIAL AND METHODS Twenty grams of oral glycine per day were administered during 6 months to 28 type 2 diabetic patients aged 58 ± 6 years, with auditory pathway neuropathy. Hearing tests and evoked otoacustic potentials were performed regularly. Fifteen diabetic patients aged 49 ± 8 years, without auditory nerve neuropathy did not receive glycine and were followed as a control group. RESULTS Among patients receiving glycine, a significant improvement in left ear audiometry at 125, 250 and 500 Hz and right ear audiometry at 500 Hz, was observed. Waves I, III and V (p= 0.02) of evoked otoacustic potentials improved significantly in the left ear and wave I in the right ear. Among controls, waves V and III of evoked otoacoustic potentials had a significant impairment in the left ear. CONCLUSIONS There was an improvement in auditory evoked potentials in patients receiving glycine and an impairment in untreated control patients.