A prospective randomized controlled trial evaluating alcohol on loudness perception in cochlear implant users.
AIM: The aim of this study was to determine the effects of alcohol on the psychophysical responses in patients with cochlear implants. This has not been previously studied. It was also hoped to provide information that could suggest possible sites of action of the known effects of alcohol on the auditory pathway. DESIGN: A prospective randomized placebo-controlled trial, with full ethical approval. PARTICIPANTS: Eight successful cochlear implant users were selected, of whom two had bilateral implants which were tested separately. In total 10 cochlear implants were tested. INTERVENTION: Alcohol was given in the form of vodka (50% alcohol, 1 mL/kg body weight) with 500 mL of orange and cranberry juice. The placebo control was given in the form of 500 mL of orange and cranberry juice alone. OUTCOME MEASUREMENT: The 'comfort level' (C level) was recorded before, and 1 h after alcohol or placebo ingestion for each patient's cochlear implant. Blood alcohol concentration was determined prior to alcohol or placebo consumption and then repeated after 45, 60, 90 and 180 min. RESULTS: The mean blood alcohol concentration 1 h after ingestion was 50 mg/dL. In the 'alcohol' arm the mean electrical unit increase in the C level was 19.9 with a standard deviation of 2.2. In the control arm the mean change in C level was 0.10 with a standard deviation of 0.3. CONCLUSIONS: In this first prospective randomized control study of the effect of alcohol on sound perception in cochlear implant users, alcohol significantly increased the upper end of the dynamic range (C levels) in comparison with placebo (P = <0.0001 using paired t-test analysis). This effect is likely to be the result of change in the auditory pathways proximal to the cochlea.