The effects of midazolam on pure tone audiometry, speech audiometry, and audiological reaction times in human volunteers

Auditory evoked potentials are effected by benzodiazepines, as is cortical processing of auditory stimuli. The effect of benzodiazepines on auditory s ensitivity has not, however, been studied. We designed the present study to investigate the effect of sedative doses of midazolam on pure tone and spe ech audiometry and on audiological reaction times in healthy volunteers. Th irty volunteers underwent baseline audiological assessment for pure tones a nd speech and had their audiological reaction times measured at 10 and 50 d b above their threshold hearing level at a frequency of 1 kHz. Subjects wer e then randomly assigned to one of two groups. Group A (n = 15) received mi dazolam (0.04 mg/kg) IV, and Group B (n = 15) received a similar volume of placebo IV. The audiological tests were repeated 5 min later, and performan ce was compared with baseline data. Scheffe post hoc tests were used to ass ess the significance of changes in each group. There was no pre- to posttes t change in audiological performance in either the placebo g-roup (P = 0.19 4) or the midazolam group (P = 0.957). Speech audiometry performance was li kewise unaffected by midazolam (P = 0.154). Reaction time at the 10-dB and 50-dB sensation levels were both significantly prolonged after midazolam ad ministration (P = 0.023 and P = 0.012, respectively). In this study, we dem onstrate that sedation with midazolam (0.04 mg/kg) does not alter pure tone or speech audiometric thresholds, but it does significantly delay the reac tion time to auditory stimuli. Medical practitioners should advise midazola m-sedated patients of their impaired reaction to auditory warning signals ( e.g., traffic and car hems) as part of the day-ward discharge recommendatio ns. Implications: In this study, we demonstrate that sedation of healthy vo lunteers with the benzodiazepine midazolam, in the common clinical dosage, does not affect their hearing capability as measured by pure tone and speec h audiometry. However, one's ability to react to auditory signals is impair ed after midazolam, which may have implications for patients after day-case procedures.