Auditory nerve and brain stem responses. Comparison in awake and unconscious subjects

The recording of auditory nerve and brain stem responses to click stimuli is being used for the diagnosis of several conditions such as suspected hearing loss and suspected neurological disorders. The responses obtained in the patient group (often infants and children) are compared with those obtained in normal subjects of similar age who, for ethical reasons, are not sedated. In this study, recordings were made in normal subjects while they were awake and when they were unconscious in drug-induced sleep (being prepared for dental surgery). No significant difference could be observed between the recordings obtained in the awake state and when unconscious in the same subjects. Therefore, one is justified in using recordings made in awake subjects as controls for recordings made in other unconscious patients.