A Study of Auditory Evoked Responses during Sleep

Abstract

The evoked responses to tones in different stages of sleep were studied on a group of normally hearing students. The stage of sleep was monitored by experienced workers in EEG and the responses recorded together with the stage of sleep in which they were elicited. Attention was paid to the shape, amplitude, latency, and clarity (i.e. the ease with which a decision between ‘response’ and ‘no response’ for a given stimulus could be reached) of responses. Statistical attention was paid to the relationship between stage of sleep and the above qualities of the responses

It was found most useful to stimulate with a 1 000-Hz tone of 75 dB ISO intensity since this gave a clear response without disturbing the depth of sleep. Responses when awake were taken as a control. The most favorable periods, from this study, appeared to be stages two and three (after Osward); the least favorable were stages four and that of rapid eye movement (REM)

It is hoped that this study will form a useful background against which drug-affected evoked responses can be studied (as in the topic of sedation for ERA)

Key Words:

• Electric response audiometry (ERA)
• Brain potentials
• Evoked response patterns
• Latency of evoked response
• Amplitude of individual waves of response