Middle components of the auditory evoked response in young children.

The purpose of this study was to ascertain whether the middle components of the auditory evoked response could be obtained consistently from normal young children during sleep. The wave pattern of the response was unstable and was not reproducible in sleeping children. Comparing the detectability of each peak in waking children with that of each peak in sleeping children, there was little difference in the detectabilty of the Po peak between the two test conditions, and the Na peak was only about 10% lower in sleeping subjects than in waking ones. However, a considerable decrease in the detectability of the Pa peak was found during sleep. Later peaks, such as the Nb and Pb peaks, which are usually elicited in waking adults, could scarcely be found in children, either in the sleeping or in the wakeful state. In this study, no clear difference of detectability in each peak could be demonstrated between the two filter conditions. From these results, it is concluded that the middle components of the electroencephalic response in sleep differ from those in the waking state, especially in children. Moreover, it seems that the decrease in the appearance of the response during sleep may be related to the depth of sleep. Po-Na may be the most suitable index for electric response audiometry in young children.