EVALUATION OF ACOUSTICALLY EVOKED SLOW VERTEX RESPONSE (SVR)

MAINLY WITH PEAK LATENCY OF SVR

Abstract

The latency and amplitude of the acoustically evoked slow vertex response (SVR) were examined in 10 normal adults and 22 infants. The recordings of the evoked responses and judgements were carried out by the Juntendo method.
The results were as follows:
(1) The distribution of the latencies of SVR:
Adults: The latencies of SVR were 50-100 msec in 21% of the whole examined cases, and 62% in 100-200 msec.
Infants: The latencies of SVR were 50-100 msec in 15% of the whole examined cases, 27% in 100-200 msec, and 44% in 200-500 msec.
The variation of latencies of the SVR were greater in infants than in adults. Especially, SVR of infants showed longer latencies than 500 msec in 14%.
(2) SVR showed shorter latencies in accordance with the increase of the sound intensity both in adults and infants. When the sound intensity was high, the latencies showed no remarkable difference between adults and infants. However, at or around the response threshold, in other words, at low intensity levels, the latencies of SVR in infants were approximately twice as long as those in adults.
(3) The frequencies of the examined sound had little influence upon the latencies of SVR.
(4) SVR in adults were quite stable, however, test-retest examination revealed that the latencies of SVR in infants differed greatly case by case, especially at low intensity levels.
(5) Comparing the distribution of the peak latencies of SVR with those of false positive response, "responses" with longer latencies than 1 second should be neglected because of the high possibility of false positive responses.