ASA 128th Meeting - Austin, Texas - 1994 Nov 28 .. Dec 02
3aSP21. Event-related vertex potentials preceding vowel onset.
Nancy Holland
A. Yonovitz
Conley Speech and Hear. Ctr., Dept. of Commun. Disord., Univ. of Maine,
Orono, ME 04469)
Neural events prior to speech were determined by averaging vertex-recorded
potentials 512 ms before vocalization. In a manner analogous to auditory-evoked
potentials, it would seem plausible to identify specific sites along motor
pathways that yield cortically recordable electrical potentials that are
precursory to vocalization. In this study, subjects repeatedly phonated a schwa
500 times. The repetition rate was approximately 8/min with the subject
initiating each trial. The onset of vocalization was detected by a throat
microphone that provided the trigger. The sample rate 25 000 samples/s) was
sufficient to observe brief time periods 10 ms) along the averaged prespeech
time epoch. The results indicated that repeatable, biphasic potentials were
obtained during the time period between 45 and 250 ms before the onset of the
vowel trigger. Interwave latencies between wavelets were highly related within
and between subjects. The technique of event-related potentials may be a useful
procedure for studying the electrophysiology of speech production in normal and
disordered speakers.