Electrolarynx providing voice pitch pattern.

Abstract

How pitch pattern contributes to naturality of speech was inverstigated based upon psychophysical experiments, in order to improve the naturality of an electrolarynx.From the results, greatest naturality was obtained when pitch frequency increased at 0.45 Hz/msec within 60 msec just after the onset of vowels.Naturality was evaluated to be improved when the pitch frequency gradually decreased linearly after the pitch frequency reached the maxium Furthermore, fluctuation of the waveform was also found to play an important role in naturality.Based on these findings, a new model of electrolarynx was designed which could produce optimal pitch pattern.With it, patients were also able to control pitch frequency at will.This proved that patients could produce almost the same intonation as that of continuous speech of a normal person by controlling the pitch frequency.