ABSTRACT
Objective To investigate the characteristics of acoustic parameters and spectrograph of organic and functional voice disorder and evaluate the value of acoustic analysis technique by computer in the differential diagnosis of voice disorder. MethodsThe voice signals of sustained vowel "a" were measured with a microcomputer (Dr.Speech Software) in 70 healthy adults, 60 patients with varying organic diseases of vocal cords and 50 cases with functional voice disorder. The acoustic parame ters (jitter, shimmer, NNE) and spectrographic characteristics were analyzed and compared. ResultsIn 60 patients with organic diseases of vocal cords, all the acoustic parameters were significantly increased and the spectrograph showed irregularity,breakage or lack of harmonic waves and formants, and increase of noise. In 50 cases with functional voice disorder, the shimmer and NNE were significantly increased but the jitter was usually normal. The spectrograph showed pathologic changes of harmonic waves and formants in middle and high frequencies. The normal acoustic characteristics could be found in 94% (47/50) of the patients with functional voice disorder. ConcluisionThe acoustic analysis by computer technique is of value in the differential diagnosis of or ganic and functional voice disorder.