Effects of stimulation techniques on vocal responses: Implications for assessment and treatment

During voice evaluation and treatment it is customary for clinicians to eli cit samples of the vowel /a/ from clients using various elicitation techniq ues. The purpose of this study was to compare the effects of four commonly used stimulation tasks on the laryngeal mechanism. Eleven female singing st udents, studying at a university music school, served as subjects for the s tudy. The subjects phonated the vowel /a/ using 4 vocal stimulation techniq ues: yawn-sigh, gentle onset, focus, and the use of the voiceless fricative . Videoendoscopic and acoustic evaluations of their productions were done. Results show that, in the first 100 ms following the end of the formant tra nsition, these techniques affected voice differently. The fundamental frequ ency was found to be highest in the yawn-sigh condition, whereas the maximu m frequency perturbation was obtained for the voiceless fricative condition . Planned comparisons were made by comparing the data across 2 dimensions: (1) vowels elicited with voiced contexts versus those elicited with voicele ss consonantal contexts and (2) vowels elicited with obstruent versus vowel s elicited with nonobstruent consonantal contexts. Some changes in acoustic parameters brought about: by these stimulation techniques may be explained on the basis of coarticulatory effects of the consonantal context.