Acoustic and perceptual analysis of modal and falsetto registers in females with dysphonia

Are Instructions to Manipulate Specific Parameters of Laryngeal Function Associated with Auditory-Perceptual Ratings of Voice Quality in Nondisordered Speakers?

OBJECTIVES/HYPOTHESIS

This preliminary study investigated whether auditory-perceptual judgments of voice quality by experienced speech language pathologists were associated with instructions given to speakers to manipulate specific laryngeal postures.

STUDY DESIGN

Experimental, within-subject design.

METHODS

Nine speakers were instructed and trained to manipulate three vocal parameters implicated in functional voice disorders-false vocal fold constriction, vocal fold mass, and larynx height-while reading a standard passage. Experienced judges rated these standard passages in terms of the widely used perceptual voice qualities breathiness, roughness, vocal strain, glottal fry, tone onset, tone color, loudness, and pitch.

RESULTS

Between-subject factorial analysis of variance, controlling for judge unreliability, revealed some evidence that perceptual judgments are strongly associated with underlying laryngeal muscle activity that can then serve clinical planning of goals for intervention. Eta² effect sizes were large for all dependent measures, ranging from 0.39 for pitch to 0.77 for strained.

CONCLUSIONS

Although these results are encouraging, they were obtained under ideal conditions. Further research is warranted.

Differentiated vocal tract control and the reliability of interpretations of nasendoscopic assessment

Training specific vocal techniques can be effective in treating nonorganic dysphonias. Evaluation of vocal function in these studies has included auditory-perceptual assessment, aerodynamic measurement, acoustic analysis, self-report, and visual inspection of the larynx. Reliability of judgments made using visual rating tools for nasendoscopic and videostroboscopic visualization of the larynx when diagnosing vocal function and disorder has been the focus of previous research. However, detailed analysis of factors that affect reliability and consistency of perceptual ratings of laryngoscopic footage has not been investigated in voice therapy outcome studies. This study evaluated clinicians' judgments of the effectiveness of training differentiated vocal tract control of false vocal fold activity (FVFA), true vocal fold mass (TVFM) and larynx height (LH). A within-subject, experimental design was used to assess participants' mastery in manipulating FVFA, TVFM, and LH assessed via laryngoscopic visualization of the larynx. Three experienced speech pathologists rated the nasendoscopy footage with accompanying acoustic recordings of 12 speakers. Intrajudge consistency, interjudge reliability, and interjudge agreement of perceptual ratings were investigated. Twelve vocally trained unimpaired speakers used differentiated biomechanical manipulation of various laryngeal muscles to produce eight specific vocal qualities each. These manipulated vocal qualities were rated by three experienced voice clinicians who demonstrated higher levels of intrajudge consistency and interjudge agreement when identifying rather than quantifying the degree of a voice quality based on their visual and auditory perceptions of the different vocal features. The findings suggest that unimpaired speakers can be trained successfully to manipulate and change individual biomechanical aspects of their vocal functions as demonstrated by the visual- and auditory-perceptual judgments of expert voice clinicians. These judgments are vulnerable to issues of reliability and suggests that judges used auditory-perceptual judgments when interpreting laryngoscopic footage, particularly when the view of laryngeal features is compromised.

Breathing-impaired speech after brain haemorrhage: a case study

Results are presented from an auditory and acoustic analysis of the speech of an adult male with impaired prosody and articulation due to brain haemorrhage. They show marked effects on phonation, speech rate and articulator velocity, and a speech rhythm disrupted by "intrusive" stresses. These effects are discussed in relation to the speaker's very short breath-groups and consequent need to take breath within intonation-groups and even within rhythm-groups. The speaker appears to have various strategies for dealing with his speech problems to preserve the structural cohesion of his utterances, some seemingly more successful than others, including planning his frequent breath pauses, using falsetto phonation, control of pitch and inspiring air orally for rapid intake. Finally, it is suggested that these and other strategies designed to compensate for limitations and shortcomings in the speech production system should be recognized as a form of linguistic creativity.