Influence of consonant voicing characteristics on sentence production in abductor versus adductor spasmodic dysphonia.
OBJECTIVE
This study evaluated the hypotheses that sentence production by speakers with adductor (AD) and abductor (AB) spasmodic dysphonia (SD) may be differentially influenced by consonant voicing and manner features, in comparison with healthy, matched, nondysphonic controls.


METHODS
This was a prospective, single blind study, using a between-groups, repeated measures design for the independent variables of perceived voice quality and sentence duration.


METHODS
Sixteen subjects with ADSD and 10 subjects with ABSD, as well as 26 matched healthy controls produced four short, simple sentences that were systematically loaded with voiced or voiceless consonants of either obstruant or continuant manner categories. Experienced voice clinicians, who were "blind" as to speakers' group affixations, used visual analog scaling to judge the overall voice quality of each sentence. Acoustic sentence durations were also measured.


RESULTS
Speakers with ABSD or ADSD demonstrated significantly poorer than normal voice quality on all sentences. Speakers with ABSD exhibited longer than normal duration for voiceless consonant sentences. Speakers with ADSD had poorer voice quality for voiced than for voiceless consonant sentences. Speakers with ABSD had longer durations for voiceless than for voiced consonant sentences.


CONCLUSIONS
The two subtypes of SD exhibit differential performance on the basis of consonant voicing in short, simple sentences; however, each subgroup manifested voicing-related differences on a different variable (voice quality vs sentence duration). Findings suggest different underlying pathophysiological mechanisms for ABSD and ADSD. Findings also support inclusion of short, simple sentences containing voiced or voiceless consonants as part of the diagnostic protocol for SD, with measurement of sentence duration in addition to judments of voice quality severity.
School of Communication Sciences and Disorders, The University of Memphis, Memphis, Tennessee. Electronic address: mcannito@memphis.edu.
Michael P
MP
Cannito
Mathematics Department, Milwaukee School of Engineering, Milwaukee, Wisconsin.
Lesya B
LB
Chorna
School of Communication Sciences and Disorders, The University of Memphis, Memphis, Tennessee.
Joel C
JC
Kahane
Department of Otolaryngology, Head & Neck Surgery, Detroit Medical Center, Detroit, Michigan; Michigan State University College of Osteopathic Medicine, Detroit, Michigan.
James P
JP
Dworkin
D000162:Acoustics; D000328:Adult; D000368:Aged; D016022:Case-Control Studies; D004311:Double-Blind Method; D055154:Dysphonia / Q000175:diagnosis / Q000503:physiopathology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D011446:Prospective Studies; D012720:Severity of Illness Index; D013018:Sound Spectrography; D013061:Speech Acoustics; D013067:Speech Perception; D013068:Speech Production Measurement; D013997:Time Factors; D014833:Voice Quality
Abductor spasmodic dysphonia; Adductor spasmodic dysphonia; Consonant voicing characteristics; Sentence production