Differentiation of adductor-type spasmodic dysphonia from muscle tension dysphonia by spectral analysis.
OBJECTIVE
To determine the utility of spectral analysis in the differentiation of adductor-type spasmodic dysphonia (AdSD) from muscle tension dysphonia (MTD).


METHODS
Prospective blinded study.


METHODS
Forty-seven samples of AdSD-connected speech spectrograms from 27 subjects and 17 samples of MTD-connected speech spectrograms from 15 subjects were selected from clinical charts and de-identified. These spectrograms were reviewed independently and blindly by two speech language pathologists experienced in spectrography. The speech language pathologists designated the spectrogram as consistent with AdSD and MTD, and these designations were compared with actual clinical diagnoses.


RESULTS
The ability to differentiate AdSD from MTD with spectral analysis was 94% for rater #1 and 98% for rater #2. No MTD subjects were incorrectly diagnosed as having SD (100% specificity).


CONCLUSIONS
This study suggests that experienced speech language pathologists can distinguish AdSD from MTD with a high degree of sensitivity and specificity based on spectral analysis. Spectral analysis is especially useful in cases where perceptual analysis and clinical evaluation alone are insufficient.
Rees
Catherine J
CJ
Department of Otolaryngology-Head and Neck Surgery UC Davis, Sacramento.
Blalock
P David
PD
Kemp
Shannon E
SE
Halum
Stacey L
SL
Koufman
Jamie A
JA
D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D003937:Diagnosis, Differential; D005260:Female; D006801:Humans; D007821:Laryngeal Muscles / Q000503:physiopathology; D008297:Male; D008875:Middle Aged; D009129:Muscle Tonus / Q000502:physiology; D011237:Predictive Value of Tests; D011446:Prospective Studies; D012680:Sensitivity and Specificity; D012815:Signal Processing, Computer-Assisted; D016037:Single-Blind Method; D013018:Sound Spectrography / Q000379:methods*; D013035:Spasm / Q000503:physiopathology; D013066:Speech-Language Pathology; D014831:Voice / Q000502:physiology; D014832:Voice Disorders / Q000175:diagnosis* / Q000503:physiopathology