Perceptual-acoustic relationships in spasmodic dysphonia.

Perceptual ratings were obtained from voice samples of 19 patients with adductor spasmodic dysphonia before and 1 week after unilateral treatment with Botulinum toxin. Five experienced listeners judged samples of sustained phonation using a seven-point equal-interval scale. The perceptual parameters assessed were overall severity, strain-strangled voice quality, and breathiness. Perceptual results were related to the standard deviation of fundamental frequency and the voice break factor, two acoustic parameters previously shown to be significantly improved following Botulinum toxin injection. Results indicate that in general the spasmodic dysphonia voice is perceived as less severe, less strain-strangled, and more breathy 1 week after treatment. Interrelations among perceptual parameters and relationships with acoustic analyses are discussed.