A variant of spasmodic dysphonia in which the spasms push the vocal cords together, choking off or straining the voice. Adductor spasmodic dysphonia (AD-SD), also called strain-strangle phonation, is the most common variant of spasmodic dysphonia, comprising about 90% of the cases. It is to be distinguished from abductor spasmodic dysphonia (AB-SD), a variant in which the spasms pull the vocal cords apart.
In its classic variant, the adductory spasms of adductor spasmodic dysphonia are intermittent, each time clamping the vocal cords together momentarily, so that words or syllables in a person’s speech are intermittently choked out. In its tonic variant, the adductory spasms are more constant and sustained than intermittent, so that instead of interrupting the person’s speech, the spasms cause a constant strained or “tight” vocal quality.
Occasionally, a person has both abductory and adductory spasms; this is called mixed AB-AD spasmodic dysphonia. For more about spasmodic dysphonia in general and the treatment options for it, see our main entry.
AD-SD (1 of 2)
Sustained, clear phonation, standard light. Note vibratory blur of the vocal cord margins. The false vocal cords (lines) are in normal relation to the true vocal cords.
AD-SD (2 of 2)
Involuntary adductory spasm. Note that the false vocal cords suddenly over-close (arrows) as a result of the adductory spasm, and voice momentarily stops (along with vibratory blur).
Adductory spasm (1 of 2)
Continuous phonation, standard light. Note the position of the false cords in relation to each other, and also the distance between the anterior face of the arytenoids and the petiole of the epiglottis.
Adductory spasm (2 of 2)
A moment later, an adductory spasm occurs. The spasm may momentarily stop the voice (phonatory arrest). Note the inward squeezing of the entire supraglottis (false cords, arytenoids, and petiole).
Pure AD-SD tonic only, moderate severity: