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.