A variant of spasmodic dysphonia (SD) in which the spasms (and their effect on the voice) are sustained rather than intermittent. Tonic variant spasmodic dysphonia is to be distinguished from classic variant SD.
Individuals with a tonic variant of adductor SD have a sustained strained-sounding voice. Individuals with a tonic variant of abductor SD have a voice that is more or less continuously breathy. Tonic variant SD goes undiagnosed or misdiagnosed far more frequently than does classic variant SD.
“Pure” tonic-variant adductory Spasmodic Dysphonia
Four subtypes of adductor SD, tonic variant :
Non dysphonic variant
Stage whisper variant
Vocal fry variant