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

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Strained and pressed sounding voice (1 of 4)

At speech pitch of B3 (247 Hz), the not only true, but also false cords are continually compressed together and voice is very strained and pressed-sounding.

False cords relax (2 of 4)

Just a note higher, at C4 (262 Hz), false cords relax a little to reveal the true cords.

Voice quality less strained (3 of 4)

An octave above, in falsetto, true cords are now nearly completely seen. Voice quality is less strained. This exemplifies the common but not universal finding that falsetto is less affected by the dystonia than chest register.

Adductory tone during breathing (4 of 4)

This patient's larynx also demonstrates marked adductory tone during breathing, though not to the point of classifying this individual as having a respiratory dystonia component.


Four subtypes of adductor SD, tonic variant :

Non dysphonic variant

Cry variant

Stage whisper variant

Vocal fry variant