Procedures for the selection of spastic dysphonia patients for recurrent laryngeal nerve section.

Patients with spastic dysphonia were studied to identify the characteristics of patients benefiting from recurrent laryngeal nerve (RLN) surgery. Studies included laryngeal video recordings made during speech, measures of frequency and amplitude variations during extended phonation, the effects of altered auditory feedback on dysfluencies, and temporary unilateral RLN block. Two patients had vocal fold adductor spasms during connected speech, had increased acoustic phonatory tremor in frequency, were not benefited by altered auditory feedback, and responded favorably to nerve block. Subsequent RLN section improved the speech of both patients. Other patients had speech blocks, repetitions and prolongations, vocal fold tremors during phonation, reduced dysfluencies during altered auditory feedback, and were not benefited by temporary nerve block. Two subtypes of spastic dysphonic patients are proposed.