A review of 20 cases of spastic dysphonia.

Twenty patients with the distinct nosological entity of adductor spastic dysphonia (SD) were seen at St Vincent's Hospital, Sydney over a 6-year period. Nine of these patients also experienced a tremulous voice associated with evidence of an essential tremor (ET) elsewhere, including head, trunk and limbs. The mean age of onset in patients with SD was 45 years and in those with SD with ET was 52 years. In 10 patients the onset was gradual, with the remaining 10 experiencing an abrupt onset, in 3 related to an upper respiratory tract infection and in 7 to psychosocial stress. Factors which frequently resulted in a worsening of speech included stress, public speaking, tiredness, strong emotions, upper respiratory tract infections and prolonged use of the voice. In patients with SD alone temporary relieving factors included spontaneous statements, use of a quiet voice, slow speech, high and low pitch, yawning, chewing, swallowing, laughing and on first waking in the morning. The response to therapy was variable. Two patients underwent recurrent laryngeal nerve sectioning.