Clinical aspects of spasmodic dysphonia.
The clinical features of 12 patients with spasmodic dysphonia are described. In 11 patients, the voice was strained, harsh, tight, and tremulous, and was low in volume and pitch. Speech, which was sometimes barely intelligible, was interrupted by irregular stoppages and catches of the voice; it required considerable effort, and was accompanied by facial grimacing. The dysphonia was part of a more widespread neurological disorder (idiopathic torsion dystonia) in one case, while it coexisted with blepharospasm in another, and with postural tremor in two. There was a buccolingual hyskinesia in another of these 11 patients, but this may have been related to her previous drug regime. In the twelfth patient, who had a familial tremor, the voice was characterised by marked breathiness, with intermittent aphonia. The disorder is probably due to a focal dystonia of the laryngeal musculature, and this would be consistent with the type of neurological disorders that were associated with it in our cases. Symptomatic benefit follows the therapeutic division of one of the recurrent laryngeal nerves, in selected cases.