Treatment Options for Adductor Spasmodic Dysphonia

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Adductor spasmodic dysphonia, the more common form of laryngeal dystonia, is typically treated today with two therapeutic modalities, medically and behaviorally. Although both interventions provide some measure of relief from the symptoms of adductor spasmodic dysphonia, to date there is no cure. Adductor spasmodic dysphonia is a devastating voice disorder.

Spasmodic dysphonia, means spastic-like voice disorder. It isn't a true spastic motor disorder as descending cortical inhibition remains present, though faulty. At one time spasmodic dysphonia was thought to be a hysterical or functional vocal disorder. When first described in 1871 it was called 'nervous hoarseness' (Aronson and Hartman, 1981, JSHR, 46:52). But it is clear now that included in its pathophysiology is familial genetic predispositions (DYT allele, and others). Spasmodic dysphonia is thought to originate from some presently unknown derangement of the basal ganglia, as do a number of other motor disorders (i.e., Parkinson's disease). It is interesting that those motor disorders manifesting tremor as a feature of their pathology, also have basal ganglia origins (Brown and Simonson, 1963, Neurology, 2:520). Spasmodic dysphonia has been shown to have vocal tremor in 66% those diagnosed (Charpied and Grillone, 1997; unpublished data). Typical features of the dysphonia voice are the strain-strangle, associated excessive tension and respiratory exertion, and voice breaks in speech but not in vegetative tasks.

Electromyographic data seem to indicate that vocal strain represented selective hyperactivity of the adductor musculature, the lateral cricoarytenoid (LCA), with abnormal resting electromyographic levels in the posterior cricoarytenoid, thyroarytenoid (TA) and cricoarytenoid muscles (Cyrus, et al, Otolaryngology-HNS, 2001, 124:23). Thus, electromyographic evidence appears to argue for imbalance between the adductors and abductors favoring the adductors. These data indicate that an excessive adduction, LCA activity, and shortening of the vocal folds, TA activity, during phonation results in strained closure leading to significantly increased subglottal pressure.

Of the two treatment modalities, the medical injection of the clostridium bacterial toxin, Botulinum, provides the greatest relief to patients, although there is great individual variation. Within one to three weeks after injection patients report an absence of the strain-strangle, a decrease in the effortful, broken voice, and a decrease in their sense of dread when speaking events present themselves. Side effects of cough or choke at mealtimes and breathiness pass, usually without complication. In some patients the presence of tremor becomes more noticeable after injection. Hence, the behavioral mode of intervention for adductor spasmodic dysphonia, speech therapy, would have little efficacy immediately after the injection effect has begun. Where speech therapy has its greatest value is in teaching patients who do not go through injection therapy or are in-between injections to manage the symptoms of the disorder with proper compensatory strategies. These include relaxation techniques, use of diaphragmatic breathing and easy onset tone production, reduced number of words per utterance, with the goals of reducing both excessive adduction and increased subglottal pressure. Sometimes, slight pitch elevation for automatic responses and use of vegetative gestures also help as 'starters' of clearer vocalizations.

Mr. Charpied is the Director of the Department of Speech Pathology, in the Department of Otolaryngology - Head and Neck Surgery, with the University Rochester's School of Medicine and Dentistry and Strong Memorial Hospital. A clinically certified Speech Pathologist who specializes in voice and swallowing, Mr. Charpied has developed techniques and manuals on the diagnosis, treatment and management of voice and swallowing disorders. He teaches at Nazareth College, as well in the ENT resident program. His research interests include anatomy of the larynx, quantification of laryngeal function through image analysis, and the use of computers as a clinical tool. Besides publications and numerous abstracts, Mr. Charpied's introductory text for Speech Pathology students, Anatomic and Physiologic Elements of Human Communication," has been submitted for publication. He is currently completing a text titled, "Neurologic Basis of Human Communicative Behavior."