Mark K. Lyons, Orland K. Boucher and Virgilio G. H. Evidente
The co-existence of essential tremor and spasmodic dysphonia has been reported in the literature. Spasmodic dysphonia is a primary focal dystonia manifested by loss of control of the vocal muscles during speech secondary to laryngeal muscle spasms. The pathophysiology is not well understood. Deep brain stimulation surgery (DBS) for other focal dystonias has been well reported. Voice and laryngo-videostroboscopic examinations can aid in confirmation of spasmodic dysphonia as opposed to voice tremor due to the underlying essential tremor. We report the long term follow up of a patient who underwent bilateral thalamic deep brain stimulation surgery for essential tremor and coincident spasmodic dysphonia, and report the effects of unilateral versus bilateral stimulation on her dysphonia. The topic literature is reviewed and the potential neuroanatomical pathophysiologic mechanisms of this finding are also discussed. .