Abstract
Objective: Spasmodic dysphonia (SD) is clinically characterized by irregular hyperadduction of vocal folds leading to a strained/strangled, hoarse, and effortful voice with break in pitch and phonation. The aim of the present study is to evaluate the cerebral activity in patients with adductor SD in response to phonation.
Method: Six patients with adductor spasmodic dysphonia and 29 healthy subjects participated. Brain activity was evaluated using functional magnetic resonance imaging (fMRI). The experimental task consisted of alternate phonation conditions: vocalization (a prolonged vowel, |i:|) and no vocalization. The cues of both conditions were randomly presented to subjects.
Results: Activation areas in SD, compared with controls, were in right inferior frontal gyrus, right supramarginal gyrus, right middle temporal gyrus, and right superior temporal gyrus. On the contrary, decreased brain activity in SD group was observed in bilateral primary sensory area, right inferior parietal cortex, bilateral precentral gyrus, bilateral rolandic operculum, bilateral SMA, left anterior cingulate cortex, bilateral middle cingulate gyrus, right temporal pole, right superior pole, bilateral cerebellum, left inferior frontal gyrus, right insula lobe, bilateral thalamus, and right basal ganglia.
Conclusion: The present fMRI study demonstrated that brain activity during phonation in SD resembled those in other local dystonia diseases, especially in sensorimotor area, supplementary motor area, basal ganglia, thalamus, and cerebellum. Although sample size was quite limited, it is likely that spasmodic dysphonia is one aspect of local dystonia.
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