Neural Representations of the Voice Tremor Spectrum

Area of Science:

• Neuroscience
• Movement Disorders
• Speech Science

Background:

• Voice tremor, including essential tremor of voice (ETv) and dystonic tremor of voice (DTv), involves involuntary laryngeal muscle oscillations.
• Differential diagnosis between ETv and DTv is challenging due to overlapping clinical features.
• The underlying pathophysiology of voice tremor's diverse presentations is not fully understood.

Purpose of the Study:

• To investigate disorder-specific neural alterations in ETv and DTv using multimodal neuroimaging.
• To correlate neural findings with the clinical severity of ETv and DTv.
• To elucidate the pathophysiological spectrum of voice tremor disorders.

Main Methods:

• Functional MRI (fMRI) assessed brain activity during speech production.
• High-resolution MRI examined cortical thickness and gray matter volume.
• Diffusion-weighted imaging evaluated white matter integrity.

Main Results:

• Both ETv and DTv exhibited overlapping cortical alterations in sensorimotor regions crucial for speech integration.
• ETv showed unique cerebellar abnormalities, while DTv displayed abnormalities in the premotor cortex, insula, and superior temporal gyrus.
• Cortical changes in ETv correlated with symptom severity; premotor cortex changes in DTv also correlated with severity.

Conclusions:

• Findings suggest a pathophysiological spectrum for ETv and DTv.
• The results favor a heterogeneous classification of voice tremor disorders over a dichotomous one.
• This study provides insights into the neural basis of voice tremor heterogeneity.