Type II thyroplasty changes cortical activation in patients with spasmodic dysphonia

Area of Science:

• Neurology
• Otolaryngology
• Speech-Language Pathology

Background:

• Spasmodic dysphonia (SD) is a neurological disorder causing strained, choked voice quality and voice stoppages.
• Symptoms worsen with communication anxiety but improve with certain treatments.
• The impact of symptom-reversing treatments on SD patients' brain activity remains undocumented.

Purpose of the Study:

• To investigate brain activity changes in SD patients before and after surgical intervention.
• To determine if peripheral treatment for SD affects central nervous system function.

Main Methods:

• Three patients with adductor spasmodic dysphonia underwent lateralization thyroplasty.
• Positron emission tomography (PET) scans were conducted pre- and post-surgery during vocalization.

Main Results:

• Pre-operatively, patients showed abnormal brain activation in the cordal supplementary motor area (SMA), auditory association areas, and thalamus.
• Post-surgery, vocal strain was significantly reduced or eliminated.
• PET scans revealed normalized brain activation patterns, with decreased activity in the cordal SMA, auditory areas, and thalamus, and increased activity in the rostral SMA.

Conclusions:

• Surgical treatment of SD, by altering a peripheral organ, reversed abnormal central nervous system activity.
• This study provides the first evidence linking peripheral treatment efficacy to the normalization of brain function in SD.