Development and validation of the vocal tremor scoring system

Area of Science:

• Otolaryngology
• Neurology
• Speech-Language Pathology

Background:

• Essential tremor (ET) affects 4% of the population, with 25% experiencing vocal tract involvement (essential tremor of voice, ETV).
• Variable success rates in treating vocal tremor stem from imprecise identification of affected areas.
• A standardized assessment system is crucial for effective ETV management.

Purpose of the Study:

• To develop and validate a standardized assessment tool for rating vocal tremor location and severity.
• To establish the Vocal Tremor Scoring System (VTSS) for clinical application and research.
• To assess the VTSS's ability to predict treatment outcomes for ETV.

Main Methods:

• A clinical consensus conference developed the VTSS for standardized vocal tremor rating.
• Video-perceptual analysis validated the tool's reliability and interrater agreement.
• The VTSS was applied to 10 patient examinations treated with botulinum toxin A (BtxA) to evaluate predictive accuracy.

Main Results:

• The VTSS assesses severity across multiple vocal tract sites, including the true vocal folds and palate.
• High interrater reliability (≥0.914) and excellent intrarater reliability were demonstrated for the VTSS.
• VTSS scores accurately predicted favorable outcomes in 100% of patients receiving BtxA when true vocal fold scores met specific criteria.

Conclusions:

• The VTSS is the first standardized system for rating vocal tremor's anatomic sites and severity.
• This tool enhances communication among otolaryngologists and facilitates research in ETV treatments.
• Utilizing the VTSS improves patient selection and success rates for intralaryngeal botulinum toxin therapy.