Consensus-Based Attributes for Identifying Patients With Spasmodic Dysphonia and Other Voice Disorders

Area of Science:

• Laryngology and Speech Science
• Clinical Research Methodology
• Diagnostic Criteria Development

Background:

• Research on adductor spasmodic dysphonia (ADSD), abductor SD (ABSD), voice tremor (VT), and muscular tension dysphonia (MTD) is limited by inconsistent patient selection criteria.
• Previous studies showed poor interrater agreement among specialists classifying these voice disorders without standardized guidelines.

Purpose of the Study:

• To assess expert agreement in classifying patients with ADSD, ABSD, VT, and MTD without standard guidelines.
• To develop consensus-based attributes for classifying these voice disorders for research purposes.

Main Methods:

• A multicenter observational study initially assessed interrater agreement among blinded experts classifying 178 patients.
• A subsequent 4-stage Delphi method involved a panel of 13 experts and 46 community specialists to identify and rank classification attributes.
• Patient classification was based on speech and nasolaryngoscopy video recordings.

Main Results:

• Initial classification without guidelines showed poor interrater agreement (κ < 0.40) and low agreement percentages (highest 34% with 11 categories).
• The Delphi method successfully generated 18 consensus attributes for classifying ADSD, ABSD, VT, and MTD from speech and nasolaryngoscopic examinations.
• Improved agreement was observed when using a reduced set of 6 categories (highest κ = 0.40).

Conclusions:

• Specialists exhibit poor agreement when classifying patients with ADSD, ABSD, VT, and MTD without established guidelines.
• The Delphi-based development of the Spasmodic Dysphonia Attributes Inventory provides a standardized tool for research classification of these voice disorders.