Etiology and Diagnosis in Spasmodic Dysphonia

Abstract

Spasmodic dysphonia (SD) is a rare neurological disorder whose etiology is still unknown. In most cases, diagnosis is achieved mainly through perceptual evaluation of the patient's voice. Nevertheless some care must be taken in order to avoid misdiagnosis. The present paper is divided into three parts. The first part discusses the SD as first reported in the literature and its definition, and gives an overview of the historical aspects of SD as to how voice professionals have changed their approach towards the disease over the years. The second part depicts the most important approaches that a voice professional should pursue in order to achieve adequate diagnosis of SD. Although acoustic-perceptual evaluation is the main means of diagnosing SD, two other aspects should be considered. One is observation of laryngeal behavior during phonation of predetermined tasks. The other is careful history-taking from patients suspected of SD in order to distinguish them from other patients with other voice disorders who have similar or identical voice characteristics. The third part describes the major differential diagnoses that should be considered with all the patients suspected of SD. © 2001, The Japan Society of Logopedics and Phoniatrics. All rights reserved.