On the Definition and Terminology of Neurogenic Speech Disorders (Dysarthria)

Abstract

Speech is produced by coordinated movements of the speech organs, and speech disorders can be caused by disturbance of the neuromuscular system. Because a neurogenic speech disorder may impair the social life of an individual, it has been considered as one of the major speech-language disorders. This article is intended to present a historical review of neurogenic speech disorders (dysarthria) in terms of definition and terminology. After two classic papers on dysarthria appeared from Mayo Clinic (Darley et al. 1969), the definition of dysarthria has been unified with the following features: 1) any dimension of speech can be affected (not only articulation but also respiration, phonation, resonance and/or prosody); 2) it is caused by neuro-muscular dysfunction; and 3) it is a collective name for various types. Although "dysarthrias" and "pure dysarthria" have been used, "dysarthria" is the most used terminology in the literature. Although there has been confusion about terminology (translated labels) in Japan, "dysarthria" or a few proposed terms in Japanese are currently used.