ACOUSTIC ANALYSIS OF DYSARTHRIA ASSOCIATED WITH MULTIPLE-SCLEROSIS

Approximately 40% of all individuals with multiple sclerosis (MS) present some degree of speech impairment. MS speakers with dysarthria are a heterogeneous group and the speech disorder is characterized by disturbances of the temporal patterning of speech as well as articulatory and phonatory symptoms. Previous research also indicates that the neuromotor dysfunction manifests itself in the fundamental frequency of sustained phonation, even in the absence of other speech symptoms: The present study was designed with the specific purpose of exploring the temporal, spectral and phonatory acoustic features of five MS speakers as compared to those of two normal controls. It was found that the dysarthric symptoms of these MS speakers largely mirror their different underlying neuromotor dysfunctions, and that they exhibit temporal and articulatory deviation when compared to the normal speakers. It is also suggested that a Fourier spectrum analysis of the derived pitch of the sustained phonation in MS speakers is particularly valuable in characterizing an important but often subtle symptom of their illness.