Prevalence and characteristics of dysarthria in a multiple-sclerosis incidence cohort: relation to neurological data

Few attempts have been made to use degree and type of multiple sclerosis (MS) dysarthria in neurological evaluation. In the present study, 77 individuals drawn from an MS population were examined both by a speech pathologist and a neurologist, and data from three sources of information were subsequently combined: (1) a clinical dysarthria test procedure, (2) a perceptual analysis of speech characteristics in continuous speech, and (3) neurological deficit scoring. The speech of 15 age- and gender-matched healthy control subjects was also investigated. It was concluded that: (1) the prevalence of mild to severe dysarthria in this cohort was 51% and occurred in all components of speech production: respiration, phonation, prosody, articulation and nasality. (2) The clinical dysarthria test was sensitive in detecting subclinical speech signs. The prevalence of pathologic speech signs found on the basis of the test was found to be 62%. The prevalence of dysarthria based on the neurological evaluation alone was 20%. (3) The dysarthria of MS was a predominantly mixed dysarthria, with both ataxic and spastic speech signs frequently present in the speech of a given individual. (4) Furthermore, when a predominant type of dysarthria existed, it was not generally associated with a characteristic profile of neurological deficits. Rather, severity of speech deviation was positively correlated to overall severity of neurological involvement, type of disease course, and number of years in progression.