Differential Diagnostic Patterns of Dysarthria

TLDR

Thirty‑second speech samples from at least 30 patients in each of seven neurologic groups were independently rated by three judges on 38 speech and voice dimensions using a 7‑point severity scale. Computer analysis of these ratings revealed that speech patterns correspond to neuroanatomy and neurophysiology, enabling differentiation of five dysarthria types—flaccid, spastic, ataxic, hypokinetic, hyperkinetic—and a mixed flaccid‑spastic form in ALS, with distinct dimension patterns aiding diagnosis.

Abstract

Thirty-second speech samples were studied of at least 30 patients in each of 7 discrete neurologic groups, each patient unequivocally diagnosed as being a representative of his diagnostic group. Three judges independently rated each of these samples on each of 38 dimensions of speech and voice using a 7-point scale of severity. Computer analysis based on the means of the three ratings on each patient on each dimension yielded results leading to these conclusions: (1) Speech indeed follows neuroanatomy and neurophysiology. There are multiple types or patterns of dysarthria, each mirroring a different kind of abnormality of motor functioning. (2) These patterns of dysarthria can be differentiated; they sound different. They consist of definitive groupings of certain dimensions of speech and voice, deviant to distinctive degrees. (3) Five types of dysarthria were delineated: flaccid dysarthria (in bulbar palsy), spastic dysarthria (in pseudobulbar palsy), ataxic dysarthria (in cerebellar disorders), hypokinetic dysarthria (in parkinsonism), and hyperkinetic dysarthria (in dystonia and chorea). Also, a mixed dysarthria combining elements of flaccid and spastic dysarthrias was identified in amyotrophic lateral sclerosis. (4) Observed occurrence of a single dimension uniquely in a given neurologic disease and distinctive co-occurrence of several dimensions can aid diagnostically in identification of neurologic disorders.