Differential Diagnostic Patterns of Dysarthria

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.