A Description of Phonetic, Acoustic, and Physiological Changes Associated With Improved Intelligibility in a Speaker With Spastic Dysarthria

Spastic dysarthria is a motor speech disorder produced by bilateral damage to the direct (pyramidal) and indirect (extrapyramidal) activation pathways of the central nervous system. This case report describes the recovery of an individual with severe spastic dysarthria and illustrates the close relationship between intelligibility measures and acoustic and physiological parameters. Detailed phonetic feature analyses combined with acoustic and physiological information helped to clarify (a) the loci of the intelligibility deficit, (b) the features of deviant speech whose improvement would lead to the greatest gains with treatment, and (c) the changes contributing to improvement in intelligibility observed over a 30-month treatment/recovery period. Though auditory-perceptual analysis remains the foundation of day-to-day dysarthria assessment, this case illustrates the potential for instrumental assessment to (a) supplement perceptual assessment techniques, (b) parse speech subsystem deficits, and (c) track ...