Subgroups of Ataxic Dysarthria

Abstract

The role of the cerebellum in speech production is related to coordination and timing. When the cerebellar circuit is disrupted, the resulting speech disturbance is known as ataxic dysarthria. Features of this disruption include irregular articulatory breakdowns, distorted vowels, excess and equal stress, prolonged phonemes, and excess loudness variation. However, the manner in which these attributes present themselves is varied across the population. There is some suggestion in the literature that subgroups of ataxic dysarthria may exist, but these subgroups have never been developed or defined. The purpose of this pilot study was to determine a feasible, perceptual method for identifying and differentiating these proposed subgroups. To this end, a theoretical framework was created from existing literature which clustered speech symptoms according to notions of instability or inflexibility. Ten experienced speech-language pathologists listened to samples of speakers with ataxic dysarthria and completed rating forms of the speech features. Results suggested that five speakers fit the pattern of instability, one speaker aligned with inflexibility, and 4 speakers had a mixed presentation. The potential emergence of subgroups is promising and has implications for clinical and research practices. Additional research is warranted.