Investigating Perceptual Subgroups of Ataxic Dysarthria

Abstract

Ataxic dysarthria can present with considerable variation of symptoms, bringing into question whether it is a single entity. Recent evidence suggests that subgroups of ataxic dysarthria may exist and likely emerge from motor control patterns of inflexibility and/or instability (Hartelius et al., 2000). To further examine this theory, eleven speakers with ataxic dysarthria completed speech diadochokinetic and polysyllabic word repetition tasks. Ten listeners perceptually rated speech samples using an online visual analog scale to identify the presence of subgroups in speakers with ataxic dysarthria. Based on the diadochokinetic tasks, namely the alternating motion rate (AMR) task, nine of the eleven speakers were found to align with the instability profile. The results complement converging evidence of the existence of subgroups and provide a potential link between the instability/inflexibility theory and the relative contribution of cerebellar feedforward/feedback mechanisms in ataxic dysarthria.