Inducing speech errors in dysarthria using tongue twisters

Although tongue twisters have been widely use to study speech production in healthy speakers, few studies have employed this methodology for individuals with speech impairment. The present study compared tongue twister errors produced by adults with dysarthria and age-matched healthy controls. Eight speakers (four female, four male; mean age = 54.5 years) with spastic (mixed-spastic) dysarthria of varying aetiology (cerebral palsy, multiple sclerosis, multiple system atrophy) and eight controls (four female, four male; mean age = 56.9 years) were audio-recorded producing tongue twisters. One word in each tongue twister was marked for prominence. Speakers with dysarthria produced significantly more errors and spoke slower than healthy controls. The effect of prominence was significant for both groups-words spoken with prosodic prominence were significantly less error prone compared with words without prominence. While both groups produced most errors on words in the third position (of four-word utterances), speakers with dysarthria also produced high rates of errors on the first and fourth words. This preliminary investigation demonstrated the promise of applying the tongue twister paradigm to speakers with dysarthria and contributes to the evidence base for the implementation of prosodic strategies in speech intervention.