Pre-speech tongue movements and verbal reaction times in acquired apraxia of speech

Difficulty in initiating utterances is one of the main characteristics of acquired apraxia of speech (AOS), yet few studies of the disorder have examined the lingual movements that occur prior to the acoustic onset. Research into verbal reaction time in a control population shows that lingual movement commences some time before the acoustic onset, and that the reaction time (RT) - the interval between the onset of articulation and the acoustic onset - is influenced by phonetic factors and speech preparation processes such as inhalation. Since speakers with AOS frequently make "groping" articulations and silent posturing prior to producing audible speech in an attempt to adopt the correct articulatory configuration, it is likely that RT in this population is strongly influenced by pre-speech lingual activity. This project proposes to examine this relationship and the wider implications for speech timing in AOS, using ultrasound tongue imaging and acoustic analysis.