An EPG study of lingual errors in adults with acquired aphasia: Implications for models of speech production.

Abstract

For a model of speech production to be comprehensive it must be able to account for both disordered and normal speech. The study of disordered speech often relies on perceptual judgements which are not always accurate enough representations of the speech process for such models. Perceptual judgements often encourage categorical decisions such as alveolar versus velar plosive which may not reflect articulatory reality. Evidence from EPG studies has identified non categorical errors, for example, so-called misdirected articulatory gestures (MAGs) which appear to be characteristic of aphasic speech. These involve distinctive lingual/palatal contacts which often remain undetected auditorily. For example, analysis of EPG data reveals cases where a perceived alveolar plosive may in reality be a double alveolar/velar articulation due to the presence of a velar MAG. This paper describes MAGs in ten aphasics and provides an explanation for them in relation to a modified model of interactive spreading activation.