title: A causal test of the motor theory of speech perception: a case of impaired speech production and spared speech perception.
abstract: The debate about the causal role of the motor system in speech perception has been reignited by demonstrations that motor processes are engaged during the processing of speech sounds. Here, we evaluate which aspects of auditory speech processing are affected, and which are not, in a stroke patient with dysfunction of the speech motor system. We found that the patient showed a normal phonemic categorical boundary when discriminating two non-words that differ by a minimal pair (e.g., ADA-AGA). However, using the same stimuli, the patient was unable to identify or label the non-word stimuli (using a button-press response). A control task showed that he could identify speech sounds by speaker gender, ruling out a general labelling impairment. These data suggest that while the motor system is not causally involved in perception of the speech signal, it may be used when other cues (e.g., meaning, context) are not available.
authors.affiliation: a Department of Brain & Cognitive Sciences , University of Rochester , Rochester , NY , USA.
authors.forename: Alena
authors.initials: A
authors.lastname: Stasenko
authors.forename: Cory
authors.initials: C
authors.lastname: Bonn
authors.forename: Alex
authors.initials: A
authors.lastname: Teghipco
authors.forename: Frank E
authors.initials: FE
authors.lastname: Garcea
authors.forename: Catherine
authors.initials: C
authors.lastname: Sweet
authors.forename: Mary
authors.initials: M
authors.lastname: Dombovy
authors.forename: Joyce
authors.initials: J
authors.lastname: McDonough
authors.forename: Bradford Z
authors.initials: BZ
authors.lastname: Mahon
mesh_terms: D000161:Acoustic Stimulation; D001072:Apraxias / Q000150:complications / Q000503:physiopathology; D016022:Case-Control Studies; D003463:Cues; D005260:Female; D006801:Humans; D008297:Male; D008570:Memory, Short-Term / Q000502:physiology; D008875:Middle Aged; D059167:Mirror Neurons / Q000502:physiology; D008959:Models, Neurological; D009483:Neuropsychological Tests; D010700:Phonetics; D011578:Psycholinguistics; D011597:Psychomotor Performance / Q000502:physiology*; D012737:Sex Factors; D013018:Sound Spectrography; D013060:Speech; D013064:Speech Disorders / Q000150:complications / Q000503:physiopathology*; D013067:Speech Perception / Q000502:physiology*; D020521:Stroke / Q000150:complications / Q000503:physiopathology; D014059:Tongue / Q000033:anatomy & histology / Q000502:physiology; D014831:Voice / Q000502:physiology
keywords: apraxia of speech; categorical perception; mirror neurons; motor theory of speech perception