The Relationship Between Apraxia of Speech and Oral Apraxia: Association or Dissociation?
Acquired apraxia of speech (AOS) is a motor speech disorder that affects the implementation of articulatory gestures and the fluency and intelligibility of speech. Oral apraxia (OA) is an impairment of nonspeech volitional movement. Although many speakers with AOS also display difficulties with volitional nonspeech oral movements, the relationship between the 2 conditions is unclear. This study explored the relationship between speech and volitional nonspeech oral movement impairment in a sample of 50 participants with AOS. We examined levels of association and dissociation between speech and OA using a battery of nonspeech oromotor, speech, and auditory/aphasia tasks. There was evidence of a moderate positive association between the 2 impairments across participants. However, individual profiles revealed patterns of dissociation between the 2 in a few cases, with evidence of double dissociation of speech and oral apraxic impairment. We discuss the implications of these relationships for models of oral motor and speech control.
Department of Human Communication Sciences, University of Sheffield, Sheffield, UK s.whiteside@sheffield.ac.uk.
Sandra P
SP
Whiteside
Department of Human Communication Sciences, University of Sheffield, Sheffield, UK.
Lucy
L
Dyson
Department of Human Communication Sciences, University of Sheffield, Sheffield, UK.
Patricia E
PE
Cowell
Division of Psychology and Language Sciences, University College London, London, UK.
Rosemary A
RA
Varley
D000161:Acoustic Stimulation; D000328:Adult; D000368:Aged; D000369:Aged, 80 and over; D001072:Apraxias / Q000503:physiopathology*; D032882:Comprehension / Q000502:physiology; D016002:Discriminant Analysis; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D009483:Neuropsychological Tests; D012720:Severity of Illness Index; D013060:Speech / Q000502:physiology*; D013064:Speech Disorders; D018709:Statistics, Nonparametric
Association; Dissociation; Oral apraxia; Speech apraxia; Stroke