TY - JOUR
T1 - Speech motor planning in the context of phonetically similar words
T2 - Evidence from apraxia of speech and aphasia
AU - Mailend, Marja Liisa
AU - Maas, Edwin
AU - Beeson, Pélagie M.
AU - Story, Brad H.
AU - Forster, Kenneth I.
N1 - Funding Information:
Research reported in this publication was supported by the National Institute On Deafness And Other Communication Disorders of the National Institutes of Health under Award Number F31DC014375 and it was completed as part of the first author's doctoral dissertation at the University of Arizona. We would like to thank Fabiane Hirsch, Lisa Jackson, Kindle Rising, Chelsea Bayley, Janet Hawley, and Andrew DeMarco for assistance with participant recruitment; and Cailey Busker and Patrice Moritz for assistance with establishing reliability. Finally, we thank our participants for volunteering their time and cooperation in support of this research.
Publisher Copyright:
© 2019 Elsevier Ltd
PY - 2019/4
Y1 - 2019/4
N2 - The purpose of this study was to test two competing hypotheses about the nature of the impairment in apraxia of speech (AOS). The Reduced Buffer Capacity Hypothesis argues that people with AOS can hold only one syllable at a time in the speech motor planning buffer. The Program Retrieval Deficit Hypothesis, states that people with AOS have difficulty accessing the intended motor program in the context where several motor programs are activated simultaneously. The participants included eight speakers with AOS, most of whom also had aphasia, nine speakers with aphasia without AOS, and 25 age-matched control speakers. The experimental paradigm prompted single word production following three types of primes. In most trials, prime and target were the same (e.g., bill-bill). On some trials, the initial consonant differed in one phonetic feature (e.g., bill-dill; Similar) or in all phonetic features (fill-bill; Different). The dependent measures were accuracy and reaction time. The results revealed a switch cost – longer reaction times in trials where the prime and target differed compared to trials where they were the same words – in all groups; however, the switch cost was significantly larger in the AOS group compared to the other two groups. These findings are in line with the prediction of the Program Retrieval Deficit Hypothesis and suggest that speakers with AOS have difficulty with selecting one program over another when several programs compete for selection.
AB - The purpose of this study was to test two competing hypotheses about the nature of the impairment in apraxia of speech (AOS). The Reduced Buffer Capacity Hypothesis argues that people with AOS can hold only one syllable at a time in the speech motor planning buffer. The Program Retrieval Deficit Hypothesis, states that people with AOS have difficulty accessing the intended motor program in the context where several motor programs are activated simultaneously. The participants included eight speakers with AOS, most of whom also had aphasia, nine speakers with aphasia without AOS, and 25 age-matched control speakers. The experimental paradigm prompted single word production following three types of primes. In most trials, prime and target were the same (e.g., bill-bill). On some trials, the initial consonant differed in one phonetic feature (e.g., bill-dill; Similar) or in all phonetic features (fill-bill; Different). The dependent measures were accuracy and reaction time. The results revealed a switch cost – longer reaction times in trials where the prime and target differed compared to trials where they were the same words – in all groups; however, the switch cost was significantly larger in the AOS group compared to the other two groups. These findings are in line with the prediction of the Program Retrieval Deficit Hypothesis and suggest that speakers with AOS have difficulty with selecting one program over another when several programs compete for selection.
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U2 - 10.1016/j.neuropsychologia.2019.02.018
DO - 10.1016/j.neuropsychologia.2019.02.018
M3 - Article
C2 - 30817912
AN - SCOPUS:85062538357
SN - 0028-3932
VL - 127
SP - 171
EP - 184
JO - Neuropsychologia
JF - Neuropsychologia
ER -