Effects of Lexical Stress on Noun and Verb Production in Aphasia
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1
Boston University, Speech, Language and Hearing Sciences, United States
Introduction: Word retrieval deficits are a hallmark symptom of aphasia. Theoretical models show how and when errors can arise during retrieval (Bock & Levelt, 1994; Dell, Schwartz, Martin, Saffran, & Gagnon, 1997), but they do not explain how syntactic class and lexical stress affect retrieval. Patients with aphasia (PWA) have been found to show selective retrieval deficits for words based on whether they’re nouns or verbs (Miceli, Silveri, Villa, & Caramazza, 1984). PWA have also shown more phonology errors when producing bisyllabic words with unstressed first syllables (weak-strong) compared to words with stressed first syllables (strong-weak) (Nickels & Howard, 1999). English two-syllable nouns predominantly have strong-weak stress while verbs predominantly have weak-strong stress (Kelly & Bock, 1988), but it is unknown whether PWA are prone to make errors when producing nouns or verbs because of their stress patterns. The current study examined how syntactic class and lexical stress affect production errors in PWA.
Methods: 11 PWA and 12 healthy controls participated in a single-word production task. Participants repeated 80 two-syllable words presented auditorily, with the written word shown for 1 second. Half the stimuli were nouns and half were verbs. Stimuli were counterbalanced for strong-weak and weak-strong stress patterns. Participants’ responses were transcribed using stress-marked broad transcription and scored on binary scales for overall accuracy, presence of phonology errors, and presence of stress-assignment errors.
Results: Pearson’s chi-squared test showed that controls had significantly higher overall accuracy than PWA (χ2 = 246.87, p < 0.001, controls were at ceiling). The patient data were examined using three logistic regression models. A 2 (syntactic class) x 2 (lexical stress pattern) logistic regression showed that PWA had lower overall accuracy on weak-strong words compared to strong-weak words (β = -0.471, z = -5.446, p < 0.001). A second 2 x 2 logistic regression analysis of phonology errors showed that PWA produced more phonology errors on weak-strong words than strong-weak words (β = 0.494, z = 5.506, p < 0.001). There was a trend toward PWA producing more phonology errors in verbs than nouns (β = 0.174, z = 1.937, p = 0.0527) and the interaction between syntactic class and stress approached significance (β = -0.162, z = -1.809 p = 0.0705). A third 2 x 2 logistic regression analysis showed no significant main effect of syntactic class (β = 0.0256, z = 0.190, p = 0.850), stress (β = 0.162, z = 1.202, p = 0.229), or interaction effect (β = -0.0569, z = -0.422, p = 0.673) on stress-assignment errors.
Discussion: Results indicated that lexical stress patterns affect PWA’s overall accuracy and phonology in single-word production. PWA were more prone to make phonology errors on weak-strong words. However, PWA were not more likely to make stress assignment errors on weak-strong words. These findings support Nickels and Howard (1999), and they show that weak-strong stress influences phonology errors in PWA for both nouns and verbs during production. Implications for theoretical models are considered.
Acknowledgements
The authors would like to thank Shreya Chaturvedi and Christine Wu for their assistance and contributions. They would also like to thank all the participations for their involvement in this study.
References
Bock, J. K., & Levelt, W. J. M. (1994). Language Production: Grammatical Encoding. Handbook of Psycholinguistics, 945–984.
Dell, G. S., Schwartz, M. F., Martin, N., Saffran, E. M., & Gagnon, D. a. (1997). Lexical access in aphasic and nonaphasic speakers. Psychological Review, 104(4), 801–838. http://doi.org/10.1037/0033-295X.104.4.801
Kelly, M. H., & Bock, J. K. (1988). Stress in Time. Journal of Experimental Psychology: Human Perception and Performance, I(3), 389–403.
Miceli, G., Silveri, M. C., Villa, G., & Caramazza, A. (1984). Miceli, Silveri, Villa et al. (1984) On the Basis for the Agrammatic’s Difficulty in Producing Main Verbs. Cortex, 20, 207–220.
Nickels, L., & Howard, D. (1999). Effects of lexical stress on aphasic word production. Clinical Linguistics & Phonetics, 13(4), 269–294. http://doi.org/10.1080/026992099299086
Keywords:
lexical stress,
word production,
nouns & verbs,
word retrieval,
Aphasia
Conference:
Academy of Aphasia 55th Annual Meeting , Baltimore, United States, 5 Nov - 7 Nov, 2017.
Presentation Type:
poster presentation
Topic:
General Submission
Citation:
Quillen
IA and
Kiran
S
(2019). Effects of Lexical Stress on Noun and Verb Production in Aphasia.
Conference Abstract:
Academy of Aphasia 55th Annual Meeting .
doi: 10.3389/conf.fnhum.2017.223.00035
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Received:
02 May 2017;
Published Online:
25 Jan 2019.
*
Correspondence:
Mr. Ian A Quillen, Boston University, Speech, Language and Hearing Sciences, Boston, MA, 02215, United States, iquillen@bu.edu