Understanding Fluency in Aphasia
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1
University of Iowa, Communication Science and Disorders, United States
Introduction
The diagnosis of aphasia syndromes has been plagued since its earliest days by variable terminology and a lack of agreement on which dimensions yield the greatest diagnostic accuracy and clinical utility. Even categorizing aphasia dichotomously by the fluency of language output is not very reliable. Gordon (1998) found that practicing speech‐language pathologists relied primarily on reduced grammaticality, articulatory effort, and word-finding difficulties when rating the fluency of speech samples from 10 participants with aphasia (PwA). However, only half of the PwA were rated as fluent or nonfluent by a consensus of at least two‐thirds of the clinicians. We propose that the multi-dimensional nature of fluency is a major contributor to its lack of reliability. To investigate this, we examined the consistency of fluency classifications, and the spontaneous speech characteristics contributing to those classifications.
Method
Participants included 249 unique PwA in the AphasiaBank database (MacWhinney, Fromm, Forbes, & Holland, 2011) who had both fluency scale scores from the Western Aphasia Battery-Revised (WAB-R, Kertesz, 2006) and fluency classifications by clinicians, allowing comparison of these two measures. In addition, all had Cinderella story samples, from which we generated spontaneous speech measures. WAB fluency scores and all spontaneous speech measures were transformed to z-scores to facilitate comparisons.
Results
Agreement on fluency category was 86% overall, but was considerably higher for participants classified as fluent (91%) than nonfluent (78%) by WAB-R rating. Twenty-four PwA were designated as fluent by WAB-R, but nonfluent by clinicians. Compared to PwA with matching fluent classifications (n=126), these mismatching cases spoke more slowly, had shorter utterances, and produced relatively fewer prepositions, verbs, and pronouns, but more nouns (all ps<.01). These comparisons are illustrated in Figure 1. Twelve PwA were classified as nonfluent by WAB-R but perceived as fluent by clinicians. Relative to PwA classified as nonfluent by both WAB and clinicians (n=87), the mismatching PwA produced relatively more verbs and prepositions (p<.05; see Figure 1). Note that all of the spontaneous speech measures shown in Figure 1 significantly differentiated fluent and nonfluent groups, whether using WAB classifications or clinician judgements.
Discussion
Our analysis suggests that clinicians are sensitive to a variety of differences in the spontaneous speech of PwA that the WAB-R fluency scale does not capture. This seems to be particularly true in detecting nonfluent behaviors, such as speaking at a slower rate and using shorter utterances. In addition, clinician classifications paid more attention to the lexical composition of aphasic utterances. To its detriment, the WAB-R fluency scale forces the clinician to choose the best-fitting description based on a number of subjective judgements (e.g. word-finding, content, grammaticality, and effort). However, the scale may not adequately capture the underlying deficits that give rise to these judgments, such as shorter utterances and reduced verb use. These findings suggest a need for a more reliable and objective assessment of the underlying components of fluency in aphasia to improve the reliability of aphasia classification and provide more specific information regarding treatment targets. We are addressing this need in ongoing work.
Acknowledgements
Funded by a 2017 New Century Scholars Research Grant from the American Speech-Language-Hearing Foundation, awarded to both authors (Fluency Forward: Developing a More Reliable and Clinically Useful Assessment of Fluency in Aphasia).
We would also like to acknowledge the founders of and contributors to AphasiaBank and all of the people with aphasia who have participated.
References
Gordon, J. K. (1998). The fluency dimension in aphasia. Aphasiology, 12(7/8), 673‐688.
Kertesz, A. (2006). Western Aphasia Battery‐Revised. San Antonio, TX: Pearson.
MacWhinney, B., Fromm, D., Forbes, M. & Holland, A. (2011). AphasiaBank: Methods for studying discourse. Aphasiology, 25,1286-1307.
Keywords:
Aphasia,
fluency,
diagnosis,
spontaneous speech,
Clinical judgment
Conference:
Academy of Aphasia 56th Annual Meeting, Montreal, Canada, 21 Oct - 23 Oct, 2018.
Presentation Type:
poster presentation
Topic:
Eligible for a student award
Citation:
Clough
S and
Gordon
JK
(2019). Understanding Fluency in Aphasia.
Conference Abstract:
Academy of Aphasia 56th Annual Meeting.
doi: 10.3389/conf.fnhum.2018.228.00021
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Received:
25 Apr 2018;
Published Online:
22 Jan 2019.
*
Correspondence:
Ms. Sharice Clough, University of Iowa, Communication Science and Disorders, Iowa City, United States, sharice.clough@gmail.com