Search Abstracts | Symposia | Slide Sessions | Poster Sessions
The Behavioural and Neural Correlates of Functional Communication, Speech Informativeness and Efficiency in Post-Stroke Aphasia
Poster Session A, Wednesday, September 30, 11:00 am - 1:00 pm, Wangari Maathai
Erica Adezati1, Anna Beeghly2, Sharon Antonucci2,3, Jerzy P. Szaflarski4, Erica Middleton2,3, Daniel Mirman1; 1University of Edinburgh, Edinburgh, Scotland, United Kingdom, 2Jefferson Moss Rehabilitation Research Institute (MRRI), Elkins Park, PA, United States, 3Sidney Kimmel Medical College, Thomas Jefferson University, Philadelphia, PA, United States, 4The University of Alabama at Birmingham, Birmingham, Alabama, United States
Functional communication, that is the ability to communicate in a real-world context, is a critical outcome for people with aphasia and it is therefore vital to understand its underlying mechanisms and neurological correlates. The amount of accurate information produced during speech (i.e., speech informativeness) and how timely and effortlessly the information is conveyed (i.e., efficiency) are thought to contribute to functional communication, however the relationship between these discourse measures and functional communication remains unclear. The present study aimed to examine this relationship both at the behavioural and neurological level. We analysed data from 41 individuals with aphasia resulting from a left-hemispheric ischemic stroke. Functional communication was measured using Communication and Activities of Daily Living – third edition (CADL-3). Discourse measures were derived by performing a Correct Information Unit (CIU) analysis of speech samples produced during a speech elicitation task. We studied three discourse measures: number of CIUs (#CIUs), CIUs per word (%CIUs) and CIUs per minute (CIUs/min). While #CIUs and %CIUs provide a measure of informativeness, CIUs/min is thought to capture speech efficiency. Participants were also asked to complete a battery of psycholinguistic tests including the Western Aphasia Battery (WAB), Philadelphia Naming Test, Philadelphia Repetition Test, Non-word Repetition, Semantic Category Discrimination and Camel and Cactus test. First, we computed bivariate correlations between CADL-3, the CIU measures and scores on the psycholinguistic battery. Second, we performed multivariate lesion-symptom mapping analyses of CADL-3 and the CIU measures and compared their lesion correlates using Predictive Validity Comparison. Results showed that CADL-3 and the three discourse measures were moderately to highly correlated, and they were all highly correlated with the WAB Aphasia Quotient, a measure of aphasia severity. CADL-3 scores and the CIU measures were also moderately associated with both phonological and semantic processing measures. At the neurological level, there were moderate negative correlations between CADL-3, #CIUs, CIUs/min, but not %CIUs, and lesion volume, suggesting that lesion volume is an important predictor of performance on the CADL-3 and for #CIUs and CIUs/min, but less so for %CIUs. All measures were associated with damage to a similar set of regions, including dorsal white matter tracts (particularly the arcuate fasciculus) and parietal grey matter regions. #CIUs and CIUs/min were additionally associated with damage to the frontal aslant tract and inferior frontal gyrus, while CADL-3, %CIUs and CIUs/min were associated with damage to part 3 of the superior longitudinal fasciculus. Predictive Validity Comparison confirmed that CADL-3 and each of the CIU measures were associated with similar lesion patterns. Despite strong behavioural and neurological overlap, some people with aphasia had relatively low CIU scores but preserved functional communication. The preserved functional communication may be the result of spared auditory and reading comprehension abilities and of the use of effective non-verbal or minimally verbal communication strategies. We suggest that future research further investigate communication strategies in the context of impaired speech.
Topic Areas: Disorders: Acquired,