Self-reported and partner-reported functional communication and their relation to language and non-verbal cognition in mild to moderate aphasia

Purpose: Non-verbal cognition and language functions were examined in adult stroke survivors with aphasia. The specific purpose of the study was twofold: 1) to examine the relationship between self-reported outcomes from people with aphasia (PwA), measures of non-verbal cognition (Delis-Kaplan Executive Function Systems Test (D-KEFS), Delis, Kaplan, & Kramer, 2001) and measures of language (Western Aphasia Battery-Revised (WAB-R), Kertesz, 2007; Boston Naming Test Second Edition (BNT-2), Kaplan, Goodglass, & Weintraub, 2001) and 2) to examine these same relationships using partner-reported outcomes for that same group of PwA. This study used the Aphasia Communication Outcome Measure (ACOM, Doyle et al., 2013) to gather both self-reported ACOM data and partner-reported ACOM data (ratings of the person with aphasia’s communication made by a regular conversation partner). Method: Seventeen participants with aphasia underwent examination with an extensive test battery including measures of functional communication, non-verbal cognition, and language impairment. In addition, 16 of their regular communication partners rated functional communication performance. Results: Self-reported functional communication is strongly related to the number of errors committed on the D-KEFS design fluency test (r = .81, p = .001). Furthermore, a modified form of the D-KEFS design fluency test (in which the examinee is allowed unlimited time) shows that the proportion of errors contributes significantly to a two- predictor linear regression model. These two predictors account for 66% of the variance in self-reported functional communication ratings. These results suggest that non-verbal cognition for people with mild to moderate aphasia may serve an important role in functional communication. By contrast, self-reported functional communication was uncorrelated with aphasia severity (r = .04, p = .88), naming performance on either the WAB-R (r=.059, p=.823) or the BNT-2 (r=.097, p=.713), and category fluency (r=.086, p=.741). Partner-reported functional communication was highly correlated to the naming subtest on Western Aphasia Battery-Revised (WAB-R) scores (r=.71, p=.02) and to performance on the Boston Naming Test (BNT-2; r=.56, p=.026). Partner-reported functional communication was also strongly predicted based on the number of animals named during the category fluency task on the WAB-R (r=.782, p=.000). A linear regression model including WAB-R category fluency accounted for 61.1% of the variance in partner-reported ratings. A second linear regression adding naming as a predictor was not significant (Fchange = 2.18, p=.163). By contrast, none of the non-verbal cognition measures were useful predictors of partner-reported functional communication. These results suggest that aphasia severity serves an important role in partner ratings of functional communication whereas non-verbal cognition does not. Taken together, these results suggest that PwA and their partners rely on different aspects of communication when judging functional communication. Further work to explore the use of patient-reported outcome (PRO) measures and to identify factors that contribute to self-reported functional communication is needed. The discussion addresses the appropriateness of using PRO measures in aphasia and the use of surrogate reports