Predictors of Poststroke Aphasia Recovery
Authors:   The REhabilitation and recovery of peopLE with Aphasia after StrokE (RELEASE) Collaborators, Ali Myzoon , VandenBerg Kathryn , Williams Linda J. , Williams Louise R. , Abo Masahiro , Becker Frank , Bowen Audrey , Brandenburg Caitlin , Breitenstein Caterina , Bruehl Stefanie , Copland David A. , Cranfill Tamara B. , Pietro-Bachmann Marie di , Enderby Pamela , Fillingham Joanne , Lucia Galli Federica , Gandolfi Marialuisa , Glize Bertrand , Godecke Erin , Hawkins Neil , Hilari Katerina , Hinckley Jacqueline , Horton Simon , Howard David , Jaecks Petra , Jefferies Elizabeth , Jesus Luis M.T. , Kambanaros Maria , Kyoung Kang Eun , Khedr Eman M. , Pak-Hin Kong Anthony , Kukkonen Tarja , Laganaro Marina , Lambon Ralph Matthew A. , Charlotte Laska Ann , Leemann Béatrice , Leff Alexander P. , Lima Roxele R. , Lorenz Antje , Mac Whinney Brian , Shisler Marshall Rebecca , Mattioli Flavia , Maviş İlknur , Meinzer Marcus , Nilipour Reza , Noé Enrique , Paik Nam-Jong , Palmer Rebecca , Papathanasiou Ilias , Patricio Brigida F , Pavão Martins Isabel , Price Cathy , Prizl Jakovac Tatjana , Rochon Elizabeth , Rose Miranda L , Rosso Charlotte , Rubi-Fessen Ilona , Ruiter Marina B. , Snell Claerwen , Stahl Benjamin , Szaflarski Jerzy P. , Thomas Shirley A. , van de Sandt-Koenderman Mieke , van der Meulen Ineke , Visch-Brink Evy , Worrall Linda , Harris Wright Heather , Brady Marian C. 
Published: March 2021

Background and Purpose:
The factors associated with recovery of language domains after stroke remain uncertain. We described recovery of overall-language-ability, auditory comprehension, naming, and functional-communication across participants’ age, sex, and aphasia chronicity in a large, multilingual, international aphasia dataset.

Methods:
Individual participant data meta-analysis of systematically sourced aphasia datasets described overall-language ability using the Western Aphasia Battery Aphasia-Quotient; auditory comprehension by Aachen Aphasia Test (AAT) Token Test; naming by Boston Naming Test and functional-communication by AAT Spontaneous-Speech Communication subscale. Multivariable analyses regressed absolute score-changes from baseline across language domains onto covariates identified a priori in randomized controlled trials and all study types. Change-from-baseline scores were presented as estimates of means and 95% CIs. Heterogeneity was described using relative variance. Risk of bias was considered at dataset and meta-analysis level.

Results:
Assessments at baseline (median=43.6 weeks poststroke; interquartile range [4–165.1]) and first-follow-up (median=10 weeks from baseline; interquartile range [3–26]) were available for n=943 on overall-language ability, n=1056 on auditory comprehension, n=791 on naming and n=974 on functional-communication. Younger age (<55 years, +15.4 Western Aphasia Battery Aphasia-Quotient points [CI, 10.0–20.9], +6.1 correct on AAT Token Test [CI, 3.2–8.9]; +9.3 Boston Naming Test points [CI, 4.7–13.9]; +0.8 AAT Spontaneous-Speech Communication subscale points [CI, 0.5–1.0]) and enrollment <1 month post-onset (+19.1 Western Aphasia Battery Aphasia-Quotient points [CI, 13.9–24.4]; +5.3 correct on AAT Token Test [CI, 1.7–8.8]; +11.1 Boston Naming Test points [CI, 5.7–16.5]; and +1.1 AAT Spontaneous-Speech Communication subscale point [CI, 0.7–1.4]) conferred the greatest absolute change-from-baseline across each language domain. Improvements in language scores from baseline diminished with increasing age and aphasia chronicity. Data exhibited no significant statistical heterogeneity. Risk-of-bias was low to moderate-low.

Conclusions:
Earlier intervention for poststroke aphasia was crucial to maximize language recovery across a range of language domains, although recovery continued to be observed to a lesser extent beyond 6 months poststroke.