Benchmarks of Significant Change After Aphasia Rehabilitation

Abstract

Objective: To establish benchmarks of significant change for aphasia rehabilitation outcome measures (ie, Western Aphasia Battery-Aphasia Quotient [WAB-AQ], Communicative Effectiveness Index [CETI], Boston Naming Test [BNT]) and assess if those benchmarks significantly differ across subgroups (ie, time post onset, dose frequency, treatment type).

Data sources: A comprehensive literature search of 12 databases, reference lists of previous reviews, and evidence-based practice materials was conducted.

Study selection: Randomized controlled trials, quasi-experimental studies, single-subject design, and case studies that used a standardized outcome measure to assess change were included. Titles and full-text articles were screened using a dual review process. Seventy-eight studies met criteria for inclusion.

Data extraction: Data were extracted independently, and 25% of extractions were checked for reliability. All included studies were assigned quality indicator ratings and an evidence level.

Data synthesis: Random-effects meta-analyses were conducted separately for each study design group (ie, within-/between-group comparisons). For within-group designs, the summary effect size after aphasia rehabilitation was 5.03 points (95% confidence interval, 3.95-6.10, P<.001) on the WAB-AQ, 10.37 points (6.08-14.66, P<.001) on the CETI, and 3.30 points (2.43-4.18, P<.001) on the BNT. For between-group designs, the summary effect size was 5.05 points (1.64-8.46, P=.004) on the WAB-AQ and 0.55 points (-1.33 to 2.43, P=.564) on the BNT, the latter of which was not significant. Subgroup analyses for the within-group designs showed no significant differences in the summary effect size as a function of dose frequency or treatment type.

Conclusions: This study established benchmarks of significant change on 3 standardized outcome measures used in aphasia rehabilitation.

Keywords: Aphasia; Outcome; Rehabilitation; Speech therapy; Stroke.

Figure 1.

The PRISMA flow diagram1 of study inclusion. Note: 1. Moher D, Liberati A, Tetzlaff J, Altman DG. Preferred Reporting Items for Systematic Reviews and Meta-Analyses The PRISMA Statement. PLoS Med. 2009;6(7):6.

Figure 2.

Summary effect sizes for within group studies reporting the Western Aphasia Battery-Aphasia Quotient (WAB-AQ). The difference in means column reflects the pre-treatment mean subtracted from the post-treatment mean. The lower and upper limits columns show the 95% confidence interval surrounding the difference in means. The p-value indicates the significance of the effect. The final row describes the summary effect size, 95% confidence interval, and p-value. The diamond represents the summary effect size. The squares reflect effect sizes of individual studies.

Figure 3.

Summary effect sizes for within group studies reporting the Communicative Effectiveness Index (CETI) and Boston Naming Test (BNT). Figure details are the same as for Figure 2.

Figure 4.

Summary effect sizes for between group studies reporting the Western Aphasia Battery-Aphasia Quotient (WAB-AQ) and Boston Naming Test (BNT). The diamond is the summary effect size. The squares reflect effect sizes of individual studies. The difference in means column reflects the post-treatment control group mean change subtracted from the post-treatment experimental group mean change. The lower and upper limits columns show the 95% confidence interval surrounding the difference in mean change. The p-value indicates the significance of the effect. The final row describes the summary effect size, 95% confidence interval, and p-value. The diamond represents the summary effect size. The squares reflect effect sizes of individual studies.