Dosage, Intensity, and Frequency of Language Therapy for Aphasia: A Systematic Review-Based, Individual Participant Data Network Meta-Analysis

Abstract

Background and purpose: Optimizing speech and language therapy (SLT) regimens for maximal aphasia recovery is a clinical research priority. We examined associations between SLT intensity (hours/week), dosage (total hours), frequency (days/week), duration (weeks), delivery (face to face, computer supported, individual tailoring, and home practice), content, and language outcomes for people with aphasia.

Methods: Databases including MEDLINE and Embase were searched (inception to September 2015). Published, unpublished, and emerging trials including SLT and ≥10 individual participant data on aphasia, language outcomes, and time post-onset were selected. Patient-level data on stroke, language, SLT, and trial risk of bias were independently extracted. Outcome measurement scores were standardized. A statistical inferencing, one-stage, random effects, network meta-analysis approach filtered individual participant data into an optimal model examining SLT regimen for overall language, auditory comprehension, naming, and functional communication pre-post intervention gains, adjusting for a priori-defined covariates (age, sex, time poststroke, and baseline aphasia severity), reporting estimates of mean change scores (95% CI).

Results: Data from 959 individual participant data (25 trials) were included. Greatest gains in overall language and comprehension were associated with >20 to 50 hours SLT dosage (18.37 [10.58-26.16] Western Aphasia Battery-Aphasia Quotient; 5.23 [1.51-8.95] Aachen Aphasia Test-Token Test). Greatest clinical overall language, functional communication, and comprehension gains were associated with 2 to 4 and 9+ SLT hours/week. Greatest clinical gains were associated with frequent SLT for overall language, functional communication (3-5+ days/week), and comprehension (4-5 days/week). Evidence of comprehension gains was absent for SLT ≤20 hours, <3 hours/week, and ≤3 days/week. Mixed receptive-expressive therapy, functionally tailored, with prescribed home practice was associated with the greatest overall gains. Relative variance was <30%. Risk of trial bias was low to moderate; low for meta-biases.

Conclusions: Greatest language recovery was associated with frequent, functionally tailored, receptive-expressive SLT, with prescribed home practice at a greater intensity and duration than reports of usual clinical services internationally. These exploratory findings suggest critical therapeutic ranges, informing hypothesis-testing trials and tailoring of clinical services. Registration: URL: https://www.crd.york.ac.uk/PROSPERO/; Unique identifier: CRD42018110947.

Keywords: aphasia; big data; comprehension; language therapy; meta-analysis; stroke.

Figure 1.

Individual participant data (IPD; data sets) by availability for network meta-analysis, language, demographics, and intervention. RCT indicates randomized controlled trial.

Figure 2.

Dosage (total speech and language therapy hours) by language outcome. Overall language ability (A), functional communication (B), auditory comprehension (C), and naming (D).

Figure 3.

Intensity (speech and language therapy hours weekly) by language outcome. Overall language ability (A), functional communication (B), auditory comprehension (C), and naming (D).

Figure 4.

Dosage (total speech and language therapy [SLT] hours) and associated gains from baseline (mean; 95% CI). Overall language (A): Western Aphasia Battery–Aphasia Quotient (0–100); 480 individual participant data (IPD; 11 randomized controlled trials [RCTs]); functional communication (B): Aachen Aphasia Test–Spontaneous Speech Communication (AAT-SSC; 0–5); 524 IPD (14 RCTs); auditory comprehension (C): Aachen Aphasia Test (AAT) Token Test (0–50); 540 IPD (16 RCTs); naming (D): Boston Naming Test (BNT; 0–60); 385 IPD (13 RCTs).

Figure 5.

Intensity (speech and language therapy hours/week) and associated gains from baseline (mean; 95% CI). Overall language (A): Western Aphasia Battery–Aphasia Quotient (0–100); 482 individual participant data (IPD; 11 randomized controlled trials [RCTs]); functional communication (B): Aachen Aphasia Test–Spontaneous Speech Communication (AAT-SSC; 0–5); 533 IPD (14 RCTs); auditory comprehension (C): Aachen Aphasia Test (AAT) Token Test (0–50); 540 IPD (16 RCTs); naming (D): Boston Naming Test (BNT; 0–60); 385 IPD (13 RCTs).