Abstract
Keywords
Key recommendations and suggestions of the guideline
People with aphasia after stroke, should have the opportunity to access SLT frequently (we suggest at least four times weekly), intensively (we suggest at least 3 h weekly) and for an overall dose of at least 20 h of therapy to support their language recovery and quality of life.
Alternative approaches to therapy delivery such as digitally-delivered SLT or group-based SLT approaches may augment therapy provision
We suggest that people with aphasia after stroke should be offered individually-tailored SLT by functional relevance and level of language task difficulty.
Table of Contents
Composition of the working group.....................................................................................................................4
Development of the Population, Intervention, Comparator and Outcome (PICO) questions.....................................................................................................................4
Data extraction and analysis.....................................................................................................................5
Evaluation of the quality of evidence and formulation of recommendations.....................................................................................................................6
Introduction
Aphasia is an acquired impairment associated with stroke (and other neurological damage) that impacts on the ability to speak, write, and understand spoken (auditory comprehension) and written language (reading comprehension). Aphasia (historically also referred to as dysphasia 1 ) affects approximately one-third of people after stroke. 2 Across the world, based on the latest stroke incidence figures we estimate that more than 4 million people acquired stroke-related aphasia in 2019 alone. 3 Communication challenges due to impaired speech because of muscular weakness (dysarthria) or co-ordination problems (apraxia of speech) or due to sensory, auditory perceptual or cognitive deficits are excluded from this definition.
People with aphasia experience poorer overall functional, 4 psychosocial, 5 wellbeing, 6 pain7,8 and economic outcomes4,9,10 compared to stroke survivors without aphasia, despite having greater access to in-hospital stroke rehabilitation services.2,11 Effective intervention for language and communication impairment after stroke is a clinical research priority12,13 that benefits the individual with aphasia and multidisciplinary stroke service provision.
A Cochrane review considered 27 randomised controlled trials (
Subsequently, the REhabilitation and recovery of peopLE with Aphasia after StrokE (RELEASE) international collaboration established a database of 5928 individual participants’ data (IPD) from 174 aphasia post-stroke research datasets from 28 countries, utilising a systematic review approach. It included demographic, stroke, language impairment, and speech and language therapy intervention data and subsequent outcomes across a range of language outcomes. 16
Using a systematic review informed, one-stage, IPD network meta-analysis (controlling for participants’ baseline language score, age, sex and time since stroke) they explored the importance of different parameters of SLT aphasia rehabilitation; SLT frequency (the number of days therapy was delivered weekly), intensity (the number of therapy hours delivered weekly) and overall dose (total number of therapy hours across the intervention). RELEASE suggested important insights into a critical therapeutic range for SLT frequency, dose, and intensity associated with optimal language gains, though further confirmatory study designs are needed to test the hypotheses generated and to develop more tailored speech and language therapy interventions. 16
The ESO commissioned this aphasia rehabilitation guideline because of the high epidemiological and societal burden experienced by people with aphasia and their families after stroke; and the associated burden on healthcare professionals and the effective provision of stroke services to people with aphasia. These recommendations are based on findings from randomised controlled trials (RCTs) and RCT meta-analyses. Recommendations were agreed through consensus amongst the members of the guideline working group using the GRADE approach 17 and the ESO standard operating procedure for guideline development, 18 and have the approval of the ESO Guideline and Executive Committees.
The aim of this guideline is to provide recommendations to guide stroke healthcare professionals in the clinical management and decision making relating to aphasia rehabilitation dose, intensity, frequency, the use of brain stimulation, and SLT delivery approaches.
Methods
Composition of the working group
This guideline was initiated by the ESO. Co-chairpersons (MCB, KH) were selected to assemble and coordinate the Guideline Module Working Group (Supplement 1). The final group contained 12 aphasia rehabilitation experts reflecting a broad spectrum of professionals involved in aphasia rehabilitation: SLT (MCB, JI, FC, CJ, KH), speech and hearing sciences (LMTJ), psychology (KH, MM), physical and rehabilitation medicine (KSS, FB), neuropsychology (PM), clinical linguistics (IvdM) and neurology (AF) from 10 European countries. The working group was supported by three methodologists (PC, LH, SH) and three fellows who assisted with abstract and full-text screening, data extraction, quality ratings and drafting the text (CM, HPØ and NN). The group also benefitted from the support of the ESO administrator (YB). The ESO Guideline Board and Executive Committee approved the composition of the group.
Development of the Population, Intervention, Comparator and Outcome (PICO) questions
This guideline was prepared according to the ESO standard operating procedure, 18 and the GRADE framework 17 . The working group developed a list of topics and corresponding questions of greatest clinical interest. Using the PICO approach (Population, Intervention, Comparator and Outcome), 10 clinically relevant questions were formulated, reviewed by two external reviewers, and approved by members of the ESO Guideline Board and Executive Committee. Outcomes were rated by members of the working group as: critical, important or of limited importance according to GRADE criteria based on a Delphi approach (Table 1). For this guideline, we included data gathered on standardised outcome measurement instruments that captured overall language ability, functional communication, expressive language (and/or naming), auditory comprehension, communicative confidence, psychosocial well-being and quality of life. Safety, reported as adverse events and side effects, was considered in the context of brain stimulation intervention, specifically transcranial direct current stimulation (tDCS). As they were not rated as critical outcomes, reading and writing outcomes were not considered in this guideline (Supplement 2 for PICOs and rating of outcomes per PICO). We excluded qualitative data and data from informal, non-psychometrically tested or unpublished assessment tools, such as discourse analysis or informal tests of naming ability.
Rating of outcome importance as part of the Delphi process.
Literature search (identification and selection of relevant studies)
Search strategies were developed by the working group and an ESO guideline methodologist (SH) that reflected the scope of literature to inform the 10 approved PICO questions. Existing relevant and validated search strategies (e.g. within a published Cochrane review) were consulted so that our searching overlapped but did not duplicate pre-existing search activities. Where a recent high-quality systematic review addressed our guideline questions, the corresponding search strategy, data, and meta-synthesis results were referred to, extracted, or updated as necessary and appropriate to the objectives and methods of our guideline development procedures. The search strategies are detailed in Supplements 3 and 4.
Two electronic database searches informed this guideline; one relating to SLT intervention evidence base searched the following databases: MEDLINE, EMBASE, CINAHL, PsychInfo, the Cochrane central register of controlled trials, from 2015 to 10/03/2023; the second informed the evidence summary for tDCS delivered alongside SLT for aphasia after stroke and searched the same databases, from 2018 to 10/03/2023. Reference lists of relevant reviews with meta-analyses, included RCTs and working group members’ personal reference libraries were also screened for additional relevant records.
Search results were loaded into the web based Covidence platform (Health Innovation, Melbourne, Australia) for working group screening. Two group members were assigned to independently screen each title and abstract. Rating disagreements were resolved by a third reviewer, where necessary. Potentially relevant records were tagged by PICO questions. Two or more group members were subsequently assigned to assess the relevance of full texts retrieved by PICO question.
Studies included were RCTs involving participants that had received SLT for stroke-related aphasia. Where data were limited, we considered high-quality systematic review based individual participant data (IPD) meta-analyses. Specific inclusion/exclusion criteria were applied to the data informing each PICO (Supplement 5). Relevant interventions included all SLT approaches and the use of tDCS, categorised by stimulation location and principles, in conjunction with SLT. Spinal, brain stem and other non-invasive brain stimulation (such as transcranial magnetic stimulation) were excluded.
Data extraction and analysis
We developed and piloted a data extraction form which included categories that support high quality data extraction of complex interventions. 19 We extracted data from all included trials (Supplement 6). All primary dataset reports identified (main publication, additional reports, abstracts, including correspondence with the trialists) informed the data extraction. Where possible, this was supplemented by unpublished data from trialists typically provided to clarify areas of uncertainty in data extraction. Where trials recruited mixed populations, we sought the stroke specific data only, using agreed definitions to categorise participant populations. 20 Some trials randomised participants across several groups (typically two intervention groups compared to a control condition). Meta-analysis was conducted in paired comparisons; each intervention was compared to the control condition with the analysis adjusted to ensure we did not double count participants 21 with trial labels expanded to indicate which intervention was included in that comparison. For all multi-armed RCTs, only the randomised groups that met our eligibility criteria were included. Trial reports emerging from the same research centre (or involving the same investigators) over a similar publication period, were carefully considered in relation to the trials’ design, objectives, and interventions to ensure that we did not double count a single trial reported over two or more publications in any one meta-analysis calculation. We also checked for duplicate representation of participants across such trials. To reduce the risk of any recent SLT trial participation or an associated trial intervention having an impact on the participant’s baseline or outcome data in the subsequent trial, wherever possible we excluded duplicate participant’s data from the subsequent trial.
Evidence of the benefit of different approaches to SLT (and SLT with tDCS) were sought on a range of language, participation, wellbeing and quality of life outcomes, and in tDCS trials, we also extracted adverse events reports. In cross-over trials, data were extracted up to the point that participants changed intervention. Meta-analysis was performed using the Review Manager (RevMan, Version 5.4 or RevManWeb) Cochrane Collaboration software. For continuous outcomes we calculated the mean difference (MD) or standardised mean difference (SMD). Where the available data were reported using a single outcome measurement instrument, we meta-analysed (or in the context of a single trial’s data, presented) the data using MD, representing the mean point difference on that measurement instrument.
21
Where two or more outcome measurement instruments were used to capture a single outcome, the data were meta-analysed using SMD, a statistical value that does not directly reflect a unit of measurement on any of the contributing measurement instruments. We used odds ratios for adverse event data. All data syntheses calculated a 95% confidence interval (CI), used inverse variance and a random effects model.
21
Heterogeneity was checked. Interpretation of the percentage of effect estimate variability that may be due to heterogeneity drew on published guidance; where it may represent substantial (
The working group agreed a-priori to prioritise final value summary scores (post intervention, and where available follow-up as well) over change from baseline scores. Where an RCT only reported change from baseline outcome data, these were reported and presented in the
Evaluation of the quality of evidence and formulation of recommendations
With the approval of the European Stroke Organisation’s Guideline Committee, the risk of bias for each included RCT was assessed with the Cochrane Risk of Bias (RoB) tool 22 with each RoB domain considered and judged separately, with ratings resolved by a third reviewer, where necessary. As for many rehabilitation interventions, it was considered unfeasible to blind participants or providers to most behavioural SLT interventions for aphasia. Therefore, we considered risk of bias at study level as it related to the RoB domains that could be influenced, and then in aggregate for each of the evidence synthesis comparisons. 17 For each PICO question, and each outcome, the following were considered: risk of bias based on the available evidence (RCTs or IPD meta-analysis); inconsistency of results; indirectness of evidence, imprecision of results, and other possible bias. GRADE (Table 2) evidence profiles were formulated for each PICO. 17
GRADE quality of evidence.
The working group discussed and agreed the final summaries of the quality and strength of evidence and recommendations for each PICO question. In deciding the strength of the recommendations (Table 3), the group considered the quality of the evidence, in addition to any available data on values and preferences of people with stroke and aphasia, and the balance of desirable and undesirable effects, as recommended by the ESO Guideline standard operating procedure.
18
The working group reviewed and agreed this guideline document. Consensus was required for recommendations. The expert consensus statements were agreed using a Delphi approach. The final draft was subsequently reviewed and approved by two external reviewers, members of the ESO Guidelines Board, the ESO Executive Committee, in addition to the Editor and external peer reviewers of the
Formatting based on strength of recommendations.
Sensitivity and subgroup analysis
Sensitivity analyses were conducted to consider the impact of any decisions made in the data synthesis such as choice of outcome data. For example, where a single RCT reported data from two measurement instruments of relevance to a single outcome, data from either measurement instrument could have been included in the synthesis. In such situations we chose one dataset and then checked whether inclusion of the alternative dataset would have impacted on the meta-synthesis findings. Where data permitted, we planned subgroup analyses to examine time since aphasia onset.
Search results
An electronic database search identified 2974 records (after removing 1162 duplicates) of potential relevance to our planned evidence synthesis relating to SLT interventions for aphasia rehabilitation. We reviewed 373 full texts in detail and together with 10 trials drawn from the relevant Cochrane review, 28 trials were included in our subsequent analyses (Supplement 7). A further 668 records (after removing 196 duplicates) were identified in our second electronic search and were screened for evidence relating to the effectiveness of tDCS alongside SLT for aphasia. We reviewed 116 full text records and 17 trials were included in our analyses (Supplement 8). A total of 45 trials across all PICOs were included in our analyses.
Results
Functional communication and quality of life (post-intervention) meta-analyses and associated risk of bias tables are reported below (Figures 1–18) with all other outcome meta-analyses and meta-analysis of data gathered at follow-up timepoints available in Supplemental Files 9–17. The meta-analyses, GRADE evidence profiles (Supplement 18), and risk of bias (below and in Supplement 19) informed our recommendations.
Risk of bias profile for studies included in PICO 1 (immediately postintervention) analysis.
(a) PICO 1 Functional communication and (b) PICO 1 Quality of Life.
Risk of bias profile for studies included in PICO 2 (immediately postintervention) analysis.
(a) PICO 2 Functional communication and (b) PICO 2 Quality of Life.
Risk of bias profile for studies included in PICO 3 (immediately postintervention) analysis.
(a) PICO 3 Functional communication and (b) PICO 3 Quality of Life.
Risk of bias profile for studies included in PICO 4a (immediately postintervention) analysis.
(a) PICO 4a Functional communication and (b) PICO 4a Quality of Life.
Risk of bias profile for studies included in PICO 4b (immediately postintervention) analysis.
PICO 4b Functional communication.
Risk of bias profile for studies included in PICO 5a (immediately postintervention) analysis.
(a) PICO 5a Functional communication and (b) PICO 5a Quality of Life.
PICO 5b Risk of bias profile for studies (immediately post intervention) analysis.
(a) PICO 5b Functional communication and (b) PICO 5b Quality of Life.
PICO 6a Risk of bias profile for studies included (immediately post intervention) analysis.
(a) PICO 6a Functional communication, (b) PICO 6a Quality of Life, (c) PICO 6b Functional communication, and (d) PICO 6d Functional communication.
Risk of bias profile for studies included in PICO 7b (immediately post intervention analysis).
PICO 7b Quality of Life.
Analysis of current evidence
Overall, the evidence is based on five RCTs (randomised
Three RCTs reported on
Three RCTs reported data at
Additional information
Additional high-quality evidence relevant to this question was available from the RELEASE network meta-analysis which controlled for baseline age, sex, and time since stroke and drew on IPD from 16 RCTs 28 (the group summaries from two trials also informed the ESO randomised paired comparison meta-analyses described above). The IPD meta-analyses examined individual participants’ change from baseline on measures of overall language (480 IPD, 11 RCTs); functional communication (524 IPD, 14 RCTs), auditory comprehension (540 IPD, 16 RCTs) and naming (385 IPD, 13 RCTs). The greatest gains in overall language (18.37 Western Aphasia Battery-Aphasia Quotient (WAB-AQ) points, 95% CI [10.58–26.16], 31 IPD, 4 RCTs) and auditory comprehension (5.23 (Aachen Aphasia Test-Token Test (AAT-TT) points, 95% CI [1.51–8.95], 90 IPD, 7 RCTs) were associated with 20–50 h of SLT. The greatest gains in functional communication (0.94 AAT-Spontaneous Speech Communication (AAT-SSC) points, 95% CI [ 0.34–1.55], 11 IPD, 3 RCTs) were in the context of a slightly lower SLT dosage of 14–20 h, but this was based on a very small number of IPD and RCTs; the second highest gains occurred in the context of 20–50 h of SLT (0.77 AAT-SSC points, 95% CI [0.43–1.1], 96 IPD, 9 RCTs) and a higher number of IPD and RCTs.
In summary, RELEASE data supported the provision of SLT ⩾ 20 h in relation to overall language, auditory comprehension and potentially functional communication. 28 In our meta-synthesis the total difference in favour of high dose SLT was significant for quality of life and, in sensitivity analysis, for functional communication.
Analysis of current evidence
The evidence is based on eight RCTs (randomised
The low intensity group (typically a usual care control intervention) had access to SLT ranging from less than an hour,
25
1.5 h,
26
to 2–2.3 h29
–32 per week. Five RCTs measured
A smaller number of studies measured
Additional information
The RELEASE IPD network meta-analysis was informed by 16 RCTs (with summary data from three included in the ESO-led paired group-level summary data meta-analyses described above). The IPD meta-analyses drew on individual participants’ change from baseline on overall language (482 IPD, 11 RCTs); functional communication (533 IPD, 14 RCTs), auditory comprehension (540 IPD, 16 RCTs) and naming (385 IPD, 13 RCTs). High intensity SLT significantly contributed to auditory comprehension outcomes with peak gains from baseline associated with SLT more than 9 h per week (7.3 AAT-TT points, 95% CI [ 4.09–10.52], 141 IPD, 6 RCTs).
28
Gains were observed across different SLT intensities for overall language (482 IPD,
In summary, no comparison in our guideline meta-synthesis favoured low intensity usual care SLT interventions. Where significant differences between the high and low intensity SLT groups were observed, these favoured the provision of high intensity SLT. We noted that though our PICO defined high intensity SLT as ⩾3 h per week, high intensity in all but one of the included trials ranged from 4 h weekly 29 to much higher intensities of ⩾10 h26,31 and 15 h. 24 Nevertheless, individual abilities and preferences should also be considered in planning therapy intensity. Cochrane review evidence identified that participants in the acute-early subacute stages post stroke (within 3 months of aphasia onset) exhibited significant language benefits in the context of higher intensity SLT compared to participants with access to lower intensity SLT. However, those results were confounded by significantly higher dropouts (and lower adherence) to the higher intensity SLT. These significant gains and the dropout and adherence patterns were not evident amongst participants that were two or more years after aphasia onset. 14
Analysis of current evidence
Evidence synthesis for each outcome was based on data from up to three RCTs (randomised
Two studies reported
Additional information
The RELEASE IPD meta-analysis drew from 16 RCTs. None were represented in the ESO-led, paired group-level summary data meta-analyses described above. The IPD meta-analyses drew on individual participants’ change from baseline on overall language (482 IPD, 11 RCTs); functional communication (526 IPD, 14 RCTs), auditory comprehension (540 IPD, 16 RCTs) and naming (385 IPD, 13 RCTs). The greatest improvement, observed in overall language, was associated with SLT 5 days per week (14.95 WAB-AQ points, 95% CI [8.67–21.23],194 IPD, 6 RCTs). 28 Numerically lower, but clinically similar gains were observed for three-four and six SLT days per week but based on fewer IPD and RCTs. Significant functional communication gains from baseline were observed (526 IPD,14 RCTs) for SLT ⩽ 5 days per week with the greatest numerical gain associated with SLT 5 days per week (0.78 AAT-SSC points, 95% CI [0.48–1.09],155 IPD, 8 RCTs). On measures of auditory comprehension (540 IPD, 16 RCTs), SLT 4 or 5 days per week was associated with significant clinical gains from baseline, with SLT 4 days per week associated with the greatest numerical gains (5.86 AAT-TT points, 95% CI [1.64–10.01],114 IPD, 5 RCTs). It was notable that no significant gains from baseline were observed in the context of SLT interventions delivered 3 days weekly or less. Overall, the RELEASE data suggested that SLT delivered 4–5 days per week was associated with the greatest overall language, functional communication, and auditory comprehension gains. 28
Analysis of current evidence
The search identified 7 RCTs (randomised
Digital interventions considered varied. They examined the effectiveness of computer-based language exercises targeting specific linguistic components (e.g. word-picture matching, naming),37,39 remote telerehabilitation,38,41 or virtual reality and gaming software developed for people with aphasia.35,36 For example, in one study participants participated in virtual reality training consisting of interactive virtual scenarios. 36
Four RCTs found no difference between digitally delivered and in-person SLT on measures of
Three studies reported
Additional information
Evidence from the RELEASE IPD network meta-analysis suggested a slight, but clinically insignificant effect in the direction of in-person SLT.
16
The analysis regarding
In summary, current evidence suggests in person and digitally delivered SLT lead to similar gains. Where a difference was observed, based on one small study, that difference favoured a greater increase in communicative confidence after in-person SLT. 38 Other guidelines (e.g. the Australian and New Zealand Living Clinical Guidelines for Stroke Management, 42 National Clinical Guideline for Stroke for the United Kingdom and Ireland 43 ) suggest that basic rehabilitation principles should apply to both in-person and digital therapy, such as personalisation to individuals’ needs, goals and preferences, and monitoring and adjustment of the intervention by the therapist.
Analysis of current evidence
In this guideline the term ‘digital augmentation’ was defined as an enrichment of the SLT intervention, where the participants received SLT comprising a digital element in addition to in-person SLT. Our search identified six relevant RCTs (randomised
Five studies compared the groups’
Three studies reported
Analysis of current evidence
Seven RCTs that compared one-to-one SLT with group SLT for aphasia informed this PICO (randomised
We defined group SLT as therapy involving two or more people with aphasia. SLT approaches delivered included high intensity group therapy (such as constraint induced aphasia therapy or multimodality aphasia therapy)
24
while other group therapy was digitally delivered.
35
No differences were found between the interventions on
Fewer studies looked at
Analysis of current evidence
Meta-synthesis was not conducted for this PICO question. Two potentially eligible trials were identified in our search, but suitable outcome data were unavailable from one unpublished trial,
53
leaving one small trial eligible for inclusion (randomised
Analysis of current evidence
The evidence for tDCS alongside SLT for aphasia is based on data from 17 RCTs (randomised
a. Left Hemisphere anodal tDCS plus SLT versus sham tDCS plus SLT
b. Left Hemisphere cathodal tDCS plus SLT versus sham tDCS plus SLT
c. Right Hemisphere anodal tDCS plus SLT versus sham tDCS plus SLT
d. Right Hemisphere cathodal tDCS plus SLT versus sham tDCS plus SLT
e. Cerebellar (anodal or cathodal) tDCS plus SLT versus sham tDCS plus SLT
f. Individualised Left Hemisphere (anodal or cathodal) tDCS plus SLT versus sham tDCS plus SLT
PICO 6 (a) Left Hemisphere anodal tDCS plus SLT versus sham tDCS plus SLT
Twelve RCTs (randomised
A further small study also compared anodal left hemisphere tDCS administered to the left primary motor cortex during a 2-week computerised SLT naming therapy intervention to sham tDCS plus SLT (
Similarly, in the studies above, there was no difference between the interventions at
PICO 6 (b) Left Hemisphere cathodal tDCS plus SLT versus sham tDCS plus SLT
Left hemispheric cathodal tDCS plus SLT was compared with sham tDCS plus SLT by one very small trial
58
which found that
No
PICO 6 (c) Right Hemisphere anodal tDCS plus SLT versus sham tDCS plus SLT
A very small study compared right hemispheric anodal tDCS with a reference electrode on the contra-lateral frontopolar cortex delivered alongside SLT to a sham tDCS intervention and SLT.
56
Outcomes immediately after treatment favoured the provision of right hemispheric anodal tDCS with SLT for
PICO 6 (d) Right Hemisphere cathodal tDCS plus SLT versus sham tDCS plus SLT
Two RCTs (
PICO 6 (e) Cerebellum anodal or cathodal tDCS plus SLT versus sham tDCS plus SLT
One study compared effects of
PICO 6 (f) Individualised left hemisphere anodal or cathodal tDCS plus SLT versus sham tDCS plus SLT
One small trial (randomised
Additional information
Previous systematic reviews and meta-analyses of RCTs investigated potential short- or long-term benefits of anodal or cathodal tDCS in combination with different types of SLT interventions.72 –74 Inclusion criteria and meta-syntheses varied substantially across reviews, results were based on a small number of trials and participants, low to very low-quality evidence, and results were inconclusive. Hence, there is an urgent need for larger multi-centre trials of tDCS alongside SLT for aphasia using validated outcome measures and improved reporting of individual participant characteristics (e.g. time since stroke), interventions and adverse events. Owing to the large heterogeneity of lesion and symptom patterns across studies, exploration of individually tailored tDCS approaches (e.g. optimisation of current flow to intended target regions based on computational modelling) is warranted. 75 Notably, the absence of serious adverse effects reports associated with tDCS is a common finding so far, suggesting that tDCS may be a safe non-invasive brain stimulation approach for people with stroke-related aphasia, while abiding with current safety guidelines. 76
The expert consensus statement below was developed. All members agreed that left- or right-sided cortical or cerebellar tDCS (anodal or cathodal) should only be delivered alongside SLT in a high-quality trial context, where validated outcome measurement instruments are used, participant demographics are fully described and adverse events (even if none are observed) are reported. For the expert consensus statement below, of the 12 voting members of the working group, 10 agreed with the first statement, and 12 agreed with the remaining statement.
Analysis of current evidence
We identified no trials that specifically compared individually-tailored SLT by functional relevance to non-tailored SLT interventions. Future studies should consider tailoring treatment to individual needs by functional relevance to inform the evidence in this area.
Additional information
The RELEASE study extracted data on whether individual trial participants’ therapy interventions were tailored by functional relevance. Using IPD network meta-analysis and controlling for participants’ baseline age, sex and time since stroke, they found that SLT that was individually-tailored for functional relevance significantly contributed to auditory comprehension outcomes. 28
Significant gains on measures of auditory comprehension were only associated with functionally relevant SLT (5.26 AAT-TT points, 95% CI [2.05–8.47], 194 IPD, 7 RCTs). 28 On other outcomes, when significant changes from baseline were observed, higher gains occurred in the context of functionally relevant SLT for overall language ability (16.47 WAB-AQ points, 95% CI [10.95–21.99], 232 IPD, 6 RCTs), naming (8.79 Boston Naming Test (BNT) points, 95% CI [1.95–15.63], 113 IPD, 5 RCTs), and functional communication (0.74 AAT-SSC points, 95% CI [0.38–1.10], 249 IPD, 6 RCTs) than with non-tailored SLT interventions.
Analysis of current evidence
One small RCT (
Additional information
In the RELEASE network meta-analysis involving 495 IPD from an additional 17 RCTs, individually-tailored SLT by level of language task difficulty significantly contributed to auditory comprehension. 28 Significant auditory comprehension gains from baseline were only evident when SLT was tailored by level of language difficulty (4.57 TT-AAT points, 95% CI [1.55–7.60], 331 IPD, 10 RCTs). In contrast, SLT that was not tailored by level of language difficulty was associated with greater gains from baseline on measures of naming (10.21 BNT points, 95% CI [2.75–17.67], 79 IPD, 4 RCTs) and functional communication (0.81 AAT-SSC points, 95% CI [0.34–1.27], 141 IPD, 5 RCTs) compared to interventions tailored for level of language task difficulty. Similar overall language gains from baseline occurred in SLT tailored and non-tailored by level of language task difficulty.
Discussion
The ESO Aphasia Rehabilitation guideline offers a rigorous, in-depth and up-to-date evidence synthesis of the effectiveness of interventions for stroke-related aphasia where language (overall ability, expressive and receptive language), functional ability and quality of life benefits were considered. This evidence synthesis reflects significant updates on existing reviews of SLT and non-invasive tDCS for aphasia after stroke. 14 Where our pre-specified clinically relevant questions could not be informed by the available group-level syntheses, the findings of a recent IPD network meta-analysis informed our guideline recommendations. 28 The guideline aims to support multidisciplinary stroke rehabilitation team members’ clinical decision-making for the benefit of people with aphasia after stroke.
Aphasia has a profound impact on people’s lives, affecting their language, their ability to communicate and interact with their environment (functional communication) and their overall quality of life. People with aphasia have lower quality of life than those with stroke but without aphasia. 78 SLT benefits language recovery after stroke 14 and earlier intervention is associated with greater language gains (which may be achieved through a variety of mechanisms) and notable gains may continue to be made in the long term.16,79,88 The priority clinical question of ‘how’ therapy is delivered and the impact on language, quality of life and safety of brain stimulation were considered. Existing SLT guideline recommendations for aphasia typically stop short of quantifying specific therapeutic dose, intensity, or frequency. 80 Consequently, the standard dosage of SLT for aphasia varies widely across and within countries81 –84 with some reported levels considered to be so low as to be of questionable benefit to language recovery, a problem that extends across stroke rehabilitation disciplinary areas. 85
Following ESO guideline and meta-analysis processes we made a strong recommendation for interventions of ⩾20 SLT hours. Our confidence is based on the balance of the current evidence syntheses (including 28 ) and the lack of possible risks. We made weak recommendations for higher weekly SLT intensity (⩾3 h; noting intensity was ⩾4 h in all but one of the eight included RCTs), frequency (⩾4 days) and tailored SLT approaches. Our positive suggestions for intensity and frequency were made in the context of a therapeutic intervention which was highly unlikely to result in harm and thus outweighed any associated risks. Tailored SLT approaches are often mentioned as best practice recommendations, while our recommendation is based on best available evidence.
We identified fewer trials that compared standard in-person, one-to-one SLT with alternative therapy delivery models such as digital or group therapy, or augmentation of more traditional delivery models with digital therapy. We confidently suggest these alternative models can be used to augment traditional SLT dosage in resource constrained contexts, being unlikely to cause harm and outweighing any associated risks.
In the absence of evidence supporting the use of tDCS brain stimulation alongside SLT, such interventions should be considered experimental and should only be delivered in the context of a well-regulated clinical trial where potential adverse events and side effects are fully reported. Synthesis of tDCS trials was based on stimulation site and principles rather than a broad lumping approach. Several trials (
Our recommendations (summarised in Table 4) were informed by trials that recruited participants across the post-stroke trajectory; from acute to chronic stages of recovery.
20
The data identified was insufficient to support our planned subgroup analysis based on post-stroke timepoints. While insights continue to emerge from trial-level and large aphasia-specific IPD subgroup meta-analyses, to date these have been insufficiently powered to support definitive conclusions relating to the language recovery gains at specific timepoints.79,87
–89 Evidence from the wider stroke rehabilitation literature highlights the importance of early access to stroke rehabilitation
90
and specifically aphasia rehabilitation.
91
New evidence suggests that with personalised, intensive and high dose speech and language therapy [6–7 weeks of intensive therapy (10 h per week, median (IQR) dosage = 6861
–76], young people (46–62 years) in the chronic stages post-stroke may (after adjusting for spontaneous recovery) make similar gains across language modalities to those in subacute stages (early
Synoptic table of all recommendations and expert consensus statements.
A recent systematic synthesis of stroke guidelines referring to aphasia therapy drew recommendations from 200 international stroke guidelines
91
and recommended aphasia treatment starts within 1 month of onset. Another systematic stroke guideline synthesis considered guidelines rated as high quality from Australia, Canada, UK and US and recommended offering people with aphasia ‘early, frequent, intensive treatment, as tolerated’.
92
Our recommendations extend those by adding specificity and important guidance on overall dose and regime. For some settings, offering SLT as recommended in this guideline may require an increase in current service provision; and alternative models of therapy delivery including for example group therapy and augmenting SLT with digital content. For others, usual care may be in excess of these recommended levels (⩾20 h of therapy, ⩾3 h weekly) and in such contexts, we highlight that our recommendations indicate
Our large multidisciplinary expert working group supported detailed and accurate data extraction, and clinically relevant comparisons and syntheses which prioritised a-priori the analysis of final value scores. To date, the evidence base for aphasia rehabilitation is predominantly based on a relatively small number of small-medium scaled studies, as is the case for much of the stroke rehabilitation interventions. Meta-analysis of trials’ average or group-level outcome summary scores offers an improvement on isolated trial reports from multiple small-medium scale studies by providing an evidence synthesis which considers the study size, precision and risk of bias. More recently, IPD meta-analysis has been undertaken, based on individual performance records, important individual characteristics (e.g. time post stroke or baseline aphasia severity) and where relevant, their specific treatment profile.16,88,89 We drew on the findings from both meta-synthesis approaches in developing this guideline. While there was a small overlap in the individual participant data informing these different meta-analysis approaches for two of the 10 PICOs addressed in this guideline (215 IPD in total), we have carefully highlighted where, and the degree to which this overlap occurred. While our preference would always be for many large-scaled trials in this field, such trials are just beginning to emerge. We hope that these clinical guidelines and consensus statements by experts in the field and associated evidence syntheses will not only contribute to improved clinical practice but also research developments (including larger trials evaluating more specific therapy comparisons and meta-analyses of such trials) in the future.
Our brain stimulation comparisons and evidence syntheses were carefully constructed to ensure meaningful comparisons. They were based on target hemisphere (left or right) and tDCS polarity (anodal or cathodal) resulting in six separate meta-syntheses. We carefully extracted data on standardised outcome measurement instruments, at study level (where relevant across multiple published reports of a single trial), and up to the point of intervention cross-over to avoid carry over effects. We also performed a detailed review of IPD across brain stimulation trials and removed any overlapping or duplication of trial participants in our analyses.
Our recommendations are based on a narrow approach focussed on 10 PICOs. Additional clinically relevant SLT and brain stimulation review questions (such as the effectiveness of transcranial magnetic stimulation 96 ) and outcomes (such as reading and writing) could have been included in this review but for feasibility reasons were postponed for future guideline updates. Similarly, we relied on published reports of patient preferences and priorities. Due to limited direct trial-based comparisons in the literature, 16 examination of the effectiveness of different SLT approaches was not within the scope of this guideline.
Methodologically, two of our PICO questions would have been best addressed in non-inferiority trial designs. Moreover, blinding of participants to rehabilitation interventions is always problematic. Though brain stimulation can be compared to a placebo (sham) condition, it is difficult to blind participants to differences in SLT provision or delivery models. Lack of participant blinding contributes to risk of bias, lower GRADE ratings, and lower confidence in the evidence synthesis, thus reducing the strength of rehabilitation recommendations and potentially the impact of guidelines on clinical services. Lastly, future guidelines may revisit our a-priori decision to prioritise the meta-analysis of final value scores over change scores which may better reflect treatment response in a heterogeneous clinical population, though such a decision would carry the inherent risk that change score data may not be available for older trials.
Future research
Our review highlighted clinical-evidence gaps, small sample sizes (within trials and meta-analysis comparisons), use of non-validated outcome measurement instruments, and limited follow-up data with short timelines. More specific trial comparisons, evaluated within adequately funded studies of sufficient size and power that employ the highest quality methodologies (including use of the aphasia core outcome set97,98), detailed description of SLT interventions and home practice to support intervention comparisons and routinely captured follow-up data (up to a year post-intervention) are required to further the evidence base and in turn clinical guidelines. Greater insight is also required into the contribution social support for people with aphasia makes to measures of quality of life. While non-inferiority trials may inform clinical decision making, such trials are not without their own methodological challenges.99,100 We recognise the challenges of applying these requirements in the context of aphasia trials. Multicentred trials are becoming more common across settings with similar language, healthcare contexts and resources. The multilingual global population needs language-specific and culturally relevant outcome measurement instruments to capture language abilities and deficits. In turn, language-specific versions of outcome measurement instruments should be treated as separate outcome measurements within meta-analyses. While trials of language-based interventions will always require outcome measurement instruments that reflect the linguistic and cultural variations across global languages, adoption of the consensus core outcome set would improve trial quality and relevant secondary data analyses.97,101 Moreover, transparent and complete reporting of participant descriptors, social support, data and trials which address areas of priority would advance our field of research for the benefit of people with aphasia and the healthcare professionals that work with them.12,13,15,102,103
Conclusion
Although a third of stroke survivors experience aphasia, high quality trial data on the impact of SLT and brain stimulation on important aphasia outcomes is limited to a relatively small number of trials. For some clinically relevant research questions such as the benefit of tailoring in-person SLT interventions by functional relevance or level of language difficulty, we were unable to identify a trial-level comparison. This ESO aphasia rehabilitation clinical guideline not only supports clinical management and decision making relating to aphasia but also informs the development and design of future aphasia rehabilitation trials.
Supplemental Material
sj-docx-1-eso-10.1177_23969873241311025 – Supplemental material for European Stroke Organisation (ESO) guideline on aphasia rehabilitation
Supplemental material, sj-docx-1-eso-10.1177_23969873241311025 for European Stroke Organisation (ESO) guideline on aphasia rehabilitation by Marian C Brady, Claire Mills, Hege Prag Øra, Natalia Novaes, Frank Becker, Fofi Constantinidou, Agnes Flöel, Katharina S Sunnerhagen, Jytte Isaksen, Caroline Jagoe, Luis MT Jesus, Paola Marangolo, Marcus Meinzer, Ineke van der Meulen, Pauline Campbell, Leonard Ho, Salman Hussain and Katerina Hilari in European Stroke Journal
Footnotes
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