Improving coordination of international aphasia research

The last decade has seen an increase in the development, conduct and publication of high-quality aphasia studies including well-powered randomised controlled trials (Breitenstein et al., 2017; Godecke et al., 2020; Kristinsson et al., 2021; Nouwens et al., 2017; Palmer et al., 2019; Rose et al., 2019). Within this period, we have seen an increase in coordinated and collaborative aphasia research, exemplified by the establishment of international aphasia research collaborations, such as the Collaboration of Aphasia Trialists (CATs; www.aphasiatrials.org) and the international individual participant data (IPD) meta-analysis group RELEASE (REhabilitation and recovery of peopLE with Aphasia after StrokE) (Brady et al., 2020). This is demonstrative of a change in the way aphasia research is being conducted, moving beyond addressing historically region and discipline-specific aphasia activities, to improving international standards to achieve parity between and amongst studies conducted in different regions. Increasing the scale of aphasia research means that investigators are better placed to address the highly heterogenous nature of aphasia. This special issue describes such coordinated activities, each addressing different stages of the aphasia research pathway: generating consensus on definitions and interventions, adapting tools to facilitate international use, building on the existing evidence base, as well as planning coordinated international research.

Defining health conditions is an essential step in framing diagnostic categories, developing targeted and effective interventions, and enabling potential communities of people with the condition to form. There has been no universal agreement about the definition of aphasia and historical definitions do not encompass the broad domains of the International Classification of Functioning, Disability and Health (ICF) (World Health Organization Geneva, 2001) known to be impacted by aphasia. To tackle this challenge Berg et al. (2021) undertook an e-Delphi consensus study of more than 117 international aphasia researchers from 31 countries to attempt to establish consensus on an expanded definition of aphasia. Their results highlight consensus for an expanded definition that includes the broader ICF domains, but differences in opinion concerning the nature of the brain injuries underpinning aphasia and application of the key constructs of impairment versus disability. This expanded definition offers a platform for further consensus work involving people with lived experience of aphasia.

Valid and reliable outcome measurements are crucial for investigating the effects of aphasia interventions. Wallace et al. (2021) carried out a scoping review to identify all the available standardised measurement instruments validated with people with aphasia and to examine their aims, constructs, structure, and possible cultural adaptations. They found 146 outcome measures, the majority focusing on body functions, and none on patient-reported treatment impact or satisfaction. The work provides an excellent resource for clinicians and researchers seeking validated outcome measures suited to their particular aims and contexts.

Accurate and detailed description of research methods is a fundamental to enable correct interpretation of the study results and future study replication. In complex interventions utilised in aphasia rehabilitation protocols, this detail is essential to understand the therapeutic goal, the targets of the therapy, the proposed mechanisms of action, and what the therapist and client do (ingredients) (Fridriksson et al., in press). To examine the quality of reporting and identify a framework for improved reporting, Dipper et al. (2021) carried out an umbrella review across the full range of aphasia rehabilitation study designs for 93 studies yielded from three existing reviews. They applied the TIDieR checklist (Hoffmann et al., 2014) and a new qualitative checklist designed for this study, the Quality of Therapy Reporting, to the studies. Their results highlight the vast range of therapeutic approaches represented in the research literature, and the lack of specificity in intervention description. Dipper et al. highlight steps to take to address these reporting gaps.

Availability of reliable, validated outcome measures in a range of languages is essential for assessment of an increasingly multilingual clinical population, and for coordinated international research. Maviş et al. (2021) describe the adaptation of the Comprehensive Aphasia Test (CAT) for use in a Turkish population (CAT-TR), as part of a wider drive to produce culturally appropriate adaptations of the CAT. They examined imageability, familiarity and naming agreement in the CAT language battery subtests. The adapted CAT was then administered to people with aphasia and healthy, matched controls. Imageability and familiarity ratings of each word were strongly, positively correlated. Their adaptation, along with others undertaken and currently underway (CATs Working Group 2, 2021), will contribute to improved assessments across international research and clinical populations.

Additional themes explored in this Special Issue include a need to reduce research waste by building on the existing aphasia research evidence base. The RELEASE group describe the establishment of an international aphasia research database for the purpose of planned analyses into predictors and outcomes after post-stroke aphasia (Williams et al., in press). This group use big data principles to systematically identify, recruit, collate and analyse data from 174 contributions, encompassing 5,928 individual participants’ data, and including international information on demography, language impairment, therapy approaches and regimes, and outcomes. Such activities demonstrate how existing data can be reused to increase the lifespan of the data and contribute to high-quality research long after the original study has concluded.

In addition to harnessing the potential of existing study data, this Special Issue highlighted a need for prospective, coordinated international research efforts. The International Population Registry for AphasIa after StrokE (I-PRAISE; Ali et al., in press) protocol describes an international effort to coordinate prospective data collection to set up a population registry. Finally, the need to establish a coordinated international aphasia research strategy is emphasised to minimise duplication of effort and maximise research for the benefit of people with aphasia, their families and the professionals that support them (Ali et al., 2021). Such international, collaborative activities have the potential to propel research in the field, bringing experts together, increasing global relevance of the research and translating into benefit for a wider, international aphasia population. We look forward to the Collaboration of Aphasia Trialists expanding to bring together more researchers from different countries, settings and disciplines to deliver high-quality aphasia research and ultimately improve quality of life for people living with aphasia.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Additional information

Funding

This work was supported by the Tavistock Trust for Aphasia.