Improving research outcome measurement in aphasia: Development of a core outcome set

Abstract

Aphasia treatment research lacks a consistent approach to outcome measurement. There is heterogeneity in the outcome measures used across treatment trials and a lack of research evidence exploring the outcome constructs which are most important to key stakeholders. The efficiency, relevancy, transparency, and overall quality of aphasia treatment research could be increased through the development of a core outcome set (COS)—an agreed standardised set of outcomes for use in treatment trials. The overarching aim of this research was to generate evidence-based recommendations for outcome constructs and outcome measures for a COS for aphasia treatment research. The thesis is comprised of a review of the literature (chapter 2) and two phases of research: (1) a trilogy of stakeholder consensus studies and a synthesis of the results; and (2) a scoping systematic review of studies reporting the measurement properties of standardised outcome instruments validated with people with aphasia. The World Health Organization International Classification of Functioning Disability and Health (ICF) was used across all studies to provide a common framework for the analysis of results. Study 1 aimed to gain consensus on important aphasia treatment outcomes from the perspective of people with aphasia and their families. A total of 39 people with aphasia and 29 family members participated in one of 16 nominal groups across seven countries. Qualitative content analysis revealed six themes describing: (1) Improved communication; (2) Increased life participation; (3) Changed attitudes through increased awareness and education about aphasia; (4) Recovered normality; (5) Improved physical and emotional well-being; and (6) Improved health services (people with aphasia) and Improved health and support services (family members). Prioritised outcomes for both participant groups linked to all ICF components; primarily Activity/Participation (39%) and Body Functions (36%) for people with aphasia, and Activity/Participation (49%) and Environmental Factors (28%) for family members. Outcomes prioritised by family members relating to the person with aphasia, primarily linked to Body Functions (60%). Study 2 aimed to gain consensus on important aphasia treatment outcomes from the perspective of aphasia treatment researchers. Purposively sampled researchers were invited to participate in a three-round e-Delphi exercise. Eighty researchers commenced round 1, with 72 completing the entire survey. High response rates (≥85%) were achieved in subsequent rounds. Researchers reached consensus that it is essential to measure language function and specific patient-reported outcomes (impact of treatment; communication-related quality of life; satisfaction with intervention; satisfaction with ability to communicate; and satisfaction with participation) in all aphasia treatment research. Outcomes reaching consensus linked to all ICF components. Study 3 aimed to gain consensus on important treatment outcomes from the perspective of aphasia clinicians and managers, again using a three-round e-Delphi exercise. In total, 265 clinicians and 53 managers (n=318) from 25 countries participated in round 1. A total of 51 outcomes reached consensus after the third round. The two outcomes with the highest levels of consensus both related to communication in the dyad. Outcomes relating to people with aphasia most frequently linked to the ICF Activity/Participation component (52%), whilst outcomes relating to significant others were evenly divided between the Activity/Participation component (36%) and Environmental Factors (36%). The results of studies 1-3 were synthesised through a comparison of ICF coding (study 4). Results revealed that important outcomes from aphasia treatment occur at all levels of the ICF. Within these components, congruence across three or more stakeholder groups was evident for outcomes which related to Mental functions (Emotional functions, Mental functions of language, Energy and drive functions); Communication (Communicating by language, signs and symbols, receiving and producing messages, conversations, and using communication devices and techniques); Services, systems, and policies (Health services, systems and policies), and quality of life. Study 5 was a scoping systematic review of studies reporting the measurement properties of standardised outcome instruments which have been validated with people with aphasia. In total, 184 references for 79 outcomes instruments were included in the review. The vast majority of outcome instruments related to Body Functions (n=49). No outcome instruments were reported to primarily measure constructs relating to Environmental Factors. A number of outcome instruments measured constructs which did not fall within the ICF, these included measures of quality of life (n=7), life satisfaction (n=1), and knowledge about aphasia and stroke (n=1). This program of research identified that important aphasia treatment outcomes span the ICF and also go beyond – encompassing quality of life. Stakeholders reported outcomes relating to: language; emotional wellbeing; communication; health services; and quality of life should be measured routinely. This research has highlighted the large number of outcome instruments available for use with people with aphasia, which predominately measure Body Functions. Targeted development of appropriate instruments is required in some construct areas. Outcome constructs identified in phase 1 of this research were paired with outcome instruments identified in phase 2, to provide recommendations for an international COS consensus meeting.