Process and outcome measures used in acceptance and commitment therapy research, with adults with acquired neurological conditions: a systematic review

Background: Acceptance and Commitment Therapy (ACT) interventions may promote wellbeing in neurological populations, but there is a lack of evidence to inform measure selection in research. Purpose: To identify and classify the measures used in ACT with adults with acquired neurological conditions.Methods: PRISMA guided systematic review. MEDLINE, PsycInfo and CINAHL databases searched (27/05/2020) with forward and backward searching. All study types included. Extraction of ACT process-of-change and health-related outcome measures. Outcomes coded using the Core Outcome Measures in Effectiveness Trials (COMET) taxonomy.Results: 204 papers screened. 34 studies included. Conditions included multiple sclerosis (n=17), traumatic brain injury (n=9) and stroke (n=8). 25 process-of-change measures extracted. Psychological flexibility was the most common process measured (AAQ-II most commonly used, n=14 studies). 76 health-related outcome measures extracted. Measures exploring quality of life, health status, anxiety and depression occurred most frequently. The Hospital Anxiety and Depression Scale was the most commonly used measure (n=8 studies). Conclusions: Future studies should follow reporting guidelines and consider the consistent use of measures to support synthesis of results. This could be achieved through the development of a Core Outcome Set – a standardised set of measures to be used across trials of ACT with adults with neurological conditions.