Treatment fidelity monitoring, reporting and findings in a complex aphasia intervention trial: a substudy of the Very Early Rehabilitation in SpEech (VERSE) trial

BACKGROUND: Treatment fidelity is inconsistently reported in aphasia research, contributing to uncertainty about the effectiveness of types of aphasia therapy following stroke. We outline the processes and outcomes of treatment fidelity monitoring in a pre-specified secondary analysis of the VERSE trial. METHODS: VERSE was a 3-arm, single-blinded RCT with a 12-week primary endpoint comparing Usual Care (UC) to two higher intensity treatments: Usual Care-Plus (UC-Plus) and VERSE, a prescribed intervention. Primary outcome results were previously reported. This secondary analysis focused on treatment fidelity. Video-recorded treatment sessions in the higher intensity study arms were evaluated for treatment adherence and treatment differentiation. Treatment components were evaluated using a pre-determined fidelity checklist. Primary outcome: prescribed amount of therapy time (minutes); secondary outcomes: (i) adherence to therapy protocol (%) and (ii) treatment differentiation between control and high intensity groups. RESULTS: Two hundred forty-six participants were randomised to Usual Care (n=81), Usual Care-Plus (n=82), and VERSE (n=83). One hundred thirty-five (82%) participants in higher intensity intervention arms received the minimum prescribed therapy minutes. From 10,805 (UC 7787; UC-Plus 1450; VERSE 1568) service events, 431 treatment protocol deviations were noted in 114 participants. Four hundred thirty-seven videos were evaluated. The VERSE therapists achieved over 84% adherence to key protocol elements. Higher stroke and aphasia severity, older age, and being in the UC-Plus group predicted more treatment deviations. CONCLUSIONS: We found high levels of treatment adherence and differentiation between the intervention arms, providing greater confidence interpreting our results. The comprehensive systems for intervention fidelity monitoring and reporting in this trial make an important contribution to aphasia research and, we argue, should set a new standard for future aphasia studies. TRIAL REGISTRATION: ACTRN 12613000776707 SUPPLEMENTARY INFORMATION: The online version contains supplementary material available at 10.1186/s13063-022-06433-3.