Delivering motivational interviewing early post stroke: standardisation of the intervention

Background We applied Motivational Interviewing (MI) techniques, early after stroke, to facilitate psychological adjustment to life post-stroke. In our trial, MI-plus-usual-care increased the likelihood of normal mood at 3-months post-stroke, compared to usual-care alone. Whilst appropriate training, manuals, and supervision may increase adherence to core principles of this complex intervention, unintended variability in implementation inevitably remains. We aimed to explore the impact of variability on participant outcome. Methods Using our trial data (411 participants), we explored variation in MI delivery, examining: therapist characteristics (stroke care expertise/knowledge, psychology training); MI content (fidelity to MI techniques assessed with Motivational Interviewing Treatment Integrity code, describing therapist behaviours as MI-consistent, MI-neutral or MI-inconsistent); and MI dose (number/duration of sessions). Results The four MI therapists (two nurses/two psychologists) had varying expertise and MI delivery. Across therapists, mean average session duration ranged 29.5-47.8 min. The percentage of participants completing the per-protocol four sessions ranged 47%-74%. These variations were not related to participant outcome. There were uniformly high frequencies (>99%) of MI-consistent and MI-neutral interactions, and low frequencies (<1%) of MI-inconsistent interactions. Conclusions Variation in therapist characteristics and MI dose did not affect participant outcome. These may have been tolerated due to high fidelity to MI principles.