(PS9-81) Developing Cognitive Behavioral Therapy Components for Multiple Sclerosis Fatigue Using the Multiphase Optimization Strategy: Results from a Pilot Trial

Abstract Text: Fatigue affects 80% of people with multiple sclerosis (MS), and nearly half report it as their most disabling symptom. Cognitive behavioral therapy (CBT) is an effective but resource-intensive treatment for MS fatigue, requiring 8-16 hour-long sessions delivered by a specialized clinician. The active components of CBT for fatigue and their mechanisms are unclear, and CBT for fatigue is not widely accessible due to implementation barriers. Thus, we are using the Multiphase Optimization Strategy (MOST) to examine the main effects of CBT components for MS fatigue, explore their mechanisms, and assemble a CBT-based treatment package for MS fatigue that balances efficacy and efficiency. In preparation for a factorial randomized controlled trial (RCT), we separated CBT for MS fatigue into three components — relaxation training (RT), behavioral activation (BA), and cognitive therapy (CT) — each consisting of four individual therapy sessions. We conducted a pilot trial to refine the components and research protocol. Adults with MS (N=21) were recruited from the research registry of a university MS center and randomly assigned to a component. Average participant age was 48 (SD=13), 62% identified as a woman, and 62% identified as White. We refined components based on qualitative feedback and explored pre- to post-intervention change in primary outcomes (fatigue; participation in social roles and activities) and putative mediators for each component (RT: serenity; BA: activity engagement; CT: fatigue catastrophizing). In this analysis, we focused on the quantitative outcomes by exploring pre-post intervention change using Hedge’s g, given the small pilot sample. We expected that each CBT component would have a small to medium impact on reducing fatigue impact and increasing participation, and that RT would increase feelings of serenity, BA would increase activity engagement, and CT would decrease fatigue catastrophizing. As expected, fatigue impact decreased at post-intervention with large effect sizes (CT: g=.96, BA: g=1.32, and RT: g=.72). Similarly, the CT (g=.56) and BA (g=.70) groups had medium to large improvements in ability to participate at post-intervention, though change in the RT group was negligible (g=.07). Proposed mediators also improved as expected (serenity in RT: g=.80, activity engagement in BA: g=1.23, fatigue catastrophizing in CT: g=.39). These pilot results align with prior findings suggesting that CBT is an effective treatment for MS fatigue. Though RT may be less effective at improving participation in social roles, no component clearly underperformed, which supported our decision to test all three components in a larger factorial RCT. The RCT will allow us to examine the efficacy of CBT components for improving MS fatigue and participation and further explore putative mediators, with the end goal of producing an effective, efficient, and accessible MS fatigue treatment.