Effectiveness of intensive exposure therapy for persistent post-concussion symptoms: an aggregated single-case design approach

The fear-avoidance model suggests that catastrophising and avoidance behaviours can maintain persistent post-concussion symptoms (PPCS) after mild traumatic brain injury (mTBI). Although exposure therapy has shown preliminary success in this population, its effectiveness in mTBI remains unproven. This study investigated the therapeutic effects of this therapy across different settings. Twenty participants with PPCS took part in five concurrent multiple-baseline, multi-phase single-case experimental design studies. Phases included: baseline (A), exploration (B), active exposure (C), booster (D), and follow-up (E). Participants endorsed daily visual analogue scales assessing activity avoidance, satisfaction with daily functioning, and symptom experience. Data were aggregated and analysed using multi-level modelling. Results showed that the therapy effectively reduced avoidance behaviour, increased satisfaction, and reduced symptom burden. Phase B did not differ from baseline, whereas phase C, D, and E differed from baseline for avoidance (phase C: estimate = -4.33, p < .001; phase D: estimate = -4.02, p < .001; phase E: estimate = -3.92, p = .002), and satisfaction. Improvements in symptom burden were seen between baseline and phases D and E. Further analyses revealed that sex, treatment setting, and history of mental health treatment moderated the effects of avoidance. No other moderation effects were found. The rigorous study design, multiple replications, and robust statistical methods provide preliminary support for the effectiveness of this innovative therapy for PPCS. Additionally, findings reinforce the relevance of the fear-avoidance model and add to the growing evidence highlighting the benefits of exposure therapy - particularly intensive exposure approaches - for mTBI.