Abstract
Background: Evidence-based practice is a central paradigm in healthcare, aiming to integrate best available research evidence with clinical expertise and patient values. While this model has had profound influence, its application within rehabilitation has proven complex. Rehabilitation is inherently multifaceted, personalised, interdisciplinary and delivered across varied contexts, challenging the limits of randomised controlled trial (RCT) methodology. Research into rehabilitation for traumatic brain injury (TBI), a particularly heterogeneous and life-altering condition, exemplifies these challenges. Despite an increasing production of systematic reviews, there is an apparent lack of transformative or actionable evidence in the field. This raises fundamental questions about what constitutes "best available evidence" in the practice of complex, personcentred TBI rehabilitation.
Aim: To critically examine and contribute to understandings of evidence-based TBI rehabilitation by analysing the current state of evidence presented in systematic reviews and by developing an abbreviated grounded theory on the lived experiences of expert researchers in the field.
Methods: This thesis comprised two studies: an overview of all systematic reviews on TBI rehabilitation interventions and an abbreviated grounded theory study on the lived experiences of internationally recognised TBI rehabilitation researchers. The overview involved a search of six electronic databases from inception to March 2023. Selection of reviews and quality assessment (AMSTAR-2 for review methods; GRADE for certainty of evidence) were undertaken in duplicate. Novel methods were developed to synthesize and present the overview findings. The abbreviated grounded theory study involved semistructured interviews and constant comparative methods for data extract and synthesis.
Results: The overview of systematic reviews revealed a sobering reality: from a total of 135 reviews (published 2005-2023) and 142 discrete overview findings, no high-certainty evidence could be identified that supported the effectiveness of any rehabilitation intervention for improving quality of life, activity, or participation outcomes among people with TBI. While some reviews report limited or inconclusive evidence of benefit, the overall certainty of this evidence remained low or very low.
The abbreviated grounded theory study shed light on the complex realities of conducting RCTs and systematic reviews in TBI rehabilitation. Researchers expressed strong uncertainty about whether these methods were fit for purpose in such contexts. While successful RCTs do exist, they are exceptionally difficult to conduct and heavily reliant on specific enabling conditions. Participants also expressed concern that traditional hierarchies of evidence failed to capture the complexities of rehabilitation, particularly for heterogeneous populations such as people with TBI.
Conclusions: Advancing rehabilitation for people with TBI requires multiple concurrent shifts: greater international collaboration, higher-quality RCTs, greater uptake of alternative research designs, and more judicious and flexible use of reviews methods. A framework tailored to the complexity of rehabilitation interventions is essential, along with collaborative efforts to broaden and deepen data on functioning. Equally important are shared practices for outcome measurement, improved stakeholder research literacy, and stronger knowledge translation strategies. Ultimately, progress depends on a shared understanding of rehabilitation, functioning, and TBI itself, on recognising rehabilitation as a vital contributor to public health, and on research being used as a multidimensional tool for generating meaningful, life-relevant knowledge.