1. Introduction 

In Denmark approximately 25.000 cases of mTBI are diagnosed each year1 with an additional estimated 25% undiagnosed,2 bringing the national incidence rate up to 545 pr. 100.000. This is in line with the international rate where incidents of mTBI, including diagnosed and undiagnosed, are estimated to be about 600 per 100.000 worldwide, or around 45 million a year.3 Of these, roughly 75-90% experience gradual remission of symptoms within 14 days, whereas 10-25% continue having symptoms, which may then devolve into Post-Concussion Syndrome (PCS).4,5 While no consensus on the timeframe exists, PCS can be defined as experiencing persistent symptoms of a mTBI for longer than 3 months, as by the DSM-5 criteria, with additional psychosocial sequelae.6,7 Patients often experience difficulties in maintaining their social, professional and physical levels of activity, and may be at risk of not participating in and contributing to the financial state of society. A Danish survey found that 19% of all mTBI patients were on sick leave for more than a month and that 2% had still not returned a year after the initial trauma.8 In the U.S., a report from the Agency for Health Research and Quality found that TBI patients across all levels of severity had a higher prevalence of long term depression at 30%, which is more than three times the national average at 8-10%, as well as higher rates of anxiety and PTSD.9
An increasing amount of evidence shows that an active approach, contrary to earlier beliefs about a ”wait and see approach”, can improve outcomes and long term prognosis.10–12 The international consensus statement on Concussion in Sports from 2016 in Berlin recommends a period of 24-48 hours of physical and cognitive rest after the initial trauma, followed by a progressively active rehabilitation.13 It is well established that PCS patients can experience barriers towards physical and cognitive activity, with higher levels of cognitive exertion associated with longer duration of symptoms in some,14 and that adequate management between rest and activity is a central yet complex part of the recovery process.15–17 These barriers often manifest as exercise intolerance, cervicogenic headaches, rapid eye exhaustion, dizziness, nausea, excessive fatigue, and a low threshold for managing sensory input.18–22 Therefore, it is important to clarify the parameters of an active approach to treatment in a rehabilitation setting. In this context, an active approach can be both an up or downregulation of physical and mental stimulation, as well as providing education and tools to promote patient self-efficacy.
One of the major challenges in dealing with PCS is categorizing the underlying pathologies and understanding their effect on the symptomatology, to which the evidence suggests a multitude of neurophysiological and psychosomatic mechanisms. These mechanisms include disruptions in cerebral blood flow (CBF),23,24changes in brain metabolism,25 axon damage,26 changes in autonomic and neuroendocrine function,27–30 cervical injury and postural weakness,31 disturbances in the vestibular and oculomotor system,32,33 and neuropsychological dysfunctions.34,35 These myriad of components and overlapping comorbidities adds to the complexity of PCS, and highlights the difficulties of having a single treatment regimen. It may also explain the varying responses to clinical assessment.36
A useful tool in organizing and providing the most relevant care is the evidence-based practice (EBP) model originally coined by Sackett37 and further developed through Straus38 and Howick.39 While different iterations exists, the model formulates three dimensions of best practice: Best Research Evidence which is the highest graded and most appropriate evidence in the scientific literature, Clinical Expertise which is the clinical experience and knowledge, and Patient Preferences which is the individual patient preferences, their values or larger group characteristics. Using the EBP model practitioners can more easily stratify the individual variables and formulate a cohesive plan of action to target the multifaceted nature of PCS.
By applying two distinct interventions, this paper will examine how an active and individualized approach can be used in the treatment of PCS. The empirical data will be derived from two case studies, each consisting of two cases with separate protocols, highlighting the aspects of overcoming symptoms of PCS with insight from the cases, as well as an inclusion of the relevant literature. This will be viewed through the lens of a modified EBP model and ultimately summarized in a visual presentation, to more appropriately transfer knowledge to the clinical practice.