While there are a many patients who can be successfully managed in a primary care setting, there is an increasing recognition that many patients have a more delayed course and may require more active treatment. With this in mind, it would be ideal to be able to identify those patients who are at risk of a delayed recovery and those that will require a more active rehabilitation approach and to initiate an early referral for further assessments and treatment.

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There is an increasing body of evidence that suggests that there may be clues in a patient’s history that may help predict delayed recovery. The Concussion in Sport Group’s (CSIG) 5th consensus statement provides some guidance, suggesting that the strongest predictor of a slower recovery is the severity of the person’s initial symptoms in the first few days post injury.¹ Additional risk factors for a prolonged recovery include the development of subacute problems with migraine headaches or depression, a pre-existing mental health condition and being an adolescent. The impact of several factors that have traditionally been thought to be related to injury severity, such as loss of consciousness, retrograde amnesia or post-traumatic amnesia is inconsistent in the literature as risk factors for prolonged recovery. It was previously thought that a diagnosis of ADHD was also a risk factor but it appears this may impact on the planning and interventions around returning to work or school rather than prolonged recovery per se. Josh McKeown, a PhD student working in our Sports Concussion Clinic, looked at some of the clinical factors that may impact into recovery from our clinical data from February 2017 – December 2018, with a cohort of 568 patients. His paper titled “Predicting Sport-related mTBI Symptom Resolution Trajectory Using Initial Clinical Assessment Findings: A Retrospective Cohort Study” was published in Sports Medicine in 2019.² He was able to show through a complex logistic regression model that being female, reporting a higher positive symptom total (using data from the SCAT5 symptom checklist) and a symptom cluster that was not ‘physiological dominant’ (for example when the symptoms appeared more likely to be relate to the cervical spine or vestibular system) at initial assessment could predict those likely to have mTBI symptom resolution greater than 14 days. Unfortunately, he was not able to further sub-divide physiologically dominant symptoms into physical, cognitive, emotional or fatigue but it is my feeling that cognitive dominant patients (symptoms of poor concentration, poor memory, feeling slowed down, feeling like head is in a fog) have a more prolonged recovery as well.

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Based on the available data the patients who have the following characteristics may be less likely to recover. Clinicians assessing patients presenting after a concussion should consider using these factors to risk stratify those that are likely to recover quickly and could follow a graduated return to sport and those that are likely to benefit from referral for a specific active rehabilitation plan.

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1. Female gender
2. Non-physiological dominant cluster (vestibular dominant / cognitive dominant)
3. High positive symptom total using SAC-5 symptom scores (total = 22)
4. Patients with current or previous mental health diagnoses
5. History of migraines

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Once we have identified those who may be less likely to recover we need to make sure that they receive appropriate treatment. Prolonged rest, which has until recently been the treatment of choice, is no longer the preferred treatment option and can lead to prolonged morbidity. A more proactive approach, involving early active rehabilitation should now be considered to be the core treatment. In most situations, this involves aerobic activity, physiotherapy interventions and targeted treatment of a patient’s individual symptoms. This approach is especially important in athletic populations as periods of physical inactivity can have detrimental effects not only of physical performance but also psychological well-being. The appropriate level of physical activity is best assessed through one of two exercise modalities, either a modified Balke protocol on a treadmill (BCTT) or a staged cycle protocol on a stationary bike (BCBT). Both of these are safe validated tests that come from Buffalo Group led by Drs Barry Willer and John Leddy who have been instrumental in moving us more into an active approach to managing concussion.^{3 4} The treadmill protocol is likely well known to many practitioners, involving a one-minute incremental increase in work until termination which is either test cessation at 20 minutes or patient related measured increase in baseline symptoms. The BCBT may be well less known. This protocol involves 2-minute stages during which workloads are progressively increased at a set cadence. Practically the cycle test involves longer stages, smaller increases in intensity and requires the patient to be able to comfortably maintain a set RPM throughout the test. It has been shown that patients with acute concussion who were exercise intolerant on the BCTT were also intolerant on the BCBT, with symptom exacerbation occurring at a mean of 8.1 minutes on the BCTT versus 14.6 minutes on the BCBT. Furthermore, the heart rate at symptom exacerbation on BCBT is equivalent to the BCTT for the assessment of exercise tolerance after concussion in adolescents, allowing both modes to be used interchangeably at clinician’s discretion.⁵ This is used to then develop a sub-symptom exercise programme set at 90% of the achieved HR at test cessation. This achieves the physiological stimulation designed to increase production of brain derived neurotrophic factor (BDNF) to improve neural recovery, neural function and neural plasticity as well as benefiting the patient's psychological well-being.

1. McCrory P, Meeuwisse W, Dvorak J, et al. Consensus statement on concussion in sport—the 5th International conference on concussion in sport held in Berlin, October 2016. Br J Sports Med 2018;51:838-47. doi: doi:10.1136/bjsports-2017-097699
2. McGeown J, Kara S, Fulcher M, et al. Predicting Sport‑related mTBI Symptom Resolution Trajectory Using Initial Clinical Assessment Findings: A Retrospective Cohort Study. Sports Med 2019
3. Leddy J, Hinds A, Miecznikowski J, et al. Safety and prognostic utility of provocative exercise testing in acutely concussed adolescents: A randomized trial. Clin J Sport Med 2018;28(1):13-20.
4. Leddy JJ, Haider MN, Ellis MJ, et al. Early Subthreshold Aerobic Exercise for Sport-Related Concussion: A Randomized Clinical Trial. JAMA Pediatr 2019 doi: 10.1001/jamapediatrics.2018.4397 [published Online First: 2019/02/05]
5. Haider MN, Johnson SL, Mannix R, et al. The Buffalo Concussion Bike Test for Concussion Assessment in Adolescents. Sports Health 2019;11(6):492-97. doi: 10.1177/1941738119870189 [published Online First: 2019/09/06]

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