Little Uniformity Seen In Criteria Used In Studies Evaluating Return To Play Decisions After Sport-Related Concussion

Experts recommend that return to play (RTP) decisions after a sport-related concussion (SRC) be based on multiple measures of recovery (1), but a recent literature review by researchers at SUNY-Buffalo (2) found only a minority of studies used multiple measures or had clearly defined return to sport criteria.

The disparate RTP criteria prompted the authors to recommend that, in the absence of a more objective definition of sport-related concussion and a consensus regarding a set of reliable measures of RTP readiness, a multimodal approach be used to promote consistent study design in SRC research and uniform and safe applications of RTP strategies in clinical practice.

Symptom resolution most common recovery measure

The study identified a variety of measures used to make the RTP decision, with eight conducting follow-up exams to validate the return to sport decision:

Symptom resolution or return to baseline: All 43 studies reported using some version of a symptom assessment to determine return to play readiness. Of those 31 used either the Post-Concussion Symptom Scale (which is part of the SCAT) or the symptom checklist from ImPACT.

Basing return to play readiness solely on symptom resolution, they noted, presented clinicians with four challenges.

Symptom reports are not specific to concussions.
Symptom resolution may not coincide with brain recovery, since physiological abnormalities – such as impaired cerebral blood flow and abnormalities seen using sophisticated brain imaging – persisting beyond reported symptom resolution have been reported in multiple studies of sport-related concussion (3)
While resolution of symptoms is recognized as a critical part of recovery, symptom reporting alone is problematic because athletes often under-report symptoms.
Symptom recovery is not consistently defined as an ‘asymptomatic state’, with 7 studies using a cut-off of a minimal symptom score (less than 7 out of a maximum of 132); 14 studies using a cut-off of ‘symptom free’ (symptom score of zero); 10 studies using ‘return to baseline symptoms’ as their recovery measure – the measure used by the most widely accepted guidelines for return to sport (the Concussion in Sport Group guidelines most recently promulgated after the Berlin Fifth International Conference on Concussion in Sport)(“CSG guidelines”)(1) ; and the remaining 12 either failing to specify what qualified as a normal level of symptoms or using a symptom checklist which did not measure severity on a 7-point (Lykert) scale.

Cognitive recovery or return to baseline (100%): The second most common measure used by researchers in determining return to play readiness (used in 27 of the studies) was return to baseline using neurocognitive testing, usually with a computer test like ImPACT, which assesses symptoms and aspects of cognition including visual memory, verbal memory, visual motor speed and reaction time that can be compared with individual pre-injury or age-normative values. Numerous studies, however, have noted limitations in using these tests in terms of test-retest reliability.

No exacerbation of symptoms with physical exertion (86%) : Consistent with the CSG guidelines, which recommend completion of a graduated return to sport strategy without exacerbation of symptoms, the principal of return to normal exercise tolerance was used in 21 studies to establish physiological recovery from concussion. Seventeen used a non-specific definition of provocative exercise to test for exacerbation of symptoms. Three evaluated exercise tolerance after concussion using the Buffalo Concussion Treadmill Test (BCTT)(all from the institution where the test was developed), which establishes physiological recovery from concussion in adolescents by measuring cerebral blood flow during exercise, and, the authors claim, is the “only functional test that has been shown to safely and reliably diagnose and establish recovery from exercise intolerance after SRC.^* One clearly described the return to sport protocol from the 2012 CSG guidelines.

Normalization of balance (30%): Because persisting and untreated balance problems could lead to future injuries on the playing field, thirteen used normalization of balance to measure return to sport. Of those, eleven used the BESS (Balanced Error Scoring System) test, which is part of the SCAT, one used the Sensory Organization Test, and one did not specify how balance was assessed.

Normal specialized physical examination (12%): Vestibular and visual dysfunction, including accommodation disorder, symptoms with vestibular ocular reflex (VOR) testing, or receded near point of convergence, are common following concussion and have been associated with prolonged concussion symptomatology. Five studies measured recovery through vestibular-ocular examination.

Successful return to school (5%):

No exacerbation of symptoms with physical exertion (2%)

Normalization of cerebral blood flow (2%)

Minority of studies used multiple measures of recovery

Of the studies that used multiple criteria to assess return to sport readiness, the breakdown was as follows:

11: symptoms and cognitive performance;
10: symptoms, cognitive performance, and physical exertion test;
5: symptoms, cognitive performance, and balance;
4: symptoms and physical exertion test;
4: symptoms, cognitive performance, balance and physical exertion test;
2: symptoms, cognitive performance, balance and return to learn;
1: symptoms and cognitive exercise test;
1: symptoms, cognitive performance, physical exertion test and cerebral blood flow;
1: symptoms, cognitive performance, physical exertion test, special physical exam and return to learn; and
1: symptoms, balance, and physical exertion test.

Weekly multimodal testing recommended

The authors encouraged researchers and clinicians to use standardized multiple criteria to establish recovery from a sport-related concussion, and suggested that testing on a weekly basis for up to 1 month following SRC (including general health questionnaires, symptoms, neurocognitive and balance testing and exertion testing) may be the best approach for determining recovery from concussion in young athletes.

* The authors, it should be noted, were the developers of the BCTT.

McCrory P , Meeuwisse W , Dvořák 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 2017;51:838–47.doi:10.1136/bjsports-2017-097699
Haider MN, Leddy JJ, Pavlesen S, et al. A systematic review of criteria used to define recovery from sport-related concussion in youth athletes. Br. J. Sports Med 2018;52:1179-1190.
Kamins J, Bigler E, Covassin T, et al. What is the physiological time to recovery after concussion? A systematic review. Br. J. Sports Med 2017;51:935-40.