Table 3.

Definitions of Return to Sport

Article	Return to Sport Criteria	Definition of Return to Sport	Special considerations
Anzalone 91	3 = somatic symptoms, cognitive performance and special physical exam.	A patient was cleared to begin the graduated return to play protocol after he or she had remained symptom free for a minimum of 48 hours, displayed a normal physical examination, exhibited a normal VOMS, and achieved neurocognitive testing scores that were at the patient’s baseline or within normal limits.	Different recovery times for each part of the vestibulo-ocular exam.
Baker 92	3 = somatic symptoms, cognitive performance and physical exertion test.	Recovery from sport-related concussion was self-assessment of asymptomatic or minimal symptoms (PCSS1= 0–6), then confirmed by computerized cognitive test (ANAM3 or ImPACT4) and no symptom exacerbation on voluntary exhaustion on BCTT2.	Only those student athletes that recovered during the 2–3 month time period were included in the analysis.
Black 64	3 = somatic symptoms, cognitive performance and balance.	Once all concussion-related symptoms on the SCAT had resolved, athletes were allowed to attempt the ImPACT. The athlete was recovered if the ImPACT scores were considered passable by the sports medicine doctor or certified athletic trainer.
Broglio 93	3 = somatic symptoms, cognitive performance and balance.	Axon Sports Computerized Cognitive Assessment Tool (CCAT) for neurocognition and SCAT for symptoms were used to measure recovery following sport concussion.	Electroencephalogram was performed during auditory oddball and go/no-go tasks but no significant differences were seen between injured and controls.
Brooks 51	2 = somatic symptoms and physical exertion test.	After resolution of clinical symptoms and signs, athletes gradually increased activity under supervision of a team physician. Athletes who remained asymptomatic throughout rehabilitation were cleared for return to play.
Brown 90	4 = somatic symptoms, cognitive performance, balance, and physical exertion test.	Athletes were considered recovered when they were symptom-free at rest, symptom-free with exertion and after discontinuing medicines prescribed for post-concussion symptoms, their BESS5 scores were back to baseline where available and their computerized neurocognitive test (ImPACT) scores were at or above baseline values.	Did not include participants who recovered in less than 3 weeks. Included some participants who had concussions that were similar to sport-related concussion; for example, falling off a jungle gym.
Buckley 47	3 = somatic symptoms, cognitive performance, and balance.	Recovery from sport related concussion was self-reported asymptomatic (GSC6= 0) and baseline values on ImPACT, BESS and SAC7.	The study measured recovery from sport related concussion for those recommended rest after concussion versus those not recommended rest after concussion.
Clausen 41	2 = somatic symptoms and physical exertion test.	Recovery was defined as self-reported asymptomatic (PCSS= 0–6) and ability to exercise to voluntary exhaustion without exacerbation of concussion symptoms on the BCTT. Secondary outcomes of recovery were recovery of cerebral blood flow velocity measured by Transcranial Doppler in the MCA9 and exercise to exhaustion without symptom exacerbation while achieving 85% of maximal heart rate and 90% of predicted VO2 max.	Females with PCS8 lasting for more than 6 weeks but less than 12 weeks completed a sub-symptom threshold aerobic exercise treatment program with physiological measures before and after treatment.
Collins 48	3 = somatic symptoms, cognitive performance and physical exertion test	All athletes needed to exhibit an asymptomatic presentation at rest and with physical exertion, as well as intact neurocognitive test performance on ImPACT	Measured the efficacy of new helmet design.
Corwin 89	5 = somatic symptoms, cognitive performance, academic performance, physical exertion test, and special physical exam.	Both clinical and computerized neurocognitive testing (ImPACT) were used. Clinical clearance for sports participation included ability to carry full cognitive workload in school, be asymptomatic with physical exertion and have normal VOMS10 Assessment.	The sample (200 participants) had vestibular signs after concussion whereas the controls did not have vestibular signs after concussion. Only 77% of the entire sample were sports related concussions, rest were similar injuries.
Crowe 42	2 = somatic symptoms and cognitive performance.	Return to baseline on CogSport for Kids11. Supplementary test= BRIEF-P and BRIEF-SR12 and CHQ13 were also completed on day 30. CogSport symptom scale > 7 was considered significant.	Six out of 10 participants were injured during contact sports, the remaining were injured due to falls or blows.
Darling 35	4 = somatic symptoms, cognitive performance, balance, physical exertion test.	Recovery was defined as no or minimal symptoms (PCSS) and normalization of balance (BESS) on the SCAT-2, return to baseline on neurocognitive testing (ImPACT or ANAM) and no exacerbation of symptoms on BCTT.	This study was a retrospective chart review and follow-up via telephonic interview after two months to check for exacerbation of symptoms or difficulties with school after the return to play decision was made. Only 91 put of 117 had follow-ups.
Elbin 53	3 = somatic symptoms, cognitive performance and physical exertion test.	Athletes were required to be symptom-free (PCSS) at rest and after physical exertion before receiving medical clearance. Athletes were also required to demonstrate neurocognitive performance (ImPACT) within normal limits (i.e., 80% confidence intervals using reliable change indices) of their own baseline scores after exertion. When symptom-free at rest, athletes were asked to schedule a clearance appointment, which included neurocognitive testing and a standardized exertion test.
Field 94	2 = somatic symptoms and cognitive performance	The PCSS was used to measure symptoms and a 25-minute battery of neuropsychological testing (paper-pencil tests) to measure neurocognitive ability after concussion.
Gill 54	4 = somatic symptoms, cognitive performance, physical exertion test and balance	Athletes had to be asymptomatic at rest and with each step of the return to play progression before returning to their sport. In addition, cognition (ImPACT) and postural stability (BESS) had to be at preinjury levels.	There was a concussed athlete group vs a non-concussed athlete group. There was also a second control group of non-athletes.
Henry 37	3 = somatic symptoms, cognitive performance, and special physical exam.	Recovery defined as symptom free (PCSS=0), return to baseline on ImPACT, DHI14 and vestibular-oculomotor exam except near-point convergence. Scores from DHI and vestibular-oculomotor exam were combined to form an aggregate score.
Hutchison 55	2 = somatic symptoms and exertion test.	Clinical recovery was defined as symptom free on Rivermead Post Concussion Symptom Questionnaire and no symptoms during the return to play protocol (exertion testing).	Other tests performed were Profile of Mood States – Short Form and Perceived Stress Scales. They were not used as a marker of recovery.
Iverson 95	3 = somatic symptoms, cognitive performance and physical exertion test.	The athlete must not have had an ImPACT neurocognitive composite score that was significantly worse than baseline or below the 10th percentile. They also had to be asymptomatic at rest on PCSS (PCSS<7) and after light aerobic exercise.
Kontos 49	3 = somatic symptoms, cognitive performance, physical exertion test.	Recovery determined by a trained clinician by being symptom free at rest, back to baseline cognitive performance (ImPACT) at rest and symptom free after exertion.	The sample was divided into three groups based on post-concussion headaches and recovery time for each was given separately.
Kriz 57	2 = somatic symptoms and cognitive performance.	PCSS was measured at initial and follow-up assessments. Pre-injury baseline (when available) and post-injury neurocognitive function was assessed with ImPACT and used in decision-making regarding return to school and return to play for injured student-athletes.	This study compared the level of physical development before and after puberty to recovery from sport-related concussion.
Lau 32	3 = somatic symptoms, cognitive performance and physical exertion text.	Recovery was defined as clearance to return to play which was defined as asymptomatic at both rest and after exertion protocols (Zurich Guidelines), PCSS less than 7, the athlete must have had 2 ImPACT scores that were statistically lower than baseline or age-normative data and athlete’s neurocognitive composite score must have been above the tenth percentile for his age.	The study sample was divided into groups based on recovery times. Rapid recovery group recovered in 4.31 ±1.74 days and protracted group recovered in 29.61 ±6.65 days.
Lax 96	2 = somatic symptoms and cognitive exertion test.	Recovery was defined at resolution of symptoms on PCS-R15 and then ability to perform a neurocognitive battery in one sitting without symptom exacerbation. The neurocognitive battery consisted of Children’s Color Trails, Rey Auditory Verbal Learning Test, Rey Complex Figure Test, Stroop Color and Word Test Children’s version, Symbol Digit Modalities Test and verbal fluency component of NEPSY-II16.	Although all these neurocognitive tests were performed, the only goal was to complete them without exacerbation of symptoms.
Lovell 97	2 = somatic symptoms and cognitive performance.	Recovery was monitored using ImPACT’s PCSS and neurocognitive testing.	Only mild concussions were included in this study (i.e, no loss of consciousness)
Lovell 59	3 = somatic symptoms, cognitive performance and physical exertion test.	For an athlete to be recovered, all ImPACT composite scores were required to be above baseline levels or within the normal range and athletes had to be asymptomatic at rest and during graduated aerobic exercises.	fMRI was also done and compared with clinical recovery.
Lynall 60	4 = somatic symptoms, cognitive performance, balance and special physical exam.	After concussion, the athlete has to complete a clinical battery of tests including computerized neurocognitive testing, graded symptom checklist (both part of CNS Vital Signs) and SOT17 and these results had to be comparable to baseline values. Recovery was complemented by a thorough clinical exam by physician. Additional testing may be conducted if requested by the physician.	This study tried to see if there were any difference in preseason baseline testing scores before and after a concussion hence they described the time from recovery to next preseason baseline.
	3 = somatic symptoms, cognitive performance, and balance.	When ImPACT, balance and symptoms (PCSS) had returned to baseline, the athlete was determined to be recovered. Exercise intolerance was also measured in this study but was not a criterion for recovery.	Method of assessing balance was not specified. This randomized control trial evaluated the efficacy of moderate physical exercise on a bike versus rest as a treatment modality after acute concussion.
Makdissi 61	3 = somatic symptoms, cognitive performance and physical exertion test.	Clinical recovery was defined as return to full training or competitive play, it included symptom resolution both at rest and exertion, and recovery of cognitive function (DSST18, TMT-B19). The team doctor also had to make the return to play decision. CogSport was also used to measure cognitive recovery, but due to time and resource limitations, not all teams were able to use it as part of the testing protocol.
Maugans 81	4 = somatic symptoms, cognitive performance, physical exertion test and cerebral blood flow.	Clinical recovery was defined as symptom resolution on the ImPACT, return to normal physical and cognitive activity. Recovery of cerebral blood flow was defined as return to control values. MRI20 and H-MRS21 were performed during this study, but were not statistically significant and were not used to measure clinical recovery.	27% of patients recovered cerebral blood flow within 14 days and > 64% after 30 days but clinical recovery was within 14 days.
Mautner 44	2 = somatic symptoms and cognitive performance.	Post-concussion recovery was defined as a return to equivalent baseline neurocognitive score on ImPACT and concussion symptom score of less than or equal to 7.	In this study, patients with self-reported ADHD plus sport-related concussion were compared to controls without ADHD but with sport-related concussion.
McClincy 62	3 = somatic symptoms, cognitive performance and physical exertion test.	To determine when an athlete was completely recovered from concussion, their post-concussion data were compared to their baseline data. All athletes diagnosed with an in season concussion did not return to play until they were symptom free at rest and with exertion and their ImPACT data had returned to baseline levels.	On day 14, only verbal memory scores were significantly different from baseline.
McDevit 98	4 = somatic symptoms, cognitive performance, balance and special physical exam.	Full return to play was determined by treating physician which included objective screening (including vestibular-ocular assessments), balance (BESS) and ImPACT. Gene testing for GRIN2A promoter polymorphs was also done to see if it would have any correlation to recovery time.	This study tested the relationship of the gene and the duration of post concussive symptoms.
Mcgrath 45	2 = somatic symptoms and cognitive performance.	The athletic trainer made the decision that participant was symptom free (this does not mean PCSS=0), ImPACT scores returned to baseline at rest. After the patients were symptom free at rest, they participated in a physical exertion protocol and neurocognitive tests were retested. This did not affect the already made diagnosis of clinically recovered.	The participants were classified as post physical exertion neurocognitive test pass or fail.
Meehan 50	4 = somatic symptoms, cognitive performance, balance and physical exertion test.	Recovery is defined as symptom free (PCSS=0) at rest and exertion after discontinuing any medication for post concussive symptoms, ImPACT scores at or above baseline, BESS at baseline. Baseline score were not available for majority of the participants, so they were compared to age normative date.
Miller 99	2 = somatic symptoms, balance and physical exertion test	Recovery was defined as patients who were free of symptoms on the SCAT2 both at rest and with exertion.	Participants injured in motor sports like motocross were also included.
Morgan 100	2 = somatic symptoms and physical exertion test.	The controls were defined as recovered by clearance from a trained health care provider of symptom resolution (PCSS) at rest and exertion. They did not use the Likert Scale on the PCSS, instead scored them as present or absent.	In this study, the controls were the ones who recovered from a concussion within 3 weeks and the study sample developed PCS.
Murugavel 56	3 = somatic symptoms, cognitive performance and physical exertion test.	Athletes were cleared to return to full contact play once they were symptom free at rest, had successfully completed the exertional program and were neurocognitively functioning at baseline levels on ImPACT.
Nelson 65	3 = somatic symptoms, cognitive performance and balance.	Recovery was defined in two ways: (1) GSC, BESS, SAC and traditional paper-pencil neurocognitive tests at each baseline and post-injury time point to look for evidence of differential recovery patterns across high school and collegiate athletes, and (2) compared concussed athletes (for high school and collegiate groups separately) with uninjured control participants at each time point.
Newsome 66	2 = somatic symptoms and cognitive performance.	Resolution of post-concussion symptoms, recovery of cognitive performance on ImPACT to preseason level, and clearance by a licensed health provider to return to play by day 30 post-injury.	After the athlete was recovered, functional connectivity was assessed 1 month after sport-related concussion.
Ono 101	2 = somatic symptoms and cognitive performance.	Recovery was measured as the number of days to return to baseline neurocognitive and symptom scores on ImPACT
Ransom 63	2 = somatic symptoms and cognitive performance.	Recovered participants were those that had no elevation of symptoms on PCSI22 (was adjusted by subtracting post injury scores by baseline scores) and no impairment on neurocognitive testing (age 5–12 used Multimodal Assessment of Cognition and Symptoms for Children and age 13–18 used ImPACT). Participants and their parents also completed the CLASS23 to measure post injury academic experiences but that was not part of the recovery criteria.	The participants were labeled as recovered or not on average of 28th day from their concussion based on the tests.
Slobounov 84	2 = somatic symptoms and cognitive performance.	All patients were cleared for sport participation 10–15 days post-injury. Postural responses to visual field motion in a virtual reality environment were recorded up to 30 days after concussion.	Despite clinical recovery, all athletes had persistent abnormalities of balance (incoherence with visual field motion responses) during a “moving room” condition displayed on a virtual reality device, consistent with subtle ongoing abnormal postural control. Postural control was significantly worse and took longer to recover in those suffering a second concussion during the study period.
Slobounov 82	2 = somatic symptoms and cognitive performance.	All the athletes were cleared for sports participation based on Subjective Symptom Rating scale, DSST18, and Trails “B” Test. EEG24 was done on day 7, 15, 30, 6 months and 12 months but did not contribute to the return to play decision.
Terwilliger 67	4 = somatic symptoms, cognitive performance, balance and academic performance.	Date of recovery was determined by clinician based on child and parent report of the resolution of symptoms (PCSI-SR13 and PCSI-P) plus cognition, balance, and school performance having returned to normal functioning.	They divided the participants into single and repeat injury groups and measured the difference in their return to play time.

¹PCSS= Post Concussion Symptom Scale, part of the Sport Concussion Assessment Tool (SCAT)⁷¹ and ImPACT.

²BCTT= Buffalo Concussion Treadmill Test,¹⁰² a progressive, graded treadmill test which leads to voluntary exhaustion.

³ANAM= Automated Neuropsychological Assessment Metrics,⁷⁴ a computerized neurocognitive test.

⁴ImPACT= Immediate Post-concussion Assessment and Cognitive Test,⁴³ a computerized neurocognitive test.

⁵BESS= Balance Error Scoring System,¹⁰³ a test for static balance also part of the SCAT.

⁶GSC= Graded Symptom Checklist,¹⁰⁴ a 17 item Likert style symptom list promoted by the National Athletic Trainer Association.

⁷SAC= Standard Assessment of Concussion,¹⁰⁵ a standardized onsite tool for checking concussion symptoms.

⁸PCS= Post-Concussion Syndrome.

⁹MCA= Middle Cerebral Artery.

¹⁰VOMS= Vestibular/Ocular Motor Screening Assessment, a standardized concussion screening assessment validated by the University of Pittsburg.¹⁰⁶

¹¹CogSport for Kids= A computerized neurocognitive test with includes a post-concussion symptom checklist (PCSC).⁷⁵

¹²BRIEF-P/SR= Behavioral Rating Inventory of Executive Function – Parent/Self-Report¹⁰⁷ is a measure to assess executive function in day to day environments for ages 12 and greater.

¹³CHQ= Child Health Questionnaire¹⁰⁸ is a measure of functional health status and well-being.

¹⁴DHI= Dizziness Handicap Inventory,¹⁰⁹ a measure to assess general dizziness.

¹⁵PCS-R= Post Concussion Symptom Scale-Revised,¹¹⁰ a 22 item self-report symptom questionnaire with a Likert scale.

¹⁶NEPSY-II= Developmental Neuropsychological Assessment Second Edition,¹¹¹ a comprehensive neuropsychological battery designed to create neuropsychological profiles for children.

¹⁷SOT= Sensory Organization Test performed on the NeuroCom Smart Balance Master.¹¹²

¹⁸DSST= Digit Symbol Substitution Test.

¹⁹TMT= Trail Making Test. CNS Vital Signs= A computerized neurocognitive test which includes a graded symptom checklist.⁷⁶

²⁰MRI= Magnetic Resonance Imaging.

²¹H-MRS= Hydrogen Magnetic Resonance Spectroscopy.

²²PCSI= Post-Concussion Symptom Inventory,¹¹³ a self-report form for concussion symptoms.

²³CLASS= Concussion Learning Assessment and School Survey,⁶³ a tool to measure post injury academic experiences.

²⁴EEG= Electroencephalogram.