Time Interval Between Concussions and Symptom Duration€¦ · Time Interval Between Concussions and Symptom Duration ... To test the hypothesis that children with a previous his-

Time Interval Between Concussions and SymptomDuration

WHAT’S KNOWN ON THIS SUBJECT: Although concussion isincreasingly being diagnosed in the pediatric population, little isknown about what factors lead to prolonged postconcussivesymptoms in children. In particular, the effect of previous historyof concussion on recovery from a repeat injury is unclear.

WHAT THIS STUDY ADDS: Children with a history of previousconcussion, particularly recent or multiple concussions, are atincreased risk for prolonged symptoms after concussion. Thissuggests that repeat concussion, particularly within a vulnerabletime window, may lead to longer duration of symptoms.

abstractOBJECTIVE: To test the hypothesis that children with a previous his-tory of concussion have a longer duration of symptoms after a repeatconcussion than those without such a history.

METHODS: Prospective cohort study of consecutive patients 11 to 22years old presenting to the emergency department of a children’shospital with an acute concussion. The main outcome measure wastime to symptom resolution, assessed by the Rivermead Post-Concussion Symptoms Questionnaire (RPSQ). Patients and providerscompleted a questionnaire describing mechanism of injury,associated symptoms, past medical history, examination findings,diagnostic studies, and the RPSQ. Patients were then seriallyadministered the RPSQ for 3 months after the concussion or untilall symptoms resolved.

RESULTS: A total of 280 patients were enrolled over 12 months. Patientswith a history of previous concussion had a longer duration of symp-toms than those without previous concussion (24 vs 12 days, P = .02).Median symptom duration was even longer for patients with multipleprevious concussions (28 days, P = .03) and for those who hadsustained a concussion within the previous year (35 days, P = .007)compared with patients without those risk factors. In a multivariatemodel, previous concussion, absence of loss of consciousness, age$13, and initial RPSQ score .18 were significant predictors of pro-longed recovery.

CONCLUSIONS: Children with a history of a previous concussion,particularly recent or multiple concussions, are at increasedrisk for prolonged symptoms after concussion. These findingshave direct implications on the management of patients with con-cussion who are at high risk for repeat injuries. Pediatrics2013;132:8–17

AUTHORS: Matthew A. Eisenberg, MD, John Andrea, BS,William Meehan, MD and Rebekah Mannix, MD, MPH

Division of Emergency Medicine, Boston Children’s Hospital,Harvard Medical School, Boston, Massachusetts

KEY WORDSbrain concussion, emergency medicine, pediatrics,postconcussion syndrome, traumatic brain injury

ABBREVIATIONSADHD—attention-deficit/hyperactivity disorderED—emergency departmentLOC—loss of consciousnessmTBI—mild traumatic brain injuryRPSQ—Rivermead Post-Concussion Symptoms Questionnaire

Dr Eisenberg was responsible for study conception and design,data acquisition and analysis, and drafting and review of thearticle; Mr Andrea was responsible for data acquisition andanalysis, and drafting and review of the article; Dr Meehan wasresponsible for study conception, study design, and articlereview; Dr Mannix was responsible for study conception, studydesign, data analysis, and article review; and all authorsapproved the final version of this manuscript.

www.pediatrics.org/cgi/doi/10.1542/peds.2013-0432

doi:10.1542/peds.2013-0432

Accepted for publication Mar 27, 2013

Address correspondence to Matthew A. Eisenberg, MD, Division ofEmergency Medicine, Boston Children’s Hospital, 300 LongwoodAve, Boston, MA 02115. E-mail: [email protected]

PEDIATRICS (ISSN Numbers: Print, 0031-4005; Online, 1098-4275).

Copyright © 2013 by the American Academy of Pediatrics

FINANCIAL DISCLOSURE: The authors have indicated they haveno financial relationships relevant to this article to disclose.

FUNDING: No external funding. Expenses related to use ofresearch coordinators were paid by the Division of EmergencyMedicine, Boston Children’s Hospital.

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Approximately 144 000 children pres-ent each year to US emergency depart-ments (EDs) with concussion,1,2 andmillions more are treated by athletictrainers, primary care doctors, oroutpatient specialists.3 Despite in-creasing scientific research into con-cussion, however, relatively little isknown about what factors lead toprolonged postconcussive symptomsin children. This lack of prognosticdata has led to significant uncertaintyamong patients, families, and healthcare providers as to which patientswould benefit from specialist follow-up,extended academic accommodations,prolonged abstinence from athleticparticipation, and even permanentcessation of high-risk activity.

Although a large and expanding body ofliterature has examined concussion inadults,4–6 the data that exist on pediatricconcussion is composed primarily ofsmaller case series and retrospectivestudies.7–9 Few studies have examinedrisk factors for prolonged symptomduration in children,10–14 and they havegenerated conflicting results on themodifying effect of previous concussion.Supporting an association betweenprevious history of concussion and pro-longed symptom duration, Moser et al7

showed that high school athletes withmultiple previous concussions had per-sistent neurocognitive deficits indis-tinguishable from those in the acuterecovery phase of concussion. Similarly,in an analysis of 119 children with mildtraumatic brain injury (mTBI), Ponsfordet al15 demonstrated that previous headinjury was predictive of persistent con-cussive symptoms 3 months after theinjury. However, 2 larger studies, a sec-ondary analysis of an mTBI cohortpresenting to a pediatric ED and a pro-spective study of concussed high schoolathletes, found no association betweenprevious concussion and duration ofpostconcussive symptoms.16,17

Animal models of mTBI offer a possibleexplanation for this variation, sug-gesting that both timing and number ofinjuries modify the effects of previousinjury. In particular, several studies inrodents suggest that the effect ofmultipleconcussions iscumulative,andthat the time elapsed between con-cussions to allow for return of normalphysiologic function may be the key tothe course of recovery.18–22

Despite this, no clinical study hascharacterized the vulnerable windowduringwhichrepeat concussionresultsin worse outcome among children, orthe critical number of injuries thatconfers increased risk of prolongedrecovery. If reinjury within a window ofvulnerabilityconfershigherriskof long-term neurocognitive deficits, then ab-stinence from at-risk activities mayultimately improve outcomes. Theobjective of this study was to charac-terize the effect of previous concussionon recovery from concussion amongchildren presenting to an ED. We hy-pothesized that those with a previoushistory of concussion would havea longer time to symptom resolutionthan those without such a history, andthat those who sustained a concussionwithin the previous year would havea longer time to symptom resolutionthan those with more remote injuries.

METHODS

Study Design

We conducted a prospective cohortstudy of consecutive patients aged 11 to22 years who presented to the ED ofa tertiary care children’s hospitalwithin 72 hours of a concussion fromSeptember 1, 2011, to August 31, 2012.

Definition

Concussion was defined as a blunt in-jury to the head resulting in either (1)alteration in mental status or (2) any ofthe following symptoms that started

within4hoursof the injuryandwerenotpresent before the injury: headache,nausea, vomiting, dizziness/balanceproblems, fatigue, drowsiness, blur-red vision, memory difficulty, or diffi-culty concentrating in the absence ofindications for head imaging orwithoutintracranial hemorrhagewhen imagingwas obtained. Although there has beencontroversy regarding the definition ofconcussion for clinical research,23–26

we chose this broad definition so as toinclude both those who had alterationof consciousness and those who pre-sented with typical postconcussivesymptoms following a head injury.6,27,28

Patientswereexcluded from the study ifany of the following were present: (1)Glasgow Coma Score,13 on arrival tothe ED, (2) coexisting skull or long-bonefracture, (3) coexisting injury to intra-abdominal or intrathoracic organ orspinal cord, (4) cognitive or develop-mental disability preventing patientfrom completing the questionnaire, or(5) involvement of either law enforce-ment or ED social workers for victimsof an assault. These criteria were de-signed to distinguish postconcussivesymptoms from symptoms related toother injuries or psychological stressesrelated to major trauma or assault.

Primary Outcome

The primary outcome was time to res-olution of postconcussive symptomsassessed via the Rivermead Post-Concussion Symptoms Questionnaire(RPSQ), a 16-item concussion symptominventory checklist.29 The RPSQ hasbeen used extensively in both adult andpediatric studies of mTBI,10,30,31 showna high degree of interrater and test-retest reliability,29,32 and been shownto be valid and unbiased in youngchildren.31,33 The questionnaire wasavailable to study participants in bothEnglish and Spanish. Patients wereconsidered symptom-free when all in-ventories of the RPSQ were scored

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a 0 (symptom not present) or 1 (symp-tom present at preinjury baseline).Patients filled out the survey indepen-dently or with assistance of parents atthe discretion of the patient and family.

Enrollment and Consent

Study participants were enrolled dur-ing their ED visit by trained researchcoordinators after informed consent(and assent for patients ,18 years)was obtained. Eligible patients whowere not contacted during their ED visitwere offered enrollment the followingday if they were still within 72 hours ofthe injury. On enrollment, patientscompleted an electronic questionnaireasking for demographic information(including self-reported race andethnicity), mechanism of injury, asso-ciated symptoms, such as loss of con-sciousness (LOC) and amnesia, relevantpast medical history, and the RPSQ.Providers completed a questionnairewith physical examination findings, di-agnostic studies, and information oninterventions, disposition, and dis-charge instructions.

Follow-up

An online follow-up questionnaire con-taining theRPSQwassent electronicallytopatients1, 2, 4, 6, 8, and12weeksaftertheir ED visit or until they met criteriafor symptom resolution. Patients whoreported resolution of symptoms wereprompted to provide the last date onwhich symptoms occurred. Patientswith incomplete or inconsistent datawere called to resolve these issues.Patients were considered lost to follow-up if they failed to respond to 2 con-secutive questionnaires. Study datawere collected and managed usingREDCap (Research Electronic DataCapture, Nashville, TN) electronic datacapture tools hosted at Boston Child-ren’s Hospital.34

Statistical Analysis

Statistical analysis was performed byusing PASW Statistics 18 (IBM SPSSStatistics, IBMCorporation, Chicago, IL).We estimated that 250 patients wouldbe required to demonstrate a 5-daydifference in time to resolution ofsymptoms between those with andwithout previous concussion, usinga 2-tailed a of 0.05 and power of 90%.

Data were analyzed by Student’s t-testor Wilcoxon Rank Sum test as appro-priate. Our primary outcome, time tosymptom resolution, was assessed asa continuous variable ranging from0 to 90 days. Potential predictors thatwere continuous in nature were di-chotomized before analysis accordingto their median value. The only excep-tion to this was age; 13 years or olderwas chosen rather than the median asa proxy for pubertal status.

In univariate analysis of time to symp-tom resolution, Kaplan-Meier analysiswith log-rank tests of significance wasused to best account for censored data.To adjust for confounders, we con-structed a multivariate Cox regression

model using predictors with P ,.05 on univariate screening. WhereKaplan-Meier analysis was performed,“median” refers to median survivaltime (where “survival” signifies per-sistence of symptoms), a measure thattakes into account expected duration ofsymptoms for censored patients. Val-ues were considered statistically sig-nificant if P , .05. The institutionalreview board approved this study be-fore onset of data collection.

RESULTS

Study Population

A total of 302 patientswere approachedfor the study and 280 (93%) were en-rolled over a 12-month period (Fig 1);207 patients (74%) completed thestudy, 28 (10%) completed at least 1follow-up questionnaire but did notcomplete the study, and 45 (16%) werelost to follow-up. Nonwhite patients,Hispanic patients and patients withattention-deficit/hyperactivity disorder(ADHD) were more likely to be lost tofollow-up (Table 1).

FIGURE 1Flow sheet of included and excluded patients. GCS, Glasgow Coma Score; ICD-9, International Classi-fication of Diseases, Ninth Revision.

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Patient Presentation

Most patients (66.0%) were enrolled inthe study on the day their concussionoccurred, with 24.7% enrolled the fol-lowing day, 7.2% enrolled 2 days later,and 1.7% 3 days later.

A majority of (63.8%) patients wereinjured playing a sport, with the mostcommon sports being hockey (14%),soccer (9.4%), football (8.5%), andbasketball (8.1%). The most commonpresenting symptoms (RPSQ score $

2) were headache (85.1%), fatigue(64.7%), and dizziness (63.0%). An ab-normal physical finding was noted in10.6% of patients, with the most com-mon abnormalities being altered gaitor balance (4.3%) and altered mentalstatus (2.4%). Among the 20.8% ofpatients who had neuroimaging per-formed, there were no abnormalitiesidentified related to trauma. On dis-charge, 65.9% of patients were pre-scribed a period of cognitive rest,92.4% were recommended to take timeoff from athletics, and 63.8% were ad-vised to follow-up with their primarycare doctor, 45.5% in a sports concus-sion clinic, and 6.2% with anotherspecialist.

Time to Recovery

Median time to symptomresolution andpercentage of patients symptomatic 7,28, and 90daysafter the concussionare

shown in Table 2. In univariate analysis,history of previous concussion (Fig 2A),age $13, initial RPSQ score .18, fe-male gender, history of depression,absence of LOC, and abnormal neuro-logic examination on presentationwere all predictive of a longer time tosymptom resolution (Table 2). Amongpatients with a previous concussion,those who had a concussion in the pastyear had nearly 3 times the medianduration of symptoms compared withthose who had no previous concussionor whose most recent concussion oc-curred .1 year previous (Fig 2B).Similarly, patients with 2 or more pre-vious concussions had more thandouble the median symptom durationcompared with patients with 0 or 1previous concussion (Fig 2C).

In the multivariate model, patients witha history of previous concussion, ab-sence of LOC, age$13, and RPSQ score.18 had significantly longer symptomduration than patients without theserisk factors (Table 3).

DISCUSSION

Our study demonstrates that previousconcussion is predictive of a longertime to symptom resolution after pe-diatric concussion. Importantly, wefound that the effect of previous con-cussion on symptom duration wasstrongly influenced by both the number

of previous concussions and the timeelapsed since the most recent previousconcussion. Both study participantswithmultipleprevious concussionsandthose who had sustained a concussionwithin thepreviousyearhadamarkedlygreater duration of symptoms thanthose with no previous concussion.Conversely, patients who had onlya single previous concussion that oc-curred more than a year before theircurrent injury had no statistical dif-ference in duration of symptoms fromchildrenwithoutapreviousconcussion.These findings, which suggest bothtemporal vulnerability and a dose-response effect of previous injuries,support previous research in animalmodels of concussive brain injury.18–22

Previous studies in rodents have dem-onstrated cumulative effects of repet-itivemild head injuries.19,21 Additionally,several of these studies suggest atemporal window of vulnerability where-in the repeat trauma has a more pro-nounced effect. One study observedthat whereas mice concussed atmonthly intervals performed similarlyto noninjured mice on tests of learningand memory, animals concussed atweekly and daily intervals developedpersistent cognitive deficits, with thedaily concussion group showing ongo-ing effects up to 1 year after the injurycompared with controls.22 Other ani-mal models have offered possible bi-ological mechanisms for this temporalvulnerability. Longhi et al18 showed ev-idence of axonal injury and cytoskeletaldamage that was significantly greaterin mice that received a second con-cussion within 3 to 5 days of an initialhead injury than those who had beensubjected to only a single concussion.Vagnozzi et al20 found a similar effectin rats and correlated it to reversibleimpairments in mitochondrial enzymes.

Ourstudydemonstrates this temporallysensitive effect of previous concussionfor the first time in humans. This has

TABLE 1 Characteristics of Patients With and Without Follow-up Data

Included in Study, n = 235 Lost to Follow-up, n = 45 P

Mean age 14.3 13.6 .05Male gender, n (%) 135 (57.4) 28 (62.2) .55Nonwhite race, n (%) 50 (21.3) 19 (42.2) .003Hispanic ethnicity, n (%) 20 (8.5) 10 (22.2) .005Sports-related concussion, n (%) 150 (63.8) 23 (51.1) .11LOC, n (%) 52 (22.1) 10 (22.2) .97Amnesia, n (%) 101 (43.0) 15 (33.3) .22Previous concussion, n (%) 68 (28.9) 11 (24.4) .54PMH migraine, n (%) 29 (12.3) 9 (20.0) .17PMH LD, n (%) 30 (12.8) 5 (11.1) .75PMH ADHD, n (%) 35 (14.9) 13 (28.9) .02PMH depression, n (%) 15 (6.4) 5 (11.1) .34PMH anxiety, n (%) 21 (8.9) 5 (11.1) .58Mean total RPSQ score 18.83 18.13 .75

LD, learning disability; PMH, previous medical history.

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TABLE 2 Time to Symptom Resolution Stratified by Risk Factor

n Median Days toSymptom Resolution

% With Symptoms onDay 7,a n = 234b

% With Symptoms onDay 28,a n = 218b

% With Symptoms onDay 90,a n = 207b

Pc

All Patients 235 13 77 32 15GenderMale 135 12 70 26 12 .02Female 100 15 87 39 18

Age, y,13 61 11 69 20 7 .009$13 174 15 80 36 17

Race/Ethnicity:d

White 185 14 79 34 15 .24Nonwhite 50 11 72 23 13Hispanic 20 18 85 38 18 .72Non-Hispanic 208 13 77 31 15

Initial RPSQ score#18 121 10 68 21 9 ,.001.18 114 22 88 43 20

Mechanism of injuryCollision 80 14 75 36 18 .33Fall 138 12 78 30 15 .82Struck by object 44 12 74 31 16 .96Motor vehicle collision 6 11 83 33 0 .72Bicycle/scooter accident 10 10 70 40 10 .77Playing sport 150 14 80 31 13 .94

Injury factorsd

+LOC 52 11 69 26 6 .0052LOC 179 14 80 34 17+Amnesia 101 14 78 33 11 .702Amnesia 133 13 77 31 17

Previous medical historyPrevious concussion 68 22 85 44 21 .04No previous concussion 167 12 74 26 12Concussion ,1 y ago 21 35 86 81 42 .007e

Concussion .1 y previous 47 14 85 30 12.1 previous concussion 19 28 89 61 32 .03f

1 previous concussion 49 14 84 38 16Migraine headache 29 13 83 35 20 .74Learning disability 30 13 70 41 16 .97ADD/ADHD 35 26 80 48 23 .10Depression 15 28 87 57 48 .01Anxiety 21 32 76 66 20 .08

Home medicationsOral contraceptive 11 19 82 36 12 .59SSRI 9 12 56 43 29 .70Stimulant 8 33 75 61 22 .35Antihistamine 33 16 79 32 19 .70

Family historyConcussion 78 14 81 32 7 .72Migraine 91 13 79 34 16 .62

Physical examinationGCS ,15 10 14 70 18 18 .94Abnormal neurologic exam 22 27 91 47 35 .03

DispositionAdmitted 10 9 70 30 0 .39Cognitive rest advised 114 14 75 37 17 .10Physical rest advised 179 13 78 32 15 .76

ADD, attention deficit disorder; GCS, Glasgow Coma Scale; SSRI, selective serotonin reuptake inhibitor.a Cumulative proportion estimated with ongoing symptoms at given time by Kaplan-Meier analysis.b Number of patients in the study minus patients censored previous to given time interval.c Calculated as log-rank tests of significance via Kaplan-Meier analysis. Where not otherwise specified, referent group is patients without given risk factor.d Numbers add up to less than 235 because of missing data.e Calculated via 3-way analysis of patients with no previous concussion, previous concussion within past year, and previous concussion greater than 1 y ago.f Calculated via 3-way analysis of patients with no previous concussion, 1 previous concussion, and more than 1 previous concussion.

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direct implications on themanagementof athletes and other at-risk individualswho sustain concussions, supporting

the concept that sufficient time to re-cover from a concussion may improvelong-term outcomes. However, we did

not find an association betweenphysician-advised cognitive or physicalrest and duration of symptoms, which

FIGURE 2A, Kaplan-Meier curve of proportion of patients with ongoing symptoms by previous concussion history. B, Kaplan-Meier curve of proportion of patients withongoingsymptomsby timingofmost recentpreviousconcussion. C,Kaplan-Meiercurveofproportionofpatientswithongoingsymptomsbynumberof previousconcussions.

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may reflect the limitations of our ob-servational study. Previous studieslookingat theeffectof cognitiverestandabstinence from sports have been in-conclusive, limited by either observa-tional or retrospective studydesign.35,36

A randomized control trial will likely benecessary to address the utility of thisintervention in patients.

Notably, there were several other riskfactors associated with prolonged timeto recovery in our study. Patients withmoreseveresymptomsatpresentation,representedbyanRPSQscore.18, hadmore than double the median duration

of symptoms compared with patientswith RPSQ scores below this threshold,consistent with the findings of multipleprevious studies.17,37,38 Additionally,our study suggests that patients 13years and older had a longer durationof symptoms than younger children.Most previous studies examining themodifying effect of age on concussionrecovery have compared high schoolage patients with young adults.39 OnlyBabcock et al16 previously comparedpreadolescent children to adolescents,likewise finding that younger age pre-dicted a faster recovery. It is uncertainwhether the difference between youn-ger children and adolescents reflectsdiffering neurobiology between the 2groups or more severe mechanisms ofinjury in sports such as ice hockey andfootball, where games between olderchildren involve more contact andhigher-force impacts.

In our ED cohort, we demonstrate anassociation between LOC and shorterduration of symptoms. This is in con-

trast to previous studies that haveshown that LOC was a risk factor forprolonged recovery or had no effect atall.12,16,17 Our findings may reflect a re-ferral bias, in which patients with LOCare more likely present to the ED on thebasis of this factor alone, whereasthose without LOC may be referred tothe ED only when their symptoms orinjury mechanism are severe. Alterna-tively, it is possible that patients wholose consciousness as a result of theirinjury may be more likely to complywith medical recommendations of phys-ical and cognitive rest than those whodid not lose consciousness, thus speed-ing recovery from their injury. We can-not, however, eliminate the possibilitythat there is a biological basis to thisfinding, in which mechanisms of injuryresponsible for LOC and those re-sponsible for long-term neurocognitivesequelae may differ.

Some of the potential predictors ofprolonged recovery that did not haveastatisticalassociationwithdurationof

FIGURE 2Continued.

TABLE 3 Multivariate Cox Regression Modelof Prolonged Recovery

Risk Factor Hazard Ratio P

Nonwhite race 0.844 .40Hispanic ethnicity 1.01 .97Female gender 1.294 .11Age 13 or older 1.404 .04RPSQ . 18 1.638 .002Previous concussion 1.489 .03Loss of consciousness 0.648 .02History of depression 1.978 .09

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symptoms in our study are also note-worthy. In the multivariate analysis, fe-male gender did not predict prolongedrecovery, although there appeared tobe a difference between the genders inunivariate analysis. This is nearly iden-tical to the results of Babcock et al,16 andlikely because female patients had moresevere symptoms at presentation in ourstudy (mean initial RPSQ 21.3 vs 17.0 inmale patients,P= .02), thus representinga confounding variable. Whether thisfinding is indicative of the fact that fe-male patients have more severe symp-toms from concussion in general, assuggested in several previous studies,40–42

or is due to referral bias in which fe-male individuals preferentially presentto the ED when symptoms are moresevere than male counterparts cannotbe ascertained from our data.

We also observed that patients witha history of migraine headaches, de-pression,ADHD,andanxietydidnothaveprolonged symptoms after concussion;however, small sample size limits ourability to detect relationships in thesespecific patient populations.

Patients in our study had a longerduration of symptoms than most pre-vious reports in the literature, whichhave frequently shown symptoms re-solvingby7to10daysafter the injury.5,17,43

This may be because of differences instudy populations, as children pre-senting to an ED may represent a moresevere subset of concussed patientsthan the outpatient cohorts previouslystudied. The RPSQ may also be moresensitive to ongoing symptoms thanthe self-assessment tools or neuro-cognitive testing used in many otherstudies.

There are several limitations to ourstudy. Although we enrolled 93% ofpatients approached to participate,there were additional patients whowere not contacted by the researchcoordinators. The most common rea-sons for this were arrival to the EDduring a time when no research co-ordinator was available and shortlength of ED stay, leading to dischargebefore the patient could be contactedabout enrollment. Second, by usingsurvival analysis to best account forcensored data, we assumed that therewas no difference between patientswhowerecensoredandthosewhowerenot. Although this assumption appearsto be valid based on similar de-mographics and symptom scores ofcensored versusnoncensoredpatients,it is possible that patients ultimatelyfailed to complete the study because ofmore bothersome symptoms or, con-versely, more rapid symptom resolu-tion. A final limitation is the accuracy ofself-reported symptoms: certain sub-groups of the population, notably ath-letes, may have had an incentive toreport symptom resolution to expeditereturn-to-play; others may report symp-toms that are no longer present to avoidschoolwork; still others may have a diffi-cult time understanding the questions ofthe RPSQ.

Despite these limitations, our study hadseveral strengths, including a largesample size and prospective methodol-ogy. We enrolled a high percentage ofeligible patients and most patientscontinued participation until symptomresolution. By serially surveying patientsat short time intervals andasking for thespecific date of symptom resolutionwithin that interval, our estimates of

symptom duration are likely to be moreaccurate than if we used a single follow-upquestionnairemonthsafter theinjury.

Finally, unlike previous studies thatfocused on particular subgroups ofpatients, such as participants in a par-ticular sport, our study examined alleligible patients who presented toa tertiary care ED. As a result, westudiedadiversegroup in termsof bothdemographics and mechanisms of in-jury, potentially making our studymoregeneralizable to medical providerspracticing in the primary care and EDsettings than samples of selectedpopulations.

CONCLUSION

Children with a history of a previousconcussion, particularly those withrecent or multiple concussions, are atincreased risk for prolonged symptomsafter concussion. These findings havedirect implications on themanagementof concussion patients, particularlythose at high risk for future concussiveinjuries, such as athletes.

ACKNOWLEDGMENTSMichaelMonutaeux, ScD, provided sta-tistical guidance and support. RichBachur, MD, and Mark Neuman, MD,provided mentorship and manuscriptreview. Chris Landrigan, MD, assistedwith manuscript review. Mark Berry,MA, provided programming and ad-ministrative support. The research co-ordinator team (Elizabeth Paulsen, BS,Lucy Abernethy, BA, Kaitlin Morris, BA,Hillary Chu, BA, and Jessica LeSage,BS) enrolled and followed up withpatients and provided administrativesupport.

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REMOTE MONITORING: At our University, all students taking an examination mustbe monitored by a proctor who is physically present in the room in which theexamination is being given. Although somewhat cumbersome, the system workswhen all students take the exam together in one place. However, the policy beginsto break down when several students need to take exams at different times, orhave accommodations allowing extra time to complete the exam. Suddenly, we donot have enough proctors. The situation is even more complex when one con-sidersmassive open online courses (MOOC) which can have enrollments of 40,000or more students. Historically not for credit, more MOOC courses are offeringexaminations and course credits, and monitoring students for cheating whiletaking a test in an MOOC is challenging. Requiring students to take examinationsin a regional testing center is often unrealistic and too costly for most. However,a few companies now offer electronic surveillance of MOOC test-takers (using thekind of gadgetry one might expect someone like James Bond, not an onlinecourse, to need). This surveillance is just as good as, if not better than, using liveproctors in traditional courses. As reported in The New York Times (Technology:March 3, 2013), test-taker identity can be confirmed remotely by checking photoIDs and signatures – and, in a new twist, by comparing typing styles (e.g., howlong individual keys are depressed while typing a specified phrase) to those onrecord. Techniques to detect cheating include video monitoring, keystroke sur-veillance, screen sharing, and the use of sophisticated computer algorithms.Students can be monitored in real time, or sessions can be recorded and thenreplayed later (at high speed) in order to detect any aberrations. The costs tomonitor the examination are often borne by the student, and range from around$15 to $100 (depending on the class and type of monitoring). A number of uni-versities already make use of the programs offered by these companies, andreport high satisfaction. While many of these techniques have been designed forMOOC, there is no reason they cannot be applied to examinations given in tra-ditional classes at “brick and mortar” universities. While some complain thata webcam is intrusive, so is an exam monitor. I personally hope we can moveaway from sit-down exams at a specified time with a proctor, and move to a moreopen system where students take the exam when ready, where ready, using thesame proctor-free technology being used in MOOCs.

Noted by WVR, MD

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