Relationship Between Post-Concussion Headache and Neuropsychological Test Performance in High School Athletes

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1 Relationship Between Post-Concussion Headache and Neuropsychological Test Performance in High School Athletes Publihsed In: American Journal of Sports Medicine 2003;31(2): Michael W. Collins, Ph.D. 1 ; Melvin Field, M.D. 2 Mark R. Lovell, Ph.D. 1 ; Grant Iverson, Ph.D. 3 ; Karen M. Johnston, M.D., Ph.D. 4 ; Joseph Maroon, M.D. 2 ; Freddie H. Fu, M.D., DSc. (Hon.) 1 Contact: Michael W. Collins, Ph.D. Phone: (412) UPMC Sports Concussion Program Fax: (412) Department of Orthopaedic Surgery collinsmw@msx.upmc.edu Center for Sports Medicine 3200 South Water St. Pittsburgh, PA Document Word Count = 3,452 1 University of Pittsburgh Medical Center; Pittsburgh, PA. (Dept. of Orthopaedic Surgery) 2 University of Pittsburgh Medical Center; Pittsburgh, PA. (Dept. of Neurological Surgery) 3 University of British Columbia, Vancouver, Canada (Dept. of Psychiatry) 4 McGill University, Montreal, Canada (Dept. of Neurosurgery) Running Title: Headache and Sports Concussion ABSTRACT The relevance of headache to outcome following sports concussion is poorly understood and no studies exist examining this issue. The current study was conducted to investigate whether postconcussion headaches are associated with neurocognitive deficits and/or presence of other postconcussion symptoms at approximately one-week post injury. Study participants included 110 high school athletes who sustained concussion. Concussed athletes were divided into two groups, those reporting no headache at approximately day 7 post-injury and those reporting headaches. Dependent measures included symptom and neurocognitive test results collected via ImPACT, a computerized neuropsychological test battery. Groups were compared across both cognitive and symptom domains as well to the presentation of on-field markers of concussion severity at the time of injury. Results suggest that athletes reporting post-traumatic headache demonstrated significantly worse performance on Reaction Time (p <.001) and Memory (p <.02) cognitive composite scores as compared to athletes not reporting headache. These athletes also reported significantly more symptoms other than headache (p <.001) and were more likely to have demonstrated on-field anterograde amnesia (X 2 = 4.2, p =.04). Our study suggests that any degree of post-concussion headache in high school athletes is likely associated with an incomplete recovery following concussion. Key Words: Headache, Concussion, High school athlete, Recovery, Neuropsychological testing, Mild traumatic brain injury, ImPACT 1

2 Relationship Between Post-Concussion Headache and Neuropsychological Test Perforamance in High School Athletes In the United States, approximately seven million high school and collegiate athletes participate in organized sports annually. 25 Within this group, a minimum of 50,000 to over 300,000 athletes suffer from concussion per season. 28,30,11 Over 15 grading systems and returnto-play parameters have been published since 1973 to assist the team physician, athletic trainer and coach in the evaluation and management of concussion. Variability in these management directives is attributable to a lack of scientific foundation, and thus an arbitrary delineation of concussion grades and return-to-play criteria. 3,17 At the current time, most concussion scales predicate return to play based upon the presence and duration of loss of consciousness (LOC) and/or amnesia. Importantly, however, neither needs to be present in order for an injury to be classified as a concussion. In fact, a recent study of concussion in high school and collegiate football players revealed that LOC and amnesia occur relatively infrequently, representing 9% and 28% of concussion cases respectively. 13 A more common feature of sports concussion is the occurrence of post-traumatic headache. Recent studies by McCrory 23 and Guskiewicz 13 have respectively reported the frequency of post-concussive headache to be as low as 40% to as high as 86%. Despite the high prevalence of post-concussion headache, no current concussion grading scale includes this specific symptom as a criterion in defining severity of injury. In a general sense, most widely quoted guidelines such as the Sports Medicine Committee of the Colorado Medical Society 26, the American Academy of Neurology 19, and the Cantu grading system 1 note that persistent symptoms (e.g. headache) is a contraindication for returning to play following concussion. Alternatively, because of the high frequency of headache in athletes without concussion, 31 some physicians have advocated return to play in athletes who have persistent headache but normal neurological sideline exams. 27 Lack of prospective research in this regard has led to varied management options and subsequent confusion when headache is the primary clinical complaint. Recent recommendations from an international meeting on the topic of sports concussion, 4,5,6 and prior recommendations from the American Orthopaedic Society for Sports Medicine 32, have reinforced the need to reevaluate all concussion severity grading systems. Both groups have stressed the need for collection of prospective data regarding signs and symptoms of injury for correlation with outcome. In 1997, the International Headache Society and the World Health Organization proposed a classification scheme for headaches. 16 This nomenclature did not adequately address differences among the various headache types commonly evidenced in athletes. To help clarify these issues, McCrory later published an article focusing specifically on headache and exercise. 24 In his article, exercise-related headache syndromes were classified into nine subtypes (Table 1). Acute post-traumatic headache was further delineated into six distinct classifications, though the author acknowledged that co-morbidity and overlap of these headache subtypes are the norm. The management of post-traumatic headache is further complicated by the high percentage of athletes with other forms of non-traumatic exercise-related headaches. In a general sense, the significance of sports-related post-traumatic headache remains unknown. To date, no outcome study exists examining this issue in athletes. The current study was designed to investigate whether general post-concussion headaches are associated with neurocognitive and other symptom impairment at approximately one-week 2

3 post injury in a large subset of high school athletes. Outcome variables for this study were derived from a computerized neuropsychological test battery. Four composite scores from this battery of tests were utilized, including a post-concussion symptom scale score and overall scores for reaction time, processing speed, and memory. It was hypothesized that high school athletes reporting headache at approximately one week post-injury would report significantly more other concussion symptoms, in general, than athletes who did not experience headache. Moreover, it was hypothesized that concussed athletes reporting headache would perform more poorly on neuropsychological testing than athletes without a reported headache. Subjects MATERIAL AND METHODS Appropriate review for research with human subjects was granted to conduct this study. Participants were 110 high school athletes who sustained a sports-related concussion during the 2000 and 2001 athletic seasons. Concussed athletes were included from 20 select high schools participating in the UPMC Sports Concussion Program within the states of Pennsylvania (10 schools participated in the current study), Michigan (2), Illinois (2), Oregon (3) and Maine (3). The UPMC Sports Concussion Program is an ongoing clinical program that provides oversight and consultation regarding the implementation of neuropsychological tests to assist team medical staff in making objective return to play decisions following the occurrence of sports-related concussion. All athletes sustaining sports concussion from these specific institutions were included in the current analysis. The average age of the sample was 15.8 years (SD = 1.2), and 84.5% were male. The majority of concussed athletes were football players (63.6%). Other represented sports included basketball (12.7%), soccer (11.8%), hockey (3.6%), lacrosse (2.7%), softball (1.8%), track (.9%), volleyball (.9%), and wrestling (.9%). Half of the subjects (50.9%) reported at least one previous concussion, 33.6% reported that this was their first concussion, and 15.5% had missing data on this variable. Exclusion criteria for the current study included a positive post-injury CT scan or MRI (e.g. hematoma, skull fracture), pre-existing history of neurologic disease (e.g. seizure disorder, brain tumor), post-traumatic amnesia of greater than 24 hours, or refusal to participate in the study. Initial on-field assessment of concussion was made by certified athletic trainers or physicians who were present at the time of injury. Concussion was diagnosed based upon one or more of the following criteria as identified by on-field, court, rink examination: 1) any observable alteration in mental status or consciousness; 2) the presence of loss of consciousness and/or presence of anterograde amnesia (difficulty in forming new memory after trauma) or retrograde amnesia (difficulty in recalling events during period immediately preceding trauma); 3) evidence of a constellation of post-concussion symptoms, such as cognitive fogginess, nausea/vomiting, dizziness, balance problems, visual changes, presence of post-traumatic headache, etc following a collision involving the head or body. Protocol and Outcome Measures Dependent measures were collected through the administration of ImPACT, a computerized neuropsychological test battery utilized by all participating institutions, designed specifically for sports-related concussion. The test battery consists of seven individual cognitive test modules. Composite scores in the areas of memory, reaction time, and processing speed are 3

4 computed by standardized formulas derived from the results of the seven individual cognitive tasks. (Table 2) In addition, the computerized inventory is inclusive of the Post-Concussion Symptom Scale 20 that is now being utilized throughout both amateur and professional sports. (Table 3) This Likert scale consists of 19 symptoms commonly associated with concussion (e.g. headache, dizziness, sleep deficits, nausea, feeling slowed down, etc.) that are graded from 0 (asymptomatic) to 6 (severely symptomatic). A more detailed description of the computerized test battery and rationale for its development and individual tests has been described in detail previously. 21 Insert Tables 2 and 3 about Here Post-Concussion Evaluation All concussed athletes were referred and subsequently evaluated via computerized neuropsychological testing 5-10 days post diagnosis of concussion (mean = 6.8 days). Administration of the inventory was supervised by a team of clinical neuropsychologists, athletic trainers, or physicians who were thoroughly trained in the use and implementation of the test battery. Training was completed at each site through a half-day seminar presented by one of the lead authors (MWC or MRL). At the training seminar, staff members were also trained to identify and document the presence and duration of on-field markers of concussion severity, including the presence and duration of disorientation, anterograde/retrograde amnesia, and/or loss of consciousness. For the purposes of this study, on-field disorientation was assessed by questioning the athlete s postinjury awareness and orientation to surroundings (e.g. name, current stadium, city, opposing team, current month/day). On-field anterograde amnesia was assessed through immediate and delayed (e.g. 0, 5, 15 minute) memory for three words (e.g. girl, dog, green). Anterograde amnesia was further documented at the post-injury follow-up evaluation by assessing the athlete s ability to recall all information subsequent to trauma. Any loss of memory in this latter regard indicated the positive presence of anterograde amnesia. On-field retrograde amnesia was assessed by having the athlete recall events occurring just prior to trauma (e.g. events in first quarter, memory for play preceding trauma, score of the game). Retrograde amnesia was further documented at the post-injury evaluation by assessing the athlete s ability to recall information prior to trauma. Any loss of memory in this latter regard indicated positive presence of retrograde amnesia. Loss of consciousness was documented when an athlete was unresponsive to external stimuli and in paralytic coma as reported by teammates and/or on-field evaluation. By definition, athletes experiencing LOC also experienced a concomitant anterograde amnesia. For the purposes of this study, athletes with any degree of LOC were categorized in the positive LOC group rather than the anterograde amnesia group, regardless of the length of associated amnesia. ImPACT includes a detailed post-injury evaluation form, which allows the administrator to document the presence and duration of these common markers of injury. It should be noted that ImPACT is a self-administered test battery and all aspects of the evaluation are implemented in a standardized fashion. Further, results of the evaluation are automatically computer scored and generated within a five page clinical report. Therefore, there was no variation in administration or scoring technique between participating sites. 4

5 RESULTS Data Analysis and Formulation of Headache Groups Data collected from individual concussed athletes at participating institutions were pooled and analyzed using Statistical Package for the Social Sciences 10.0 statistical software (SPSS, Inc, Chicago, IL). 29 Concussed athletes were divided into two groups on the basis of self-reported headache at the time of the post-injury neuropsychological evaluation. The first group reported no headaches at this follow-up interval (n = 73), whereas the second group reported experiencing headaches (n = 36). Concussed athletes were included in the headache group if they endorsed any degree of headache on the Post-Concussion Symptom Scale. Headache severity was rated on a 6-point scale, with 1 indicating very mild headache and 6 indicating severe. The breakdown of this group by headache severity was as follows: 1 = 13.9%, 2 = 25.0%, 3 = 41.7%, 4 = 13.9%, and 5 = 5.6%. The headache and no headache groups did not differ in age (p <.80), gender composition (p <.81), or history of previous concussions (p <.28). A subset of the concussed athletes in our sample underwent pre-injury baseline neuropsychological testing conducted prior to the 2000 and 2001 athletic seasons. Specifically, there were 53 subjects in the no headache group and 20 subjects in the headache group that underwent preseason evaluation. T-tests were used to compare the preseason test scores for the two groups. The groups did not differ at baseline in terms of total self-reported symptoms (p <.23), pre-injury headache presentation (p <.81), memory performance (p <.43), reaction time (p <.21), or processing speed (p <.41). Post-Concussion Symptom and Cognitive Test Results At approximately 7 days post-concussion, athletes with headaches experienced a large number of other post-concussion symptoms, compared to the athletes with no headaches (p <.001; d = 1.55, very large effect size). In addition, athletes with post-concussion headaches had significantly slower reaction times (p <.001; d =.80, large effect) and reduced memory performance (p <.02; d =.60, medium effect) as measured by the neuropsychological cognitive composite scores. The two groups did not differ on the processing speed composite score. Descriptive statistics, mean comparisons, and effect sizes are presented in Table 4. These differences in total symptoms, reaction time, and overall memory performance are illustrated graphically in Figures 1-3. Insert Table 4 About Here Insert Figures 1-3 About Here Athletes with reported headaches at approximately day 7 post-injury were subdivided into two groups; those with mild headache (i.e., 2 or 1 on the scale) versus those with moderate to severe headache (3 or greater on the scale). Fourteen subjects had mild headaches and 22 had moderate to severe headaches. These subgroups were compared on the primary dependent measures. Those with moderate to severe headaches reported a much greater number of other postconcussion symptoms relative to those with mild headache (means = 30.2 versus 8.3; p =.001; d = 1.2, very large effect size). There were no statistically significant differences between 5

6 the two groups on the three neuropsychological composite scores. However, all ImPACT composite scores were reduced in the group with moderate to severe headaches. Given the small sample size, there was low power in these latter analyses. It is notable that the effect size for the reaction time composite was.46, a medium effect, indicating that there was approximately a onehalf standard deviation difference between groups. The effect sizes for memory and processing speed were small (i.e., d =.19 and.32, respectively). Relationship of Headache to On-Field Markers of Concussion Severity The two groups comprising the total sample were used to investigate the relation between on-field injury severity markers and headache status at one-week post injury. Chi-square, between-group comparisons were conducted using the on-field markers as dependent variables. As seen in Table 5, athletes with post-concussion headache were significantly more likely to experience on-field anterograde amnesia (X 2 = 4.2, p =.04). However, they were not more likely to experience an initial on-field loss of consciousness, retrograde amnesia, or disorientation. If the four primary on-field severity markers are considered simultaneously, 9.4% of athletes with no headache evidenced 3 or 4 of these markers, whereas 29.6% of the postconcussion headache group evidenced 3 or 4 abnormal markers. An odds ratio revealed that players with post-concussion headache are approximately 4 times more likely to demonstrate 3-4 abnormal on-field markers of concussion severity. A variable representing on-field mental status change for five or more minutes was also created. We chose a 5-minute time cutoff to differentiate transient from more severe injuries. This time cutoff was utilized since it represents a common unit of time that can be tracked relatively easily on the athletic playing field. Approximately 16% of players with no headache had prolonged post-injury mental status changes compared to 48% of players with headaches at approximately day 7 post-injury. An odds ratio revealed that players with headaches at day 7 post-injury are nearly 5 times more likely to demonstrate five or more minutes of sidelineassessed mental status change. Insert Table 5 About Here DISCUSSION The significance of headache following sports-related concussion is frequently questioned by physicians, athletic trainers and coaches who care for the concussed athlete. Given that up to 86% of athletes sustaining concussion report post-traumatic headache, 13 this is a relevant and common concern. Somewhat disconcerting, however, is that no prospective study has examined the issue of whether post-concussion headache is associated with neurocognitive impairment and presence of other post-concussion symptoms and thus suggestive of incomplete recovery. Moreover, no studies currently exist examining the issue of headache or even general clinical outcome following sports concussion in high school athletes. In our current study, findings suggest that high school athletes with any degree of selfreported headache at approximately one-week post injury are likely to have persistent adverse effects from their concussion. These post-concussion difficulties include the significant presence of other post-concussion symptoms and attenuated neurocognitive functioning. There was also a trend suggesting that more severe headaches, those rated as moderate to severe versus those rated 6

7 as mild, might be associated with even worse neurocognitive status. Unfortunately, we had insufficient sample size to investigate this latter issue fully. The presence of post-concussion headache at approximately 7 days post-injury appears associated with a large number of post-concussion symptoms other than headache. There was a pronounced difference in the total number of symptoms reported by the two groups as evidenced in Table 4 and Figure 1. This was not felt to be unusual as multiple symptoms can be elicited from the athlete in the concussed state if appropriately assessed. Since headache is the most common finding after concussion, the presence of other symptoms would likely increase the chance of having a concurrent headache. Athletes presenting with headache at approximately day 7 post-injury also demonstrated significantly slowed reaction times and reduced memory performance, as measured by ImPACT, a computerized neuropsychological test battery. Thus, it appears that high school athletes with post-concussion headaches have slower neurocognitive recovery curves. The underlying physiological rationale to explain this association is difficult to ascertain, especially given the lack of specificity regarding headache subtype in our sample. Other results from our analysis revealed that high school athletes with persistent postconcussion headaches sustained more severe concussions, as a group. Specifically, they were 4 times more likely to evidence 3 or 4 abnormal on-field injury severity markers, and were also 5 times more likely to show sideline-assessed mental status changes of five minutes or more. In terms of individual on-field severity markers, anterograde amnesia was significantly related to the presence of headaches at approximately day 7 post-injury. Loss of consciousness, retrograde amnesia, and disorientation did not individually differentiate the two groups. Findings from the current study do not appear attributable to preexisting differences between groups. Specifically, approximately two-thirds of our sample underwent baseline, or pre-injury, baseline neurocognitive and symptom evaluation. Comparisons between post-injury headache groups at baseline revealed no differences in terms of presence of concussion-related symptoms or neurocognitive test results. Moreover, these groups did not differ in terms of age, gender composition or history of previous concussions. Specific methodological limitations of the current study deserve mention. First, given that our current analysis examined athletes at one time interval (on average, at 7 days post trauma), it is not possible to specifically determine the exact timeframe and nature of headache onset and resolution. Specifically, it is not possible to ascertain when the symptoms of headache appeared within our sample (i.e. at the time of injury versus delayed onset) and the relationship of headache to the onset of other post-concussion symptoms. Similarly, the current analysis does not present data outlining whether resolution of post-concussion headache is directly correlated with resolution of the ImPACT neurocognitive test data. In short, if the resolution of headache is correlated with a return to baseline on cognitive and other symptom measures, this marker of injury may potentially serve as an indicator in determining safe return to sport participation following concussive injury. Future studies are needed to prospectively examine the specific temporal pattern of post-traumatic headache and its relationship to other concussive symptoms and pre-post injury neurocognitive status. In addition, it should be noted that the current analysis examined general postconcussion headache without taking into account specific headache and exercise-related headache syndromes (please refer to Table 1). As outlined by McCrory, 24 further studies are needed to examine the issue of sports-concussion headache and to develop uniform headache categorizations similar to those outlined by the International Headache Society diagnostic 7

8 criteria 16. These studies may wish to determine the incidence and relevance of specific exerciserelated headache syndromes in the athlete (e.g. acute post-traumatic, cervicogenic, migraine, etc.). Lastly, based upon our experience, the relationship between exertion (e.g. physical activity) and post-concussion headache presentation is salient. The current study did not measure or control for the post-injury level of exertion or physical/mental activity. Thus, future studies might examine the role of exertion on the presence and duration of headache status, other symptom presentation, and outcome. Such data may help to elucidate better management recommendations during recovery from concussion. Notwithstanding our outlined study limitations, findings from our analysis suggest that it may be possible to have a simplified general management and return-to-play heuristic for sports medicine practitioners. That is, the presence of post-concussion headache in the high school athlete is significantly associated with increased risk for incomplete recovery. It appears that high school athletes with any degree of self-reported headache at approximately one-week post injury are likely to have persistent adverse effects of concussion across multiple domains (i.e. symptom and neurocognitive). Therefore, until follow-up studies are completed, it is recommended that high school athletes presenting with post-injury headache, regardless of severity, be managed conservatively in terms of return to sport participation. Results of this study are in accordance with a recent published international consensus statement 4,5,6 stating that concussed athletes who are symptomatic should be withheld from sport competition. Athletes presenting with post-concussion headache may benefit from increased scrutiny in regards to follow-up (e.g. repeat physical examination, symptom assessment) and potential individualized evaluation to help delineate underlying deficits associated with injury. Several diagnostic procedures and referral sources are currently available for the sports medicine practitioner. For example, past and recent research has elucidated the sensitivity of neuropsychological testing to help delineate the presence of underlying deficits associated with injury. 2,8,15 Moreover, other neurodiagnostic techniques, such as postural stability testing 12,14, functional magnetic resonance imaging 18,22, positron emission tomography 10, and electrophysiological measures 7,9 may also help to uncover lingering effects of concussive injury. 8

9 REFERENCES 1. Cantu RC: Posttraumatic retrograde and anterograde amnesia: pathophysiology and implications in grading and safe return to play. J Athletic Training 36: , Collins MW, Grindel SJ, Lovell MR, et al: Relationship between concussion and neuropsychological test performance in college football players. JAMA 282: , Collins MW, Lovell MR, McKeag DB: Current issues in managing sports-related concussion. JAMA 282: , Concussion in Sport Group, IOC, FIFA, IIHF- Summary and agreement statement of the 1 st International Conference on Concussion in Sport, Vienna, Br J Sports Med (in press) 5. Concussion in Sport Group, IOC, FIFA, IIHF- Summary and agreement statement of the 1 st International Conference on Concussion in Sport, Vienna, Clin J Sport Med (in press) 6. Concussion in Sport Group, IOC, FIFA, IIHF- Summary and agreement statement of the 1 st International Conference on Concussion in Sport, Vienna, Physician and Sport Med (in press) 7. Dupuis F, Johnston KM, Lavoie B, et al: Concussion in athletes produce brain dysfunction as revealed by event-related potentials. NeuroReport 11: , Echemendia RJ, Putukian M, Macklin RS, et al: Neuropsychological test performance prior to and following sports related mild traumatic brain injury. Clin J Sports Med 11:23-31, Gaetz M, Goodman D, Weinberg H: Electrophysiological evidence for the cumulative effects of concussion. Brain Inj 14: , George JK, Alavi A, Zimmerman R: Metabolic (PET) correlates of anatomic lesions (CT/MRI) produced by head trauma. J Nucl Med 30:802, Gerberich SG, Priest JD, Boen JR, et al: Concussion incidences and severity in secondary school varsity football players. Am J Public Health 73: , Guskiewicz K, Riemann B, Perrin D, Nashner L: Alternative approaches to the assessment of mild head injuries in athletes. Med Sci Sports Ex 29: , Guskiewicz KM, Weaver NL, Padua DA, et al: Epidemiology of concussion in collegiate and high school football players. Amer J Sports Med 28: , Guskiewicz KM, Ross SE, Marshall SW: Postural stability and neuropsychological deficits after concussion in collegiate athletes. J Athletic Training 36: , Hinton-Bayre AD, Geffen GM, Geffen LB: Concussion in contact sports: reliable change indices of impairment and recovery. J Clin Exp Neuropsychology 21:70-86, International Headache Society. Headache Classification Committee of the International Headache Society: classification and diagnostic criteria for headache disorders, cranial neuralgias and facial pain. Cephalgia 18 Suppl: , Johnston KM, McCrory P, Mohtadi NG, et al: Evidence-based review of sports-related concussion: Clinical Science. Clin J Sports Med 11: , Johnston KM, Ptito A, Chankowsky J, et al: New frontiers in diagnostic imaging in concussive head injury. Clin J Sport Med 11: ,

10 19. Kelly JP, Rosenberg JH: Diagnosis and management of concussion in sports. Neurology 48: , Lovell MR, Collins MW: Neuropsychological assessment of the college football player. J Head Trauma Rehab 13:9-26, Maroon JC, Lovell MR, Norwig J, et al: Cerebral concussion in athletes: evaluation and neuropsychological testing. Neurosurgery 47: , McCallister TW, Saykin AJ, Flashman LA, et al: Brain activation during working memory 1 month after mild traumatic brain injury: a functional MRI study. Neurology 53: , McCrory PR, Ariens T, Berkovic SF: The nature and duration of acute concussive symptoms in Australian football. Clin J Sport Med 10: , McCrory P: Headaches and Exercise. Sports Med 30: , National Federation of State High School Associations. Athletic Participation Totals, Official Website. Indianapolis, IN, Report of the Sports Medicine Committee. Guidelines for the management of concussion in sports. Colorado Medical Society, (Revised May 1991). Class III 27. Sallis RE, Jones K: Prevalence of headaches in football players. Med Sci Sports Exer 32: , Sosin DM, Sniezek JE, Thurman DJ: Incidence of mild and moderate brain injury in the United States. Brain Inj 10: 47-54, Statistical Package for the Social Sciences. SPSS, Inc. Chicago, IL Thurman DJ, Branche CM, Sniezek JE: The epidemiology of sports-related traumatic brain injuries in the United States: recent developments. J Head Trauma Rehab 13:1-8, Williams S, Nukada J: Sport and Exercise headache. Part 1: Prevalence amongst university students. Br J Sports Med 28:90-95, Wojtys EM, Hovda D, Landry G, et al: Concussion in sports. Am J Sports Med 27: ,

11 Table 1. Exercise-Related Headache Syndromes Headache Syndrome IHS Classification Code Migraine 1.1 to 1.7 Tension-Type 2.1 to 2.3 Cervicogenic 11.2 Benign Exertional 4.5 Effort none Acute Post-Traumatic 5.1 to 5.2 Exertional Compression 4.2 High Altitude Hypercapnia 10.2 McCrory P. Headaches and exercise. Sports Med 2000;30:

12 Table 2. ImPACT Neurocognitive Test Modules. Test Module Cognitive Processes Measured Word Discrimination Symbol memory Sequential Digit Tracking Visual Span Symbol-matching Color Track Three Letters Attention, verbal recognition Visual working memory, visual processing speed Sustained attention, reaction time Visual attention, immediate memory Visual processing speed, learning and memory Concentration, response inhibition, reaction time Working memory, visual-motor response speed *Results from above tests are computed into overall Memory, Reaction Time, and Processing Speed composite scores. 12

13 Table 3. Postconcussion Symptom Scale Symptom Rating None Moderate Severe Headache Nausea Confusion/Disorientation Difficulty Recalling Incident Emesis Balance Problems Fatigue Trouble Falling Asleep Sleeping More Than Usual Drowsiness Sensitivity to Light/Noise Irritability Increased Sadness Nervousness Numbness or Tingling Feeling Slowed Down Sensation of Being in a fog Difficulty with Concentration Difficulty with Memory Total Score *Lovell MR & Collins MW. Neuropsychological assessment of the college football player. J Head Trauma Rehab 1999;9:

14 Table 4. Descriptive statistics, mean comparisons, and effect sizes for Headache groups No Headache Presence of Headache Variable Mean SD Mean SD p Effect Size Symptom Total Score < Reaction Time Composite < Processing Speed Composite Memory Composite P-values are based on independent t-tests. Nonparametric, Mann Whitney U tests revealed identical results. Cohen s effect sizes (d) are interpreted as follows: small effect =.2, medium effect =.5 and large effect =.8. Higher scores are reflective of worse performance on Symptom and Reaction time Composite scores, whereas lower scores are reflective of worse performance on Processing Speed and Memory Composite scores. 14

15 Table 5. On-field Concussion Severity Markers by Headache Group. Variable N No Headache Presence of Headache Х 2 p Odds Ratio 95% Confidence Interval Positive LOC % 12.1% Retrograde Amnesia % 29.6% Anterograde Amnesia % 44.4% Disorientation % 77.3% Abnormal Markers % 29.6% Min. Mental Status * % 48.0% Due to the natural difficulties with collecting on-field markers, varying degrees of missing data were present. The number of subjects who had each marker coded ranged from 70 to 101. *Five or more minutes of retrograde amnesia, anterograde amnesia or disorientation. 15

16 Figure 1. ImPACT symptom total score at 6.8 days post-concussion No Headache Lingering Headache *Higher score equals worse performance Note: p <.001; d = 1.55, very large effect size 16

17 Figure 2. ImPACT reaction time composite score at 6.8 days post-concussion No Headache Lingering Headache *Higher score equals worse performance Note: p <.001; d =.80, large effect size 17

18 Figure 3. ImPACT memory composite score at 6.8 days post-concussion No Headache Lingering Headache *Lower score equals worse performance Note: p <.015; d =.60, medium effect size 18