Understanding Concussion Assessment and Evaluation
Philip Schatz, PhD Saint Joseph’s University, Philadelphia PA
[email protected]
Cerebral Concussion • Mild traumatic brain injury • Alteration in consciousness due to a blow to the head or acceleration/deceleration/rotational force • Does NOT imply or require loss of consciousness. • Usually temporary changes in mental status • Temporary changes in somatic functioning • May produce a wide range of symptoms • Normal structural neuroimaging CISG, Vienna (2001); Prague (2004)
Post Concussion Symptoms “Oh man… I was licking the dreamsicle” -- Professional wrestler, reflecting on a concussion
Head Games Chris Nowinski
Post Concussion Symptoms “Physical”: • Pressure in head • Headache • Balance troubles • Visual Disturbance • Numbness • Tingling • Feeling slow • Sensitivity to light/noise
“Psychological”: • Feeling like in a “fog” • Difficulty concentrating • Difficulty remembering • Irritability • Sadness • Nervousness
COMMONLY REPORTED SYMPTOMS High School/University Athletes within 3 days of injury
Headache (71%) Feeling slowed down (58%) Difficulty concentrating (57%) Dizziness (55%) “Fogginess” (53%) Fatigue (50%) Visual Blurring or double vision (49%) Light sensitivity (47%) Memory dysfunction (43%) Balance problems (43%)
Physiological Changes • Shearing or strain injury of axons • Diffuse microscopic changes to axons • Microscopic tearing of small blood vessels • Metabolic cascade resulting in imbalance between glucose demands and regional CBF supply (vulnerable to SIS) Giza & Hovda, JAT, 36(3), 228-35
Neurometabolic Changes
Incidence of Mild TBI 75 to 85 % of all head injuries 1.0 to 1.5 million cases per year in US 300,000 from sports (an underestimate?)
Most cases go unreported
Incidence of Mild TBI Question: What sport has the highest incidence of concussion (if you know, don’t say it)
Previous Findings: Epidemiology • By Sport: SPORT Equestrian Boxing Rugby Soccer Football Bicycling Martial Arts Auto Racing Ice Hockey
% RANGE 3 - 91 1 - 70 2 - 25 4 - 22 2 - 20 0 - 13.8 0 - 11 0 - 10.5 3 - 7.5
Ruchinskas, et al., 1997, Applied Neuropsych
Epidemiology: Issues (Macciocchi) – Recognition one occurred may be easier then measuring concussion severity – Diagnosis for epidemiological purposes may be more difficult than it seems • Discrepancy between # of players reporting and the # who believed they sustained one • Post-season, players reported symptoms but didn’t connect them to concussive injuries • 70% of football and 63% of soccer players reported postconcussion symptoms
Epidemiology: Methods (Macciocchi) – Quasi-experimental comparison- athletes examined pre-season, followed for a period of time • Look at # of concussions sustained over that period • Generalize from cohort to population
– Use date from “surveillance systems” • Monitor concussive injuries on a broader scale • Sometimes are organization-based, such as NCAA
Epidemiology: Terminology (Macciocchi) – Athletic Exposure (AE) • Period of time when an athlete could have sustained an injury, such as practice or game • Confounded by time (a 5-minutes shift is the same as an entire game)
– Injury Rate (IR) • Number of injuries incurred relative to the total number of exposures • Often stated as “per 1000 AE’s”
Epidemiology: High School – 20% or 250,000 per year in football (Gerberich, et al. 1985)
– 25,520 per season (Powell, 1995) – NATA High School Study – – – – – –
57,716 occurrences of mTBI per year 5.3% of football injuries 4.4% of wrestling injuries 3.4% of boys soccer 2.6% girls soccer 2.3% girls basketball
Epidemiology: NCAA • College: NCAA Injury Surveillance System – – – – – – –
1.6 to 6.4% of all injuries Ice Hockey - 4.5% of all injuries (.56 per 1,000 AE) Football .43 per 1,000 AE Wrestling .49 per 1,000 AE Soccer (Men = .35/Women=.58) Lacrosse (Men= .33/Women=.62) Basketball (Men=.16.Women=.29)
Concussion Base Rates • History of Previous Concussion: 10-80% • Recent Trend Upwards: (% with 1+ Previous Concussion) – Collins, et al (1999) 53% – Kaushik (2005) 75% – Moser, Schatz, Jordan (2005) 63% • Different “breed” of youth athletes in 2000’s vs. 1980’s?
What about Gender? Hillary, Mann, Schatz, ACN, 2002 Study Powell, Barber-Foss Powell, Barber-Foss Powell, Barber-Foss NCAA
Study Dick Dick Boden, et al. NCAA Powell, Barber-Foss Powell, Barber-Foss Powell, Barber-Foss J. Kelly, J. Rosenberg
Sport (% of All Injuries) Soccer Basketball Baseball/Softball Soccer
Males 3.9% 2.6% 1.7% 4.7%
Females 4.3% 3.6% 2.7% 4.4%
Total % of all injuries
3.23%
3.75%
Sport (Injuries per 1000 AE) Soccer Lacrosse Soccer Soccer Soccer Basketball Baseball/Softball Soccer
Males 0.348 0.334 0.6 0.44 0.18 0.11 0.05 0.25
Females 0.578 0.618 0.4 0.46 0.23 0.16 0.1 0.24
Total Ave per 1000 AE Soccer Ave per 1000 AE Other Ave per 1000 AE
0.289 0.364 0.165
0.348 0.382 0.293
Epidemiology: Gender Covassin, Swanik, Sachs, JAT, 2003)
NCAA Injury Surveillance System: 3-year study • Of 14,591 reported injuries, 5.9% were classified as concussions Concussions during practices: Female athletes: Male athletes
167 (3.6%) 148 (5.2%)
Concussions during games: Female athletes: Male athletes:
304 (9.5%) 254 (6.4%)
Epidemiology: Gender Covassin, Swanik, Sachs, JAT, 2003)
Barnes, et al, 1998, Am J Sports Med: • Female athletes could be at more risk due to their smaller size or greater ball-to-head size ratio. • Female athletes may have weaker neck muscles than male athletes. Boden et al, 1998, Am J Sports Med: • Male athletes may be more skilled at protecting their heads from injury, but there are no data to support this hypothesis.
Gender Differences at Baseline 1209 NCAA Division 1 Athletes - 5 Northeastern Universities • Completed ImPACT at baseline • Female athletes performed significantly better than male athletes on baseline verbal memory scores (p = 0.001) • Male athletes performed significantly better than female athletes on baseline visual memory scores (p = 0.001).
Covassin, Swanik, Sachs, Kendrick, Schatz, Zillmer, Kaminaris, (BJSM, 2007)
Gender Differences at Baseline Female athletes endorsed a significant number of mild baseline symptoms as compared to male athletes: • Headache, nausea, fatigue, need more sleep, drowsiness, sensitive to noise, sadness, nervousness, more emotional, difficulty concentrating, visual problems. • Effect sizes ranged from .13 (Sleep) to .40 (Emotional)
Covassin, Swanik, Sachs, Kendrick, Schatz, Zillmer, Kaminaris, (BJSM, 2007)
Recommended schedule for measuring post-concussion status
NP Sideline RETURN TO Testing Testing PLAY?
BASELINE NP TESTING
INJURY PRE-SEASON
1-2 DAYS AFTER INJURY
Historical Aspects: UVA Football Study - Barth, et al., 1989 Trail Making B: Pre-Season and Post-Injury Performances
Historical Aspects: Neuropsych Measures-Trails B
Historical Aspects: Neuropsych Measures-Digit Symbol
Historical Aspects: Neuropsych Measures - PASAT
Historical Aspects: Neuropsych Measures - COWAT Tell me as many words that you can think of that start with the letter… F…A…S.
Historical Aspects: Neuropsych Measures - STROOP
Historical Aspects: Neuropsych Measures - STROOP
Historical Aspects: Neuropsych Measures - STROOP
Historical Aspects: Neuropsych Measures - STROOP
Historical Aspects: UVA Football Study - Barth, et al., 1989 PASAT-4: Pre-Season and Post-Injury Performances
Historical Aspects: Echemendia PSU: Hockey: COWAT
% Relative to Baseline
20 0 Baseline
2 Hour
48 Hour
1 Week
-20 -40 -60 Concussed
Control
1 Month
Historical Aspects: • Egocentric view: – The Virginia Football Study – Echemendia’s PSU Program – Saint Joseph’s University • Division I, No Football, 400+ varsity athletes
– Where can I find a place? – Computers circa 1998
What We Knew: 2000 • Effects of Cerebral Concussions last up to 7-10 days – Primarily attention and concentration Alves, Rimel, Nelson, 1987, Clinical Sports Medicine, 6(1), 211-8 Barth, et al., 1989, in H. Levin’s Mild Head Injury: Oxford Press
• Effects of cerebral concussions last up to 30 days and beyond (Echemendia, et al., 1999) – Extends to other cognitive processes Echemendia & Julian, 2001, NP Review 11(2), 69-88
What We Knew: 2000 • LOC is not a predictor of concussion, and incidence of LOC does not effect cognitive performance (Lovell, et al, J. Clin Sports Med, 1999)
• Individuals with history of Concussion and/or Learning Disability show lowered baseline performance on testing. (Collins, et al., JAMA, 1999)
Current Research: How do I develop a Concussion Program at SJU? (Hopefully) based on Professional and Collegiate Concussion Management Programs
• • • • •
NFL - Majority NHL - Mandatory Baseline, Serial Post-concussion Evals. Wide Network of Neuropsychologists Colleges test teams pre-season
SJU Concussion Pilot Study: Trails B
SJU Concussion Pilot : Digit-Symbol
SJU Concussion Pilot Study: d2
There already was a trend towards computer-based assessment
• CRI (HeadMinder.com)…………. 1999 – Web based
• CogSport (CogState.com)………..1999 – Windows/Mac
• ImPACT (ImPACTtest.com)……. 2000 – Windows based
Why should we opt for computer-based assessment? • Sensitive to RT, Processing Speed • Randomized Trials: Improved reliability • Ability to test entire team at once (benefit?) • Better/Objective date for Athletic Trainers, Team Physicians • Assistance with Return to play decisions (Schatz & Zillmer, 2003, Applied Neuropsych; Schatz & Browndyke, 2003, JHTR)
Why should we not opt for computer-based assessment? • Perhaps timing is not millisecondaccurate • Limited validation with np “standards” • Little qualitative or “verbal” data • Can be used by Athletic Trainers, Team Physicians in absence of Neuropsych • May determine return to play decisions (Schatz & Zillmer, 2003, Applied Neuropsych)
There’s a whole lot of post-concussion tests and schedules Comparison of Post-concussion Assessment Schedules and Measures. (From McKeever & Schatz, Applied Neuropsychology, 10, 2003)
Study NCAA- Multiple sports (Echmendia, et al., 2001) NCAA-Football (Collins, et al., 1999)
Schedule of Serial Post-Concussion Assessments Hours Days 1-2 24-48 3 5 7 10 30 2 24 7 30 1
3
5
24
5
Prof. Hockey Players (Echemendia, 2001)
24
5b
Prof. Football Players (Lovell & Collins, 1998)
24
Prof. Rugby Players (Hinton-Bayre, et al., 1999) aAthletes
dHVLT, hTrails, kDig.
7
Span, fSDMT, mCOWAT,
nPegboard
NCAA-Football (Barth, et al., 1989)
Prof. Rugby Players (McCrory, et al., 1997)
Measures Used cPC, dHVLT, fSDMT, gStroop, hTrails, jVIGIL/W, kDig. Span, lPSU,mCOWAT
eSDMT, hTrails, oPASAT
10 7b
cPC, dHVLT, fSDMT, iTrails, lPSU, mCOWAT, pBVMT-R dHVLT, fSDMT, hTrails, kDig.
5
Span, mCOWAT,
nPegboard
1
eSDMT, rChoice
5 3a
7a
35 a
eSDMT, qDigit
RT., rMemory, rOrientation
Symbol, rSpeed of Comprehension
tested 1 to 3 days, 1-2weeks, 3-5 weeks post-concussion; bAthletes tested 5 to 7 days post-concussion
Power In Numbers: Philadelphia Sports Concussion Program • • • • •
Mandatory for Participation in Athletics Drexel, Temple, SJU… Delaware, Rutgers Baseline, 24-48 hr, 3, 5, 7, 10, weekly if Sx ImPACT @ 4 schools, CRI @ Temple Dissertations (McKeever, Covassin, Schneider), Master’s Theses – Validate multiple measures (ImPACT, CRI, CogSport, Trails, Digit Symbol, d2) – Gender, Sport, History, Club Sports, Cheerleaders, School Norms
Cross-Validation of Computer-Based Measures - Rationale (Schatz & Putz, Applied Neuropsych 2006)
• Limited “shared validation” of existing computer-based measures with standards • SDMT correlates with: – ImPACT Processing Speed (r=.70) and Reaction Time (r=.60) – CRI Processing Speed (r=.60, r=.67)
• Trails correlates with: – – – –
CRI Response Speed (A: r=.73; B: r=.74) CRI Processing Speed (B: r=.37) CogSport Complex RT (B: r=.34) CogSport Simple RT (B: r=.44)
Cross-Validation of Computer-Based Measures - Methodology • 30 Normal Volunteers • Computer-based: ImPACT, CRI, CogSport, d2, Trails A&B, Digit Symbol • Paper-based: Trails A&B, Digit Symbol • Administration: MWF, Individually – Grouping A: ImPACT, d2 Test of Attention (computerized) – Grouping B: CRI, Trails A and B. and Digit Symbol (pencil and paper). – Grouping C: CogSport, Trails A and B, and Digit Symbol (computerized).
– ABC, ACB, BAC BCA, CAB, CBA.
Cross-Validation Example: ImPACT CRT
Cross-Validation Example: CogSport CRT
Cross-Validation Example: CRI CRT
Cued Reaction Time: Press the spacebar as quickly as possible only when a white circle immediately follows the presentation of a black square.
Cross-Validation of Computer-Based Measures - SRT Results IMPACT
IMP ACT SRT
--.
HD_CRT
COG_CRT
.598* .001
.407* .026
.649** .001
.380** .038
.641** .001
.442* .014
DIGSYM -.455* .012
---
.404* .027
.391* .032
.292 .118
.428* .018
.232 .217
-.526** .003
---
.333 .072
.421* .021
.055 .772
.315 .091
-.303 .104
---
.420* .021
.544** .002
.535** .002
-.281 .132
.277 .138
.172 .362
-.076 .689
.613** .001
-.373* .042
HD_SRT
HD_SRT . HD_CRT
COG_CRT
COG_SRT
TRA
TRB
COG_SRT
---
TRA
---
TRB
---
-.381* .038
Cross-Validation of Computer-Based Measures - CRT Results IMPACT
IMP ACT SRT
--.
HD_CRT
COG_CRT
.598* .001
.407* .026
.649** .001
.380** .038
.641** .001
.442* .014
DIGSYM -.455* .012
---
.404* .027
.391* .032
.292 .118
.428* .018
.232 .217
-.526** .003
---
.333 .072
.421* .021
.055 .772
.315 .091
-.303 .104
---
.420* .021
.544** .002
.535** .002
-.281 .132
.277 .138
.172 .362
-.076 .689
.613** .001
-.373* .042
HD_SRT
HD_SRT . HD_CRT
COG_CRT
COG_SRT
TRA
TRB
COG_SRT
---
TRA
---
TRB
---
-.381* .038
Cross-Validation of Computer-Based Measures - Processing Speed Results
Digit Symbol Trails B
-.381*
Digit Symbol
-
ImPACT
-
p < . 05*, p < .004**, p < .001***
ImPACT
HeadMinder
-.506**
.601***
.542**
-.610***
-
-.373*
Cross-Validation of Computer-Based Measures - Memory Results
ImPACT Visual ImPACT Verbal
.340
CogSport Visual -.160
-.102 -.058
ImPACT Visual
-
-.012
CogSport Visual
-
-
p < .05*
CogSport Learning
.723*
Cross-Validation of Computer-Based Measures - Implications • These tests share some common variance on constructs such as processing speed and reaction time, but not within the domain of memory. • The Processing Speed Indices/measures (ImPACT, HeadMinder, Trails B and Digit Symbol) correlated the most consistently. • Baseline evaluations using one measure can not be used as a basis for post-concussion assessment using another measure.
Cross-Validation of Computer-Based Measures - Limitations • Small sample size. • Reliance on univariate correlations. • Subjects assessed independently. • No concussed subjects. • Not comparing tests’ sensitivity to effects of concussion.
Meanwhile… Concussion Effects on Youth Athletes? Relying on symptoms alone may be dangerous Attentional processes, memory, and cognitive speed are key elements of testing Younger athletes deserve particular attention
Prolonged Effects of Concussion? (Schatz & McNamara ACN 2001 [Abstract])
• Self-reported history of concussion • 56 college freshmen, ages 17-19
• Divided into independent groups on the basis of concussion history: – 19 with one or more previous concussion, – 39 with self-reported history of no previous concussions.
Prolonged Effects of Concussion? (Schatz & McNamara ACN 2001 [Abstract])
Mild, enduring effects of cerebral concussion can be identified in otherwise healthy college freshmen with a history of concussion.These enduring effects of previous cerebral concussions appear to involve attentional processes, and warrant further investigation.
Prolonged Effects of Concussion? (Moser & Schatz ACN 2001; Moser, Schatz, Jordan, Neurosurgery 2005)
• Youth Athletes from a college-prep boarding school (Ivy-bound) • Mandatory participation in sports • Multiple sports over 5-10 years • No concussion program in place • Attempt to understand/replicate
Dependent Measure: RBANS Subtests measure multiple neurocognitive domains •
Immediate Memory
•
Visuospatial/Contructional
List Memory - recall of 10 words presented orally. Story Memory - recall of short story presented orally.
Figure Copy - Copy of multi-part geometric drawing. Line Orientation - identify lines from a drawing.
•
Language Picture Naming - Naming of pictures of objects. Semantic Fluency - Name examples from category in one minute.
•
Attention Digit Span - Repeat a string of digits presented orally. Coding - Matches geometric shapes corresponding to numbers.
•
Delayed Memory List Recall - Recall 10 words learned in the List Learning subtest. List Recognition - recognition of 20 words presented orally. Story Memory - Recall of short story learned earlier. Figure Recall - Draw, from memory, the figure shown earlier.
Prolonged Effects: Pilot Study (Moser & Schatz, Arch Clinical Neuropsych 2001)
Youth athlete volunteers, divided into independent groups on the basis of concussion history. • Zero or One Previous Concussion: 8 healthy volunteers with either no history of concussion, or had sustained one previous concussion (not within the past six months). • Two+ Previous Concussions: 13 youth athletes who had sustained two or more previous concussions (not within the past six months). • Recent Concussion: 13 youth athletes who had sustained a recent concussion, with no identified medical or neuropsychological difficulties related to concussion one week after testing.
Prolonged Effects: Pilot Results
RBANS Mean Raw Scores Concussion Group n Total Coding Attention _____________________________________________________________ 0-1 Previous 8 Mean 252.63 63.88 77.38 Concussion SD 14.10 7.18 9.59 _____________________________________________________________ 2 or More Previous 13 Mean 240.54 55.92 68.69 Concussions SD 14.85 6.68 8.10 _____________________________________________________________ Rece nt 13 Mean 233.77 53.15 65.38 Concussion SD 15.92 10.71 9.20 _____________________________________________________________ RBANS Coding: [F(2,31)=3.98; p = .029; r = .50] RBANS Attn: [F(2,32)=4.59; p = .018; r = .55] Note: High er Mean Scores = Stronger Cognitive Functioning. Analyses are two-tailed; Effect sizes denoted by "r".
Follow-up Study (Moser, Schatz & Jordan, Neurosurgery 2005)
238 youth athlete volunteers ... divided into four independent groups on the basis of concussion history. • No Concussion: 82 healthy volunteers with no history of concussion.
• One Previous Concussion: 56 youth athletes who had sustained one previous concussion (not within the past six months). • Two+ Previous Concussions: 51 youth athletes who had sustained two or more previous concussions (not within the past six months). • Recent Concussion: 49 youth athletes who had sustained a recent concussion, with no identified medical or neuropsychological difficulties related to concussion within one week of testing.
Prolonged Effects-GPA GPA by Concus s ion Gr oup
3.55
3.5
3.45
3.4
3.35
3.3
3.25
3.2
3.15
3.1
3.05 No Concussion: (82)
One Previous: (56)
Two+ Pr evious: ( 51)
Concussion Group
Recent: (49)
Prolonged Effects-RBANS RBANS Subte st by Concus s ion Gr oup
80 No Concussion: (82) One Previous: (56) 70
Two+ Pr evious: ( 51) Recent: (49)
60
50
40
30
20
10
0 *Attn
IMM
DEM RBANS Subtest
Lang
VisC
Prolonged Effects: Results
• Multivariate Analysis of Variance (MANOVA) revealed a significant overall effect of concussion history on cognition [F(21,672)=1.8; p=.015]. • Univariate F-tests revealed significant main effects of concussion history on Attention [F(3,228)=4.72; p=.003] and GPA [F(3,228 =5.76; p=.001].
Prolonged Effects in Youth Athletes • Health non-concussed youth athletes with a history of concussion often show subtle deficits in attention and concentration at baseline assessment. • These enduring effects of previous cerebral concussions can be detected using traditional measures. • Concussions appear to occur in female athletes at a greater rate/frequency.
Youth Athletes: What we think we know: Contributing to these findings: •A more vulnerable and susceptible youth brain •Participation in multiple sports over a long period of years.
Emotionality • Feeling more emotional • Sadness • Nervousness • Irritability
Somatic Symptoms
Cognitive Symptoms • Attention Problems
• Visual Problems • Dizziness • Balance Difficulties • Headaches • Light Sensitivity • Nausea
• Memory dysfunction • “Fogginess” • Fatigue • Cognitive slowing
Sleep Disturbance •Difficulty falling asleep • Sleeping less than usual
Factor Analysis, Post-Concussion Symptom Scale N=327, High School,Univ Athletes Within 7 Days of Concussion (Pardini et al, 2004)
Post-Concussion Gender Differences Covassin, Schatz, Swanik, Neurosurgery, 2007)
79 NCAA Division 1 Athletes • Completed ImPACT at baseline • Sustained concussion warranting serial assessment up to 10 days post-concussion • Average 3, 8 days post-concussion • Males (N=41): Baseball, cheerleading, football, ice hockey, lacrosse, soccer, volleyball, and wrestling • Females (N=38): basketball, cheerleading, gymnastics, lacrosse, soccer, softball, volleyball,
Post-Concussion Gender Differences Covassin, Schatz, Swanik, Neurosurgery, 2007)
Baseline: No Gender differences [F(5,73)=.80; P=0.55] Post-Concussion: 3x2 mixed-factoral design MANOVA
• Time (Baseline, 3 days, 8 days): [F(2,76)=1670; P=0.0001; ES=.98] • Gender:
[F(1, 77)=.16; p=.69; ES=.002]
•Time x Gender Interaction: ]F(2,76)=.54; p=.59, ES=.01]
Post-Concussion Gender Differences Covassin, Schatz, Swanik, Neurosurgery, 2007)
Post-Concussion Symptoms: Male athletes reported significantly higher symptom scores for: • Sadness [F(1,77)=13.05, P=0.001] • Vomiting [F(1,77)= 5.95, P=0.017]
Post-Concussion Gender Differences Covassin, Schatz, Swanik, Neurosurgery, 2007)
Reliable Change Indices (RCI): At Time 1 (up to 3 days post-injury): • 58% of participants had one or more reliable declines in performance or increases in symptom reporting At Time 2 (up to 10 days post-injury): • 30% of participants were still showing one or more reliable changes from pre-season levels.
NEW MANAGEMENT STRATEGIES CIS Group, Vienna (2001), Prague (2004) Removal of symptomatic athletes from play Graduated return to play
Neuropsychological testing recommended “One of the Cornerstones of Management”
Aubry, Cantu, Dvorak, Graf-Baumann, Johnston, Kelly, Lovell, McCrory, Meeuwise, Schasmasch, 2001. Clinical J. Sports Med.
Current Large-Scale Programs Neuropsychological Testing
20 NFL Teams IRL, F1, CHAMP Car NASCAR USA Olympic Hockey USA Hockey 400 + High Schools in US 60 Sports Medicine Clinics in US Pro Boxing in California USA Ski Team USA Soccer Juniors
Ontario Hockey League New Zealand Rugby S. African Rugby World Cup Soccer 150 + Universities in US Many Neuropsychology Clinics in US Major League Baseball Major League Baseball Umpires
WHY USE NEUROPSYCHOLOGICAL TESTING? Unique Contribution To The Diagnostic Puzzle
Testing Provides Unique Information Concussed Athletes Often Deny Symptoms Athletes May Lack Awareness of Symptoms
UNIQUE CONTRIBUTION OF NEUROPSYCHOLOGICAL TESTING TO CONCUSSION MANAGEMENT Symptomatic
Testing reveals cognitive deficits in asymptomatic athletes within 4 days post-injury
Asymptomatic
100 95 90 85 80 75 70 65 60 55 50 Ve rbal Memory
N=215, MANOVA p95%)
Poor (95%)
P oor (
