literature review- concussions
TRANSCRIPT
IMPACT© AND OTHER NEUROPSYCHOLOGICAL AND NEUROCOGNITIVE
TESTS: A LITERATURE REVIEW
A Paper Submitted to the Graduate Faculty
of theNorth Dakota State University
of Agriculture and Applied Science
By
Kaylee Lea Knoff
In Partial Fulfillment of the Requirementsfor the Degree of
MASTER OF SCIENCE
Major Department:Health, Nutrition, and Exercise Sciences
July 2008
Fargo, North Dakota
iii
ABSTRACT
Knoff, Kaylee Lea; Department of Health, Nutrition and Exercise Sciences; College of Human Development and Education; North Dakota State University; July 2008. ImPACT© and Other Neuropsychological and Neurocognitive Tests: A Literature Review. Major Professor: Dr. Pamela Hansen.
Sport-related concussions are a serious problem that can have potentially
catastrophic complications if improperly managed. A concussion is a disturbance in brain
function occurring from rapid acceleration or deceleration forces. A sport-related
concussion is commonly evaluated with a clinical examination and self-reporting of post-
concussion symptoms. Concussed athletes may underreport concussion-related symptoms
in order to accelerate return to play. Allowing an athlete to return to play before being
asymptomatic may predispose the athlete to further injury, so the athlete’s cognitive
functioning should be considered when making return-to-play decisions. This
comprehensive paper reviews the literature involving neuropsychological and
neurocognitive testing in detecting post-concussive abnormalities following a concussion.
These tests include Immediate Post-Concussion Assessment and Testing (ImPACT©),
Concussion Resolution Index (CRI), and Standardized Assessment of Concussion (SAC).
In addition, literature on return-to-play guidelines was investigated.
iv
ACKNOWLEDGMENTS
I would like to thank my adviser and chairperson of my committee, Dr. Pamela
Hansen, for her time, effort, encouragement, and dedication she has provided throughout
this literature review and furthermore my degree. I have nothing but sincere appreciation
towards my graduate degree committee members, Dr. Donna Terbizan, Dr. Linda
Manikowske, and Kara Gange, for all their time and suggestions they offered to complete
my literature review. Finally, I would like to thank my instructors, my family, and my
peers for all their support throughout my graduate school experience at NDSU.
v
TABLE OF CONTENTS
ABSTRACT………………………………………………………………………………..iii
ACKNOWLEDGMENTS………………………………………………………………….iv
LIST OF TABLES…………………………………………………………………………vi
CHAPTER 1. INTRODUCTION…………………………………………………………..1
Purpose Statement………………………………………………………………..…2
Definitions…………………………………………………………………………..2
Project Significance…………………………………………………………….…...4
Specific Objectives…………………………………………………………….........4
Steps of How Review Will Be Conducted…………………………………….........4
Organization of Paper……………………………………………………………….5
CHAPTER 2. LITERATURE REVIEW…...……………………………………………....6
Diagnosing a Concussion…………………………………………………………...6
Neuropsychological Testing…………………………………………………….....13
Immediate Post-Concussion Assessment and Testing (ImPACT©)………14
Concussion Resolution Index (CRI)………………………………………18
Standardized Assessment of Concussion (SAC)…………………………..21
Return-to-Play Guidelines…………………………………………………………24
CHAPTER 3. DISCUSSION……………………………………………………………...29
REFERENCES…………………………………………………………………………….31
APPENDIX A. IMPACT© SAMPLE CLINICAL REPORT…………………………….37
APPENDIX B. CRI SAMPLE REPORT………………………………………………….42
APPENDIX C. SAC SAMPLE TEST…………………………………………………….43
vi
LIST OF TABLES
Table Page
1. Grading Scales for Athletic Head Injury…………………………………………..10 2. The ImPACT© Neuropsychological Test Battery………………………………...15 3. Guidelines for Returning to Play After Repeat or Recurrent Concussions..............25
1
CHAPTER 1
INTRODUCTION
A concussion is a disturbance in brain function occurring from rapid acceleration or
deceleration forces as a result of violent shaking of the head. Common signs and symptoms
of a concussion include dizziness, confusion, amnesia, or loss of consciousness (Anderson,
Hall, & Martin, 2004). An athlete who receives a direct blow to the head or body contact
causing forceful movement of the neck must be carefully evaluated for a possible brain
injury (Prentice, 2006).
According to Covassin, Swanik, and Sachs (2003), interest in concussion signs and
symptoms, evaluation, and long-term consequences has increased in recent years.
Concussions are more common in some collegiate sports than previously noted. Notebaert
and Guskiewicz (2005) reported that no simple tests can be performed on the brain to
determine the severity of a closed head injury and to help clinicians establish goals for
return-to-play. Litt (1994) reported a 16-year-old football player who developed a
headache following a collision during a game. When his headache persisted for one week,
he underwent a computerized tomographic (CT) scan to determine the cause. The findings
were normal, and the athlete was diagnosed with a concussion. Seventeen days post-injury,
the athlete reported to be asymptomatic at rest and with exertion. The athlete continued to
deny symptoms and was cleared for unlimited participation 30 days post-injury. In the next
game, the athlete collided with an opposing player, ran to the sidelines, and deteriorated on
the sidelines after complaining of dizziness. The athlete was transported to the local
medical facility, and neurosurgeons diagnosed a right subdural hematoma by CT scan. In
an interview four months post-operatively, the athlete admitted having experienced
2
constant symptoms between the first and second injuries (Litt, 1994). Notebaert and
Guskiewicz (2005) stated that the current tendency is to base the return-to-play decision on
the athlete’s self-reporting of symptoms and ability to perform sport specific tasks without
a recurrence of concussion symptoms. However, relying exclusively on this information
can be dangerous because it generates an incomplete picture, predisposing the athlete to
further injury.
Purpose Statement
The purpose of this comprehensive paper was to review the literature evaluating
popular neuropsychological and neurocognitive tests for detecting post-concussive
abnormalities following injury. These tests included Immediate Post-Concussion
Assessment and Testing (ImPACT©), Concussion Resolution Index (CRI), and
Standardized Assessment of Concussion (SAC). In addition, literature on return-to-play
guidelines was investigated.
Definitions
Concussion: Violent shaking or jarring action of the brain resulting in immediate or
transient impairment of neural function, such as alteration of consciousness, and
disturbance of vision and equilibrium (Anderson, Martin, & Hall, 2004).
Immediate Post-Concussion Assessment and Cognitive Testing (ImPACT©): A
computer administered neuropsychological test battery consisting of seven individual test
modules that measure aspects of cognitive functioning including attention, memory,
reaction time, and information processing speed (Lovell et al., 2003).
Concussion Resolution Index (CRI): A Web-based computerized neuropsychological
assessment instrument designed specifically to compare an athlete’s post-concussion
3
performance with his or her own pretrauma baseline performance (Erlanger, Saliba, Barth,
Almquist, Webright, & Freeman, 2001).
Standardized Assessment of Concussion (SAC): An abbreviated neuropsychological test
designed to provide medical personnel and athletic trainers responsible for clinical decision
making in the care of athletes with immediate objective data concerning the presence and
severity of neurocognitive impairment associated with a concussion (Prentice, 2006).
Balance Error Scoring System (BESS): A sideline measure of balance that uses double-
leg, single-leg, and tandem stances on both firm and foam surfaces (Patel, Mihalik,
Notebaert, Guskiewicz, & Prentice, 2007).
Computed Tomography (CT): A form of radiography that provides cross-section of
tissue that is 100 times more sensitive than radiographs. It is effective in detecting stress
fractures, tumors, bleeding, and soft tissue abnormalities (Cuppet & Walsh, 2005).
Post-Concussion Syndrome: Delayed condition characterized by persistent headaches,
blurred vision, irritability, and inability to concentrate (Anderson et al., 2004).
Cantu Grading Scale: A concussion grading scale that uses the duration of loss of
consciousness and post-traumatic amnesia to differentiate mild, moderate, and severe
concussive injury (Anderson et al., 2004).
Neurocognitive Testing: A helpful piece of additional information to assist in diagnosing
and managing concussions in order to provide the greatest amount of objective clinical
information during the post-concussion evaluation (Van Kampen, Lovell, Pardini, Collins,
& Fu, 2006).
Neuropsychological Testing: The administration of various tests of cognitive abilities
(e.g. memory, attention, language, visuospatial skills, etc), tests of psychological
4
functioning (e.g. personality inventories, psychiatric symptom scales), and some limited
testing of sensory and motor functioning (Randolph, McCrea, & Barr, 2005).
Subdural Hematoma: The most common cause of death in athletes, resulting from
acceleration or deceleration forces, tearing vessels bridging the dura mater and the brain
(Prentice, 2006).
Project Significance
The significance of this paper was to help gain a better understanding of the
reliability and effectiveness of neuropsychological and neurocognitive testing in return-to-
play decision making.
Specific Objectives
1. To review the literature involving ImPACT© to determine its reliability and
effectiveness in assessing a concussion.
2. To review the literature involving the CRI to determine its reliability and effectiveness
in assessing a concussion.
3. To review the literature involving SAC to determine its reliability and effectiveness in
assessing a concussion.
4. To review the literature involving return-to-play guidelines.
Steps of How Review Will Be Conducted
Research was conducted by obtaining information from the Journal of Athletic
Training website, from a variety of journal articles available on the ImPACT© website,
and various databases at NDSU, including Medline and EBSCO. In addition, the
bibliographies at the end of various research articles were reviewed and used as a source in
collecting research articles.
5
Organization of Paper
Chapter 1 discusses the Purpose Statement, Definitions, Project Significance,
Specific Objectives, and how the review was conducted. Chapter 2 reviews the literature
on the various neuropsychological and neurocognitive tests, and return-to-play guidelines.
Chapter 3 includes the Discussion of concussions and the evaluation tests.
6
CHAPTER 2
LITERATURE REVIEW
Concussions are a common injury in athletics, particularly in contact sports.
Determining whether an athlete returns to play is a difficult decision for a certified athletic
trainer. This literature review examines neuropsychological and neurocognitive testing.
The following are discussed: concussion diagnosis, Immediate Post-Concussion
Assessment and Testing (ImPACT©), Concussion Resolution Index (CRI), Standardized
Assessment of Concussion (SAC), and return-to-play guidelines.
Diagnosing a Concussion
Anderson et al. (2004) define a concussion as violent shaking of the brain, caused
by acceleration or deceleration forces. Prentice (2006) however, defines a concussion as a
direct blow to the head or body contact, causing the head to snap forward, backward, or
rotate to the side, possibly resulting in unconsciousness. But, Cantu (2001) stated that there
is no universal agreement on the definition and grading of concussions. Despite the various
definitions, all authors agree that a concussion results from the brain shaking within the
skull, either at the point of contact, or on the opposite side of the head. Therefore, for the
purpose of this literature review, Anderson et al.’s definition was used.
Although the severity of the signs and symptoms vary by definition, most athletes
that suffer a concussion state they have a headache, feel dizzy, and nauseated. According
to Anderson et al. (2004), common signs and symptoms of a concussion include confusion,
dizziness, amnesia, and occasionally loss of consciousness. Prentice (2006) reported
typical symptoms to include various types of amnesia, cognitive deficits, and motor,
coordination, or balance deficits. Cantu (2001), however, stated that ordinary symptoms
7
include feeling stunned or seeing bright lights, brief loss of consciousness, loss of balance,
headaches, personality changes, and cognitive and memory dysfunction. These authors are
in agreement that typical symptoms of a concussion include dizziness, confusion, loss of
consciousness, and amnesia. This literature review used the signs and symptoms described
by Anderson et al. (2004).
Assessing a concussion requires the athletic trainer to complete a thorough
evaluation. Onate, Guskiewicz, Riemann, and Prentice (2000) reported that objective
sideline assessment of a mild head injury includes the use of symptom checklists, cognitive
tests, and postural control tests. Various methods of postural stability analyses have been
proposed for assessing mild head injury, yet few of these tests can be used for immediate
sideline assessment. The typical sideline evaluation consists of assessing orientation to
time, place, person, situation, and simple memory and concentration tests. Establishing
normative cognitive baseline allows the practitioner to make a more objective decision so
that an athlete can safely return to competition. Onate, Beck, and Van Lunen (2007)
assessed whether testing environment affects Balance Error Scoring System (BESS) scores
in healthy collegiate baseball players. The BESS is a system developed as a standardized,
objective assessment tool for the clinical sideline assessment of postural control. The
BESS uses three stances, including double-leg, single-leg, and tandem, on both firm and
foam surfaces. Onate et al. (2007) found that BESS performance was impaired when
participants were tested in a sideline environment compared with a clinical environment.
Consistent environment settings should be used for both baseline and follow-up testing
after concussion. Onate et al. (2007) recommend future researchers to focus on various
sporting environments in practices and games, testing in different environmental
8
conditions, such as hot or cold temperatures; and the effect of ankle taping, and ankle or
knee bracing on BESS scores.
Certified athletic trainers also need to be aware of the exertion effects when
administering the BESS after physical activity. According to Susco, Valovich McLeod,
Gansneder, and Schultz (2004), a significant decrease in BESS performance with exertion
was found. Exertion had the greatest effects on the tandem and single-leg stance conditions
at 0, 5, 10, and 15 minutes following activity. Administering the BESS immediately after a
concussive injury could cause false-positive findings. Therefore, Susco et al. (2004)
reported that waiting 15 to 20 minutes before performing the BESS following injury would
decrease the exertion factor and enhance the accuracy of the post-concussive results.
Wilkins, Valovich McLeod, Perrin, and Gansneder (2004) also found exertion to affect the
BESS. Significant increases in total errors were found when the athletes were fatigued
when administering the BESS. Thus, clinicians who use the BESS as part of their sideline
assessment for concussion should not administer the test immediately after a concussion
due to the effects of fatigue.
Meanwhile, Valovich, Perrin, and Gansneder (2003) found a significant practice
effect on the BESS during the course of repeated administration. After repeatedly testing
32 uninjured subjects on the BESS, the number of BESS errors decreased with each test
session, especially with the single-leg stance on a foam surface. Errors scored on day five
and seven were significantly lower than the baseline score. Therefore, Valovich et al.
recommended that clinicians consider practice effects on the BESS when readministering
concussion evaluations to track recovery of an athlete or to determine whether an athlete is
ready to return-to-play.
9
In certain situations, secondary signs and symptoms of a concussion may arise.
This is known as post-concussion syndrome. Anderson et al. (2004) stated that post-
concussion syndrome occurs more frequently in women than men. Cognitive impairments
may vary from 48 hours post-trauma, lasting to several weeks or months following the
concussion. Typical symptoms of the syndrome include decreased attention span,
persistent headaches, blurred vision, vertigo, or irritability.
If an athlete returns to play prior to being asymptomatic, the athlete may be
predisposed to further injury, resulting in second impact syndrome. Anderson et al. (2004)
reported that second impact syndrome occurs when an individual who has sustained a head
injury, usually a concussion, sustains another head injury before the individual is entirely
asymptomatic. The individual may appear stunned, but often finishes the play, and usually
walks off the field under their own power. Intracranial pressure is increased as a result of
vascular engorgement, the brain stem becomes compromised, and the individual may
collapse with rapidly dilating pupils, loss of eye movement, coma, and respiratory failure
(Anderson et al., 2004).
According to Anderson et al. (2004), once a concussion has been diagnosed, the
concussion is categorized into various grades in order to determine the severity of the head
injury. There are over 16 different classification schemes that define the various degrees of
a concussion. Anderson et al. reported four grading scales: Cantu; Torg; Colorado Medical
Society; and American Academy of Neurology. Anderson et al. (2004) stated that Robert
C. Cantu developed a concussion classification that many sports medicine clinicians have
adopted. The Cantu grading scale uses the duration of loss of consciousness and post-
traumatic amnesia to differentiate mild, moderate, and severe concussions. Dr. Joseph Torg
10
developed another classification system that includes six separate grades of concussion,
including facial expression, determining orientation of time, place, and person, testing for
any post-traumatic and retrograde amnesia, and gait evaluation. The Colorado Medical
Society is a concussion grading scale that was developed after a single head injury death
from second impact syndrome in a high school athlete in Colorado. This athlete served as a
means for Dr. James Kelly and the Colorado Medical Society to study head injuries and
their management. The guidelines created stricter requirements for assessing the severity of
concussions and required emergency transport to the hospital for all individuals that
experienced unconsciousness for any length of time. The American Academy of
Neurology created a modification to the Colorado Medical Society that included nine
features of concussions frequently observed, and early and late symptoms of concussions
(Anderson et al., 2004). Cantu (2001) stated that concussion grading guidelines all focus
on loss of consciousness and post-traumatic amnesia as key signs in the grading schemes.
(See Table 1.)
Table 1. Grading Scales for Athletic Head Injury (Anderson et al., 2004) Grade I/Mild Grade II/Moderate Grade III/SevereCantu No LOC or PTA <1 hour LOC < 5 minutes LOC >5 minutes
PTA 1-24 hours PTA >24 hoursTorg Grade I-II Grade III-IV Grade V-VI
No LOC or amnesia LOC < few minutes LOC/coma, confusion, (except PTA) PTA or retrograde amnesia amnesia
CMS No LOC, confusion, No LOC, confusion, with amnesia LOC no amnesiaAAN No LOC No LOC Any LOC
Sxs <15 minutes Sxs >15 minutes
AAN= American Academy of Neurology; CMS= Colorado Medical Society; Cantu= Dr. Robert Cantu; Torg= Dr. Joseph S. Torg; LOC= Loss of consciousness; PTA= post-traumatic amnesia; and Sxs= symptoms (i.e., confusion, amnesia, etc.).
11
The National Athletic Trainers’ Association position statement on management of
sport related concussions states that the two most recognizable signs of a concussion are
loss of consciousness and amnesia (Guskiewicz, Bruce, Cantu, Ferrara, Kelly, McCrea, et
al., 2004). But Guskiewicz, et al. (2004) noted that neither is required for an injury to be
classified as a concussion. Most grading scales rely on loss of consciousness and amnesia
as primary factors for predicting the severity of a concussion. However, recent research
suggests that these two factors are not good predictors of the severity of a concussion.
Guskiewicz et al. reported that there is no association between loss of consciousness and
duration of symptoms, or loss of consciousness and neuropsychological and balance tests
at three, 24, 48, 72, and 96 hours post injury. Amnesia, however, appears to be less clear.
Guskiewicz et al. stated that amnesia was recently found to predict symptom and
neurocognitive deficits at two days post injury. Yet, additional research is warranted to
help improve clinical decision making.
Concussions are more prevalent in collision sports like football, rugby, and soccer.
In a research study by Marshall and Spencer (2001), it was found that concussions are a
major concern in rugby. Participants are unshielded from collision forces and the cranium
is subjected to violent acceleration or deceleration forces and rotational forces. Any player
who self-reports or is diagnosed as having a concussion is subject to an automatic three-
week suspension, so many concussions go unreported. Two rugby teams were followed for
three years. Seventeen concussions were recorded and accounted for about 25% of all
reported injuries. Concussions were graded on the Cantu grading scale. Marshall and
Spencer reported 14 concussions as grade one, two were grade two, and one was grade
three. The rate for all injuries overall was 1.5 per 1000 athlete-exposures. The concussion
12
rate was 11.3 per 100. Concussions accounted for 25% of all days lost from rugby
participation due to injury. Due to the limited medical personnel and administrative rules
that suspend athletes from playing, the incidence of concussions go unreported, and efforts
to prevent, recognize, and manage these injuries need to be implemented (Marshall &
Spencer, 2001).
Macciocchi, Barth, Littlefield, and Cantu (2001) analyzed neurocognitive and
neurobehavioral consequences of an athlete sustaining one concussion and an athlete with
two or more concussions in collegiate football players. The primary goal was to determine
if a second concussion produced identifiable cognitive deficits above and beyond those
observed after a single injury. All players were assessed preseason to establish baseline
functioning. Players completed several neuropsychological measures to assess various
aspects of visual and auditory attention, as well as information processing speed. No
statistically significant difference in test performance was seen between players with one
or two concussions within a four year time period. The amount of symptom complaints
increased significantly after one or two concussions, but symptom reports returned to
baseline by 10 days post-injury. Ives, Alderman, and Stred (2007) reported a 14 year old
patient that suffered four head traumas over a four month period. Two years later, the
patient was diagnosed with hypopituitarism. Currently, the patient is being treated with
physiologic replacement hormones with resumption of linear growth and strength. Ives et
al. (2001) reported that hypopituitarism symptoms are often masked by trauma and post-
concussion symptoms and may not appear until months or years after the trauma.
Randolph (2001) also assessed multiple concussions, and reported that each traumatic
episode to the brain results in further depletion of the reserve capacity. This limits the rate
13
and the degree in which functional recovery can occur. The depletion could have two
effects, including permanent loss of some neurocognitive functions resulting from repeated
trauma, and increased sensitivity to the effects of normal aging such as premature
Parkinson disease or Alzheimer disease. However, Macciocchi et al. concluded that
neurocognitive and neurobehavioral consequences of only two concussions did not appear
to be significantly different from those of one concussion. Because of the limitations on
data interpretation, additional studies are needed to clarify the neuropsychological
consequences of multiple concussions (Macciocchi et al., 2001).
Neuropsychological Testing
According to Prentice (2006), neuropsychological testing is a type of assessment
that focuses on short-term memory, working memory, attention, concentration, visual
spatial capacity, verbal learning, information processing speed, and reaction time.
Neuropsychological testing has been developed for use in both on-field and off-field
evaluation. Computerized neuropsychological testing programs were developed and are
being utilized in the athletic setting today. According to Prentice, these computerized tests
show great success for eliminating some of the logical challenges of baseline testing, while
testing hundreds of athletes simultaneously. Therefore, computerized neuropsychological
testing has the potential to make a significant contribution to concussion management
(Prentice, 2006).
According to Barr (2001), neuropsychological testing is a proven method for
evaluating symptoms of a concussion. Applying these neuropsychological tests to athletes
has required some procedural modifications, including the use of brief test batteries,
collection of pre-season data, and evaluation of subtle postconcusive changes in test scores
14
over time. Echemendia, Putukian, Mackin, Juliam, and Shoss (2001) found
neuropsychological testing to be useful in the detection of cognitive impairment following
a mild traumatic brain injury. However, a battery of tests should be used, rather than any
single test to capture the variability that exists among injured athletes. Schatz and Putz
(2006) also noted the importance of using the same tests at baseline and post-trauma to
increase accuracy of results. Clinicians obtaining baseline evaluations using one measure
should not use the baseline as a basis for post-concussion assessment using another
measure.
Barr (2001) reported that athletic trainers and other related personnel need to be
aware of the training and methodological issues associated with neuropsychological
testing. The advantages and limitations of these tests will eventually enhance the athletic
trainer’s ability to use information from neuropsychological testing in an effective manner.
However, Schatz and Putz (2006) stated that neuropsychological tests are most accurate
when an athlete performs the same test at baseline and post-trauma.
Immediate Post-Concussion Assessment and Testing (ImPACT©)
ImPACT© is the world’s most widely used computerized sports concussion
evaluation system, and has been accepted by team doctors and athletic trainers for several
top sports leagues in the world. These leagues include the National Football League, Major
League Baseball, the NCAA, and more than 1,000 high schools nationwide. ImPACT© is
now available for the first time via the Internet to all of the Major League Soccer teams
and players (ImPACT© Applications, Inc., 2007).
15
According to Schatz, Pardini, Lovell, Collins, and Podell (2005), the ImPACT©
Test Battery was developed to help increase the availability of neuropsychological testing
in athletics. (See Table 2.)
Table 2. The ImPACT© Neuropsychological Test Battery (Schatz et al., 2005)
Test name Neurocognitive domain measured
Word Memory Verbal recognition memory (learning and retention)Design Memory Spatial recognition memory (learning and retention)X’s and O’s Visual working memory and cognitive speedSymbol Match Memory and visual-motor speedColor Match Impulse inhibition and visual-motor speedThree Letter Memory Verbal working memory and cognitive speed
Schatz et al. (2005) reported that ImPACT© consists of three main parts:
demographic data, neuropsychological tests, and the Post Concussion Symptom Scale. The
Post Concussion Symptom Scale is a detailed, 21-symptom checklist used by concussed
athletes to rate the severity of their symptoms. These parts are combined to provide data
that assists in accurately assessing concussive injuries. ImPACT© consists of six
neuropsychological tests, each targeting different aspects of cognitive functioning,
including attention, memory, processing speed, and reaction time. Some of these test
components have two distinct subtests that measure various cognitive functions. (See
Appendix A) From these six tests, composite scores are created, which include verbal
memory, visual memory, visual motor speed, and reaction time (Schatz et al., 2005).
McClincy, Lovell, Pardini, Collins, and Spore (2006) examined recovery time from
concussive injury in various high school and collegiate athletes. ImPACT© was used to
examine the cognitive performance of 104 concussed athletes at baseline, 2, 7, and 14 days
16
post-injury. No concussed athletes returned to play until being symptom free at rest and
exertion, and their ImPACT© data had returned to baseline levels. Seventy eight
concussions suffered were grade one, and the remainder were diagnosed as grade two and
grade three concussions. Differences between baseline and day two post-injury scores were
observed for all ImPACT© composites. At day seven, all scores were significantly lower,
but verbal memory was the only significant low score by day 14. McClincy et al. found
cognitive performance deficits persisting for seven and even fourteen days in some cases.
Therefore, the athlete’s post-concussion cognitive functioning should be considered when
making return-to-play decisions.
Similar to McClincy et al. (2006), Schatz et al. (2005) analyzed ImPACT© and
found similar results. All athletes in this study underwent a baseline evaluation, and were
administered ImPACT© before the 2000, 2001, or 2002 athletic seasons. Concussed
athletes were tested within 72 hours of sustaining a concussion, and data were compared to
non-concussed high school athletes with no previous history of concussions.
Approximately 61 of the 72 concussed participants in the concussion group and 59 of the
66 participants in the control group were correctly classified. Using these data, the
sensitivity of ImPACT© was about 82% and the specificity was 89.4%. Schatz et al.
concluded ImPACT© to be a useful tool for the assessment of the neurocognitive and
neurobehavioral effects of concussion and can assist the practitioner by providing post-
injury cognitive symptoms before making return-to-play decisions. However, Schatz et al.
reported a need for future research to address decision making at the individual level,
thereby focusing on the combination of post-concussion symptom scores and ImPACT©
composite score changes to identify a concussion.
17
Sport related concussion is commonly evaluated with a clinical examination and
the athlete’s report of both current and post-concussion symptoms. According to Broglio,
Macciocchi, and Ferrara (2007), concussed athletes may underreport concussion-related
symptoms in order to accelerate return-to-play. Reliance on athlete-reported post-
concussion symptoms when making return-to-play decisions may expose athletes to further
injury if complete recovery has not occurred. In this study by Broglio and Macciocchi et al.
(2007), the purpose was to evaluate the presence of neurocognitive decrements in
concussed athletes no longer reporting concussion related symptoms. Twenty one Division
I collegiate athletes that had previously completed a baseline assessment on the ImPACT©
test participated in this study. Other criteria to participate in this study included concussed
athletes that had a follow-up assessment completed within 72 hours of the injury, and
denied experiencing any symptoms at the self-reported symptomatic period after injury.
When assessed within 72 hours of sustaining a concussion, 17 athletes showed deficits on
at least one ImPACT© variable. At the asymptomatic time point, eight concussed athletes
continued to demonstrate neurocognitive impairment on at least one ImPACT© variable.
In addition, Iverson, Gaetz, Lovell, and Collins (2002) reported that athletes with persistent
fogginess following concussion demonstrated slower reaction times, reduced memory
performance, and slower processing speed on ImPACT©. The athletes with persistent
fogginess also experienced a large number of other post-concussion symptoms, compared
to the athletes with no reported fogginess. Broglio and Macciocchi et al. (2007) found that
neurocognitive decrements may persist when athletes no longer report concussion-related
symptoms. Therefore, the exclusive use of symptom reports in making a return-to-play
decision is not advised.
18
A similar study by Van Kempen et al. (2006) also supported neurocognitive
testing. Their study was designed to determine the effectiveness of computer-based
neurocognitive testing to detect post-concussive abnormalities following injury. High
school and college athletes diagnosed with a concussion were tested two days after injury.
Post-injury neurocognitive performance and symptom scores were compared with pre-
injury scores. Ninety three percent of the 122 concussed athletes had either abnormal
neurocognitive test results or a significant increase in symptoms, relative to their own
baseline. Similar to Broglio and Macciocchi et al. (2007), Van Kempen et al. (2006)
concluded the reliance on patients’ self-reported symptoms after concussion is likely to
result in misdiagnosed concussions and may result in premature return-to-play.
Neurocognitive testing increases the accuracy of detecting concussions when used in
conjunction with self reported symptoms.
ImPACT© can be a valuable tool for an athletic trainer. Although the test was
found to have low to moderate reliability, researchers feel confident that ImPACT© may
help a clinician make an accurate return-to-play decision, while also obtaining objective
information to help prove the athlete is or is not ready to return-to-play.
Concussion Resolution Index (CRI)
According to Erlanger et al. (2001), the CRI is a Web-based computerized
neuropsychological assessment battery designed specifically to compare an athlete’s
postconcussion trauma to their preseason baseline. The CRI was developed for both
athletic trainers and other professionals to assist in managing and monitoring the resolution
of symptoms following a concussion. The CRI was generated to address concerns
regarding the use of current assessment techniques, including issues of test-retest effects,
19
practice effects, the need for alternate forms, ease of administration, time efficiency, and
cost. The CRI uses specific measures of cognitive functions associated with
postconcussion syndrome including memory, reaction time, speed of decision making, and
speed of information processing. (See Appendix B) Six subtests are administered at
baseline and again post-trauma at each evaluation. These six subtests include three speeded
test indices and two error scores. Two subtests that make up the Processing Speed index
include Animal Decoding and Symbol Scanning. Animal Decoding is when athletes are
instructed to type in numbers keyed to animals and pictures. Symbol Scanning is where
athletes must rapidly determine whether identified sets of symbols are present among a set
of distractors. Reaction time is measured when athletes press the space bar when a target
shape appears on the screen, and Cued Reaction Time is measured when an athlete presses
the space bar when a target shape appears immediately after the “cue”. These subtests
comprise the Simple Reaction Time index. An error index is calculated based on total false
positives and false negatives. Visual Recognition 1 and Visual Recognition 2 present a
series of pictures, with some pictures repeated. Athletes must press the space bar as quickly
as possible whenever they recognize a picture from a previous exposure. An error index is
calculated based on total false positive and false negative responses on these two tests
(Erlanger et al., 2001).
Erlanger et al. (2001) conducted a study that was designed to determine the
usefulness in detecting and monitoring resolution of symptoms after sport-related
concussion, and to verify whether the CRI provides objective information for return-to-
play decisions. Neuropsychological baseline data was obtained on all subjects using the
CRI. The CRI was designed to compare an athlete’s post-concussion performance with
20
their own pre-trauma baseline performance. Athletes sustaining a concussion received
follow-up tests at 1-2 day intervals post-trauma. Twenty-three of the 26 patients were
identified as symptomatic on initial post-concussion testing. Although the CRI is still in
field trials, preliminary data indicate that the CRI may be a useful method for athletic
trainers and other professionals when tracking the resolution of symptoms after sport-
related concussion. However, Erlanger et al. reported that more research is needed to
determine optimal time frames for monitoring resolution of post-concussion symptoms in
order to obtain return-to-play guidelines.
Broglio, Ferrara, Macciocchi, Baumbartner, and Elliott (2007) examined the test-
retest reliability of commercially available computer-based neurocognitive assessments
using clinically relevant time frames. Participants completed the ImPACT©, Concussion
Sentinel, and the CRI on three days, including baseline, day 45, and day 50 post baseline
testing. The Concussion Sentinel uses seven tests to develop five output scores. These tests
include reaction time, decision making, matching, attention, and working memory.
Calculations for all output scores were generated by each computer program as an estimate
of test-retest reliability. Broglio and Ferrara et al. (2007) reported the three contemporary
computer-based concussion assessment programs to have low to moderate test-retest
reliability. To increase accuracy of results, subjects were excluded from the study if the
participants had a learning disability. Broglio and Ferrara et al. (2007) stated that the
results did not appear to be affected by factors related to poor test performance because the
subjects with a poor test baseline were excluded from the study.
In a case study reported by HeadMinder, Inc. (2001), a 16 year old high school
athlete collided with another player during a basketball game. The athlete took a baseline
21
test using the CRI during the pre-season, and took a follow-up test one day post-trauma.
The athlete scored significantly lower on the Simple and Complex Reaction Time indices.
The athlete reported to be asymptomatic at eight days post-trauma, while her performance
on the Simple and Complex Reaction time indices remained significantly lower than her
baseline performance, indicating she was still symptomatic. The athlete denied any re-
emergence of symptoms, and matched preseason scores at 14 days post-trauma, which
signify that the CRI successfully monitored her recovery. Broglio and Ferrara et al. (2007)
recommend neurocognitive evaluation to continue to be part of a multifaceted concussion
assessment program, with priority given to those scores showing the highest reliability.
Although the CRI is a relatively new test, the test shows to be an effective tool
when making return-to-play decisions. The test should not be used by itself, but should be
used in conjunction with the athlete’s self reporting of symptoms and the grading of a
concussion to determine when an athlete can return-to-play. However, additional research
is recommended.
Standardized Assessment of Concussion (SAC)
According to Valovich et al. (2003), the Standardized Assessment of Concussion
(SAC) is a mental status test designed to assess cognitive and postural stability that takes
about five to seven minutes to administer. McCrea (2001) stated that the SAC was
developed to give clinicians a more objective and standardized method of immediately
assessing an injured athlete’s mental status on the sport sideline within minutes of a mild
head injury. The instrument is designed to be a supplement to other methods of concussion
assessment, but not designed to be individually used to determine the severity of a head
injury or determine when an athlete may return-to-play. The SAC consists of measures of
22
orientation, immediate memory, concentration, and delayed recall, all totaling a composite
score of 30. (See Appendix C) According to Valovich McLeod, Barr, McCrea, and
Guskiewicz (2006), orientation is assessed by asking the athlete the day, week, month,
year, and time. A list of five unrelated words is used to measure immediate memory, and
the athlete is asked to repeat those five words three different times throughout the
evaluation. Repeating strings of numbers in the reverse order of their readings and the
months backwards is used to assess concentration. A neurological assessment is conducted
to assess strength, sensation, and coordination following a concussion. The presence of
loss of consciousness, retrograde amnesia, and post-traumatic amnesia are also
documented (McCrea, 2001). Valovich McLeod et al. (2006) assessed the test-retest
reliability and the reliable change of concussion assessments in athletes participating in
youth sports. Secondary objectives included SAC and neuropsychological assessments in
young athletes. Valovich McLeod et al. found that test-retest reliability using the SAC was
relatively low, so it is hypothesized that the SAC assesses other areas of cognitive function.
This proves that other neuropsychological tests must be used in conjunction with the SAC
to provide the most effective results (Valovich McLeod et al. 2006).
In a study done by McCrea (2001), 1325 high school and collegiate football players
were tested at baseline on the SAC. Sixty three injured subjects were evaluated
immediately on the SAC following their injury. These subjects were matched with 55
uninjured subjects that were randomly reexamined on the SAC. Once the subject had
sustained a concussion, both the subject and their respective match were tested on the
sideline, and again 48 hours post-injury under the same conditions. McCrea found a
decrease of more than four points on the SAC immediately post-trauma in the concussed
23
athlete. However, uninjured subjects retested on the sideline showed an average increase of
one point above their baseline. McCrea found the SAC to be a valuable tool for
practitioners when detecting the immediate effects of concussion on mental status and
return-to-play decision making. However, McCrea noted that screening tools should not be
used as a replacement for medical evaluation or as the sole determinant about whether an
athlete is ready to return-to-play.
Hopefully an athlete will not suffer repeated concussions. Nonetheless, Valovich et
al. (2003) assessed whether repeated administration of the SAC demonstrates a practice or
learning effect in 32 uninjured high school athletes. Sixteen subjects were randomly
assigned to a control group, and the other 16 were randomly assigned to a practice group.
All subjects were administered the SAC at an initial test session to serve as a baseline
score. However, the results differed from McCrea (2001), who noted slight improvement
with normal controls from baseline to 48 hours after baseline. The results found on the
SAC did not have a practice effect on repeated administration between baseline and day 30
in both the practice group and the control group. Therefore, Valovich et al. (2003) stated
that athletic trainers should be confident that repeated administration of the SAC does not
elicit practice effects in healthy athletes and should be used to assess the mental status of
an athlete immediately following a concussion. However, Valovich et al. (2003) noted that
using three different forms of the SAC can help decrease practice effects and increase the
accuracy of results.
Oliaro, Anderson, and Hooker (2001) recommend certified athletic trainers and
team physicians to show consistency when using appropriate grading scales. Assessment of
concussion should include a symptom checklist, BESS, and SAC. The results should be
24
compared with the athlete’s normal baseline scores, and neuropsychological and postural
stability testing should be administered at follow-up. Oliaro et al. concluded that return-to-
play decisions should be based on the grade of concussion, scores on objective tests, and
concussion symptoms during exertional activities.
The SAC was found to be a valuable instrument when immediately assessing a
concussion and determining return-to-play. The reliability of the test did not appear to
decrease with repeated administration. However, it is recommended that the athlete use a
different form of the test to help decrease learning effects. The test is not designed to be
used as the sole determinant when making return-to-play decisions, but the SAC is an
effective tool when combined with the athlete’s self reporting of symptoms and the grading
of the concussion.
Return-to-Play Guidelines
Determining whether an athlete is ready to return-to-play is a difficult decision for
an athletic trainer. According to Lovell et al. (2004) the diagnosis and management of a
concussion in athletes has become a highly debated topic in athletics. Recognition of the
potential dangerous effects of a concussion has progressed to multiple concussion
management guidelines over the past decade. These guidelines have emphasized the
importance of the presence, absence, and duration of the signs and symptoms of a
concussion. (See Table 3.) The criteria have provided valuable assistance to team medical
personnel and have lead to a greater degree of caution in managing the injury. However,
these guidelines have not undergone scientific validation, and there is controversy
regarding their effectiveness when predicting return-to-play (Lovell et al., 2004).
25
Table 3. Guidelines for Returning to Play After Repeat or Recurrent Concussions (Prentice, 2006)
Classification Grade First Concussion Second Concussion Third ConcussionColorado Medical 1(mild) RTP if asymptomatic RTP if Terminate season; Society 20 minutes asymptomatic RTP if asymptomatic Guidelines 1 week 3 months 2 (moderate) Terminate play; RTP Terminate season; Terminate season;
if asymptomatic RTP if asymptomatic RTP next season 1 week if asymptomatic
3 (severe) Terminate play; RTP in 2 weeks if Terminate season; RTP 1 month if asymptomatic for no RTP in contact asymptomatic 1 sports week
Cantu Grading 1 (mild) RTP 1 week if RTP 2 weeks if Terminate season;Scale asymptomatic asymptomatic RTP next season if
1 week asymptomatic 2 (moderate) RTP if asymptomatic Minimum 1 month; Terminate season
2 weeks RTP if asymptomatic next season if 1 week asymptomatic
3 (severe) Minimum 1 month; Terminate season; No further contact; RTP if asymptomatic RTP if asymptomatic RTP next season if
1 week asymptomaticAmerican 1 (mild) Terminate play; Terminate play;Academy of RTP 15 minutes if RTP if asymptomaticNeurology asymptomatic 1 week
2 (moderate) Terminate play; Terminate play; RTP RTP 1 week if if asymptomatic
asymptomatic 2 weeks 3 (severe) Terminate play; Terminate play;
RTP 1 week if RTP if asymptomatic brief LOC; 2 weeks 1 month with prolonged LOC
RTP= return-to-play; LOC= loss of consciousness; and Asymptomatic= no post concussive symptoms.
Recent concussion management guidelines suggest that athletes sustaining a mild
concussion may return-to-play if asymptomatic for 15 minutes (Lovell et al., 2004). These
researchers assessed the utility of a current concussion management guideline in
classifying and managing mild concussions. Forty-three high school athletes completed
neuropsychological test performance and symptom ratings prior to the season at two times
during the first week following a mild concussion. Thirty six hours post-concussion,
26
mildly concussed high school athletes demonstrated a decline in memory and a dramatic
increase in self-reported symptoms compared to baseline performance. Lovell et al. found
that athletes with a mild concussion demonstrated memory deficits and symptoms that
persisted to be worse than anticipated.
In the previous study it was noted that symptoms were worse than anticipated for a
mild concussion. In Kersey’s (1998) study, the researcher analyzed the possible
relationship between a reported mild concussion and an acute subdural hematoma in a
football athlete. A healthy athlete sustained a mild concussion, and continued symptoms
led to the diagnosis of post-concussion syndrome. Twenty five days following the
concussion, the athlete returned to play and sustained a second head injury 10 days later.
The athlete became unconscious and presented with abnormal posturing, a fixed and
dilated left pupil, shallow breathing, and right-sided paralysis. Kersey reported that a
recent concussion may increase the risk of a catastrophic injury. This case demonstrates the
importance of using concussion grading scales and adhering to return-to-play guidelines. In
addition, Kersey also recommends the use of additional diagnostic techniques to help
prevent an athlete from returning to participation too quickly.
Although an athlete may suffer a mild concussion, return-to-play guidelines are
established for the safety of the athlete. Collins, Lovell, and Mckeag (1999) reported a 25
year old hockey player that received an elbow to the face. Initially, the athlete reported
confusion the first one to two minutes, but denied a headache, nausea, dizziness, and did
not lose consciousness. After 30 minutes, the athlete reported nausea, dizziness, and had an
abnormal feeling, while he also performed poorly on the memory component of a mental
status evaluation. According to return-to-play guidelines, the athlete would return-to-play
27
within 20 minutes post-injury, if not immediately. Clearly his later signs and symptoms
suggested a severe injury. Data suggest that current mild concussion return-to-play
recommendations that allow for immediate return-to-play may be too liberal (Collins et al.,
1999).
As the guidelines state, an athlete should not return-to-play until they are
asymptomatic. An article by King (1996) stated that a range of post-concussion symptoms
are often reported after injuries, including headaches, dizziness, fatigue, irritability, double
vision, and depression. Patients with mild or moderate head injuries are usually
asymptomatic within three months of their injury. According to Kelly (2001), the
observation of loss of consciousness at the time of concussion must be viewed as reflecting
a potentially mild traumatic brain injury. This is different than a mild concussion. Loss of
consciousness is followed by more severe acute mental status abnormalities and has an
increased risk of intracranial pathology than concussion without loss of consciousness.
Collins et al. (1999) reported a 19 year old running back that made helmet to helmet
contact with a linebacker. The athlete had loss of consciousness for five seconds, and
walked off the field under his own power. The athlete reported no related symptoms and
passed a mental status examination immediately following the injury, at five, 10, and 15
minute intervals. Kelly (2001) reported that prolonged loss of consciousness represents a
neurological emergency, which may require neurosurgical intervention. Therefore,
lingering symptoms of a concussion, even without loss of consciousness, should be
monitored closely and managed according to established guidelines for safe return-to-play
(Kelly, 2001). However, Collins et al. (2003) reported the presence of amnesia, not loss of
consciousness, appears predictive of symptom and neurocognitive deficits. Athletes
28
presenting with on field amnesia should undergo comprehensive and individualized
assessment before returning to play. Collins et al. (2003) found that continued
improvement of concussion grading scales is warranted because loss of consciousness is
not predictive of concussion injury severity.
In reviewing the literature it should be noted that minimal research was found that
stated neuropsychological or neurocognitive testing are ineffective methods in evaluating a
concussion. However, there was some information found regarding the low to moderate
reliability. Because there is no simple test that can determine an athlete’s readiness for
return-to-play, ImPACT©, the CRI, and SAC may be used as a tool to assist the clinician
in making an accurate return-to-play decision. The tests should not be the lone determinant
for return-to-play, but should be used in conjunction with self reported symptoms and
grading of the concussion to produce the most accurate results.
29
CHAPTER 3
DISCUSSION
The purpose of this comprehensive paper was to review the literature evaluating
popular neuropsychological and neurocognitive tests for detecting post-concussive
abnormalities following injury. In addition, return-to-play guidelines were discussed.
Neuropsychological and neurocognitive testing are designed to be used both on-field and
off-field. Today, computerized neuropsychological tests are becoming more popular, and it
has shown to be a valuable tool when assisting a clinician when making a return-to-play
decision. ImPACT©, the CRI, and SAC are designed to be used at baseline and post-
trauma in order to provide the most accurate results. Although there was some literature
found regarding the low to moderate reliability with these tests, the question may arise as
to why clinicians continue to use these tests. These tests may provide additional
information so that the athletic trainer can make a proper clinical diagnosis based on
something other than self-reporting symptoms. An inexperienced athletic trainer may find
these tests more useful because it allows for additional information when determining if an
athlete is ready to return-to-play.
When an athlete experiences signs and symptoms of a concussion, a parent or
guardian may want their child to return-to-play sooner than the recommended return-to-
play guidelines. ImPACT©, the CRI, and SAC provide objective information so that an
outsider can understand that an athlete is not ready to participate. Relying exclusively on
the athlete’s self reporting of symptoms is not recommended. An athlete’s passion to play
sometimes results in dishonesty about their symptoms, and thus predisposes the athlete to
30
further injury. Therefore, neuropsychological and neurocognitive testing are valuable tools
when used in conjunction with self reported symptoms, and the grading of the concussion.
Return-to-play guidelines are valuable to practitioners. The criteria have lead
athletic trainers to error on the side of caution when managing a concussion. However,
these guidelines have the tendency to focus on loss of consciousness and amnesia. The
latest research shows that these factors are not the only predictors of the severity of injury.
All grading scales vary when determining an athlete’s readiness for return-to-play.
Therefore, additional research regarding the return-to-play guidelines is warranted to
improve consistency.
Although there was no formal literature found, it is within the athletic trainer’s
scope of practice to refer all concussions to a physician in order to rule out a catastrophic
head injury. Allowing an athlete to return-to-play too quickly may result in second impact
syndrome. Therefore, neuropsychological and neurocognitive tests should be used in
conjunction with the return-to-play guidelines, the self reporting of signs and symptoms,
and the grading of the concussion in order to return an athlete to play as safely as possible.
31
REFERENCES
Anderson, M., Hall, S., & Martin, M. (2004). Head and facial conditions. Foundations of
athletic training: Prevention, assessment, and management (pp. 223-259).
Philadelphia: Lippincott Williams & Wilkins.
Barr, W. B. (2001). Methodologic issues in neuropsychological testing. Journal of Athletic
Training, 36, 297-302.
Broglio, S. P., Ferrara, M. S., Macciocchi, S. N., Baumbartner, T. A., & Elliott, R. (2007).
Test-retest reliability of computerized concussion assessment programs. Journal of
Athletic Training, 42, 509-514.
Broglio, S. P., Macciocchi, S. N., & Ferrara, M. S. (2007). Neurocognitive performance of
concussed athletes when symptom free. Journal of Athletic Training, 42, 504-508.
Cantu, R. C. (2001). Post-traumatic retrograde and anterograde amnesia: Pathophysiology
and implications in grading and safe return-to-play. Journal of Athletic Training,
36, 244-248.
Collins, M. W., Iverson, G. L., Lovell, M. R., McKeag, D. B., Norwig, J., & Maroon, J.
(2003). On-field predictors of neuropsychological and symptom deficit following
sports-related concussion. Clinical Journal of Sports Medicine, 13, 222-229.
Collins, M. W., Lovell, M. R., & Mckeag, D. B. (1999). Current issues in managing sports-
related concussion. American Medical Association, 282, 2283-2285.
Covassin, T., Swanik, C. B., & Sachs., M. L. (2003). Sex differences and the incidence of
concussions among collegiate athletes. Journal of Athletic Training, 38, 238-244.
32
Cuppet, M. & Walsh, K. M. (2005). Medical evaluation techniques and equipment.
General medical conditions in the athlete (pp. 13-31). St. Louis, MO: Elsevier
Mosby.
Echemendia, R. J., Putukian, M., Mackin, R. S., Julian, L., & Shoss, N. (2001).
Neuropsychological test performance prior to and following sports-related mild
traumatic brain injury. Clinical Journal of Sports Medicine, 11, 23-31.
Erlanger, D., Saliba, E., Barth, J., Almquist, J., Webright, W., & Freeman, J. (2001).
Monitoring resolution of post-concussion symptoms in athletes: Preliminary results
of a web-based neuropsychological test protocol. Journal of Athletic Training, 36,
280-287.
Google, Inc. (2008). Retrieved July 4, 2008, from www.google.com
Guskiewicz, K. M., Bruce, S. L., Cantu, R. C., Ferrara, M. S., Kelly, J. P, McCrea, M. et
al. (2004). National athletic trainers’ position statement: Management of sport-
related concussion. Journal of Athletic Training, 39, 280-297.
HeadMinder, Inc. (2001). Retrieved May 9, 2008, from www.headminder.com
ImPACT© Applications, Inc. (2007). Retrieved May 9, 2008, from www.impacttest.com
Iverson, G. L., Gaetz, M., Lovell, M. R., & Collins, M. W. (2004). Relation between
subjective fogginess and neuropsychological testing following concussion. Journal
of the International Neuropsychological Society, 10, 904-906.
Ives, J. C., Alderman, M., & Stred, S. E. (2007). Hypopituitarism after multiple
concussions: A retrospective case study in an adolescent male. Journal of Athletic
Training, 42, 431-439.
33
Kelly, J. P. (2001). Loss of consciousness: Pathophysiology and implications in grading
and safe return-to-play. Journal of Athletic Training, 36, 249-252.
Kersey, R. D. (1998). Acute subdural hematoma after a reported mild concussion: A case
report. Journal of Athletic Training, 33, 264-268.
King, N. S. (1996). Emotional, neuropsychological, and organic factors: Their use in the
prediction of persisting post-concussion symptoms after moderate and mild head
injuries. Journal of Neurology, Neurosurgery, and Psychiatry, 61, 75-81.
Litt, D. W. (1994). Acute subdural hematoma in a high school football player. Journal of
Athletic Training, 29, 69-71.
Lovell, M R., Collins, M. W., Iverson, G. L. Johnston, K. M., Bradley, J. P. (2004). Grade
1 or “ding” concussions in high school athletes. The American Journal of Sports
Medicine, 32, 47-54.
Lovell, M. R., Collins, M. W., Iverson, G. L., Field, M., Maroon, J. C., Cantu, R., et al.
(2003). Recovery from mild concussions in high school athletes. Journal of
Neurosurgery, 98, 295-301.
Macciocchi, S. N., Barth, J. T., Littlefield, L., & Cantu, R. C. (2001). Multiple concussions
and neuropsychological functioning in collegiate football players. Journal of
Athletic Training, 36, 303-306.
Marshall, S. W., & Spencer, R. J. (2001). Concussion in rugby: The hidden epidemic.
Journal of Athletic Training, 36, 334-338.
McClincy, M. P., Lovell, M. R., Pardini, J., Collins, M. W., & Spore, M. K. (2006).
Recovery from sports concussion in high school and collegiate athletes. Brain
Injury, 20, 33-39.
34
McCrea, M. (2001). Standardized mental status testing on the sideline after sport-related
concussion. Journal of Athletic Training, 36, 274-279.
Notebaert, A. J., & Guskiewicz, K. M. (2005). Current trends in athletic training practice
for concussion assessment and management. Journal of Athletic Training, 40, 320-
325.
Oliaro, S., Anderson, S., & Hooker, D. (2001). Management of cerebral concussion in
sports: The athletic trainer’s perspective. Journal of Athletic Training, 36, 257-262.
Onate, J. A., Beck, B. C., & Van Lunen, B. L. (2007). On-field testing environment and
balance error scoring system performance during preseason screening of healthy
collegiate baseball players. Journal of Athletic Training, 42, 446-451.
Onate, J. A., Guskiewicz, K. M., Riemann, B. L., & Prentice, W. E. (2000). A comparison
of sideline versus clinical cognitive test performance in collegiate athletes. Journal
of Athletic Training, 35, 155-160.
Patel, A. V., Mihalik, J. P., Notebaert, A. J., Guskiewicz, K. M., & Prentice, W. E. (2007).
Neuropsychological performance, postural stability, and symptoms after
dehydration. Journal of Athletic Training, 42, 66-75.
Prentice, W. E. (2006). The head, face, eyes, ears, nose, and throat. Arnheim’s principles of
athletic training: A competency-based approach (pp. 872-913). New York: The
McGraw-Hill Companies.
Randolph, C. Implementation of neuropsychological testing models for the high school,
collegiate, and professional sport settings. (2001). Journal of Athletic Training, 36,
288-296.
35
Randolph, C., McCrea, M., & Barr, W. B. (2005). Is neuropsychological testing useful in
the management of sport-related concussion? Journal of Athletic Training, 40, 139-
154.
Schatz, P., Pardini, J. E., Lovell, M. R., Collins, M. W., & Podell, K. (2005). Sensitivity
and specificity of the ImPACT© test battery for concussion in athletes. Archive of
Clinical Neuropsychology, 21, 91-99.
Schatz, P., & Putz, B. O. (2006). Cross-validation of measures used for computer-based
assessment of concussion. Applied Neuropsychology, 13, 151-159.
Susco, T. M., Valovich McLeod, T. C., Gansneder, B. M., & Schultz, S. J. (2004). Balance
recovers within 20 minutes after exertion as measured by the balance error scoring
system. Journal of Athletic Training, 39, 241-246.
Valovich McCleod, T. C., Barr, W. B., McCrea, M., & Guskiewicz, K. M. (2006).
Psychometric and measurement properties of concussion assessment tools in youth
sports. Journal of Athletic Training, 41, 399-408.
Valovich, T. C., Perrin, D. H., & Gansneder, B. M. (2003). Repeat administration elicits a
practice effect with the Balance Error Scoring System but not with the standardized
assessment of concussion in high school athletes. Journal of Athletic Training, 38,
51-56.
Van Kampen, D. A., Lovell, M. R., Pardini, J. E., Collins, M. W., & Fu, F. H. (2006). The
“value added” of neurocognitive testing after sports-related concussion. The
American Journal of Sports Medicine, 34, 1630-1635.
36
Wilkins, J. C., Valovich McLeod, T. C., Perrin, D. H., & Gansneder, B. M. (2004).
Performance on the balance error scoring system decreases after fatigue. Journal of
Athletic Training, 39, 156-161.
37
APPENDIX A
IMPACT© SAMPLE CLINICAL REPORT
38
39
40
41
ImPACT© Applications, Inc. (2007).
42
APPENDIX B
CRI SAMPLE REPORT
HeadMinder, Inc. (2001).
43
APPENDIX C
SAC SAMPLE TEST
Google, Inc. (2008).