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| William B. Barr, PhD, ABPP |
Associate Professor of Neurology & Psychiatry,
NYU School of Medicine
This
year marks the 20th anniversary of the “modern era” in the study of concussion
in sports, which began in 1994 following the retirements of Merrill Hoge and Al
Toon and the National Football League’s (NFL) formation of its first Mild
Traumatic Brain Injury Committee. Since that time, we have witnessed a marked
shift from what was a pervasive attitude of denying or minimizing the effects
of head injury in sport to one where stories of the current “concussion
epidemic” or the controversy about long-term consequences of head injury in
retired athletes appear in our newspapers on a daily basis. Over the same time
period, the field of neuropsychology has received an unprecedented degree of public
attention resulting from the fact that many in our field, including members of
the Society of Clinical Neuropsychology (SCN), have provided important
contributions to the scientific study of sports concussion and development of
methods for its assessment. My goal in this SCN
NeuroBlog is to provide a brief review and critique of neuropsychology’s
role in the clinical management of sports concussion with suggestions on how we
can maintain our position as leaders with regard to this highly publicized
injury.
At
the beginning of concussion’s modern era, it was not uncommon to hear
statements from other health professionals that we were in the infancy in the
study of the head injury and without any available scientific information to
guide clinical management. Any practicing neuropsychologist at that time knew
that this was not the case. We were well aware that Dorothy Gronwall and her
colleagues in New Zealand had published a number of groundbreaking studies during
the 1970’s, using neuropsychological methods for tracking information-processing
capacity following minor head injury. During
the 1980’s, Jeffrey Barth,
Sureyya Dikmen, and Harvey Levin and colleagues
had all conducted a number of important investigations in the United States using
neuropsychological test batteries to characterize outcomes in mild head injured
subjects. The results of those studies demonstrated that recovery from milder
forms of head injury was characterized by a complex interaction of cognitive,
somatic, and emotional factors with the expression of symptoms influenced
significantly by a range of psychosocial factors.
Armed
with the findings from studies listed above, clinical neuropsychologists were
well prepared in the 1980’s and 1990’s to conduct a comprehensive assessment of
symptoms in patients they encountered following what was eventually termed as
mild traumatic brain injury (MTBI). Many at that time continued to use the Halstead-Reitan
Neuropsychological Test Battery for evaluation of these patients. However, an
increasing number of practitioners began to use a more flexible approach to neuropsychological
assessment, with test batteries comprised of measures of intelligence,
attention, executive functions, and memory. It is important to note that, most
clinicians were also including measures of symptom reporting in their test
batteries, using standardized measures such as the Minnesota Multiphasic
Personality Inventory (MMPI) and its descendants. While the clinical batteries often took
numerous (3-6) hours to complete, they provided the most effective means known
at that time for evaluating symptoms in patients with MTBI.
Neuropsychology’s
approach to head injury received a substantial boost in the late 1980’s following
research performed by Barth, Macciocchi and colleagues at the University of
Virginia, who developed the methodology for obtaining empirical data on
concussion through controlled prospective studies of athletes following head
injury. Their model of data collection, now known as the Sports Laboratory
Assessment Model (SLAM) consisted of obtaining preseason neuropsychological test
data to serve as a baseline in athletes at risk for sustaining a concussion
during competition and repeating the same tests in injured athletes and matched
controls on a serial basis to measure the effects of the injury and its pattern
of recovery. Among the major findings from early studies using the SLAM
methodology were that neuropsychological tests were established as being
sensitive to the effects of concussion and that those effects were observed to
clear rather rapidly, within a period of 5 to 10 days, in the vast majority of
cases.
Given
the fact that results from standard imaging and electrophysiological studies
were usually negative in athletes following concussion, the hope in the
beginning of the modern era of sports concussion management was that
neuropsychological testing would provide most effective means for assessing
symptoms during recovery. The SLAM methodology was promptly adapted for
clinical use by a number of neuropsychologists working primarily with
collegiate and professional football teams. Brief test batteries were assembled
and administered to entire teams through large-scale baseline testing programs.
The length of the test batteries was kept to less than 30 minutes,
understanding the need to limit the time burden for the athletes and the
assessment team. The test batteries were limited in contents to measures of
attention, processing speed, and memory, while also including a brief measure of
post-concussion symptoms. The belief was that, due to athletes’ reputed
tendency to minimize symptoms, information from the neurocognitive tests administered
serially following injury would provide the most accurate means for tracking
the effects of the injury and marking the time course of its recovery.
The
baseline testing programs in sports began with the use of paper-pencil tests
that were readily available to all licensed neuropsychologists. However, those
tests were soon replaced by computerized test batteries developed specifically
for assessment of concussion symptoms in athletes, which were promoted and sold
via a large-scale marketing campaign to physicians, certified athletic
trainers, and other clinicians in addition to neuropsychologists. The
computerized tests were claimed by their developers to provide an advantage
over the paper-pencil tests by providing a more sensitive, reliable, and
efficient means of assessing concussion symptoms. Through substantial media
exposure, the brand names of computerized tests became synonymous with baseline
testing in sports, with the science and methodology of clinical neuropsychology
relegated to a less prominent role.
While
sportscasters, the media, and the public at large were emphasizing the use of baseline
testing in sports, there was a controversy developing within the field of
neuropsychology regarding its ultimate benefits. Some investigators began to
question the increasing use of this methodology, given the lack of empirical support,
particularly from investigative teams that were independent of the test
developers. This was followed by studies, emerging over time, demonstrating
that information from neuropsychological tests added little to the
assessment of acute post-concussion symptoms compared to what was obtained
through a more brief form of sideline testing using a combination of symptom
questionnaires, balance measures, and a brief screen of cognitive functioning.
Results
from other investigations began to show that many of the tests used for serial
testing in athletes demonstrated unacceptably low levels oftest-retest reliability in addition to disappointing levels of sensitivity/specificity
for detecting the effects of concussion. The validity of the baseline test
performance came into question when measures were administered on a group basis, as
suggested by the manufacturers. Athletes began to realize the benefits of underperforming
on baseline testing so that the effects of concussion would be obscured on
repeat testing following injury, affecting the validity of a growing number of
baseline assessments. Further complications began to emerge from the fact that practitioners
without adequate training in psychometrics and brain-behavior relations were
often the ones obtaining the test results following injury, causing them in
many cases to make serious interpretive errors. Based on these findings and
trends, an international panel of experts on concussion in sports concluded in
statements published in
2012 that, “there is insufficient evidence to recommend the widespread
routine use of baseline neuropsychological testing.”
Turning
to what we have learned over the past 20 years, there has been a convergence of
information obtained through studies of animal models and humans indicating
that the acute physiological effects and symptoms associated with concussion
resolve within 7-10 days
in the vast majority (80%-95%) of injured athletes, upholding the findings
originally reported much earlier by University of Virginia group. While
cognitive deficits are known to be present during the acute time period, neuropsychological
testing does not appear to be the optimal choice for assessment at that time, since
symptoms can be monitored effectively through briefer sideline test procedures using
the Sports Concussion Assessment Tool (SCAT-3).
However,
as most neuropsychologists know, there are those individuals, including
athletes, who continue to report symptoms well beyond the window of typical
recovery from concussion. These individuals, exhibiting symptoms of what we
term as post-concussion syndrome (PCS), create clinical conundrums for most
clinicians involved in concussion management. I argue that this is the group on
whom neuropsychologists should be focusing attention. As a result of neuropsychologists’ unique
combination of training and use of empirically advanced assessment techniques, we
are the group of professionals who can provide the most valuable input for diagnosis
and management for of individuals with PCS.
Investigators
focusing on the search for the elusive biomarker of concussion often ignore the
fact that the diagnosis of concussion and subsequent PCS is based primarily on
a subject’s subjective account of his or her symptoms. We are well aware that the
reporting of those symptoms can be affected substantially by a number of
“non-injury” factors. To begin with, research has shown that those with PCS
commonly experience co-morbid conditions such as mood disorder, chronic pain, attention
deficit hyperactivity disorder (ADHD), or the effects of somatization, all of
which can result symptoms overlapping with those commonly reported in PCS. We
are also aware that a number of “normal” psychological factors secondary to
misattribution of symptoms, including “expectation
as etiology”, the “diagnosis
threat”, and the “good
old days” phenomenon can influence symptom expression in that group. We are
likely to be seeing an increase in the frequency of these misattribution phenomena
as a result of increased availability of information related to concussion
available through the popular media and Internet. Using our strengths in clinical
assessment, neuropsychologists are in an excellent position to serve as those
members of the treatment team who are in the best position to identify and
treat the co-morbid conditions and other important “non-injury” factors that
can influence the reporting of PCS symptoms in athletes and other groups.
My
belief is that the optimal time for a referral to clinical neuropsychologists
in a sports concussion setting is not immediately following the injury, but
when the athlete is continuing to report symptoms for a period of 14-days or
more. At that relatively early time point, he or she will have passed through
the typical period of symptom recovery but will have not yet reached the
critical juncture when PCS symptoms have become chronic and possibly
intractable in nature. A comprehensive neuropsychological evaluation using
tests of cognitive functioning, self-report, and performance validity performed
at that time will provide the clinician with valuable diagnostic data and
information to guide recommendations for subsequent intervention. As
demonstrated in clinical studies, early
identification and treatment of the co-morbid conditions and psychological
factors provides the most effective means known for preventing the development
of long-term PCS symptoms.
In conclusion,
while we can admire our field’s initial attempt to offer neuropsychological
testing as the primary tool for tracking the acute symptoms of concussion in
athletes, it is time to admit that these watered-down test batteries did not
end up being as useful as we had hoped.
My opinion is that clinical neuropsychologists can now play a more
important and useful role in the management of sports concussion by going back
to where we were 20 years ago by providing evaluations of athletes using more
comprehensive test batteries prior to development of chronic PCS symptoms. I am
not suggesting that we return to the use of 3-6 hour test batteries with all of
these athletes. We can clearly benefit from advances in test development and
clinical studies of concussion to narrow our test batteries down to less than
two hours, including the use of a comprehensive symptom measure such as the
MMPI-2-RF. In the end, returning to the
“psychology” in neuropsychology will enable us to provide a unique
perspective to the modern treatment team that has evolved for assessment and
treatment of sports concussion and help many of our athletes obtain the
services they need to reach a full and successful recovery.
