To that end, researchers offered new insights into the
sensitivity of onsite tests that could enable earlier detection of concussion
and treatment.
In one paper, investigators, led by Thomas Buckley, EdD,
associate professor of kinesiology and applied physiology at the University of
Delaware, assessed the reliability of the King Devick test, a rapid
number-naming test that measures the efficiency of athletes' eye movements as
they read numbers on cards or screens from left to right or top to bottom. They
enrolled 830 National Collegiate Athletic Association (NCAA) athletes, who were
all participating in the joint NCAA/United States Department of Defense Grand
Alliance Concussion Assessment, Research and Education Consortium, which is
designed to study and prevent concussion.
To determine the year-to-year reliability of the King Devick
test, researchers performed the test annually for two years in the summers of
2015 and 2016. The researchers' endpoint measure was the athletes' fastest time
to complete the test without errors each year.
They found a significant positive correlation between year
one and year two of the test (year 1: 40.8 ±7.4 seconds; year 2: 38.75±7.7
seconds, r=0.827, p<0.001), suggesting high year-to-year reliability. The
mean improvement was 2.02 seconds and the median improvement was 2.2 seconds,
suggesting that coaches should expect a modest improvement in performance of
about 2 seconds from year to year.
“We found high reliability across the board,” Dr. Buckley
said in an interview with Neurology Today. “This is one of the first accurate,
easily administrated visual tests for cognition after concussion. This shows
that an ocular-motor assessment has an important role in the overall
multifaceted concussion assessment.”
However, the test does not represent a thorough post-injury
evaluation of cognitive function, Dr. Buckley said. “These tests are supportive
of, but should not replace, the physician evaluation.”
Dr. Buckley noted that 27 percent of the athletes were found
to perform worse at year two than year one, which shows the test has some
normal variability and also supports the need for supplemental physical exams.
“This study had a huge number of collegiate athletes who
performed the test, and the researchers correlated over the course of two years
what the difference was in times,” said Amaal Starling, MD, assistant professor
of neurology at the Mayo Clinic in Scottsdale, AZ, who was not involved with
the study. “The results are very reassuring, although not surprising, that it
is a very reliable tool to use from year to year. The small mean improvement of
about two seconds emphasizes the fact that this test needs to be given for a
baseline every single year to be accurately used as a screening tool for
concussion.”
“There don't seem to be significant age-related changes, at
least within a time frame of one year,” Dr. Vargas added. “That would suggest
that there's enough consistency within the test that if we're looking at a
one-year time frame, you can be pretty confident that any changes are real
differences – that they are due to acute injuries and not worsening in
performance related to age-related changes. So that's the value added. The test
is not just sensitive, but consisten
_________________________________________________________________________
In another paper, researchers explored the possible
association between persistent post-concussion syndrome (PPCS), which includes
problems with balance, headache, fatigue, inability to concentrate, and blurry
vision and dysfunction in the autonomic nervous system.
Researchers, led by Melissa Cortez, DO, a neurologist at
University of Utah Health, enrolled 29 athletes — seven of whom had sustained
acute concussions, 11 had PPCS, and 11 served as controls.
They administered the Concussion Symptom Severity scale and
the Standardized Assessment of Concussion to all participants. Those with PPCS
and acute concussion groups (p=0.91 and p=0.32, respectively), and both
concussion groups' scores were significantly higher than those of participants
in the control group (p=0.003/0.002 and p=0.01/0.008, respectively).
However, they found that participants in the PPCS group had
significantly elevated markers of autonomic dysfunction, such as dizziness,
fatigue, and orthostatic hypotension, compared to both athletes in the acute
concussion group and non-concussed controls. These included a higher heart rate
increment on a five-minute head-up tilt test (p=0.02), reduced heart rate
variability (p=0.03), and increased scores on the COMPASS-31 scale of autonomic
symptoms (p>0.001).
The findings, the researchers wrote, are “suggestive of a
relative hyperadrenergic pattern in [PPCS], which is not present during the
acute phase of concussion.” These changes, they noted, may “explain sustained
symptoms of dizziness and fatigue associated with orthostatic intolerance [in
PPCS], and importantly, could provide potential treatment opportunities.”
Dr. Starling agreed. “For athletes who have PPCS and are
dizzy, clinicians should have a high degree of suspicion for autonomic
dysfunction, and if autonomic testing is available, they should send patients
for that testing.”
She noted that autonomic dysfunction is treatable.
“Treatment may start with conservative measures – lifestyle modifications like
fluid intake, fluids with lots of electrolytes, increasing salt, wearing
compression stockings, not eating large meals but multiple small meals, and
elevating the head of the bed during sleep, which reduces sympathetic drive.
And if autonomic dysfunction is persistent despite lifestyle modifications,
there are medications we can use for treatment. However, starting with those conservative
measures can be quite helpful.”
Going forward, Dr. Starling said: “We need to continue
working on biomarkers. That will play a huge role in future research. Until we
have those, it makes it hard to have research with consistent outcome measures.
Now, it's still quite subjective and everyone is using different outcome
measures, which makes it hard to take a finding from one study and compare it
to another study. We need more standardization, gold standard assessment tools,
and biomarkers.”
Dr. Vargas agreed. “The diversity and breadth of research
presented at the AAN Sports Concussion Conference is a testament to the fact
that there are so many aspects of concussion that we don't fully understand,
and which are in need of further research.”
http://journals.lww.com/neurotodayonline/Fulltext/2017/11020/In_the_Clinic_Concussion__Clinical_Pearls_and.6.aspxF
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