Effect of sports-related concussion on clinically measured simple
reaction time.

Eckner, J. Kutcher, J. Broglio,
S. Richardson, J. Br. J Sports Med, 2013 Jan 11. [Epub ahead of print]

Sports-related concussion results
in slowed reaction time, which can be tested by many computer-based
neurocognitive testing programs. Reaction time is related to symptom severity
and reliably acts as a sensitive measure of neurocognitive improvement during concussion
recovery. However, clinicians don’t always have access to computer-based
neurocognitive testing programs, thus in previous research Eckner, et al.
created a simple clinical assessment tool for reaction time.  The purpose of this study was to determine
the effect of concussion on clinical reaction time in a sample of athletes from
one high school and two colleges.  Clinical
reaction time was measured by conducting a simple task using a measuring stick
embedded in a weighted rubber disk that was released and caught by the tested
athlete as quickly as possible.  Athletes
were excluded in they had an upper limb injury that prevented them from
completing the clinical reaction time task or if they were recovering from a concussion
at the time of their preparticipation baseline testing.  Athletes were baseline tested during
preparticipation examinations, and within 48 hours after sustaining a concussion.
Injured athletes were paired with a non-concussed, sex, and team-matched
control athlete. 26 athletes sustained 28 concussions over the two year study
period, with 71% of the concussions seen in college football athletes.  The results of the study showed that clinical
reaction time was impaired following a concussion while the control group
showed a small in-season improvement in clinical reaction time, possibly due to
a learning effect. Additionally, the authors showed that the best diagnostic
cut-off for concussion was any decline from baseline in clinical reaction time
(75% sensitive
and 68% specific).

The results of this study are
important because it shows that clinical reaction time can be a useful test to
diagnose concussion which compares favorably to more expensive and more
time-consuming concussion assessment tools. The study results are also
encouraging because they are clinically-oriented and the test is cost-effective
(equipment for clinical RT cost less than 5 dollars).  Additional research that examines clinical
reaction time in non-football athletes would be helpful and could validate the
clinical usefulness in management of all athletes who suffer a concussion.
Still, when used as part of an assessment battery with other clinical tools
such as the graded symptom checklist (80% sensitive, 100% specific) and balance
error scoring system (34% sensitive, 91% specific) clinicians can assess
athletes for concussion in a controlled, reliable manner from the sidelines to
the exam room. Do you use any sort of reaction time assessment as part of your
concussion diagnosis and management plan? Do you feel clinical reaction time
offers any benefit over computer-based reaction time assessment?

Written by: Stephen Stache, MD
Reviewed by: Jeffrey Driban

Related Post:

Eckner JT, Kutcher JS, Broglio SP, & Richardson JK (2013). Effect of sport-related concussion on clinically measured simple reaction time. British Journal of Sports Medicine PMID: 23314889