ARTICLE IN BRIEF
In a pilot study, a new device, developed to measure reaction time, correctly identified seven of eight athletes with a physician-diagnosed concussion.
TORONTO—A simple measure of reaction time may help to determine whether athletes have sustained a concussion, researchers reported here at the AAN annual meeting in April.
In a pilot study, the tool correctly identified seven of eight athletes with a physician-diagnosed concussion.
“Research has shown that reaction time is slower after a concussion — even as long as several days after other symptoms are gone,” said James T. Eckner, MD, clinical lecturer in the Department of Physical Medicine and Rehabilitation at the University of Michigan in Ann Arbor.
“But the tests currently used to measure reaction time require computers and special software,” he said.
This limits applicability during initial sideline evaluation and may be cost-prohibitive for some athletic teams, he said.
So Dr. Eckner and his colleagues developed a simple, inexpensive device to measure reaction time: a rigid cylinder attached to a weighted disk, in this study, a hockey puck. The examiner releases the device and the athlete catches it as quickly as possible.
“The beauty is its simplicity,” Dr. Eckner said.
After the tool proved accurate in a small number of athletes, the researchers recruited 209 members of the University of Michigan football, wrestling, and women's soccer teams during preseason physical examinations. The athletes ranged in age from 19 to 23.
During the reaction-time test, the examiner held the weighted-rod a standard distance off the ground and then released it without warning. The seated athlete caught the device as quickly as possible after its release.
Reaction time was defined as the distance the rod fell before being caught, using the formula for a body falling under the influence of gravity.
Then, any athlete who sustained a physician-diagnosed concussion during the season underwent a second test within 72 hours of diagnosis, using an identical protocol, and the two reaction times were compared.
Eight athletes sustained concussions during the study. Of those, seven had longer reaction times after the concussion compared with beforehand.
The seven athletes' reaction times averaged about 193 ms at baseline (range 156 ms to 208 ms), increasing to an average of about 222 ms (200 ms to 251 ms) following their concussions. That corresponds to an average increase of 29 ms, or 15 percent, with a range of 18 to 93 ms, he said.
The tool “has the potential to become a useful part of the sports medicine practitioner's multifaceted concussion assessment battery,” he said.
The test could easily be performed on the sidelines while a game is going on, Dr. Eckner said. Also, “because of its simplicity and low cost, this test may work well with youth athletes, where there is limited access to computerized testing of reaction time,” he added.
Sport-related concussion is a common and potentially serious injury, with 1.6 to 3.8 million sport- and recreation-related mild traumatic brain injuries annually in the US, he said.
The major study limitations were the lack of uninjured control athletes and the single after-injury assessment, Dr. Eckner said.
The preliminary results need to be replicated in a larger, blinded study incorporating assessment of control subjects, he said.
Also, he said he would like to see serial after-injury assessments at standardized time points until full recovery. The researchers would also like to develop a more portable device, Dr. Eckner said.
In response to a question from the audience, he said to think of it as a complement, not a replacement, for clinical evaluation.
Asked by Neurology Today to comment on the study, Anthony G. Alessi, MD, associate clinical professor of neurology at the University of Connecticut in Hartford and a private practitioner at Neuro Diagnostics in Norwich, CT, said, that after attending the platform presentation and discussing the work with Dr. Eckner, “I believe that [the investigators] may have a simple and inexpensive way of providing crucial information in evaluating concussion.”
“Many professionals wrongly believe that traumatic brain injuries can be accurately assessed with just one tool,” he continued. “What Dr. Eckner recognizes is that this is only part of the evaluation. He is not advocating this is the one piece of the pie but a piece we need with clinical evaluation.”
Dr. Alessi agreed that the cost of the computerized tools now used to measure reaction time can be prohibitively expensive for some teams, “while this has almost no cost.”
“What remains is a large scale study to provide support. I look forward to their further studies,” he said. •