Between-seasons test-retest reliability of clinically measured reaction time in national collegiate athletic association division I athletes.

Eckner JT, Kutcher JS, Richardson JK. J Athl Train. 2011;46(4):409-14.

Reaction time is commonly impaired after a concussion and is often assessed in computerized concussion assessment programs. Unfortunately, many sports medicine clinicians, particularly those working with younger athletes, may not have access to computerized concussion assessment programs. Therefore, Eckner et al developed a simple clinical measurement of reaction time; however, the test-retest reliability (consistency) of their assessment as well as computerized reaction time assessments have not been well evaluated between seasons. The purpose of this study was to measures the 1-year test-retest reliability of the clinical and a computerized measure of reaction time among 102 NCAA Division 1 athletes (78 American football, 10 women’s soccer, and 14 wrestling athletes). Clinical and computerized assessments of reaction time were performed during preparticipation physical examinations before two consecutive seasons. The clinical assessment of reaction time used a vertical shaft with a cylindrical weight at the bottom and the distance the shaft dropped between the time of release and hand closure could be measured to determine the reaction time (the article offers more details and figures). Each athlete performed 2 practice trials and 8 data collection trials with the examiner randomizing the time until release from 2 to 5 seconds (to prevent the athlete from anticipating the drop). The computerized assessment of reaction time was completed with a computerized neuropsychological test session (pressing the “k” as rapidly as possible when shown a particular image). Unfortunately, only 62 (61%) athletes had usable computerized assessment tests at baseline and follow-up (27 athletes had an invalid testing session and 13 missed a computerized assessment). The clinical measure of reaction time had higher test-retest reliability (between year 1 and year 2) than the computerized assessment but these were both statistically similar. Among participants with both clinical and computerized assessments the clinical assessments led to faster reaction times. Furthermore, the clinical assessment had faster reaction times at follow-up, suggestive of a learning effect by the athletes. The computerized test did not differ between years 1 and 2. The clinical assessments of reaction time did not differ between athletes with and without 2 valid computerized tests; reducing the risk that athletes with an invalid test perform tests differently.

This study may be valuable to sports medicine clinicians working in settings with limited budgets and the lack of access to computerized neuropsychological tests. The authors provide previously reported test-retest reliability for computer-based reaction time measures and the data in this study are consistent with other studies that evaluated test-retest over prolong periods of times (> 30 days). It will be important to follow this research team to see how this test performs when evaluating athletes with and without concussions. Athletes showed a learning effect with this test so it will be important to see if concussions lead to changes in scores beyond measurement error and learning effects (for example, if athletes improve 11 msec due to a learning effect then a concussion may need to impair reaction time by greater than 11 msec). It will also be interesting to see the impact of repeated exposures to the test and how this test performs among younger athletes that typically do not have access to computerized testing. The authors acknowledge that reaction time is only one of many signs indicating a possibly concussion and therefore should be assessed as part of a thorough evaluation. Furthermore, they note that this test may be an adjunct to computerized testing but that it should not replace computerized testing. Remember that this test was developed as a simple and low cost measure for athletes that do not have access to computerized concussion assessments. Have any of you tried this clinical measure of reaction time before? If so, what are your experiences?

Written by: Jeffrey Driban
Reviewed by: Stephen Thomas

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Eckner JT, Kutcher JS, & Richardson JK (2011). Between-seasons test-retest reliability of clinically measured reaction time in national collegiate athletic association division I athletes. Journal of Athletic Training, 46 (4), 409-14 PMID: 21944073