Practice effects
associated with repeated assessment of a clinical test of reaction time for
head injuries

Del Rossi G, Malaguti A, Del Rossi S. J Athl Train. May 2014; 49(3): 356-359. DOI: 10.4085/1062-6059-49.2.04.

Take Home Message: Before establishing baseline measurements, participants should complete
at least one practice session when performing the ruler-drop test due to
practice effects.
who have sustained a head injury experience diminished reaction time and cognitive
function such as memorization.  While
there are computer-based programs to assess reaction time, the ruler-drop test has shown similar
reliability and is a less expensive option, comparatively. Information from the
assessment of reaction time can later be used in return to play procedures and
help clinicians determine the likelihood that an athlete has sustained a head
injury.  Del Rossi and colleagues tried
to determine if the ruler-drop test was susceptible to practice effects by
comparing whether reaction time improved over trials due to increased
familiarity with the test and procedures. 
Forty-three participants, 21 men and 22 females ranging between ages 19
to 24 years old volunteered for this study. The testing procedures consisted of
10 sessions administered two times per week for five weeks with 10 attempts in
each session.  The three fastest and
slowest reaction times were thrown out and an average of the four remaining
times were calculated.  One important
aspect of this study compared to other studies using a ruler-drop test was that
the ruler was hidden from view when dropped. 
This simple method cuts down on the ability of the participant to
predict when the ruler would drop, creating more realistic results.   The authors
confirmed that participants improve after repeated sessions of the ruler-drop test,
most notably during the first and second sessions with a decrease in reaction
time by 7 milliseconds and 13 milliseconds overall from session 1 through
findings in this study are significant in confirming that the ruler drop test
is susceptible to a practice effect after repeated sessions.  This test is important because it allows clinicians
to utilize another tool in assessing head injuries both in the clinic and on
the sidelines.  To negate the practice
effects of the ruler-drop test, multiple attempts and sessions were completed
and the outliers were thrown out in each session.  While the test was performed at 10 sessions,
there were no significant differences after the first session.  When performing baseline assessments that
authors recommend doing at least one test session before establishing true
baseline values.  We also need to be
careful to notice if an athlete intentionally reacts slower than they can
during the baseline evaluation since this could influence how we interpret the
results post concussion.  Overall, when
we use the ruler-drop test in the clinical setting the authors suggest we allow
the participant to practice and we may want to consider hiding the ruler and/or
excluding the slowest and fastest times from the testing session

Questions for
Discussion: Is it feasible to administer the ruler-drop test on the sideline to
determine reaction time? How long do you think the practice effects last when
administering the ruler-drop test?

by: Brad Duong & Eva Martinez
by: Kim Pritchard


Del Rossi, G., Malaguti, A., & Del Rossi, S. (2014). Practice Effects Associated With Repeated Assessment of a Clinical Test of Reaction Time Journal of Athletic Training, 49 (3), 356-359 DOI: 10.4085/1062-6059-49.2.04