title: Effect of sport-related concussion on clinically measured simple reaction time.
abstract: BACKGROUND
  Reaction time (RT) is a valuable component of the sport concussion assessment battery. RT is typically measured using computers running specialised software, which limits its applicability in some athletic settings and populations. To address this, we developed a simple clinical test of RT (RTclin) that involves grasping a falling measuring stick.
  
  
  OBJECTIVE
  To determine the effect of concussion on RTclin and its sensitivity and specificity for concussion.
  
  
  METHODS
  Concussed athletes (n=28) and non-concussed control team-mates (n=28) completed RTclin assessments at baseline and within 48 h of injury. Repeated measures analysis of variance compared mean baseline and follow-up RTclin values between groups. Sensitivity and specificity were calculated over a range of reliable change confidence levels.
  
  
  RESULTS
  RTclin differed significantly between groups (p<0.001): there was significant prolongation from baseline to postinjury in the concussed group (p=0.003), with a trend towards improvement in the control group (p=0.058). Sensitivity and specificity were maximised when a critical change value of 0 ms was applied (ie, any increase in RTclin from baseline was interpreted as abnormal), which corresponded to a sensitivity of 75%, specificity of 68% and a 65% reliable change confidence level.
  
  
  CONCLUSIONS
  RTclin appears sensitive to the effects of concussion and distinguished concussed and non-concussed athletes with similar sensitivity and specificity to other commonly used concussion assessment tools. Given its simplicity, low cost and minimal time requirement, RTclin should be considered a viable component of the sports medicine provider's multifaceted concussion assessment battery.
authors: Department of Physical Medicine & Rehabilitation, University of Michigan, , Ann Arbor, Michigan, USA.
authors: James T
authors: JT
authors: Eckner
authors: Jeffrey S
authors: JS
authors: Kutcher
authors: Steven P
authors: SP
authors: Broglio
authors: James K
authors: JK
authors: Richardson
mesh_terms: D000328:Adult; D001265:Athletic Injuries / Q000503:physiopathology*; D001924:Brain Concussion / Q000503:physiopathology*; D016022:Case-Control Studies; D005260:Female; D006801:Humans; D008297:Male; D012372:ROC Curve; D011930:Reaction Time / Q000502:physiology*
keywords: Concussion; Evaluation; Head injuries