Robust RT deficits were observed acutely following concussion .
Minimal magnitude differences were noted when comparing between- and within-subject effects , suggesting that pre-injury baselines may not add clinical value in determining post-injury RT impairment .
RT deficits persisted up till the intermediate-term ( 21–59 days post-injury ) timeframe and indicate lingering deficits exist .
Mean effect size differences were observed between RT measure types and computerized neurocognitive testing platforms ; however , all categories displayed negative effects consistent with impaired RT following concussion .
Reaction time ( RT ) deficits are reported following concussion , but it is unknown when these deficits normalize to pre-injury status .
It is also unclear how factors such as RT measurement technique and participant characteristics influence post-concussion RT .
The purpose of this systematic review and meta- analysis was to ( 1 ) characterize acute post-concussion ( 0–3 days ) RT impairments , ( 2 ) examine RT recovery over time , and ( 3 ) explore moderating factors related to acute RT impairment following concussion .
Clinical versus Functional Reaction Time: Implications for Postconcussion Management
ABSTRACT Purpose This study aim ed to examine the association between clinical and functional reaction time ( RT ) assessment s with and without simultaneous cognitive tasks among healthy individuals . Methods Participants ( n = 41 , 49 % female ; 22.5 ± 2.1 yr ; 172.5 ± 11.9 cm ; 71.0 ± 13.7 kg ) completed clinical ( drop stick , Stroop ) and functional ( gait , jump l and ing , single-leg hop , anticipated cut , unanticipated cut ) RT assessment s in r and om order . All RT assessment s , except Stroop and unanticipated cut , were completed under single- ( movement only ) and dual-task conditions ( movement and subtracting by 6s or 7s ) . Drop stick involved catching a r and omly dropped rod embedded in a weighted disk . Stroop assessed RT via  computerized neurocognitive testing . An instrumented walkway measured gait RT when center-of-pressure moved after r and om stimulus . All other functional RT assessment s involved participants jumping forward and performing a vertical jump ( jump l and ing ) , balancing on one leg ( single-leg hop ) , or a 45 ° cut in a known ( anticipated cut ) or unknown ( unanticipated cut ) direction . RT was determined when the sacrum moved following r and om visual stimulus . Pearson correlation coefficients and a 5 × 2 repeated- measures ANOVA compared RT assessment s and cognitive conditions . Results Stroop RT outcomes did not significantly correlate with functional RT assessment s ( r range = −0.10 to 0.24 ) . A significant assessment by cognitive task interaction ( F4,160 = 14.01 ; P < 0.001 ) revealed faster single-task RT among all assessment s compared with dual-task ( mean differences , −0.11 to −0.09 s ; P < 0.001 ) , except drop stick ( P = 0.195 ) . Single-leg hop ( 0.58 ± 0.11 s ) was significantly slower compared with jump l and ing ( 0.53 ± 0.10 s ) , anticipated cut ( 0.49 ± 0.09 s ) , gait ( 0.29 ± 0.07 s ) , and drop stick ( 0.21 ± 0.03 s ; P values ≤ 0.001 ) . Dual-task assessment s were significantly slower than single-task assessment s ( mean difference , 0.08 s ; P < 0.001 ) . Conclusions Clinical and functional RT assessment s were not correlated with each other , suggesting that sport-like RT is not being assessed after concussion . Functional and dual-task RT assessment s may add clinical value and warrant further exploration after concussion
Robust RT deficits were observed acutely following concussion .
Minimal magnitude differences were noted when comparing between- and within-subject effects , suggesting that pre-injury baselines may not add clinical value in determining post-injury RT impairment .
RT deficits persisted up till the intermediate-term ( 21–59 days post-injury ) timeframe and indicate lingering deficits exist .
Mean effect size differences were observed between RT measure types and computerized neurocognitive testing platforms ; however , all categories displayed negative effects consistent with impaired RT following concussion .
Reaction time ( RT ) deficits are reported following concussion , but it is unknown when these deficits normalize to pre-injury status .
It is also unclear how factors such as RT measurement technique and participant characteristics influence post-concussion RT .
The purpose of this systematic review and meta- analysis was to ( 1 ) characterize acute post-concussion ( 0–3 days ) RT impairments , ( 2 ) examine RT recovery over time , and ( 3 ) explore moderating factors related to acute RT impairment following concussion .