Children who sustain a mild traumatic brain injury (mTBI) are at increased odds of additive injury and continue to show altered motor performance relative to never-injured peers after being medically cleared (MC) to return to normal activities. There is a critical need to determine when children can return to activities without risk of short and long-term adverse effects, with research showing high reinjury rates for 3-12 months after RTP. The Physical and Neurological Examination for Subtle Signs (PANESS) measures subtle signs of motor impairment during gait, balance, and timed motor functions. Recent literature has demonstrated that PANESS timed motor function can distinguish between children medically cleared post-mTBI compared to never-injured controls. The present study examined performance on timed motor tasks in youth medically cleared from mTBI following medical clearance and 3-months later, compared to never-injured peers.

25 children (Mage=14.16, SD=2.46; Male=68%) were enrolled within 6 weeks of medical clearance from mTBI (Mdays post MC=33, SD=13.4, Range=2-59) along with 66 typically developing, never-injured controls (Mage=13.9, SD=2.22; Male=50%). Group differences were evaluated for the Timed Motor section of the PANESS at enrollment and at a 3-month follow-up (Mdays from enrollment to follow-up=95.90, SD=12.69, Range=62-129). This 3-month follow-up occurred on average 4 months after medical clearance (Mdays from MC to follow-up=130.08, SD=17.58, Range=92 - 164). The Timed Motor section includes Repetitive (foot tapping, hand patting, and finger tapping) and Sequential (heel-toe rocking, hand pronate/supinate, finger sequencing) raw time scores, measured in seconds. The Total Timed Motor Speed score is the combination of Repetitive and Sequential Movement and the side-to-side tongue item.

At 3-month follow-up, mTBI participants (M=67.55, SD=8.26, Range=53.66-83.88) performed worse than controls (M=63.09, SD=10.23, Range=39.86-100.51) on Total Timed Motor Speed, t(89)= 1.95, p<0.05), including when controlling for age and sex, F(1, 87)=4.67, p<0.05. At the same time point, mTBI participants (M=36.54, SD=5.47, Range=28.74-49.17) performed worse on Sequential Speed than controls (M=32.93, SD=6.1, Range=21.49-56.76), t(89)=2.59, p<0.01, including when controlling for age and sex, F(1, 87)=7.687, p<0.01). Although groups performed similarly on Sequential Speed at the initial time point, mTBI participants exhibited a trend of less improvement from initial to follow-up (MmTBI=-1.69, Mcontrol=-3.68, t(90)=1.445, p=0.076).

Although groups did not significantly differ on Timed Motor Speed items at the initial time point, the mTBI group showed consistently lower scores than controls at both time points and less improvement over time. Results indicate that Total Timed Motor Speed, specifically Sequential Speed, may be a sensitive marker of persisting differences in high-level motor and cognitive learning/control in children who have been medically cleared after mTBI. More data are needed to evaluate these findings over a longer time period, and future studies should examine behavioral markers concurrently with physiologic brain recovery over time.