Three Concussions In: How Prior Brain Injuries Change Your Baseline and What to Do About It

Athletes with a history of prior concussions present differently at baseline — and this has important implications for how their data is interpreted and how their future injuries are managed.

What the research shows

Research published in PMC (Covassin et al., 2017) in the Journal of Athletic Training confirmed that pre-existing factors including prior concussion history influence baseline neurocognitive performance on ImPACT. Athletes with previous concussions may have lower cognitive scores, higher baseline symptom reports, and different recovery trajectories after subsequent injuries.

The NCAA Concussion Study (Guskiewicz et al., 2003), published in JAMA, documented that athletes with a history of three or more concussions were three times more likely to sustain another concussion and experienced cumulative effects on cognitive function. When ADHD is also present, research published in PMC (2019) showed that these effects compound further, with multiple concussions being significantly more prevalent in athletes with ADHD and learning disabilities.

The clinical challenge

This creates a clinical challenge: is the athlete’s current baseline their true “normal,” or is it already affected by previous injuries? And if their baseline is already lower than the population average due to prior concussions, how should clinicians set appropriate recovery targets after the next one?

Why post-concussion baselines still matter

The answer is that a post-concussion baseline is still valuable — arguably even morevaluable than a first baseline. It establishes the athlete’s current functional level, which is the only clinically relevant comparison for future injuries. A clinician should not aim to return a multi-concussion athlete to a baseline from three years and two concussions ago. The goal is to return them to their current healthy function — whatever that looks like now.

Our recommendation: re-baseline after every concussion

At Headquarters, we recommend re-baselining after every concussion, once the athlete has been fully cleared as recovered. This creates an updated reference point that reflects their actual current brain function rather than a historical snapshot that may no longer be accurate. For the retirement-decision context, see when should your child stop playing contact sports?

Frequently asked questions