You can check for a concussion by watching for a combination of physical signs, cognitive changes, and balance problems in the minutes, hours, and days after a head impact. No single test confirms a concussion on its own, but a systematic check of symptoms, mental sharpness, eye responses, and balance will tell you whether something is wrong and how urgently to act.
Signs That Need Emergency Care Right Now
Before working through any screening steps, rule out a medical emergency. Call 911 or go to the emergency department if the person has any of these signs after a head injury: repeated vomiting, loss of consciousness lasting longer than 30 seconds, a headache that keeps getting worse rather than holding steady, or fluid or blood draining from the nose or ears. Pupils that are noticeably unequal in size or much larger than normal are another red flag. Large bruising behind the ears or around the eyes also warrants immediate evaluation, as these patterns can indicate a skull fracture.
Any symptom that worsens over time, rather than staying the same or gradually improving, is cause for concern. A person who seems fine at first but becomes increasingly confused or drowsy over the next few hours needs emergency attention.
Watch for Observable Signs at the Scene
In the first moments after an impact, look at the person before you start asking questions. The most telling signs are ones they can’t fake or mask: lying motionless on the ground after the hit, falling without bracing themselves, visible confusion or disorientation, a blank or vacant stare, difficulty walking or standing, or a seizure immediately after impact. Even one of these signs is enough to suspect a concussion.
Ask Questions That Test Memory and Orientation
A concussion disrupts the brain’s ability to process and recall information, so asking a few pointed questions is one of the fastest ways to screen for one. The key is to ask questions you already know the answer to, so you can verify whether the responses are correct.
If the injury happened during a game or practice, there’s a well-established set of five questions used on the sideline: What venue are we at today? Which half or period is it? Who scored last? What team did you play last week? Did your team win that game? These work because they test both orientation (knowing where and when you are) and recent memory (recalling specific events). Getting even one wrong after a head impact is a significant finding.
Outside of sports, you can adapt the same principle. Ask what day of the week it is, the current month, today’s date, the year, and the approximate time. Then give a short list of words (five to ten unrelated words like “elbow, apple, carpet, saddle, bubble”) and ask the person to repeat them back. Have them try this two or three times. After five minutes of other checks, ask them to recall the word list again. Struggling with any of these tasks suggests a problem with the brain’s short-term processing.
You can also test concentration by asking the person to recite the months of the year in reverse order, starting with December, or to count backward from a number by sevens (100, 93, 86, and so on). A concussed brain often stumbles on tasks that require sustained focus in sequence.
Check the Eyes
The eyes reveal a lot about brain function after a head injury. Start with the pupils. In a well-lit room, both pupils should be roughly the same size and should shrink when you shine a light into each eye. Unequal pupil size or a pupil that responds sluggishly to light can signal a concussion or something more serious.
Next, test how well the eyes track movement. Hold a fingertip about three feet from the person’s face and slowly move it side to side, then up and down, taking about two seconds to travel the full range. The person’s eyes should follow smoothly. Jerky or uncoordinated tracking is abnormal.
You can also check rapid eye movement by holding up two fingers about three feet apart and asking the person to snap their gaze back and forth between them as quickly as possible, ten times. Do this horizontally, then vertically. After each test, ask if it triggered a headache, dizziness, nausea, or mental fogginess, rating each on a scale of 0 to 10. A concussion commonly makes these eye movements provoke symptoms that weren’t there before.
Finally, test convergence. Have the person hold a small object at arm’s length and slowly bring it toward the tip of their nose while focusing on it. They should stop when they see two images instead of one. Measure the distance from the nose to the object. If that distance is five centimeters (about two inches) or more, convergence is considered abnormal and is a common finding after concussion.
Test Balance
Balance is one of the most sensitive indicators of a concussion because it relies on the brain integrating signals from the inner ear, the eyes, and the body’s position sensors all at once. A concussed brain struggles with this coordination.
The standard screening uses three stances, each held for 20 seconds with eyes closed and hands on hips:
- Double-leg stance: Feet together, standing still.
- Single-leg stance: Standing on the non-dominant leg only.
- Tandem stance: One foot directly in front of the other, heel to toe, with the non-dominant foot in back.
Count every error: opening the eyes, lifting hands off the hips, taking a step to catch balance, stumbling, lifting the heel or toes off the ground, or moving the hip more than about 30 degrees to compensate. A healthy person will make very few errors. Multiple errors across the three stances suggest impaired brain function.
You can add a timed walking test. Have the person walk heel-to-toe along a straight line (a hallway works fine) as quickly as they can without losing form. If you want to push the test further, ask them to count backward by sevens while they walk. Doing two things at once is disproportionately hard for a concussed brain, and the combination often exposes problems that standing balance alone might miss.
Track Symptoms Over Hours and Days
Concussion symptoms don’t always show up right away. A mild concussion that doesn’t involve loss of consciousness can feel unremarkable at first, with headaches, difficulty multitasking, and mental fogginess emerging over the following 24 to 48 hours. This is why a one-time check isn’t enough.
Keep monitoring for the full symptom list in the hours and days after injury: headache, pressure in the head, nausea, dizziness, sensitivity to light or noise, feeling slowed down, feeling “in a fog,” difficulty concentrating, difficulty remembering, fatigue, confusion, drowsiness, irritability, sadness, anxiety, and trouble falling asleep. Rate each one on a scale from 0 (not present) to 6 (severe) so you can track whether symptoms are improving, stable, or worsening.
One common concern is whether you need to wake the person up during the night. Current medical thinking is clear on this: there is no evidence that waking someone with a suspected concussion is needed or beneficial. Rest is a crucial part of recovery, and interrupting sleep every hour is actually counterproductive. A full eight hours of sleep helps the brain heal more than repeated check-ins. That said, it’s perfectly fine to quietly look in on the person to confirm they’re breathing normally and resting peacefully, without waking them. If their breathing pattern seems abnormal, wake them and seek medical attention immediately.
What Happens After a Concussion Is Identified
Once a concussion is suspected, the person should stop whatever physical activity they were doing and not return until cleared by a healthcare provider. Recovery follows a graduated six-step process recommended by the CDC, and each step requires at least 24 hours without returning symptoms before moving to the next:
- Step 1: Return to regular daily activities like school or work, with clearance from a provider to begin the progression.
- Step 2: Light aerobic activity only, such as 5 to 10 minutes on a stationary bike or light walking. No weight lifting.
- Step 3: Moderate activity that increases heart rate with body or head movement, like jogging or moderate-intensity cycling.
- Step 4: Heavy non-contact activity, including sprinting, full weightlifting routines, and sport-specific drills.
- Step 5: Full practice with contact, in a controlled setting.
- Step 6: Return to competition.
Rushing this timeline significantly increases the risk of a second concussion, which can cause far more severe damage to a brain that hasn’t finished healing. Most concussions resolve within two to four weeks with proper rest and gradual return to activity, though some people experience symptoms for longer, particularly if they’ve had previous concussions.