Concussion: symptoms, monitoring and recovery

Emergency numbers
United States: 911
United Kingdom: 999 or 112
European Union: 112
Elsewhere: your local emergency number

Short answer. Concussion is a mild traumatic brain injury that can occur without loss of consciousness. Headache, dizziness, nausea, brain fog, attention problems, irritability and sleep changes may appear immediately or in the following days. After medical assessment, recovery generally involves brief relative rest and a gradual return to activities. Sport involving a risk of impact follows specific rules.

Important. After a blow to the head, call emergency services if the person becomes difficult to wake, has a seizure, weakness on one side of the body, speech problems, increasing confusion, vomiting after the injury or a markedly worsening headache. The vomiting alert preserves the French public guidance used here. One pupil being larger than the other is also a warning sign. Loss of consciousness, amnesia or taking anticoagulants requires appropriate medical assessment, even if the person subsequently seems better. Do not try to determine the severity of an injury yourself.

How can you recognise concussion without waiting to lose consciousness?

Concussion can follow a direct blow to the head, but also a forceful movement of the body that abruptly jolts the head. Remaining conscious, finishing a conversation or walking straight after the accident does not rule it out. Diagnosis depends on the mechanism of the accident, symptoms, clinical examination and risk factors.

Symptoms differ between individuals. To observe them more clearly, they can be grouped without turning them into a checklist for self-diagnosis:

• Physical sensations: headache, nausea, dizziness, fatigue and sensitivity to noise or light.

• Attention and memory: needing to reread a sentence, difficulty following several people, feeling that thinking is slower, or forgetting some events around the impact.

• Mood and behaviour: irritability, unusual worry or stronger emotional reactions.

• Sleep: a disrupted pattern, changes in falling asleep or an increased need for rest.

What matters is the change from the person’s usual state. Someone who suddenly becomes confused, answers incoherently or deteriorates needs more than routine monitoring: seek emergency help.

What does a normal CT scan mean if you still have symptoms?

An emergency CT scan primarily looks for certain complications, particularly bleeding or a structural injury that could change treatment. Concussion may leave no abnormality visible on that scan. A normal result therefore does not mean symptoms are invented; equally, it cannot on its own prove that every risk has been excluded regardless of the examination and subsequent changes.

This explains why a CT scan is not performed automatically after every impact. The doctor considers, among other things, level of consciousness, vomiting, memory around the accident, the mechanism and certain medicines. Imaging is not a universal screening test for concussion.

What should be monitored during the first few hours?

First follow the discharge instructions from healthcare staff: these take account of the individual case. After medical assessment, a responsible adult may be asked to stay during the first 24 hours; this does not mean the person must routinely be kept from sleeping. Discharge guidance should explain the signs requiring another call to emergency services.

Three observations are particularly useful for describing progress: what changed, when, and whether it is improving or worsening. For example, saying that someone answered normally at 6 pm but became very disoriented at 8 pm is more informative than saying they are not themselves. If there is a serious sign, do not wait to finish a notebook entry: call emergency services.

The aim is not to give repeated memory tests or provoke symptoms by turning up music or making the person exercise. It is to recognise deterioration, follow the instructions received and be able to describe changes.

Should you stay in bed or stop using screens for several days?

For a concussion that has already been medically assessed, current advice generally does not recommend prolonged strict rest in a dark room. Relative rest for about one to two days is preferred, followed by the gradual reintroduction of ordinary activities and gentle movement, guided by symptoms and professional advice. This general guidance does not replace individual instructions.

For example, someone reads for ten minutes without difficulty, then their pain increases markedly after an hour of video calls. The answer is not necessarily to ban every screen for a week. They can discuss a more gradual return: short sessions, breaks, adjusted brightness and less background noise. If symptoms increase noticeably, reduce or stop the activity.

Sleep, hydration and a regular routine can make this period more manageable, but do not in themselves treat concussion. Driving requires particular caution if attention, reaction speed, vision or balance is affected.

Why does returning to sport follow a different rule?

Because returning to screen-based work and training with a risk of head impact do not expose someone to the same danger. If concussion is suspected during sport, the person must stop the activity immediately and not return to play that day. They must not resume training involving a risk of impact before assessment and clearance by a healthcare professional.

Sports protocols use progressive stages, generally under medical supervision: return to usual activities, light exercise, increasing intensity without contact, more demanding non-contact training, then, if authorised, contact and competition. This is not a timetable to follow independently to test yourself; age, sport, symptoms and medical history affect decisions.

A practical question is which activities you can do now, which still carry a risk of another impact, and when reassessment is needed. This also applies to cycling, sports involving sliding or gliding, and jobs involving a risk of falls.

If symptoms persist, how can medical follow-up help?

A persistent symptom should neither be dismissed nor automatically given a single explanation. Ongoing dizziness may warrant balance assessment; neck pain may contribute to headaches; fatigue, sleep, vision and mood may need different approaches. The professional selects appropriate investigations and referrals.

If symptoms do not resolve within two to three weeks or worsen as activities resume, the CDC recommends contacting a healthcare professional again. This is neither a guaranteed recovery date nor a reason to wait if a concerning sign appears.

You can prepare for the consultation with two simple examples: you can read quietly for fifteen minutes but lose track in meetings; you walk without difficulty but rapid movements make you dizzy. Details of specific situations often help more than a general description such as always feeling tired.