Concussion Symptoms
Concussion symptoms fall into four distinct categories—physical, cognitive, emotional, and sleep-related—with headache being the most frequently reported symptom, occurring in the majority of cases. 1
Core Symptom Categories
Physical Symptoms
The physical manifestations are typically the most prominent and include:
- Headache (most common symptom) 2
- Nausea and vomiting
- Dizziness and balance problems
- Visual disturbances (blurred vision, double vision, sensitivity to light)
- Sensitivity to noise
- Numbness or tingling
- Fatigue and drowsiness 1, 2
Cognitive Symptoms
Mental function is frequently impaired, presenting as:
- Difficulty concentrating
- Memory problems (both retrograde and anterograde amnesia)
- Confusion and mental fogginess
- Feeling "slowed down" or "in a fog"
- Difficulty remembering recent events 2, 3
Emotional/Behavioral Symptoms
Mood and behavioral changes include:
- Irritability
- Emotional lability (being more emotional than usual)
- Sadness or depression
- Nervousness or anxiety
- Personality changes 1, 2
Sleep-Related Symptoms
Sleep disturbances manifest as:
- Trouble falling asleep
- Sleeping more or less than usual
- Excessive drowsiness
- Non-restorative sleep 2, 4
Critical Warning Signs Requiring Emergency Evaluation
Certain symptoms indicate severe head injury and require immediate EMS activation: 1
- Loss of consciousness
- Worsening or severe headache
- Repeated vomiting
- Altered mental status or increasing confusion
- Seizures
- Visual changes
- Swelling or deformities of the scalp
- Focal neurological deficits
Important Clinical Nuances
Loss of consciousness occurs in less than 10% of concussions, so its absence does not rule out concussion 2. The presence of amnesia (particularly anterograde) may be a more important indicator of injury severity than loss of consciousness alone 3.
Mental fogginess may predict slower recovery and should be specifically assessed 2. The symptom burden and duration during the acute period (first 24-48 hours) are more predictive of outcome than any single symptom 5.
Symptom Evolution and Trajectory
Symptoms typically evolve over the first 24-48 hours post-injury, with most being most severe during this acute period 5, 6. In the majority of cases, symptoms resolve spontaneously following a sequential course over days to weeks 1.
However, four symptoms tend to persist longer in patients with prolonged recovery: fatigue/low energy, drowsiness, concentration difficulties, and irritability 7. Additionally, emotionality, nervousness/anxiousness, and nausea may actually increase over time in patients developing persistent symptoms 7.
Persistent Post-Concussion Symptoms
Approximately 15-20% of patients develop persisting symptoms beyond 3 weeks, which may include 8, 5:
- Chronic headaches
- Persistent dizziness and balance problems
- Vision problems
- Increased sensitivity to noise and light
- Depression, anxiety, or mood swings
- Memory and concentration difficulties
- Sleep disturbances
- Persistent fatigue
Common Pitfalls
Do not rely solely on loss of consciousness to diagnose concussion—the vast majority occur without it 2, 6. Athletes and patients frequently underreport symptoms, particularly male athletes who may fear removal from competition 2.
Coexistent injuries can mask concussion, particularly in faciomaxillary trauma where the concussion may be overlooked unless specifically assessed 3.
Pre-existing conditions matter: Patients with pre-existing mood disorders, headaches, or high baseline symptom loads are at higher risk for persistent symptoms and should be identified early 5.