Concussions (Mild Traumatic Brain Injury)

A concussion is a mild traumatic brain injury caused by a blow to the head or by the forces of a crash alone. It is the most common brain injury after motor vehicle collisions and the most under-diagnosed: many people are never told they had one because they did not hit their head, did not lose consciousness and had a normal CT scan. Most recover within a few weeks. For those who do not, the consequences can be significant, and the lack of early documentation becomes a problem.

Recognizing a concussion after a crash

• Feeling dazed, confused or “in a fog” immediately after the collision.
• Not remembering the moments before or after impact.
• Headache, nausea, dizziness or balance problems.
• Sensitivity to light and noise; blurred vision; ringing in the ears.
• Trouble concentrating or remembering in the days that follow; sleeping more or less than usual.
• Irritability, sadness or anxiety out of proportion to circumstances.

Any of these after a crash warrants medical evaluation. The CDC’s HEADS UP guidance and emergency department protocols focus on identifying the small number of patients with bleeding that requires intervention and on advising the rest about recovery.

Emergency danger signs

The CDC’s emergency guidance advises calling 911 or going to an emergency department for signs such as a worsening headache, repeated vomiting, seizures, weakness, increasing confusion, slurred speech, unequal pupils or difficulty waking after a head injury. Do not wait for an insurance appointment or use this page to decide whether an injury is mild. Symptoms and the need for testing must be assessed by a qualified clinician.

Recovery and post-concussion syndrome

Current guidance favors a brief period of relative rest (24–48 hours) followed by gradual return to activity, rather than prolonged “cocooning.” Most symptoms resolve within two to four weeks. When symptoms persist beyond about three months, the condition is often described as post-concussion syndrome or persistent post-concussive symptoms. Risk factors include prior concussions, migraine history, and anxiety or depression. Treatment is multidisciplinary: vestibular therapy for dizziness, vision therapy, cognitive rehabilitation, headache management and psychological support.

Returning to work, school and driving

Cognitive work—screens, reading, meetings—often provokes symptoms early in recovery, and gradual return with accommodations is standard. Driving requires attention and reaction time that concussion impairs; physicians commonly advise against driving until symptoms resolve. Lost work time and accommodations are part of the damages in a concussion claim and should be documented by employers and physicians.

Why insurers dismiss concussion claims and how to answer

Adjusters point to normal imaging, no loss of consciousness and “subjective” complaints. The answers are medical: imaging is expected to be normal in concussion; loss of consciousness is not required for diagnosis; and symptoms can be objectively measured through neuropsychological and vestibular testing. The practical answer is documentation: a diagnosis at the first visit, consistent reporting of symptoms, referral to appropriate specialists when symptoms persist, and statements from family or employers who observed the changes.

Children and concussions

Children and adolescents take longer to recover on average and are more vulnerable to repeat injury. School accommodations (reduced screen time, extended deadlines) should be documented in writing. Settlements for minors require court approval in California, and the possibility of later-emerging effects should be considered before settling.

Related pages

For moderate and severe injuries, see traumatic brain injuries. Concussions frequently accompany whiplash in rear-end collisions and are common in bicycle and pedestrian collisions.

Common questions

The ER did a CT scan and said it was normal. Do I still have a concussion?

Possibly. CT scans rule out bleeding; they do not show concussion. If you had symptoms consistent with concussion, the diagnosis is clinical. Follow up with your primary care physician if symptoms continue.

How long should I wait before working?

Follow your physician’s advice. Many people return gradually within a week or two with accommodations; some need longer. Get written work restrictions from your provider.

Is a concussion claim worth pursuing if I recovered in a few weeks?

A claim for a resolved concussion is modest but real, covering the medical visits, lost work and the period of impairment. It is typically part of a larger claim that includes other injuries from the same crash.

Sources and official resources

• CDC — traumatic brain injury and concussion
• CDC — concussion symptoms and emergency danger signs
• CDC — what to do after a mild TBI or concussion
• CDC HEADS UP — concussion signs and symptoms

Links go to official government, court and public-health sources. Laws change; verify current text before relying on it.