You were involved in a car crash, but you did not lose consciousness or hit your head. Your CT scan was normal, and you were allowed to go home. Now you feel foggy, dizzy, exhausted, forgetful, or unusually sensitive to light and noise.
Could you still have a concussion?
Yes. A concussion does not always cause an obvious injury, and its symptoms are not always immediate. Recognizing a concussion requires looking at how the brain and related systems are functioning—not simply whether a person passed an emergency examination or had normal imaging.
Concussions Are Not Always Obvious
Some people know immediately that something is wrong after a collision. Others walk away believing they are fine.
A person with a concussion may remain awake, answer questions correctly, speak normally, and remember the collision. There may be no visible head injury, and the person’s CT or MRI may be normal.
That does not rule out a concussion.
A concussion is commonly called a mild traumatic brain injury or mTBI. It usually affects how the brain functions at a cellular and metabolic level rather than causing a large structural injury that can be seen on routine imaging.
There is no single symptom, scan, or office test that identifies every concussion. The diagnosis is based on the complete picture: what happened during the collision, what symptoms developed, how the person’s abilities changed, and what functional testing reveals.
You Do Not Have to Hit Your Head or Black Out
A concussion can occur from a direct blow to the head, but it can also occur when a forceful hit to the body causes the head and brain to move quickly.
During a collision, the brain may bounce, rotate, or twist inside the skull. This can disrupt normal communication between brain cells and create chemical and metabolic changes in the brain.
Most people with a concussion do not lose consciousness. Some do not realize they may have sustained a brain injury until they try to return to work, drive, read, exercise, or complete other normal activities.
Why Concussion Symptoms May Be Delayed
Concussion symptoms can begin immediately, but they may also take hours or days to appear or become noticeable.
Immediately after a crash, stress hormones and adrenaline may temporarily mask symptoms. People are often focused on the damaged vehicles, other passengers, police reports, transportation, and getting home safely.
Symptoms may become more obvious later when the person places greater demands on the brain.
For example, someone may feel reasonably well while resting at home but develop symptoms when attempting to:
- Read or use a computer
- Drive in traffic
- Work under bright lights
- Follow a conversation
- Shop in a busy store
- Exercise
- Make quick decisions
- Complete several tasks at once
The CDC notes that concussion symptoms may not appear immediately and can affect how a person feels, thinks, acts, and sleeps.
Symptoms That May Suggest a Concussion
Concussions can affect several areas of brain function. The symptoms are different for every person and may change throughout recovery.
Physical Symptoms
Physical symptoms may include:
- Headaches
- Dizziness
- Balance problems
- Nausea
- Sensitivity to light
- Sensitivity to noise
- Blurred or double vision
- Unusual fatigue
- Feeling unsteady
- Motion sensitivity
- Difficulty tolerating busy visual environments
Thinking and Memory Symptoms
Changes in thinking may include:
- Feeling foggy or mentally slowed down
- Difficulty concentrating
- Forgetfulness
- Trouble following conversations
- Losing track of tasks
- Difficulty finding words
- Reading the same information repeatedly
- Taking longer to complete familiar activities
- Becoming overwhelmed when trying to multitask
Emotional Symptoms
A concussion may also affect mood and emotional control. Symptoms may include:
- Irritability
- Anxiety
- Feeling unusually emotional
- Sadness
- Frustration
- Becoming overwhelmed more easily
- Feeling unlike yourself
Sleep Symptoms
Sleep changes may include:
- Sleeping more than usual
- Sleeping less than usual
- Difficulty falling asleep
- Waking frequently
- Feeling tired despite sleeping
- Needing more naps than usual
You do not need to have every symptom to have a concussion. Even a small group of new symptoms may be important when they begin after a collision.
Family Members May Notice Changes First
People with a concussion do not always recognize their own symptoms.
A spouse, friend, family member, or coworker may notice that the person:
- Repeats questions
- Forgets conversations
- Responds more slowly
- Seems confused or distracted
- Becomes irritated more easily
- Has trouble following instructions
- Appears unusually tired
- Avoids light, noise, screens, or crowded places
- Is not behaving like their normal self
These observations may provide valuable information during a concussion evaluation, especially when the injured person cannot clearly describe what has changed.
Why a Normal CT or MRI Does Not Rule Out a Concussion
CT scans and MRIs primarily show the physical structure of the brain. They are especially important when doctors are concerned about bleeding, significant swelling, skull fracture, or another serious structural injury.
Most concussions do not create the type of large structural abnormality that appears on routine imaging.
Instead, concussion commonly disrupts how the brain is functioning. These cellular, chemical, and metabolic changes are not easily detected on a standard CT scan or MRI.
A normal scan can be reassuring because it may help rule out certain life-threatening conditions. It does not prove that the brain is functioning normally, and it does not rule out a concussion.
How Is a Concussion Diagnosed?
A concussion diagnosis requires more than asking whether someone has a headache or lost consciousness.
A thorough evaluation begins with understanding the collision:
- What direction did the impact come from?
- How did the head and body move?
- Did the person strike anything?
- What symptoms occurred immediately?
- What symptoms developed later?
- Has the person’s ability to work or function changed?
The evaluation may then examine several areas of function.
Thinking and Memory
Testing may evaluate attention, memory, reaction time, mental processing, and the ability to organize or complete tasks.
Eye Movements and Vision
The brain controls how the eyes move, focus, track objects, and work together. Abnormal eye movements can contribute to headaches, dizziness, blurred vision, reading difficulty, and screen intolerance.
Balance and the Vestibular System
The brain combines information from the eyes, inner ears, joints, and muscles to maintain balance. Concussion may interfere with this process, causing dizziness, unsteadiness, nausea, or difficulty walking in dark or visually busy environments.
Physical Exertion
Some people feel relatively normal at rest but develop symptoms when their heart rate increases. Carefully controlled exertion testing may help determine how the brain and nervous system respond to activity.
The Cervical Spine
Neck injuries can cause headaches, dizziness, visual discomfort, and balance problems that resemble or occur alongside concussion symptoms. The neck must be evaluated so that all potential sources of the patient’s symptoms are considered.
No Single Test Tells the Whole Story
Concussion is a clinical diagnosis. This means the provider must consider the history, symptoms, examination findings, functional testing, and changes in daily abilities together.
A person may perform normally on one test and still have significant problems in another area. For example, memory testing may be normal while balance, eye movements, or exercise tolerance remain abnormal.
That is why relying on only one questionnaire, one computer test, one scan, or one brief examination may miss important problems.
When to Seek Emergency Medical Care
Some symptoms following a collision may indicate a more serious brain injury rather than an uncomplicated concussion.
Call 911 or seek immediate emergency medical care for:
- A severe or worsening headache
- Repeated vomiting
- Increasing confusion or unusual behavior
- Slurred speech
- Weakness, numbness, or poor coordination
- A seizure
- One pupil that appears larger than the other
- Loss of consciousness
- Extreme drowsiness or difficulty waking
- Rapidly worsening symptoms
Emergency evaluation is necessary to look for bleeding, swelling, fracture, or another condition that may require immediate treatment.
Why Early Documentation Matters
Concussion symptoms may change over time. Early documentation helps establish:
- When each symptom began
- Whether symptoms were immediate or delayed
- How symptoms affected work and daily activities
- What functional problems were identified
- Whether symptoms improved or worsened
- What treatment, rehabilitation, or referrals were recommended
Without this information, problems with memory, concentration, balance, vision, sleep, or emotional control may later be misunderstood or attributed to something unrelated to the crash.
A clear diagnosis also helps direct the patient toward the correct care. Treatment for a neck injury may not correct a problem involving eye movements, balance, brain function, or exercise tolerance. Each contributing problem must first be identified.
Getting a Thorough Concussion Evaluation
If you feel mentally foggy, dizzy, forgetful, exhausted, unsteady, unusually emotional, or sensitive to light and noise after a car crash, those symptoms deserve attention—even if you did not hit your head, lose consciousness, or have an abnormal brain scan.
At Billings Chiropractic Injury Clinic, we evaluate the different systems that may be affected after a collision. Depending on the patient’s symptoms, this may include testing memory and concentration, eye movements, balance, the vestibular system, physical exertion tolerance, and the cervical spine.
The goal is to identify the likely sources of the patient’s symptoms, document how those symptoms are affecting daily life, and determine what care or additional referral may be appropriate.
If you are concerned that you may have sustained a concussion, a thorough evaluation may help provide answers and guide the next steps in your recovery.
