You do not need to lose consciousness to have a concussion, and most people who have one after a car accident never did. The head does not have to hit anything either. A hard enough jolt snaps the brain against the inside of the skull, and that alone can cause a concussion, also called a mild traumatic brain injury. The symptoms often do not appear at the scene at all. They show up the next morning, or three days later, once the adrenaline wears off and the person tries to go back to a normal day.
That delay is the reason concussions get missed and the reason insurance companies argue about them more than almost any other injury. A headache that starts on day four looks, on paper, like it might have nothing to do with a crash from four days earlier. It usually has everything to do with it. This article explains what a delayed concussion looks like, why a normal scan does not rule it out, and what to do in the days and weeks after a crash if something feels wrong in your head that was not wrong before.
You do not have to black out for it to count
The old idea that a concussion requires losing consciousness is wrong, and it is not how doctors diagnose one. The brain can be injured by the sudden acceleration and deceleration of a crash, a whiplash-style motion, without the head striking anything and without any period of unconsciousness. Some people feel dazed or “off” for a few seconds at the scene and dismiss it. Others feel nothing at all until later.
This matters for your claim as much as your health. If you tell an insurance company you never lost consciousness, do not let that become a reason to downplay what happened. Consciousness is one data point among many, and it is not the one that determines whether a concussion occurred.
The symptoms that arrive late
A concussion’s symptoms frequently build over hours or days rather than announcing themselves immediately. The pattern we hear most often includes a headache that starts dull and gets worse, a foggy or slowed-down feeling that makes ordinary tasks take longer, trouble sleeping or sleeping far more than usual, sensitivity to light or noise that was not there before, irritability or a short temper that feels out of character, and trouble holding onto short-term memory, like forgetting why you walked into a room.
Any one of these on its own could be explained by stress, poor sleep, or the general shock of being in a crash. Several of them together, appearing in the days after a collision in someone who felt mostly fine at the scene, is the pattern a concussion produces. Write down what you notice and when, because that timeline becomes important later, both for your treatment and for your claim.
Why a normal CT scan does not rule it out
An emergency room CT scan is designed to catch the things that need immediate surgical attention: bleeding, swelling, a skull fracture. It is not designed to detect a concussion, and a normal result does not mean your brain was not injured. Concussions are a functional injury rather than a structural one, which is why they often do not show up on standard imaging. A doctor who tells you the scan is clear is telling you something true and important, and it is not the same as telling you there is no injury.
This gap between what a CT scan shows and what a concussion is becomes the argument an insurance company makes in a low-damage crash. If the images are normal and the property damage is minor, the company’s position is often that there is no real injury, only a claim built on symptoms nobody can verify. That argument ignores how concussions work, but it gets made anyway, which is exactly why documentation matters as much as it does.
Who to see, and in what order
The emergency room is the right first stop if you have any of the classic warning signs. After that, most concussions are managed through a sequence: primary care first, to establish a baseline and rule out other causes for what you are feeling, then a referral to neurology or a concussion clinic if symptoms persist beyond a week or two or if anything is getting worse rather than better. Kaiser Woodland Hills, Providence Holy Cross and West Hills Hospital all see a steady stream of these cases out of crashes on the 101 and the 118, and a primary care referral to a neurologist through any of those systems is a normal, expected next step rather than an overreaction.
Do not wait to be seen because the first exam looked fine. Our article on waiting to see a doctor after a car accident explains why a gap in treatment is the single easiest thing an insurance company uses against an injury claim, and concussions are especially vulnerable to that argument because the symptoms are already delayed once.
Keeping a symptom diary
A simple daily log does two things at once: it helps your doctor track whether you are improving, and it becomes some of the clearest evidence in your claim. Note the date, what you experienced, how severe it was on a rough scale, and what you were doing when it happened, whether that was trying to read, sitting in bright light, or working a full shift. A diary kept in real time carries far more weight than a recollection assembled months later, because it was not written with a claim in mind. It was written because something was wrong that day.
Getting back to work, and the screens that measure it
Returning to work after a concussion is not always a single decision. Some people need a modified schedule, fewer hours, or a break from screens and bright office lighting before they can resume a full day. Cognitive screening tools, sometimes called ImPACT testing or similar computerized assessments, are used by neurologists and concussion clinics to measure reaction time, memory and processing speed against a baseline, and they give your treatment team and, eventually, your claim, an objective marker of where you stand. If your employer is pushing you back before you are ready, your treating doctor’s restriction is the document that carries weight, ahead of any timeline set by a supervisor.
Children and older adults need extra attention
Kids often cannot describe what they are feeling the way an adult can. A child who becomes unusually clingy, loses interest in things they normally enjoy, or falls behind at school in the weeks after a crash may be showing concussion symptoms without the vocabulary to say so directly. Watch for changes in behavior more than complaints, because the complaints may never come.
Older adults face a different risk. A concussion in someone over 65 carries a higher chance of complications, takes longer to resolve, and can be harder to distinguish from normal aging in the early days. Any head injury in an older adult after a crash deserves a lower threshold for going back to the doctor than it would in a younger patient.
When to go back to the emergency room
Most concussion symptoms are managed on an outpatient basis, but certain signs mean an immediate return to the emergency room rather than waiting for a scheduled appointment. Worsening headache rather than a steady or improving one, repeated vomiting, increasing confusion or difficulty waking up, slurred speech, weakness or numbness on one side, or a seizure are all reasons to go back right away. If something is trending in the wrong direction rather than slowly improving, treat that as the signal to be seen again, regardless of what an earlier scan showed.
Why the insurance company treats a low-damage crash differently
A crash that leaves little visible damage to either car produces a predictable response from the insurance company: skepticism that a brain injury could have resulted at all. The argument leans on the same intuition juries sometimes have, that a car which barely shows a dent could not have delivered enough force to hurt anyone inside it. That intuition does not match how concussions happen. The force that jolts a brain against the skull is about acceleration and deceleration, not about how much the bumper crumples, and a low-speed impact can still produce enough sudden movement to cause an injury even when the vehicles absorb very little visible damage.
Anticipating that argument is part of why documentation matters so much. A consistent medical record, a symptom diary, and a doctor willing to explain the mechanism of injury in plain terms answer the bumper photograph before it gets raised. Waiting to be seen, or letting weeks pass between appointments, hands the argument more room to work.
Keep treating even as symptoms improve
Concussion recovery is rarely a straight line. A person might feel better for several days and then have a setback after a stressful day at work or a night of poor sleep. This is a normal part of how the brain heals. It does not mean something new went wrong, and it does not erase the progress you already made. Continue attending follow-up appointments even during a good stretch, since a doctor’s note that you were improving and then had a documented setback is more useful to your treatment and your claim than a gap in the record during the weeks you felt fine.
Key points
- No loss of consciousness is required for a concussion diagnosis, and the head does not have to strike anything.
- Symptoms often arrive hours or days after the crash, including headache, fog, sleep changes, light sensitivity, irritability and memory trouble.
- A normal CT scan does not rule out a concussion, since standard imaging is built to catch structural injuries rather than functional ones.
- A symptom diary kept in real time and a doctor’s work restriction are the two documents that carry the most weight later.
- Children and older adults deserve closer attention, since both groups can present with less obvious symptoms.
Frequently asked questions
I felt fine right after the crash and only started getting headaches four days later. Does that still count?
Yes. A delayed onset is common, not a sign the headache is unrelated. See a doctor and describe the timeline exactly as it happened, including the days you felt fine, because that pattern is consistent with how concussions present.
Will the insurance company believe a concussion diagnosis without a visible head injury?
They will argue about it, particularly if property damage was minor, and that argument does not make the injury less real. A documented symptom timeline, a doctor’s diagnosis, and consistent treatment are what answer that argument.
How long do concussion symptoms usually last?
It varies widely by person, ranging from days to weeks to, in some cases, months. Your treating doctor is the one who can speak to your specific recovery, and continued symptoms are a reason to see a neurologist rather than a reason to doubt the diagnosis itself.
Do I need to see a medical specialist, or is my regular doctor enough?
Your primary care doctor or an urgent care physician can manage an uncomplicated case. If symptoms last beyond a week or two, or if anything is worsening, a referral to a neurologist or a concussion clinic is the normal next step, and it usually comes from the doctor you are already seeing.
Who pays for a concussion workup while your claim is pending is its own question, and our guide on who pays medical bills after a car accident walks through the options. A concussion claim is still a car accident claim at its core, built the same way any injury claim is built, with the medical record doing most of the work. If you or someone in your family is dealing with head injury symptoms after a crash, including in and around West Hills, call Manoukian Law Firm at (818) 818-5031 or visit our brain injury page for a free consultation. The firm helps clients in English, Spanish and Armenian. Consultations are free and there is no fee unless we win.
