Old memory problems or a new change: when should you get checked?
How to tell steady memory problems from new changes, and how fast to get help
You have lived with some memory gaps since your crash. Over the years you have built workarounds, such as a phone calendar, sticky notes and a habit of writing things down. Most days the system holds.
Then something shifts. Your partner says you are repeating stories more often. You got turned around driving to a store you have visited for years. It is easy to blame the old injury, or to shrug and call it getting older. Either explanation might be right, but neither should be assumed.
This article helps you sort steady, familiar problems from new changes, and explains which changes need 911, which need a prompt call, and which can wait for a routine visit.
Steady, improving or changing: know your baseline
Your baseline is how your memory usually works on an ordinary day, after your recovery has leveled off. It is the yardstick for spotting change.
After a mild TBI or concussion, the majority of people feel better within roughly two weeks [2]. Some people live with longer lasting problems. For many of them the pattern becomes familiar. You may know, for example, that you forget names at parties or lose track of the third errand on a list.
A new change looks different. It may be a problem you never had before, a familiar problem that is clearly getting worse, or a problem that appears suddenly. In its guidance on returning to work after a mild brain injury, the CDC recommends checking symptoms and thinking skills more than once over time [6]. That is easier when there is a baseline to compare against.
Clues that something has changed
- Other people notice a difference before you do.
- You lose skills you had kept since your injury, such as following a recipe you know well.
- Your usual memory aids stop working for you.
- You get lost on routes that are familiar [4].
- New symptoms appear alongside memory trouble, such as headaches, weakness, sleepiness or changes in mood.
Comparison compiled by Safety Behind the Wheel Foundation
Steady pattern or new change?
| What you notice | Fits a steady pattern | Points to a new change |
|---|---|---|
| Forgetting names or details | Same as the past few years | Clearly more often, over weeks or months |
| Misplacing items | Helped by your usual routines | Happening despite your routines |
| Finding your way | Fine on familiar routes | Getting lost on routes you know well |
| Thinking clearly | Tired at day’s end, as usual | Confusion that is new or comes on suddenly |
| Other symptoms | None new | New headache, weakness, sleepiness or speech trouble |
Sources: MedlinePlus pages on dementia, confusion and chronic subdural hematoma [4, 7, 3]; CDC [2].
Changes that need emergency care right away
Some changes cannot wait for an appointment. Confusion that comes on suddenly, or comes with other symptoms, is a reason to call 911 [7]. So is confusion that appears for the first time with no clear reason, or confusion that starts after a head injury [7].
A stroke can cause sudden confusion or memory loss along with weakness, numbness, trouble speaking, vision problems or loss of balance [1]. Most of the time these symptoms start suddenly and without warning [1]. A quick check uses the letters F.A.S.T. [1]. See whether one side of the Face droops, whether one Arm drifts down when both are raised, and whether Speech sounds slurred or strange [1]. The T stands for Time, because clot busting treatment must start within 4 and a half hours of the first symptoms [1].
After any new head injury, a headache that keeps getting worse, repeated vomiting, seizures, slurred speech or growing drowsiness are danger signs [2]. In rare cases, a dangerous blood clot can form and press the brain against the skull [2].
Call 911 right away
Do not wait to see whether these pass. Call 911 for any of them:
- Confusion that starts suddenly, or comes with other new symptoms [7].
- A drooping face, a weak or numb arm or leg, or trouble speaking or understanding speech [1].
- Sudden vision loss or double vision, loss of balance, or trouble walking [1].
- A sudden, severe headache [1].
- After a head injury: a headache that gets worse and will not go away, repeated vomiting, or slurred speech or unusual behavior [2].
- After a head injury: weakness or numbness, trouble with coordination, or any convulsion or seizure [2].
- After a head injury: confusion, restlessness or agitation, trouble recognizing people or places, or one pupil bigger than the other [2].
- After a head injury: loss of consciousness, heavy drowsiness, or the person cannot be woken up [2].
- Thoughts of suicide: call or text 988, or call 911 [8].
A slow bleed after a minor bump
Older adults and people on certain medicines should know about chronic subdural hematoma. It is a pocket of old blood and broken down blood products lying under the tough outer covering of the brain [3]. It is usually caused by a head injury [3].
It is more common in older adults because the brain shrinks with normal aging [3]. Certain small veins are then more likely to tear, even after a minor head injury [3]. The person or family may not even remember the injury that caused it [3].
The timing is what makes it easy to miss. In an older adult, new confusion, weakness or numbness may not appear until weeks or even months after the injury [3]. Symptoms can include drowsiness, confusion, memory problems, headache, trouble speaking or swallowing, weakness or numbness, and changes in behavior [3].
Who is at higher risk
MedlinePlus lists these risk factors [3]:
- Older age.
- Long term heavy alcohol use.
- Long term use of aspirin or anti inflammatory pain relievers such as ibuprofen.
- Blood thinning medicines such as warfarin.
- Diseases that reduce the blood’s ability to clot.
Anyone with possible signs of this kind of bleed should call their provider without delay [3]. Call 911 for a seizure or if the person passes out [3]. If you take a blood thinner, tell your care team about any fall or bump to the head. Do not stop or change the medicine on your own, since that decision belongs with your prescriber.
A general head injury guide from MedlinePlus adds that problems can come from bleeding or swelling inside the skull even when the head looks fine [9]. Symptoms may show up right away or develop slowly over hours or days [9].
A composite example
Imagine a 68 year old man who had a TBI in a crash two decades ago and has lived with mild memory problems ever since. He takes a blood thinner for a heart condition. Three weeks after slipping on an icy step, he starts mixing up words and forgetting conversations from the same morning. His wife wonders whether the old injury is “catching up” with him. His provider orders a scan the same day, given the fall and the blood thinner, and finds a slow bleed that needs treatment. The old injury was not the cause.
Other causes of new memory trouble
Not every change is an emergency. Many have causes that can be found and treated. Several of the conditions below can cause confusion, slow thinking or forgetfulness.
Medicines
Medicines are one of the listed causes of confusion [7]. MedlinePlus lists corticosteroids, sleep and sedative medicines, antihistamines and antidepressants among the medicine effects that can reduce mental sharpness [5]. Stopping certain medicines can also cause problems [5]. Bring every pill bottle, including over the counter products and supplements, to your visit, and ask a pharmacist to review them. Never stop or change a prescribed medicine without talking to your prescriber.
Vitamins, thyroid and blood sugar
Low vitamin B12 is on the list of dementia causes that may be stopped or reversed if found early [4]. So are changes in thyroid hormone, blood sugar, sodium and calcium [4]. Low blood sugar can also cause sudden confusion [7]. A provider may order blood tests, such as thyroid function tests and a vitamin B12 level, to look for these problems [4].
Mood, sleep, alcohol and infection
Depression can make it hard to concentrate [8]. Other symptoms can include trouble sleeping and low energy [8]. An underactive thyroid and some medicines, including steroids and beta blockers, can contribute to depression [8]. Lack of sleep, alcohol or drug use or withdrawal, and infections are all listed causes of confusion [7].
Hearing and vision
Hearing loss and untreated vision loss are on the list of 14 risk factors for dementia in the 2024 Lancet Commission report [10]. If you cannot hear a conversation clearly, you may not take it in well enough to remember it later. A hearing or eye exam is a simple check worth asking about.
When a change could be dementia or vascular disease
Sometimes new memory trouble is the early sign of a disease that slowly damages the brain. Dementia often first shows up as forgetfulness [4]. Early signs can include getting lost on familiar routes and misplacing things [4].
Mild cognitive impairment, often called MCI, describes memory and thinking trouble beyond what is typical for a person’s age [4]. Not everyone with MCI goes on to develop dementia [4]. That is one reason to get a proper evaluation instead of guessing.
Vascular dementia results from a string of small strokes [11]. Its symptoms can develop gradually or get worse after each small stroke. Some people improve for short periods before declining again [11]. Smoking, diabetes, heart disease and high blood pressure are among its risk factors [11].
A past brain injury does not explain every later change. Neither does age. A new decline deserves its own workup, even when you already have an old diagnosis. If you already have a diagnosis of a thinking disorder and your symptoms worsen, MedlinePlus says to get back in touch with your provider [5].
What to expect when you get checked
A visit about memory change usually starts with your story. Your provider will want to know what changed and when you first noticed it. Expect questions about whether it came on suddenly or slowly, and about sleep, mood, alcohol, medicines and recent falls. A family member who sees you often can fill in details you may miss.
Testing depends on what your provider suspects. When dementia or another brain problem is a possibility, tests may be ordered to find out whether other problems are causing the symptoms or making them worse [4]. These can include blood tests such as thyroid function tests and a vitamin B12 level, and imaging such as a head CT or an MRI [4]. You may also be offered a new assessment of memory and thinking. So the results can be compared with earlier ones.
Treatment depends on the cause. For a chronic subdural hematoma, treatment aims to ease symptoms and to limit or prevent lasting harm to the brain [3]. These bleeds often come back after they are drained. So anyone who has had one should report new symptoms early [3].
A second composite example
Imagine a 52 year old who had a concussion in a crash ten years ago and settled into a steady routine with a few memory aids. Over six months she feels foggier, more tired and slower to find words. She assumes the old injury is getting worse. Her provider checks her blood and finds an underactive thyroid, one of the conditions that can dull thinking [5]. Once it is treated, her care team plans to recheck her memory against her old baseline.
How fast to act
Use this rough guide alongside your care team’s advice. When in doubt, call.
- Call 911 now for sudden confusion, stroke signs, a seizure, or danger signs after a head injury [1, 2].
- Call your provider right away for new confusion, memory loss, weakness or numbness in the weeks after a fall or head bump [3]. This matters most for older adults and people on blood thinners [3].
- Book a prompt visit for memory or thinking problems that are new or have clearly worsened over weeks or months [4, 5].
- Raise steady, familiar problems at your next routine visit, and ask whether a recheck of your thinking skills would help [6].
Keeping records to compare
A written record gives your care team dates and details to work with, and a notebook or phone note is enough.
Checklist from Safety Behind the Wheel Foundation
- Write a short description of your usual memory now, while things are steady.
- Note the date when you first noticed any change, and what you noticed.
- Record every fall or bump to the head, even a minor one.
- Keep an up to date list of all medicines, doses and recent changes.
- Track sleep, mood and alcohol use for a couple of weeks before a visit.
- Ask a family member or friend to write down changes they see.
- Write down any driving problems, such as getting lost or missing turns.
- Bring old test results or reports from past brain injury care, if you have them.
Driving deserves a mention. Memory problems after a TBI can include losing track of your destination or the route to it [12]. If you notice new trouble finding your way on the road, stop driving until you have been checked.
Questions to ask your care team
Question checklist from Safety Behind the Wheel Foundation
- Does this change fit my old injury, or could something new be going on?
- Could any of my medicines, including over the counter ones, be affecting my memory?
- Should I have blood tests, such as thyroid function or vitamin B12?
- Given my fall and my medicines, do I need a brain scan?
- Could depression, poor sleep or hearing loss be playing a part?
- Would a new memory and thinking assessment help us compare with my past results?
- Which symptoms mean I should phone you the same day, and which mean 911?
- Is it safe for me to keep driving while we sort this out?
Frequently asked questions
Could this just be normal aging?
It might be, but that should not be assumed. Mild cognitive impairment means more memory and thinking trouble than others the same age. It does not always lead to dementia [4]. A provider can check for treatable causes before anyone settles on aging as the answer [4].
Can a problem show up weeks after a bump that seemed fine?
Yes. In older adults, a slow bleed called a chronic subdural hematoma can bring on confusion, weakness or numbness long after the fall, sometimes by weeks or months [3]. Even a bump that seemed minor can cause one [3]. Call your provider promptly if those symptoms appear [3].
Should I stop my blood thinner after a fall?
Do not stop or change it on your own. Blood thinners are a risk factor for bleeding around the brain, so tell your provider about the fall and any new symptoms, and let them decide [3].
Will I need a brain scan?
Maybe. When dementia or another brain problem is suspected, testing can include blood tests and imaging such as a head CT or MRI [4]. Your provider will decide based on your symptoms, your history and how quickly things changed.
The bottom line
Recommendation from Safety Behind the Wheel Foundation
Steady memory problems from an old injury are part of life for many survivors. New, worsening or sudden changes are different. They deserve a fresh look. Sudden confusion and stroke signs need 911, and new symptoms after even a small bump need a prompt call, especially for older adults and people on blood thinners.
Many causes of new memory trouble can be treated. Keep a simple record of your usual memory, track any falls and medicine changes, and bring those notes to your care team.
Sources and further reading
- 1MedlinePlus (U.S. National Library of Medicine). Stroke. Reviewed April 2025. medlineplus.gov/ency/article/000726.htm
- 2Centers for Disease Control and Prevention. Signs and symptoms of mild TBI and concussion. Reviewed September 2025. cdc.gov/…/index.html
- 3MedlinePlus (U.S. National Library of Medicine). Chronic subdural hematoma. Reviewed May 2026. medlineplus.gov/ency/article/000781.htm
- 4MedlinePlus (U.S. National Library of Medicine). Dementia. Reviewed January 2026. medlineplus.gov/ency/article/000739.htm
- 5MedlinePlus (U.S. National Library of Medicine). Neurocognitive disorder. Reviewed January 2026. medlineplus.gov/ency/article/001401.htm
- 6Centers for Disease Control and Prevention. Managing return to activities (HEADS UP, for health care providers). Reviewed July 2025. cdc.gov/…/index.html
- 7MedlinePlus (U.S. National Library of Medicine). Confusion. Reviewed January 2026. medlineplus.gov/ency/article/003205.htm
- 8MedlinePlus (U.S. National Library of Medicine). Depression. Reviewed April 2025. medlineplus.gov/ency/article/003213.htm
- 9MedlinePlus (U.S. National Library of Medicine). Head injury: first aid. Reviewed October 2025. medlineplus.gov/ency/article/000028.htm
- 10Alzheimer Europe. 2024 Lancet Commission underscores potential for dementia risk reduction, identifying 14 modifiable risk factors. 2024. alzheimer-europe.org/…/2024-lancet-commission-unde…
- 11MedlinePlus (U.S. National Library of Medicine). Vascular dementia. Reviewed April 2025. medlineplus.gov/ency/article/000746.htm
- 12Model Systems Knowledge Translation Center. Driving after traumatic brain injury. 2024. msktc.org/…/driving-after-traumatic-bra…
This article reflects the safety priorities of brain injury recovery and road safety education. It is general education, not medical advice, and it cannot tell you whether a change you notice is serious. Check official health sources, call 911 in an emergency, and talk with your own care team about any new or worsening symptoms. Reviewed October 2026.
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