1. How common is it?

• About 50% of patients in the acute phase of stroke have cognitive or perceptual problems (AHA/ASA 2026)
• A UK follow-up of 2,432 stroke and TIA patients (R4VaD, 2026), most with mild symptoms, found that in the first 6 weeks only 53.5% had normal cognition
• A pooled analysis by Pendlebury and Rothwell (Lancet Neurology, 2009) found that about 10% developed new dementia soon after a first stroke, and more than 1 in 3 had dementia after a recurrent stroke

Cognitive problems ≠ always dementia A doctor diagnoses "dementia" when the problem is severe enough that the person can no longer do daily tasks they used to do alone, such as managing money, taking their own medicines or travelling on their own. If they can still do them but more slowly or with some mistakes, it is called mild cognitive impairment, which has a better chance of improving.

This last figure matters most, because it shows that preventing a recurrent stroke also helps prevent dementia (read about recurrent stroke)

2. Symptoms families often notice

• Asks the same thing repeatedly; cannot remember appointments or recent conversations
• Thinks and answers slowly; can only do one thing at a time
• Cannot plan tasks they used to do alone, such as cooking, sorting medicines or paying bills
• Short attention span; cannot do physiotherapy for long
• Loses interest in surroundings; seems more passive than before
• Does not notice or attend to one side of the body or surroundings, such as eating only half the plate or bumping into things on the left (a brain perception problem, not blindness)

Problems after stroke are often unlike Alzheimer's. The main features tend to be slow thinking, poor planning and poor concentration rather than loss of old memories

3. Before concluding it is dementia, rule out these 5 things

4. What the doctor checks

The assessment usually includes

1. History from the patient and from the person who is with them every day
2. Cognitive tests such as the MoCA (the Thai version should be used) · If the patient has problems speaking or understanding, the score may be low because of communication, not memory, so an assessment method suited to that person is needed
3. Reviewing all current medicines
4. Looking at previous brain imaging in relation to the symptoms
5. Further tests as needed, such as blood tests, sleep and mood

5. How to train, according to the latest guidelines

• cognitive training through computer or tablet programs that adjust difficulty to the person's ability, supervised, at moderate to high intensity (highest recommendation level · 1). The guideline states this is better than paper-and-pencil exercises alone.
• Combining cognitive training with exercise (2a)
• Training through real-life activities such as preparing simple meals, planning the day, or practicing sorting medicines with a caregiver double-checking every time (2a)

As for brain stimulation devices (TMS, tDCS) for memory, the guideline still classifies them as research and does not yet recommend them as a main treatment.

6. How families can help at home (even with just one caregiver)

• Keep the same routine every day — times for waking, meals, medicines and training
• Use memory aids — a large calendar, a daily pill organizer, a whiteboard for appointments
• Talk about one thing at a time — short sentences, and give time to answer
• Let them do as much as they can themselves — do not do everything for them, because doing it themselves is training
• Encourage walking or light exercise every day as advised by the physiotherapist
• Watch for sudden changes — if confusion suddenly gets worse, or new slurred speech or weakness appears, call 1669 or go to hospital immediately

Read more: Activities to slow dementia in older adults · Medicines after stroke: can I stop them myself?