Early signs of dementia — how they differ from ordinary forgetfulness with age

Summary — Early symptoms of dementia are often hard to tell apart from the natural forgetfulness that comes with age. Ordinary forgetfulness can usually be overcome with a hint and does not greatly affect daily life, while early dementia brings changes such as forgetting recent events entirely, asking the same question repeatedly and struggling with familiar tasks. Early diagnosis is increasingly important, both to find treatable causes and so as not to miss the early stage targeted by recently approved treatments.

Forgetfulness versus early dementia

• Scope of memory — forgetfulness often involves part of an experience (a name, where something was put); dementia often involves the whole experience (who you met yesterday, whether you ate).
• Effect of hints — with forgetfulness, a hint brings the memory back; in dementia, hints often do not help.
• Awareness — forgetful people know they have forgotten and worry about it; as dementia progresses, awareness of forgetting itself often fades.
• Impact on daily life — forgetfulness does not greatly disrupt daily life; dementia makes familiar tasks such as managing money, cooking, taking medicines and using public transport difficult.

Early changes families may notice

The Alzheimer's Association in the United States lists the following as early signs:

• Forgetting recently learned information and asking the same questions repeatedly
• Difficulty planning or solving problems (paying bills, following a recipe)
• Difficulty completing familiar tasks
• Confusion about dates, seasons or places
• Trouble understanding visual images and spatial relationships
• Problems finding words when speaking or writing
• Misplacing things and being unable to retrace steps, sometimes suspecting others of taking them
• Decreased judgement (money, grooming)
• Withdrawal from work or social activities
• Changes in mood and personality (anxiety, suspicion, depression)

Having a few of these does not mean dementia; similar changes can be caused by depression, lack of sleep, medication side effects or thyroid disease.

What is mild cognitive impairment (MCI)?

Mild cognitive impairment is a state in which memory or other cognitive functions are lower than expected for age, but the person can still largely manage daily life independently. Some people with MCI progress to dementia within a few years, while others remain stable or improve. Because recently approved antibody treatments for Alzheimer's disease target the MCI and mild dementia stages, getting an accurate diagnosis at this point has become more meaningful.

When to seek assessment, and how diagnosis works

If such changes persist for several months or worsen, an assessment at a medical institution is advisable. Diagnosis usually involves an interview with the person and family, brief cognitive tests (such as the MMSE) and detailed neuropsychological testing, blood tests (thyroid, vitamins) and brain imaging such as MRI or CT. Where needed, amyloid PET, cerebrospinal fluid tests or recently developed blood biomarker tests may be used to confirm Alzheimer's changes.

Japan's Basic Act on Dementia

In 2023 Japan enacted the Basic Act on Dementia to Promote an Inclusive Society, in force from January 2024. Aiming for a society in which people with dementia can live with dignity and hope, it sets out national and local dementia policy, systems for early detection and consultation, and promotion of research — treating dementia not as something to hide but as a challenge for the community to meet together.

Why noticing early matters

First, treatable causes can be found. Second, if it is Alzheimer's disease, treatments available only in the early stage can be considered. Third, while the person can still make decisions, the family can plan together for future living, finances and care. Fourth, lifestyle measures that may help slow progression — blood pressure and glucose control, hearing support, exercise and social activity — can begin early.

Frequently asked questions

Q. What if a family member refuses to see a doctor?
This is a common difficulty. Options include attending together as part of a health check or another appointment, or for the family to seek advice first from a local support service. In Korea, dementia relief centres at public health centres, and in Japan, community comprehensive support centres, serve as points of contact.

Q. Is an online self-check list enough?
Checklists can prompt people to notice changes but cannot replace diagnosis. Similar results can arise from other causes such as depression, sleep problems or medication side effects, so a medical assessment is needed.

Q. Can dementia occur at a young age?
Onset before 65 is called young-onset dementia, with causes including frontotemporal dementia as well as Alzheimer's disease. Because the impact on work and family is large, early diagnosis and social support are especially important.

Q. If test results are normal, can I stop worrying?
It means there is no dementia at present; if changes continue, reassessment at intervals is advisable.

How to look up clinical trial information

Ongoing and completed clinical trials can be checked on public registries. ClinicalTrials.gov, run by the U.S. National Library of Medicine, and jRCT, run by Japan's Ministry of Health, Labour and Welfare, publish each study's purpose, eligibility criteria, intervention, outcomes, institutions and status. Results are later published as journal papers, and the reference links below this article lead to the original information. It is also worth knowing that interventions not publicly registered are difficult to verify from outside, in both design and results.

The above is general information summarising published materials. Organisation names are given to identify sources, not to introduce or recommend any medical institution. If symptoms concern you, please seek diagnosis at a medical institution.

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