World Alzheimer’s Day is observed annually on September 21 to raise global awareness about Alzheimer's disease and other forms of dementia. Forgetting a name occasionally, misplacing the keys or walking into a room and forgetting why you went there is usually not dementia. But when memory or thinking problems become persistent, progressive and begin interfering with everyday life, they deserve medical attention.
This year's World Alzheimer's Day theme “The Earlier You Know, The More You Can Do: A Dementia Diagnosis Matters” captures an important change in the way we approach dementia.
What is dementia?
Dementia is a syndrome caused by several brain disorders. Alzheimer’s disease (AD) is the commonest cause, accounting for an estimated 60-70 per cent of dementia cases. Vascular dementia, Lewy body dementia and frontotemporal dementia are other important causes; mixed pathologies are also common.
What are the early warning signs?
Memory loss is the symptom most people associate with Alzheimer’s, but the earliest manifestations can be broader.
Watch for:
• Repeatedly asking the same questions or repeating conversations
• Forgetting recently learned information while older memories remain relatively preserved
• Difficulty managing finances, medications or familiar household tasks
• Getting lost in familiar surroundings
• Difficulty finding words or following conversations
• Problems with planning, judgment or solving familiar problems
• Increasing dependence on family members for routine activities
• Changes in personality, behaviour or social functioning
A particularly important clue is loss of previously acquired abilities.
For example, someone who has managed household finances for decades but suddenly cannot balance accounts, pay bills or understand bank transactions should not simply be told that it is 'normal ageing'.
Dementia is not normal ageing
Normal ageing can cause occasional forgetfulness, whereas dementia causes progressive cognitive impairment that affects functioning and independence.
Early evaluation is important because not every memory problem is Alzheimer's disease. Depression, sleep disorders, thyroid disease, vitamin B12 deficiency, certain medications, alcohol excess and other medical conditions can produce cognitive symptoms. Some of them are treatable.
How is Alzheimer's disease diagnosed?
Diagnosis begins with a detailed history, ideally obtained from both the patient and a close family member.
The doctor assesses memory, attention, language, executive functions and day-to-day functioning. Cognitive screening tests can identify impairment, but no single bedside test can by itself establish Alzheimer's disease.
Blood tests may be performed to look for reversible or contributory causes. MRI or CT brain imaging helps identify strokes, tumours, hydrocephalus and other structural abnormalities.
There is now an important development. We can now look for biological evidence of Alzheimer's disease through amyloid and tau biomarkers. These include cerebrospinal-fluid testing, amyloid PET and, increasingly, blood-based biomarkers.
In 2025, the US FDA cleared a blood test measuring the plasma p-tau217/β-amyloid 1-42 ratio to aid diagnosis in symptomatic adults. In August 2026, another p-tau217 blood test was cleared. Importantly, these tests are not intended to replace clinical assessment or to be used indiscriminately as screening tests in healthy people.
This matters because Alzheimer's diagnosis is increasingly moving from simply asking “Does this person have dementia?” to asking “What biological disease is causing the cognitive impairment?”
Are there treatments that can actually slow Alzheimer's?
Yes, but expectations need to be realistic.
Traditional medicines such as donepezil, rivastigmine, and memantine can provide symptomatic benefit in appropriate patients. They do not stop the underlying disease.
The exciting development is the arrival of disease-modifying anti-amyloid therapies. Lecanemab and donanemab are monoclonal antibodies that target amyloid-beta in the brain. In clinical trials, they slowed the rate of cognitive and functional decline in carefully selected people with early Alzheimer's disease (mild cognitive impairment or mild dementia) with confirmed amyloid pathology. The good news is that they are now available in India too.
But these are not miracle drugs or cures. They do not restore lost memory, and their benefits are measured as slowing decline rather than reversing dementia.
They also require careful patient selection and monitoring. One important complication is amyloid-related imaging abnormalities (ARIA), which can involve brain swelling or small areas of bleeding. MRI monitoring is therefore an essential part of treatment.
What can we do even before dementia develops?
A diagnosis should not lead to therapeutic nihilism. Regular physical activity, control of blood pressure, diabetes and cholesterol, avoiding smoking, maintaining social and cognitive engagement, treating hearing loss, getting adequate sleep and avoiding alcohol can all contribute to brain health. WHO's 2026 guidance estimates that a substantial proportion of dementia risk is attributable to potentially modifiable factors.
Don't wait until memory loss becomes severe. If you or someone close to you develops persistent or progressive changes in memory, thinking, behaviour or everyday functioning, seek an evaluation. Earlier diagnosis means more time to identify reversible causes, manage risk factors, plan for the future, access appropriate support, and, for selected patients with early Alzheimer's disease, consider treatments that can slow the disease.
The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.
