Dementia: Types, Early Warning Signs, Brain Changes, Medication and Care

"Doctor, my mother keeps asking the same question over and over. She used to know the neighbourhood like the back of her hand, but last week she got lost two blocks from home. And yesterday she left the gas on and forgot entirely." I hear versions of this story nearly every week, always from families who waited longer than they wish they had.

Dementia is not an inevitable consequence of growing older. It is a brain disease. Globally, roughly 55 million people are living with dementia, and that number is projected to exceed 130 million by 2050^[1]. Early recognition matters because the treatments we have are most effective when started in the mild-to-moderate stage.

This article covers the main types of dementia, the brain pathology behind them, the early warning signs families should watch for, the medications currently available, non-pharmacological approaches, and practical guidance for caregivers.

What dementia is

Dementia is a clinical syndrome characterised by progressive decline in cognitive functions, including memory, language, judgement, spatial awareness, and executive function, to a degree that interferes with daily living and social functioning. It is not a single disease but a common endpoint of many different brain pathologies^[2].

In the DSM-5, dementia is classified as "major neurocognitive disorder." Diagnosis requires significant decline in at least one cognitive domain, confirmed by standardised testing, together with evidence that the decline is interfering with independence in everyday activities.

The four main types

Table 1. Major types of dementia

Alzheimer's disease is the most common and the most extensively studied. In clinical practice, however, many patients harbour pathology from more than one type simultaneously. Mixed dementia, most often Alzheimer's combined with vascular disease, is increasingly recognised as the norm rather than the exception.

What happens in the brain

Taking Alzheimer's disease as the principal example, several key pathological processes have been identified^[3]:

Amyloid plaques

Abnormal beta-amyloid protein accumulates outside nerve cells, forming plaques that disrupt cell-to-cell signalling. This is believed to be one of the earliest events in Alzheimer's pathology, potentially beginning decades before symptoms appear.

Tau neurofibrillary tangles

Tau protein normally stabilises the internal skeleton of nerve cells. In Alzheimer's disease, tau becomes abnormally phosphorylated and twists into tangles, destroying the cell's internal transport system and ultimately leading to cell death.

Hippocampal atrophy

The hippocampus is the brain region responsible for converting short-term memories into long-term ones. It is among the earliest structures to be attacked in Alzheimer's disease, which is why difficulty forming new memories is typically the first symptom.

Cholinergic deficit

The cholinergic system, which uses acetylcholine as its neurotransmitter, is critical for learning and memory. This system is severely damaged in Alzheimer's disease. The first-line medications for dementia work by increasing the brain's acetylcholine levels.

For Lewy body dementia, the hallmark pathology is the presence of alpha-synuclein deposits (Lewy bodies) in cortical neurons, producing the characteristic triad of visual hallucinations, parkinsonism, and fluctuating cognition^[7].

Early warning signs

Many families, looking back, say they noticed something was off a year or two before seeking help. The following signs warrant attention:

• Repeatedly asking the same question, with no memory of having asked before
• Getting lost in familiar surroundings
• Inability to manage tasks that were previously routine (cooking, handling finances)
• Declining judgement (falling for scams, wearing inappropriate clothing for the weather)
• Confusion about time or place (not knowing the day of the week or where they are)
• Difficulty finding the right word, or inability to name common objects
• Placing items in illogical locations (a remote control in the refrigerator)
• Noticeable personality changes: increased suspiciousness, irritability, withdrawal, or apathy

The dividing line between normal ageing and dementia is not whether someone forgets, but whether the forgetting has begun to erode their ability to function independently. Occasionally blanking on an appointment but remembering it later is normal. Forgetting the appointment entirely and having no recollection even when reminded is a signal that evaluation is warranted.

Treatment

Medication

The medications currently available for dementia fall into two main classes^[4]:

Table 2. Commonly used dementia medications

Cholinesterase inhibitors work by slowing the breakdown of acetylcholine, thereby increasing its availability in the brain^[4]. Memantine acts on the glutamate system, protecting nerve cells from excessive excitatory stimulation^[5].

It is important to be transparent about what these medications can and cannot do. They slow the rate of decline; they do not reverse it. Studies show that cholinesterase inhibitors can delay cognitive deterioration by roughly 6 to 12 months on average. That may sound modest, but every additional month of maintained independence carries significant meaning for the patient and their family.

In moderate-to-severe stages, combining donepezil with memantine is a widely used prescribing strategy.

Non-pharmacological approaches

• Cognitive stimulation therapy: Structured group activities (discussing current events, puzzles, word games) designed to maintain cognitive engagement
• Reminiscence therapy: Using photographs, music, and familiar objects to access long-term memories, improving mood and social interaction
• Occupational therapy: Focused training in activities of daily living (dressing, eating, toileting) and environmental modifications to support independence
• Caregiver support: The treatment of dementia extends beyond the patient. Caregiver mental health is equally important. Support groups, respite care, and individual counselling are critical resources

rTMS (repetitive transcranial magnetic stimulation)

The application of rTMS to mild cognitive impairment (MCI) and early-stage dementia is an active area of research. Preliminary studies suggest that high-frequency rTMS to the dorsolateral prefrontal cortex (DLPFC) may produce short-term improvements in certain cognitive domains^[6]. However, rTMS has not yet been incorporated into standard dementia treatment guidelines, and it is best approached as an exploratory adjunctive strategy under careful clinical supervision.

Assessment and diagnosis

A comprehensive dementia evaluation involves several components:

• MMSE (Mini-Mental State Examination): A 30-point test covering orientation, memory, attention, and language
• MoCA (Montreal Cognitive Assessment): More sensitive to early cognitive impairment than the MMSE, particularly in the domain of executive function

These tests must be administered in a clinical setting by trained professionals. Beyond cognitive testing, the workup typically includes blood tests (to exclude thyroid dysfunction, vitamin B12 deficiency, syphilis, and other reversible causes) and brain imaging (CT or MRI to assess the pattern and extent of brain atrophy).

If you are concerned about a family member's cognitive function, scheduling an evaluation with a psychiatrist or neurologist is the right first step. Many hospitals also offer dedicated memory clinics that provide integrated, multidisciplinary assessments.

When to seek help

• Memory lapses are affecting daily life (forgetting to turn off the stove, forgetting medications, getting lost)
• Judgement or problem-solving ability has noticeably declined
• Personality has changed markedly (a previously gentle person becoming hostile or suspicious)
• Language ability is deteriorating (word-finding difficulty, incoherent speech)
• Behavioural and psychological symptoms have appeared (hallucinations, delusions, wandering, day-night reversal)

The earlier the evaluation, the more treatment options remain available. Dementia medications are most effective when started in the mild-to-moderate stage. By the time the disease is severe, the window for meaningful pharmacological benefit has narrowed considerably.

Frequently asked questions

Can dementia be cured?

Most forms of dementia cannot currently be cured. Existing medications aim to slow progression, maintain function, and manage behavioural symptoms. That said, a small number of "reversible" causes of cognitive decline exist, including vitamin B12 deficiency, hypothyroidism, normal-pressure hydrocephalus, and chronic subdural haematoma. Treating the underlying cause can sometimes restore cognition, which is why a thorough workup is essential.

How can I tell the difference between normal forgetfulness and dementia?

Normal age-related forgetfulness typically involves temporarily blanking on a name or appointment, with the memory returning later. In dementia, the person has no recollection of the event at all, even when prompted. The critical distinction is whether the forgetting has begun to interfere with the ability to manage everyday activities: handling money, navigating familiar routes, following a recipe, or maintaining personal hygiene.

Can dementia be prevented?

The 2020 Lancet Commission on Dementia identified 12 modifiable risk factors that, taken together, account for roughly 40 percent of dementia cases worldwide^[1]. These include managing midlife hypertension and diabetes, maintaining hearing, regular physical exercise, sustaining social engagement and cognitive activity, limiting alcohol consumption, preventing head injuries, and reducing air pollution exposure. None of this guarantees prevention, but the evidence that these measures can significantly reduce or delay risk is robust.

I am overwhelmed caring for my family member. What should I do?

Caregiver health is a core part of dementia management. Research shows that dementia caregivers have significantly elevated rates of depression and anxiety. Please do not carry this alone. Local dementia care centres, caregiver support groups, respite care services, and individual counselling are available. If you yourself are experiencing insomnia, anxiety, or low mood, scheduling a psychiatric appointment is not an indulgence; it is a necessity.

Dr. Tam's perspective

Dementia is becoming an increasingly common diagnosis in my clinic, reflecting Taiwan's rapidly ageing population. I would like to share a few thoughts with families navigating this journey.

First, do not wait until the disease is severe before seeking evaluation. The medications and non-pharmacological interventions we have are most effective when started early. If something feels "not quite right," that is exactly the time to schedule an assessment.

Second, treating dementia goes far beyond prescribing medication. Environmental modifications, routine structuring, cognitive stimulation, and sustained social engagement all contribute meaningfully to maintaining function. These interventions do not require expensive technology; they require someone who is willing to implement them consistently.

Third, take care of yourself. Dementia caregiving can wear down even very devoted families. Protecting your own sleep, mood, and health is part of keeping the care sustainable. Getting help early is not a failure; it is part of the care plan.

References

1. Livingston G, Huntley J, Sommerlad A, et al. Dementia prevention, intervention, and care: 2020 report of the Lancet Commission. Lancet. 2020;396(10248):413-446. DOI · PubMed
2. McKhann GM, Knopman DS, Chertkow H, et al. The diagnosis of dementia due to Alzheimer's disease: recommendations from the National Institute on Aging-Alzheimer's Association workgroups. Alzheimers Dement. 2011;7(3):263-269. DOI · PubMed
3. American Psychiatric Association. Diagnostic and Statistical Manual of Mental Disorders, Fifth Edition, Text Revision (DSM-5-TR). Washington, DC: American Psychiatric Publishing; 2022.
4. Birks JS, Harvey RJ. Donepezil for dementia due to Alzheimer's disease. Cochrane Database Syst Rev. 2018;6:CD001190. DOI · PubMed
5. Matsunaga S, Kishi T, Iwata N. Memantine monotherapy for Alzheimer's disease: a systematic review and meta-analysis. PLoS ONE. 2015;10(4):e0123289. PubMed
6. Drumond Marra HL, Myczkowski ML, Maia Memória C, et al. Transcranial magnetic stimulation to address mild cognitive impairment in the elderly: a randomized controlled study. Behav Neurol. 2015;2015:287843. PubMed
7. McKeith IG, Boeve BF, Dickson DW, et al. Diagnosis and management of dementia with Lewy bodies: fourth consensus report of the DLB Consortium. Neurology. 2017;89(1):88-100. DOI · PubMed