Dementia: Symptoms, stages, causes, diagnosis, treatment and prevention

Dementia is a term many families hear when an older relative begins forgetting things, repeating questions, becoming confused or struggling with everyday tasks. But dementia is much more than ordinary forgetfulness. It can affect memory, thinking, communication, behaviour, judgment, movement and a person’s ability to manage daily life.

Importantly, dementia is not one specific disease. It describes a group of symptoms caused by different diseases or types of brain damage. Alzheimer’s disease is the most common cause, but vascular dementia, Lewy body dementia, frontotemporal dementia and mixed dementia can also occur.

Dementia is more common after the age of 65, but it is not an inevitable part of getting older. Younger people can also develop dementia, sometimes referred to as young-onset dementia when symptoms begin before 65.

Recognising symptoms early matters because some conditions that cause dementia-like symptoms can be treated, while an early diagnosis can help families plan treatment, safety, care and support.

What does dementia mean?

Dementia means a decline in cognitive abilities that is significant enough to interfere with everyday life. Cognitive abilities include memory, reasoning, language, attention, judgment, problem-solving and the ability to perform familiar activities.

A person with dementia may forget recent conversations, get lost in a familiar neighbourhood, struggle to manage money, have difficulty finding words or become unable to perform tasks they have done for years.

Dementia happens when diseases or other forms of brain damage affect nerve cells and their connections. The symptoms depend partly on which areas of the brain are affected.

It is also important to distinguish dementia from normal ageing. Occasionally forgetting a name and remembering it later can happen with normal ageing. Dementia is more concerning when memory or thinking problems are persistent, progressively worsening and interfering with independence.

What are the 10 warning signs of dementia?

The following are among the most important warning signs to watch for:

• Memory loss that interferes with everyday life
• Difficulty planning or solving problems
• Trouble completing familiar tasks
• Confusion about time or place
• Difficulty understanding visual information or judging distance
• New problems with speaking or writing
• Frequently misplacing objects and being unable to retrace steps
• Poor judgment or unusual decision-making
• Withdrawal from work, hobbies or social activities
• Noticeable changes in personality or mood

One particularly important clue is a change from the person’s previous level of functioning. If someone who has always handled household finances suddenly cannot manage bills, for example, it deserves investigation.

What is the behaviour of a person with dementia?

Dementia can affect behaviour as well as memory. A person may become anxious, irritable, suspicious, restless or withdrawn. Some people repeatedly ask the same questions, pace around the house or become distressed in unfamiliar environments.

Others may experience hallucinations or delusions, particularly with certain types of dementia. Sleep patterns can also change, with some people becoming more awake or restless at night.

It is helpful to remember that difficult behaviour is often a form of communication. Pain, hunger, thirst, constipation, loneliness, fear, an unfamiliar environment or difficulty expressing a need can all contribute.

Instead of immediately asking, “Why are they behaving like this?”, caregivers can ask, “What might they be trying to communicate?”

What causes dementia?

There are many possible causes of dementia. Common types include:

Alzheimer’s disease

Alzheimer’s disease is the most common cause of dementia. It is associated with abnormal changes involving proteins such as beta-amyloid and tau, which damage brain cells over time.

Vascular dementia

This occurs when damage to blood vessels reduces blood flow to the brain. Strokes and other vascular problems can contribute to cognitive decline.

Lewy body dementia

This is associated with abnormal deposits called Lewy bodies. Problems may include changes in attention, movement, sleep, behaviour and visual perception.

Frontotemporal dementia

This affects areas of the brain involved in behaviour, personality and language and can sometimes begin at a younger age.

Mixed dementia

Some people have more than one underlying brain disease, such as Alzheimer’s disease combined with vascular dementia.

Some dementia-like symptoms can also result from potentially treatable conditions, including certain vitamin deficiencies, thyroid problems, medication effects, infections, dehydration, brain tumours or bleeding around the brain.

What is the difference between dementia and Alzheimer’s?

The simplest way to remember the difference is:

Dementia is a broad clinical term; Alzheimer’s disease is a specific brain disease and the most common cause of dementia.

Think of dementia as an umbrella. Alzheimer’s disease is one condition underneath that umbrella, along with vascular dementia, Lewy body dementia and frontotemporal dementia.

Therefore, saying someone “has dementia” does not necessarily mean they have Alzheimer’s disease. A proper evaluation is needed to identify the likely cause.

At what age does dementia start?

Dementia becomes much more common with advancing age, particularly after 65. However, there is no single age at which dementia starts.

Some people develop symptoms before 65. Young-onset dementia accounts for a minority of dementia cases.

Age is an important risk factor, but dementia is not an inevitable consequence of ageing. Persistent cognitive changes at any age should be assessed rather than dismissed as “just getting older.”

What are the 7 stages of dementia?

One commonly used seven-stage framework is the Global Deterioration Scale (GDS). It describes a gradual progression from no noticeable impairment to very severe cognitive decline.

Stage 1: No cognitive decline

There are no obvious symptoms of dementia.

Stage 2: Very mild cognitive decline

A person may occasionally forget names, appointments or where they placed something. These changes can also occur with normal ageing.

Stage 3: Mild cognitive decline

Family members may begin noticing changes. The person may have difficulty concentrating, planning, remembering appointments or finding words.

Stage 4: Moderate cognitive decline

Problems become more obvious and begin affecting everyday independence. Managing finances, travelling, planning meals or remembering recent events may become difficult.

Stage 5: Moderately severe cognitive decline

The person may need help choosing appropriate clothing, remembering important information or managing daily activities. Confusion about time and place can become more prominent.

Stage 6: Severe cognitive decline

The person may require substantial assistance with dressing, bathing, eating and toileting. Personality and behavioural changes can become more noticeable, and recognition of family members may become difficult.

Stage 7: Very severe cognitive decline

Communication and mobility become severely affected. The person may eventually be unable to walk, sit upright, speak clearly or perform basic activities independently and may require around-the-clock care.

These stages are a framework rather than a timetable. Dementia does not progress at exactly the same speed in every person.

What are the last stages of dementia?

Late-stage dementia can involve profound dependence on caregivers. A person may have very limited speech, difficulty recognising people, problems swallowing, loss of bladder or bowel control and major difficulties with movement.

Some people become unable to walk or sit upright without assistance and spend much of their time in bed or a chair. Eating and drinking can also become increasingly difficult.

The infographic accompanying this article highlights several changes families may encounter in late-stage dementia, including loss of facial expression, inability to speak, difficulty walking or sitting independently and the need for extensive assistance with everyday activities.

At this point, care generally focuses heavily on comfort, dignity, safety, nutrition and hydration, prevention of complications and support for caregivers.

Can dementia be cured?

For most progressive forms of dementia, there is currently no cure. However, this does not mean there is nothing doctors can do.

Treatment can include medicines for specific types of dementia, management of cardiovascular risk factors, treatment of depression or anxiety where appropriate, physical activity, cognitive stimulation, rehabilitation, social engagement and caregiver support.

Some conditions that produce dementia-like symptoms can improve substantially when the underlying problem is treated. This is one reason why obtaining a proper medical assessment is so important.

For Alzheimer’s disease, newer disease-modifying treatments may be appropriate for some people with early disease, depending on their diagnosis, eligibility and medical circumstances.

How do I check for dementia?

There is no single test that can diagnose every case of dementia.

A doctor will usually begin with a detailed medical history and discussion of symptoms. A family member or caregiver may be asked what changes they have noticed because the person experiencing cognitive decline may not always recognise the extent of the problem.

Assessment may include:

• Memory and cognitive tests
• Evaluation of attention, language and reasoning
• Neurological examination
• Review of medications
• Blood tests, including tests for potentially reversible causes
• Brain imaging such as CT or MRI when appropriate
• Assessment of mood and mental health
• More specialised tests or biomarkers when clinically indicated

MRI or CT may help identify strokes, bleeding, tumours or other structural problems. Blood tests can help identify conditions such as vitamin B12 deficiency or thyroid disorders.

If you notice a persistent change in memory or behaviour, do not rely on an online dementia test alone. A medical assessment is more useful because it can investigate why the changes are happening.

What is the red flag for dementia?

One of the biggest red flags is a persistent decline in cognitive ability that interferes with normal daily activities.

For example, occasional forgetfulness is different from repeatedly forgetting important information, getting lost in familiar places, being unable to manage familiar finances or struggling to perform a task that was previously routine.

Another red flag is when other people notice a clear change in the person’s functioning or personality.

Sudden confusion, however, is different. If confusion develops suddenly over hours or days, it may represent delirium caused by an infection, medication problem, dehydration or another urgent medical condition and should receive prompt medical attention.

What is the 90-second rule for dementia patients?

You may see references online to a “90-second rule” for dementia, usually suggesting that caregivers should pause, remain calm or allow time for emotions and communication to settle.

However, there is no universally accepted medical “90-second rule” for dementia diagnosis or treatment. It should not be treated as a formal clinical protocol.

A much more useful principle is to give the person time to process what you have said. Speak calmly, use short sentences, avoid rushing them and allow pauses before repeating yourself. Communication guidance for dementia specifically recommends allowing extra processing time and avoiding too much information at once.

What are 7 things I should avoid saying to someone with dementia?

Communication can make a major difference to a person’s comfort and dignity. Try to avoid:

1. “Don’t you remember?”
   This can make the person feel tested or embarrassed.
2. “Do you recognise me?”
   If they cannot remember you, the question can increase anxiety or guilt.
3. “I already told you that.”
   Repetition is often a symptom of dementia. The person may genuinely feel they are asking for the first time.
4. “What did you do this morning?”
   Open-ended memory questions can be difficult. Offer conversation rather than testing recall.
5. “Your mother/father/spouse died years ago.”
   Depending on the person’s condition, repeatedly hearing this can feel like receiving devastating news for the first time.
6. “You need to listen to me.”
   A confrontational approach can increase distress. Try calm, simple communication instead.
7. Talking to them like a child.
   Avoid patronising language, exaggerated voices or unnecessary “elderspeak.”

The Alzheimer’s Society recommends avoiding communication that makes a person feel tested, corrected, rushed or infantilised. Short, simple sentences and calm body language are generally more helpful.

How long can a person with dementia live at home?

There is no fixed answer.

Some people with early dementia can live independently or with limited support for years. Others require substantial assistance relatively early, depending on the type and severity of dementia, physical health, safety concerns and available family or professional support.

Living at home may remain appropriate when the environment is safe and the person’s needs can be reliably met. As dementia progresses, families may need to introduce home caregivers, supervision, mobility assistance, medication support or eventually residential or nursing care.

The goal should not simply be to keep someone at home for as long as possible. The goal is to provide safe, appropriate and dignified care.

What is the typical life expectancy with dementia?

Life expectancy varies considerably.

It depends on the type of dementia, age at diagnosis, stage of disease, general health and other medical conditions. Dementia can shorten life expectancy, but there is no single number that applies to everyone.

For example, some people live many years following diagnosis, while others experience faster progression. In advanced dementia, complications such as infections, swallowing difficulties, dehydration, malnutrition and reduced mobility can become serious.

Doctors can provide a more meaningful prognosis after considering the individual’s overall health rather than relying on an average figure.

Is dementia hereditary?

Sometimes, but most dementia is not directly inherited in a simple way.

Having a parent or sibling with dementia can increase your risk, but it does not mean you will definitely develop dementia. Family history can reflect a combination of genes, shared lifestyle factors and environmental influences.

A small proportion of Alzheimer’s disease is caused by specific genetic mutations that can be inherited and strongly increase the likelihood of developing the disease. These inherited forms are uncommon.

If several close relatives developed dementia at unusually young ages, discussing the family history with a doctor or genetic counsellor may be appropriate.

How to prevent dementia?

Not every case of dementia can be prevented. However, evidence suggests that addressing several modifiable risk factors can reduce the risk of cognitive decline and dementia.

Helpful steps include:

• Exercise regularly
• Do not smoke
• Avoid harmful alcohol consumption
• Maintain a healthy weight
• Keep blood pressure under control
• Manage diabetes and blood sugar
• Monitor cholesterol
• Eat a balanced, nutritious diet
• Stay socially connected
• Keep the brain mentally active
• Address hearing loss
• Get adequate sleep
• Protect the head from injury
• Manage cardiovascular health
• Reduce exposure to air pollution where possible

WHO identifies physical inactivity, smoking, harmful alcohol use, social isolation, high blood pressure, high blood sugar, obesity, hearing and vision problems and other factors as contributors to dementia risk.

Prevention is best viewed as a lifelong approach to brain and cardiovascular health, rather than a single exercise, supplement or “brain booster.”

When should you see a doctor?

Speak to a healthcare professional if you notice persistent or worsening changes in:

• Memory
• Communication
• Personality
• Judgment
• Concentration
• Ability to manage money
• Ability to perform familiar activities
• Navigation or orientation
• Mood or behaviour

It is particularly important to seek assessment when these changes interfere with independence or everyday safety.

Early evaluation can identify potentially treatable causes, establish a baseline of cognitive function and help families understand what may be happening.

Final thoughts

Dementia affects far more than memory. It can gradually change how a person communicates, behaves, moves and manages everyday life. At the same time, every person’s experience is different.

The most important message for families is not to dismiss significant cognitive changes as normal ageing. Early assessment can help determine whether the symptoms are caused by dementia, another neurological condition or a potentially reversible medical problem.

Although many forms of dementia cannot currently be cured, appropriate treatment, rehabilitation, lifestyle changes and compassionate care can make a meaningful difference to quality of life.

For families caring for someone with dementia, patience matters just as much as medical treatment. The person may forget names, conversations or events, but they can still experience comfort, fear, affection, frustration and connection. Treating them with dignity remains important at every stage.

Frequently asked questions about dementia

Is dementia the same as Alzheimer’s disease?
No. Dementia is a broad term describing a decline in cognitive abilities that interferes with daily life. Alzheimer’s disease is a specific brain disease and the most common cause of dementia.

What is usually the first sign of dementia?
Persistent difficulty remembering recent information is common, but early dementia can also present with problems in language, planning, judgment, orientation or behaviour.

Can dementia start before 65?
Yes. Dementia can occur before 65, although it is much less common than dementia developing later in life.

Can dementia be reversed?
Some dementia-like symptoms caused by conditions such as vitamin deficiencies, thyroid disorders, medication effects or certain other medical problems may improve when the underlying cause is treated. Most progressive neurodegenerative dementias cannot currently be reversed.

What happens in late-stage dementia?
A person may become completely dependent on others for personal care, have very limited communication, experience difficulty swallowing and develop major problems with movement. Some people become bedbound and require around-the-clock care.

Does everyone with dementia eventually become unable to speak?
Not necessarily. The pattern and severity of communication problems vary according to the type and stage of dementia. In very advanced disease, however, communication can become extremely limited.

Can lifestyle changes prevent dementia?
They cannot guarantee prevention, but physical activity, not smoking, healthy eating, cardiovascular risk management, social engagement, cognitive activity and addressing hearing loss can help reduce risk.

Does having a family member with dementia mean I will get it?
No. Family history can increase risk, but most dementia is not inherited in a simple predictable way. A small proportion of Alzheimer’s disease is caused by strongly inherited genetic mutations.

Is there a test for dementia?
There is no single test for all dementia. Doctors may combine cognitive assessment, medical history, neurological examination, blood tests, brain imaging and, when appropriate, specialised biomarker testing.

How long can someone live with dementia?
It varies greatly. Age, type of dementia, stage at diagnosis, general health and other medical conditions all influence survival.

What should I do if an elderly family member is becoming forgetful?
Don’t assume it is simply normal ageing. Keep track of the changes, speak with the person’s doctor and consider a structured cognitive and medical assessment.

To consult a Neurologist at Sparsh Diagnostic Centre for treatment of Dementia, call our helpline number 9830117733.

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Disclaimer:

No content on this site, regardless of date, should ever be used as a substitute for direct medical advice from your doctor or other qualified clinician.

Sources: World Health Organization (WHO); Mayo Clinic; Cleveland Clinic; Alzheimer’s Association.

Information reviewed for accuracy against current medical guidance and educational resources. This article is intended for general educational purposes and does not replace consultation with a qualified healthcare professional.