Alzheimer's disease - Symptoms & Causes

What is Alzheimer's disease?

Alzheimer's disease is a progressive neurodegenerative brain disorder that causes dementia, with symptoms such as memory loss, cognitive decline, and behavioural changes. It is the most common cause of dementia, particularly in older adults.

The condition occurs due to damage to brain cells, associated with the build-up of abnormal proteins such as amyloid-β (Aβ) plaques and neurofibrillary tangles, which interfere with normal brain function and causes brain cell damage.

Alzheimer's disease at a glance

• It is the most common form of dementia, accounting for 60 – 80% of dementia cases worldwide
• Progressive and currently incurable
• Early symptom: short-term memory loss
• Main risk factor: increasing age (above 65)
• Affects thinking, behaviour, and daily function
• Requires long-term medical and caregiver support

What are the types of Alzheimer's disease?

Early-onset Alzheimer's disease

• Occurs before age 65
• Less common
• More likely linked to genetic mutations

Late-onset Alzheimer's disease

• Occurs after age 65
• Most common form
• Associated with age, genetics, and lifestyle factors

Alzheimer's disease vs dementia: What's the difference?

Dementia is an umbrella term for conditions that cause cognitive decline.

Alzheimer's disease is a specific type of dementia and is the most common form of it. While not all dementia is Alzheimer's disease, every case of Alzheimer's disease is classified as dementia.

What are the symptoms of Alzheimer's disease?

Early stage

• Memory loss (especially recent events)
• Word-finding difficulty
• Misplacing items
• Reduced ability to plan or organise

Middle stage

• Confusion about time and place
• Difficulty recognising familiar people
• Personality and mood changes (e.g. irritability, anxiety)
• Difficulty performing daily tasks

Late stage

• Severe memory loss
• Loss of communication ability
• Difficulty swallowing and walking
• Complete dependence on caregivers

When to seek medical attention?

Seek medical evaluation if you notice:

• Persistent or worsening memory loss
• Difficulty performing familiar tasks
• Confusion about time, place, or people
• Changes in personality, mood, or behaviour

Early diagnosis allows for better symptom management, care planning, and support.

When to visit an urgent care centre?

Visit an urgent care centre immediately if a person with Alzheimer's disease develops:

• Sudden confusion or rapid mental decline (possible delirium or infection)
• New weakness, speech difficulty, or facial drooping (possible stroke)
• Falls or head injury
• Fever or signs of infection
• Severe agitation or unsafe behaviour

These may indicate serious, potentially reversible conditions requiring urgent treatment.

What causes Alzheimer's disease?

The exact cause is not fully understood, but it is linked to:

• Age: The strongest risk factor
• Genetics: Family history and inherited gene mutations
• Gender: Females have a higher risk
• Brain changes: Build-up of amyloid plaques and tau tangles
• Cardiovascular health: High blood pressure, diabetes, and cholesterol
• Lifestyle factors: Physical inactivity, smoking, and poor diet

What are the complications of Alzheimer's disease?

As the disease progresses, complications may include:

• Loss of independence
• Malnutrition and dehydration
• Increased risk of infections (e.g. pneumonia, urinary tract infections)
• Falls and injuries
• Behavioural and psychological symptoms (agitation, depression)
• Difficulty swallowing (risk of aspiration)

How do you prevent Alzheimer's disease?

While Alzheimer's disease cannot be completely prevented, its risk may be reduced by:

• Maintaining good cardiovascular health
• Regular physical activity
• Eating a balanced, brain-healthy diet
• Staying mentally active (reading, learning new skills)
• Staying socially engaged
• Avoiding smoking and limiting alcohol
• Good quality sleep

Frequently asked questions

Is Alzheimer's disease hereditary?

Most cases are not directly inherited. However, having a family history may increase risk, particularly in early-onset Alzheimer's disease.

How fast does Alzheimer's disease progress?

Progression varies, but the disease typically worsens gradually over several years.

What is the difference between Alzheimer's disease and normal ageing?

Normal ageing may involve mild forgetfulness due to age-related memory loss, while Alzheimer's disease causes significant progressive memory loss that interferes with daily life.