What Is Alzheimer’s Disease?

According to the Alzheimer's Association, Alzheimer's is one of the most common causes of dementia. It accounts for 60-80% of dementia cases. Dementia is a medical condition which affects the brain cells leading to loss of memory. So, Alzheimer's patients lose their memory. 

Alzheimer's disease is named after Dr. Alois Alzheimer.¹ In 1906, he had a patient suffering from mental illness who had symptoms of memory loss and language issues with uncontrollable behaviour. Unfortunately, she did not survive. After her death, he examined her brain and found some abnormal clumps which are termed as amyloid plaques and tangled bundles of fibres which are termed as neurofibrillary or tau or tangles. These tangles and plaques are thought to be the cause behind this disease.


As per NHS statistics, around 850,000 people are affected by Alzheimer's in the UK. It mostly affects people above 65 years of age. As the person ages, their chances of getting affected by this disease increases.² 

This condition affects an estimated 1 in 14 people above 65 years of age and 1 in 6 people above 80 years of age.But, sometimes it affects people below 65 years of age. 1 in 20 people below 65 years are affected with early-onset Alzheimer's or young-onset Alzheimer's disease.

People assigned female at birth (AFAB) are more prone to this disease compared to people assigned male at birth (AMAB). This risk increases with age. 

Mild cognitive impairment (MCI) is the first sign of Alzheimer's. But, not every case of MCI turns into Alzheimer's.

Causes of alzheimer’s disease 

Plaques and tangles are identified as the most common causes of Alzheimer's. Plaques are caused due to build-up of protein fragments beta-amyloid in the nerve cells. Tangles are caused due to build-up of another protein called tau in the nerve cells. Scientists are still not able to detect the exact way in which these cause Alzheimer's. But, they guess that the build-up causes loss of transmission between the nerve cells. 

Nerve cells or neurons help in transmitting messages from the brain to the organs in the body and between different parts of the brain. Alzheimer's causes the loss of this ability of neurons. 

The changes start in the entorhinal cortex and hippocampus which deal with memory. Gradually, it starts affecting the cerebral cortex which is responsible for language, reasoning and behaviour.

Signs and symptoms of alzheimer’s disease 

Alzheimer's progresses and becomes more severe with age. Apart from dementia, there are various signs and symptoms related to this disorder including:²,³

Memory loss: Memory loss is the first and most prominent sign. It starts with forgetting minor things such as names or things to do. Slowly it progresses and becomes severe. Patients will start forgetting their family members, ability to read, write or drive. 

Reasoning: This disease makes it difficult to think and perform any task. Even paying bills while grocery shopping might seem a difficult task. 

Decision making: Due to this condition, decision making capacity of the individual is compromised. Normal everyday functions like cooking, driving or even dressing as per the weather can be a big task. As the condition worsens, individuals might even forget bathing or dressing.

Behavioural changes: Changes in the nerve cells can even change the behaviour, mood and personality of the affected individual. They might start experiencing depression, mood swings, hallucinations or delusions, anger, loss of trust, changes in sleeping habits or social withdrawal.

Preserved skills: As already discussed, dementia is the initial sign of this disease. Even though the individual struggles with normal daily tasks, they can still read or listen to stories, do crafts like music, dance or colouring. This is because the part of the brain which controls these activities is affected in later stages.

Management and treatment for alzheimer’s disease 

Alzheimer's is a slowly progressing disorder of the brain. Often people feel that losing some memory is a normal part of the ageing process. So, they do not think that there might be something more serious happening inside the brain. 

Alzheimer's disease is divided into four stages - preclinical, mild (early), moderate (middle) and severe (late). Let's discuss the stages, diagnosis and treatment for this disorder.⁵

Preclinical stage: This stage can last for years. In this stage, there might not be any symptoms but there might be changes in the brain.

Mild stage: Most common symptom of this stage might be memory loss. It might seem like usual memory loss due to age. The affected person might forget names or some events. The person is able to live independently at this stage.

Moderate stage: This is the longest stage that lasts up to several years. In this stage, individuals might experience trouble with reading, writing or numbers. They might lose track of places, time or have difficulty getting dressed.

Severe stage: At this stage, the individual might lose the ability to complete basic physical activities such as walking or sitting. They might need help in everyday tasks. They lose bladder and bowel control, not able to assess their surroundings and are prone to infections.

Diagnosis of alzheimer's disease 

If there are any concerns or doubts about mental health, it is better to contact the GP.²,⁴ There is no specific test for it.Instead, the doctor might ask for symptoms and do some tests to rule out infections, deficiency or depression. Some tests might be performed to check the mental abilities. 

GP might refer to a geriatrician, a doctor who specialises in treatment of old people or neurologist, a doctor who specialises in brain disorders or an adult psychiatrist, a doctor who specialises in mental health of older adults. 

Generally the symptoms worsen over time. So, a family member might be able to recognise the symptoms. Pen and paper test is conducted where the patients are asked to answer some questions on paper. After a few minutes, they might be asked to recall those same things and the specialist will assess the answers as the patient forgets things in a matter of a few minutes. 

Magnetic resonance imaging (MRI) or computed tomography (CT) can be performed to assess the change in the brain cells. 

Treatment of alzheimer's disease 

Unfortunately, there is no cure for this condition. Medications or therapies are available to relieve the symptoms. Cognitive stimulation therapy can be provided to support memory, language or problem solving skills. 

Psychiatrist, clinical psychologist, GP, occupational therapist and dementia advisers are the professionals who help the patients and their families. 

Early stage Alzheimer's patients are given drugs to reduce anxiety, help with memory troubles, improve concentration in daily tasks and slow down the progression of the disease. 

Late stage patients are given different medications to help with mental abilities or behavioural changes. 

Adopting healthy lifestyle habits, avoiding smoking and drinking can prevent the onset of this disease.


How is Alzheimer’s disease diagnosed? 

Alzheimer's disease can be diagnosed by routine tests to rule out other diseases, infection or deficiency. Pen and paper test is done in two phases. Patients are asked to answer some questions and after a few minutes, they might be asked to repeat. This might help to assess dementia. MRI or CT scans can also be used to determine the damage to brain cells.

How can I prevent Alzheimer's disease? 

Adapting healthy lifestyle habits are good for the mind as well as the body. Regular exercise, avoiding smoking or drinking and consuming a nutritious diet can help prevent Alzheimer's disease.

Who is at risk of Alzheimer’s disease? 

Alzheimer's disease mostly affects people above the age of 65 years. People AFAB are more prone to this disorder than people AMAB. Chances of getting affected by this disorder increases as the person ages.

How common is Alzheimer’s disease? 

Alzheimer's accounts for 60-80% of all the dementia cases. There are almost 850,000 cases in the UK.

When should I see a doctor? 

If there are symptoms of dementia or memory loss, concentration troubles and decision making issues, then it is better to consult a healthcare professional. 


Alzheimer's is a disorder of the brain cells. It mostly affects the population above the age of 65 years. People AFAB are more prone than people AMAB to get affected by this disorder. 

This disease happens due to build up of beta-amyloid protein leading to plaque and build up of tau protein leading to tangles in the brain cells. 

It has four stages - preclinical, mild (early), moderate (middle) and severe (late). 

In the preclinical stage, there might be changes in the brain cells but no symptoms. So, unless a patient is getting a scan there are chances it is not diagnosed.

Initial symptom of this disorder is loss of memory. So, often people get confused that this is normal due to the ageing process. In the mild stage, patients can still live independently with some support. 

Moderate stage patients might see symptoms such as difficulty in reading, writing or keeping track of numbers. 

During the severe stage, patients may lose the ability to walk, sit, bladder and bowel control. These patients might need supervision at all times as they will need support to complete their daily tasks.

There is no single test for diagnosis. MRI or CT scans might be able to diagnose the disease. Apart from that, dementia advisers, psychologists or psychiatrists might assess the symptoms and give a diagnosis. 

Unfortunately, there is no cure for this disorder. There are some medications and therapies to help the patients to relieve the symptoms of cognitive decline. 

If you or anyone in your family is showing signs of Alzheimer's, contact your GP. There is a lot of support available.


  1.  What is alzheimer’s disease? [Internet]. National Institute on Aging. [cited 2023 Feb 3]. Available from: https://www.nia.nih.gov/health/what-alzheimers-disease
  2. Alzheimer’s disease [Internet]. nhs.uk. 2018 [cited 2023 Feb 4]. Available from: https://www.nhs.uk/conditions/alzheimers-disease/
  3. Alzheimer’s disease - Symptoms and causes [Internet]. Mayo Clinic. [cited 2023 Feb 4]. Available from: https://www.mayoclinic.org/diseases-conditions/alzheimers-disease/symptoms-causes/syc-20350447
  4. Diagnosing Alzheimer’s disease | Alzheimer’s Society [Internet]. [cited 2023 Feb 4]. Available from: https://www.alzheimers.org.uk/about-dementia/types-dementia/diagnosing-alzheimers-disease
  5. Stages of alzheimer’s disease [Internet]. 2021 [cited 2023 Feb 4]. Available from: https://www.hopkinsmedicine.org/health/conditions-and-diseases/alzheimers-disease/stages-of-alzheimer-disease
This content is purely informational and isn’t medical guidance. It shouldn’t replace professional medical counsel. Always consult your physician regarding treatment risks and benefits. See our editorial standards for more details.

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Simmi Anand

B.Sc. Nuclear Medicine, Manipal University
MBA Healthcare Services, Sikkim Manipal University

An experienced Nuclear Medicine professional with a passion for writing.

She is experienced in dealing with patients suffering from different ailments, mostly cancer.

Simmi took a career break to raise her daughter with undivided attention.

During this time, she fine-tuned her writing skills and started writing stories for her child. Today, Simmi is a published author of 'Story time with proverbs' series for young ones. She also enjoys writing parenting blogs on her website www.simmianand.com.

Simmi hopes to reignite her career as a medical writer, combining her medical knowledge with her zeal for writing to produce informative health articles for her readers.

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