What is dementia?

Dementia occurs as a result of a disease process that increasingly damages the brain over time. Signs and symptoms of dementia result when once-healthy neurons (nerve cells) in the brain stop working, lose connections with other brain cells, and die. While everyone loses some neurons as they age, people with dementia experience far greater loss.

Dementia is a syndrome (usually of a chronic or progressive nature) in which there is deterioration of cognitive functioning (thinking, remembering, and reasoning) and behavioral abilities. This loss is to such an extent that it interferes with a person's daily life and activities. These functions include memory, language skills, visual perception, problem solving, self-management, and the ability to focus and pay attention. The impairment in cognitive function is commonly accompanied, and occasionally preceded, by deterioration in social behaviour, motivation or emotional control, and their personalities may change. These difficulties occur because nerve cells (neurons) in parts of the brain involved in cognitive function have been damaged or destroyed.. Consciousness is not affected.

While dementia is more common as people grow older (up to half of all people age 85 or older may have some form of dementia), it is not a normal part of aging. Many people live into their 90s and beyond without any signs of dementia.

Dementia Stats- Worldwide & India

Dementia occurs as a result of a disease process that increasingly damages the brain over time. Signs and symptoms of dementia result when once-healthy neurons (nerve cells) in the brain stop working, lose connections with other brain cells, and die. While everyone loses some neurons as they age, people with dementia experience far greater loss.


Dementia affects all groups of society and is not linked to social class, gender, ethnic group, or geographic location. Worldwide, around 55 million people have dementia, and there are nearly 10 million new cases every year, implying 1 new case every 3.2 seconds.

The total number of people with dementia is expected to increase to 78 million by 2030 and 139 million by 2050.

Dementia is one of the major causes of disability and dependency among older people worldwide. The World Health Organization (WHO) infographic given below, includes information about the symptoms of dementia, the cause, the number of people affected and the cost.


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As per Census of India 2011, the population of 60 years and above is 104 million (8.6% of the total population); amongst them, the population of 80 years and above is 11 million in India.

As per the Dementia India Strategy Report, an estimated 4.4 million people are living with dementia as of 2015. This number is projected to double by 2030 to 7.6 million and 14.3 million by 2050.

Types of dementia

Dementia is caused by a number of diseases which destroy nerve cells and damage the brain. Various disorders and factors contribute to the development of dementia. Neurodegenerative disorders result in a progressive and irreversible loss of neurons and brain functioning.


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Alzheimer’s Disease

Alzheimer’s disease is a degenerative brain disease. It destroys brain cells and nerves, disrupting the transmitters that carry messages in the brain, particularly those responsible for storing memories. In Alzheimer’s disease, neurons in other parts of the brain are eventually damaged or destroyed as well, including those that enable a person to carry out basic bodily functions such as walking and swallowing. People in the final stages of the disease are bed-bound and require around-the-clock care. Alzheimer’s disease is ultimately fatal. Alzheimer disease is the most common form of dementia and may contribute to 60–70% of cases.


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Vascular dementia

Vascular dementia occurs where blood vessels are damaged, the supply of oxygen to the brain fails and as a result, brain cells die. This cause significant changes to memory, thinking, and behavior. The symptoms of vascular dementia can occur either suddenly, following a stroke, or over time, through a series of small strokes. As per WHO, Vascular dementia accounts for 20%-30% of all cases of dementia.


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Dementia with lewy bodies

Dementia with Lewy bodies is similar to Alzheimer’s disease in that it is caused by deteriorating and dying nerve cells in the brain. Lewy body dementia is a disease associated with abnormal deposits of a protein called alpha-synuclein in the brain. These deposits, called Lewy bodies, affect chemicals in the brain whose changes, in turn, can lead to problems with thinking, movement, behavior, and mood. As per WHO, it may account for around 10% of all cases of dementia. Approximately, half the people with Lewy body disease also develop signs and symptoms of Parkinson’s disease.


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Fronto-temporal dementia

In fronto-temporal dementia (including Pick’s disease), damage is usually concentrated in the front part of the brain. Frontotemporal disorders are the result of damage to neurons (nerve cells) in parts of the brain called the frontal and temporal lobes. As neurons die in the frontal and temporal regions, these lobes atrophy, or shrink. Gradually, this damage causes difficulties in thinking and behaviors normally controlled by these parts of the brain. In the beginning, personality and behaviour are more affected than memory. Many possible symptoms can result, including unusual behaviors, emotional problems, trouble communicating, difficulty with work, or difficulty with walking.


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Mixed dementia

Mixed dementia is a combination of two or more types of dementia. It is common for people with dementia to have mixed dementia. A number of combinations are possible. For example, some people have both Alzheimer's disease and vascular dementia. Researchers are trying to better understand how underlying disease processes in mixed dementia influence each other.

The National Institute on Ageing; which is a Division of the U.S. National Institutes of Health

( ), states that other conditions have identified that can cause dementia or dementia-like symptoms. These conditions include:

  • Argyrophilic grain disease, a common, late-onset degenerative disease
  • Creutzfeldt-Jakob disease, a rare brain disorder
  • Huntington's disease, an inherited, progressive brain disease
  • Chronic traumatic encephalopathy (CTE), caused by repeated traumatic brain injury
  • HIV-associated dementia (HAD)

Other conditions that cause dementia-like symptoms can be halted or even reversed with treatment. For example, normal pressure hydrocephalus, an abnormal buildup of cerebrospinal fluid in the brain, often resolves with treatment.

What are the stages & symptoms of dementia?

The rate of progression of dementia varies between people. The symptoms of dementia tend to get worse over time. Genetics, age, and overall health, as well as the underlying cause of the dementia might play a role in how fast the disease progresses.

Dementia has distinct stages that shape treatment and impact on health in different ways. The stages may often overlap. Symptoms may appear at certain stages, then resolve, while other health effects progressively get worse.

Dementia affects each person in a different way, depending upon the impact of the disease and the person’s personality before becoming ill.

As per the World Health Organization, the signs and symptoms linked to dementia can be understood in three stages:

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Mild Stages

The early stage of dementia is often overlooked, because the onset is gradual. Common symptoms include:

  • Forgetfulness
  • Losing track of time
  • Becoming lost in familiar places
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Moderate Stages

As dementia progresses to the middle stage, the signs and symptoms become clearer and more restricting. These include:

  • Becoming forgetful of recent events and people's names
  • Becoming lost at home
  • Having increasing difficulty with communication
  • Needing help with personal care
  • Experiencing behaviour changes, including wandering and repeated questioning
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Severe Stages

The late stage of dementia is one of near total dependence and inactivity. Memory disturbances are serious and the physical signs and symptoms become more obvious. Symptoms include:

  • Becoming unaware of the time and place
  • Having difficulty recognizing relatives and friends
  • Having an increasing need for assisted self-care
  • Having difficulty walking
  • Experiencing behaviour changes that may escalate and include aggression

How is dementia diagnosed?

There is no single test for diagnosing dementia. Instead, physicians, often with the help of specialists such as neurologists and geriatricians, use a variety of approaches and tools to help make a diagnosis.

To diagnose dementia, doctors first assess whether a person has an underlying treatable condition such as abnormal thyroid function, normal pressure hydrocephalus, or a vitamin deficiency that may relate to cognitive difficulties. Early detection of symptoms is important, as some causes can be treated. In many cases, the specific type of dementia a person has may not be confirmed until after the person has died and the brain is examined.

The National Institute on Ageing; which is a Division of the U.S. National Institutes of Health (, states that a medical assessment for dementia generally includes:


Medical history

Typical questions about a person's medical and family history might include asking about whether dementia runs in the family, how and when symptoms began, changes in behavior and personality, and if the person is taking certain medications that might cause or worsen symptoms.


Physical examination

Measuring blood pressure and other vital signs may help physicians detect conditions that might cause or occur with dementia. Some conditions may be treatable.


Neurological tests

Assessing balance, sensory response, reflexes, and other cognitive functions helps identify conditions that may affect the diagnosis or are treatable with drugs.

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Other procedures are also used to diagnose dementia. These are:

Diagnosing dementia requires a careful and comprehensive medical evaluation. Although physicians can almost always determine if a person has dementia, it may be difficult to identify the exact cause. Several days or weeks may be needed for the individual to complete the required tests and examinations and for the physician to interpret the results and make a diagnosis.

How is dementia diagnosed?

People with dementia and their carers and families are often stigmatized. Stigma linked to dementia is due to lack of awareness and understanding about the disease, leading to fear. The stigma associated with dementia is a major concern for people with dementia, and specially for their carers and families. Stigma is one of the most important factors that leads to delay and avoidance of diagnosis and care.

Dementia is a demanding condition. It can be overwhelming, not only for the people who have it, but also for their carers and families. The impact of dementia on carers, family can be physical, psychological, social and economic. The society should not judge those who seek professional care for their parents with dementia. Stigma should not be attached to persons with dementia, and their families. Managing dementia at home for the family eventually tends to become very challenging. Providing professional care for someone with dementia is imperative. Children are not seeking assisted living for their parents because they are shrugging their responsibilities, but because they are being more sensitive and seeking highest quality of life for their elderly parents. A specialized dementia care assisted living home is the right place for the persons with dementia (PwD), when required.

Global Action Plan On The Public Health Response To Dementia 2017-2025

The Global action plan on the public health response to dementia 2017-2025 was adopted by World Health Organization (WHO) Member States at the 70th World Health Assembly in May 2017. It aims to improve the lives of people with dementia, their carers and families, while decreasing the impact of dementia on communities and countries. It provides a set of actions to realize the vision of a world in which dementia is prevented and people with dementia and their carers receive the care and support they need to live a life with meaning and dignity. For more details:

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