What is Dementia
The term dementia describes a set of symptoms caused by disorders that affect the brain. It is not a specific disease. Dementia affects thinking, behavior, and the ability to perform everyday tasks. Brain function is significantly impaired, interfering with normal social or professional life. A hallmark of dementia is the inability to carry out daily activities due to reduced cognitive ability.
Doctors diagnose dementia when two or more cognitive functions are significantly impaired. These cognitive functions may include memory, verbal skills, comprehension, spatial awareness, judgment, and attention. People with dementia may have difficulty solving problems and controlling emotions. Personality changes may also occur. The exact symptoms depend on the brain areas affected by the disease causing dementia.
In many forms of dementia, some nerve cells in the brain stop functioning, lose connections with other cells, and die. Dementia is usually degenerative, meaning the disease gradually spreads through the brain and symptoms worsen over time.
Who Gets Dementia
Dementia can affect anyone, but the risk increases with age. Most people with dementia are elderly, but it is important to remember that most elderly people do not develop dementia. It is not a normal part of aging but caused by brain disease. Less commonly, people under 65 develop “early-onset dementia.”
Some rare hereditary forms of dementia exist, caused by specific genetic mutations. However, most cases are not related to these genes. People with a family history of dementia have a higher risk.
Certain health and lifestyle factors also play a role in dementia risk. Untreated vascular risk factors like high blood pressure increase risk. Less mentally and physically active people are also at higher risk.
What Causes Dementia?
Many different diseases cause dementia. In most cases, the cause is unknown.
The most common types of dementia include:
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Alzheimer’s Disease
The most common form, accounting for about two-thirds of cases. It causes gradual cognitive decline, often starting with memory loss. Alzheimer’s is characterized by amyloid plaques and neurofibrillary tangles in the brain. These plaques are abnormal protein masses called beta-amyloid; tangles are twisted fibers of a protein called tau. They disrupt nerve cell communication, causing cell death. -
Vascular Dementia
Caused by damage to the brain’s blood vessels. It may result from a single stroke or multiple strokes over time. Diagnosis occurs when signs of vascular disease and cognitive decline interfere with daily life. Symptoms can begin suddenly after a stroke or gradually worsen. Symptoms vary depending on brain damage location and extent, sometimes affecting specific cognitive functions. It can resemble Alzheimer’s, and mixed Alzheimer’s and vascular dementia is common. -
Lewy Body Dementia
Characterized by Lewy bodies—abnormal protein deposits (alpha-synuclein) in nerve cells. These affect brain areas controlling movement, thinking, and behavior. Symptoms include fluctuating attention and cognition, visual hallucinations, and sometimes Parkinsonism. Overlapping conditions include Parkinson’s disease dementia and dementia with Lewy bodies. -
Frontotemporal Dementia
Involves progressive damage to the frontal and/or temporal lobes. Symptoms often begin in people in their 50s or 60s, sometimes earlier. Two main types exist: behavioral (personality and behavior changes) and language (speech difficulties). People may show socially inappropriate behavior, loss of judgment, compulsiveness, aggression, or impulsivity. Variants affect semantic understanding or fluent speech. Sometimes called frontotemporal lobar degeneration or Pick’s disease.
Early Signs
Early signs can be subtle and vague, sometimes hard to notice. Common symptoms include:
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Frequent and progressive memory loss
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Confusion
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Personality changes
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Apathy and withdrawal
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Loss of ability to perform daily tasks
Might It Not Be Dementia?
Many conditions share symptoms with dementia, so don’t assume dementia solely based on some symptoms. Conditions such as strokes, depression, alcoholism, infections, hormonal disorders, nutritional deficiencies, and brain tumors can cause dementia-like symptoms and may be treatable.
Importance of Accurate Diagnosis
Seeing a doctor early is critical. Only a doctor can diagnose dementia. A full medical evaluation can identify treatable conditions or confirm dementia.
Assessment may include:
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Medical history: Questions about past and current health, family history, medications, and cognitive or behavioral concerns. Family members may provide additional information.
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Physical exam: Includes sensory, motor, heart, and lung function to exclude other causes.
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Laboratory tests: Blood and urine tests to identify other possible causes.
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Neurological/cognitive tests: Evaluate memory, language, attention, and problem-solving to identify dementia type or cause.
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Brain imaging: CT or MRI scans to exclude tumors or strokes and detect patterns of brain tissue loss characteristic of dementia types. Functional imaging assesses brain activity.
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Psychiatric evaluation: To detect treatable conditions like depression or manage psychiatric symptoms such as anxiety or hallucinations.
Where to Start
Begin with the person’s primary doctor. After reviewing symptoms and ordering tests, the doctor may give a preliminary diagnosis or refer to specialists (neurologist, geriatrician, psychiatrist).
Some people resist visiting a doctor, either unaware of problems or afraid of the diagnosis. Suggest alternative reasons for visits (e.g., routine checkups or medication reviews). A calm approach can ease fears.
If the person refuses medical evaluation, seek advice from their doctor.
If you feel your concerns aren’t taken seriously, consider a second opinion.
Further Reading
We recommend reading our article “Caring for Someone with Dementia”, which explores communication techniques and caregiver support strategies.