Diseases & Conditions


What is dementia?

Dementia is a decline in mental function, rather than a specific condition. It is an impaired mental function which affects daily life and someone with dementia will have difficulty in at least two of the following:

  • Behavior
  • Coordination
  • Language
  • Memory
  • Mood.

Dementia usually develops in older adults, and it is most common in those over the age of 85.

What causes dementia?

Dementia happens when parts of your brain are affected by certain diseases or infections. Alzheimer’s disease is the most common cause of dementia. Other causes include:

  • Dementia due to Parkinson’s disease
  • Dementia-like conditions caused by thyroid issues or medication side effects (these are reversible)
  • Dementia with Lewy bodies
  • Frontotemporal dementia
  • Mixed dementia
  • Vascular dementia.

Are there different types of dementia?

There are three main groups of dementia:

  • Primary: Conditions and diseases in which dementia is the main illness.
  • Secondary: Due to another condition or disease.
  • Reversible dementia-like symptoms: Caused by other illnesses or factors.

Primary dementia

Alzheimer’s disease: The most common type of dementia, it is caused by the build-up of abnormal proteins in the brain which disrupt the way nerve cells in the brain communicate. The nerve cells then begin to die, spreading across the brain. Symptoms include confusion, short-term memory loss, and behavior changes. As the disease progresses, people have issues with speech, remembering old memories and walking.

Vascular dementia: This is caused by conditions like stroke or atherosclerosis. They damage blood vessels in the brain and symptoms include confusion, memory problems, and a lack of concentration. Dementia can appear suddenly after a stroke.

Lewy body dementia: When proteins called Lewy bodies build up in the brain’s nerve cells, they cause damage. Symptoms include memory loss, sleep problems, movement and balance problems and visual hallucinations and delusions.

Frontotemporal dementia (FTD): Caused by damage to the temporal and frontal lobes of the brain by a buildup of proteins. It leads to changes in personality, behavior, and language skills. FTD is the most common cause of early dementia.

Mixed dementia: A combination of types of dementia, often Alzheimer’s disease and vascular dementia. It is most common is people over the age of 80.

Other causes of dementia

Huntington’s disease: A defective gene causes the brain’s nerve cells to breakdown, leading to movement control issues. It also causes memory loss, personality changes and decision-making issues.

Parkinson’s disease: People with advanced Parkinson’s disease often develop dementia. Symptoms include problems with memory, thinking, delusions, speech and depression.

Creutzfeldt-Jakob disease: A very rare infective brain disease in which abnormal proteins group together and cause nerve cells in the brain to die. Symptoms include memory, communication, and judgment problems as well as changes in behavior, confusion and depression.

Wernicke-Korsakoff syndrome: Caused by a thiamine (vitamin B1) deficiency, this disease can lead to bleeding in areas of the brain related to memory. Symptoms include difficulty in remembering things and processing new information.

Brain injury: Seen in people who have had repeated blows to the head, it can lead to dementia symptoms years later such as memory loss, behavior changes, headaches and slurred speech.

Dementia caused by reversible factors

Normal pressure hydrocephalus (NPH): If cerebrospinal fluid builds up in the brain it can cause damage. NPH is caused by infections in the brain, a brain bleed, injury or brain surgery. Symptoms include forgetfulness, poor balance, attention span, mood swings, and falls. Doctors can drain the excess fluid via an implanted tube.

Vitamin deficiency: A lack of vitamin B1, B6, B12 and E can all cause dementia-like symptoms.

Infections: HIV infection, Lyme disease and syphilis can all cause dementia-like symptoms. Urinary tract infections (UTIs) and lung infections can also cause dementia-like symptoms in elderly patients. Infections of the central nervous system or brain, from bacteria, parasites or fungi can also cause cognitive issues.

Metabolic and endocrine conditions: Some conditions, such as Cushing’s disease, Addison’s disease, low blood sugar, high calcium levels, liver cirrhosis and thyroid issues can all mimic the effects of dementia.

Medication side effects: Sleeping pills, anti-seizure drugs, anti-anxiety drugs, anti-Parkinson’s drugs, antidepressants, sedatives, statins, and narcotic pain relievers can mimic dementia symptoms in some people.

Other causes: Brain tumors and subdural hematomas can also cause dementia-like symptoms.

Are dementia and Alzheimer’s the same?

Dementia refers to mental function and is not a specific disease. Alzheimer’s disease and other conditions like Parkinson’s disease can cause dementia. Alzheimer’s is the most common cause of dementia.

What are the symptoms of dementia?

The early symptoms of dementia can include:

  • Change in mood and behavior
  • Forgetfulness around recent events
  • Misplacing items you commonly use
  • Not knowing the month/year
  • Repeating yourself in short periods
  • Struggling to find the right words.

As dementia worsens, symptoms may include:

  • Change in sleeping pattern
  • Daily tasks becoming challenging
  • Finding it harder to find the right words
  • Further memory loss
  • Hallucinations
  • Increased anxiety, confusion, sadness or depression
  • Loss of rational thinking
  • Reduced ability to make decisions.

What causes dementia?

Dementia is caused by damage to the brain. The brain’s nerve cells are affected and stop it from being able to communicate with its different areas. Dementia can also be caused by a blocked flow of blood to your brain. If oxygen doesn’t reach the brain, its tissues quickly die.

The symptoms of damage to the brain will vary depending on which part of the brain has been affected. Some dementias cannot be reversed while other health issues can cause dementia-like symptoms. These conditions can be treated sometimes, and the dementia symptoms are reversible.

How is dementia diagnosed?

Diagnosing dementia can be difficult as many conditions can cause dementia.

Doctors will first discuss symptoms and your medical history with you in detail, and then review any medication you may be taking. They will ask about any family history of dementia and other diseases.

Tests may be performed to confirm a diagnosis, including:

Laboratory tests: These are used to rule out other conditions that may be causing dementia-like symptoms.

Imaging tests: Computed tomography (CT) and magnetic resonance imaging (MRI) can show if there has been a bleed on the brain, if there is fluid, a tumor or if a stroke has occurred. An FDG-PET scan can show brain function and cognitive decline by looking at glucose absorption in brain tissue.

Neurocognitive testing: Doctors use a number of tests to assess mental ability, such as problem solving, memory and language tests.

Psychiatric evaluation: Professionals will look for changes in mood or signs of mental health issues which may lead to memory loss.

Can dementia be treated?

Most types of dementia can be treated to some degree with medication or by managing the symptoms in other ways. Dementia, which is caused by treatable illnesses, can be reversed. However, dementia cannot be cured or reversed in most cases.

Can dementia be prevented?

Dementia cannot be prevented, but adopting a healthier lifestyle may reduce certain risk factors for developing certain forms of dementia. This includes:

  • Eating a healthy diet to keep cholesterol levels low
  • Engage your brain as often as possible with activities, puzzles and games
  • Exercise daily
  • Keep blood pressure within a healthy range
  • Maintain a healthy weight
  • Not smoking
  • Stay as socially active as possible.

What are the risk factors for dementia?

Risk factors for dementia:

  • Age: The risk of dementia increases as you age.
  • Brain injury: A previous brain injury increases your risk.
  • Downs syndrome: Increases the risk of early-onset Alzheimer’s disease.
  • Family history: Including parents or siblings with dementia.
  • Poor heart health: High cholesterol, high blood pressure, and atherosclerosis increase dementia risk.

If you or a loved one notice a change in your mental function, memory, behavior, personality or ability to perform everyday tasks, talk to a doctor.

© Copyright 2017 Cleveland Clinic Abu Dhabi. All rights reserved.

This information is provided by Cleveland Clinic Abu Dhabi, part of Mubadala Healthcare, and is not intended to replace the medical advice of your doctor or health care provider. Please consult your health care provider for advice about a specific medical condition.

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