Are there different types of dementia?

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Are there different types of dementia?

Dementias can be divided into three groups:

  • Primary (diseases and conditions in which dementia is the main illness).
  • Secondary (dementia due to another disease or condition).
  • Reversible dementia-like symptoms caused by other illnesses or causes.

Primary dementia

Types of primary dementia include:

  • Alzheimer’s disease: This is the most common type of dementia. Two abnormal proteins build up in your brain: tau and amyloid proteins. These proteins disrupt communication between nerve cells in your brain. Nerve cells die, starting in one area and spreading as more nerve cells die in other areas. Symptoms include short-term memory loss, confusion, personality and behavior changes. Trouble talking, remembering distant memories and issues with walking happen later in the disease. Alzheimer’s disease mainly affects adults who are older — up to 10% of those over age 65 and about 50% of people older than 85 have the disease. Family history is an important risk factor. Approximately 60% to 80% of people with dementia have this type.
  • Vascular dementia: This is the second most common type of dementia. It’s caused by conditions such as strokes or atherosclerosis, which block and damage blood vessels in your brain. Symptoms include memory problems, confusion and trouble concentrating and completing tasks. The decline may appear suddenly (following a major stroke) or in steps (following a series of mini strokes). Risk factors include high blood pressure, diabetes and high cholesterol levels. About 15% to 25% of people with dementia have vascular dementia.
  • Lewy body dementia: This condition involves the buildup of clumps of proteins — called Lewy bodies — in your brain’s nerve cells. Lewy bodies damage nerve cells. Symptoms include movement and balance problems, changes in sleep patterns, memory loss, planning and problem-solving difficulties, and visual hallucinations and delusions. About 5% to 10% of dementias are Lewy Body dementia.
  • Frontotemporal dementia (FTD): This dementia results from damage to the frontal and temporal lobes of your brain. The damage is caused by the buildup of abnormal proteins in these areas. It causes changes in social behavior, personality, and/or loss of language skills (speaking, understanding or forgetting the meaning of common words) or motor coordination. FTD is a common cause of early dementia, often occurring in people between the ages of 45 and 64. Between 5% and 6% of all dementias are FTD.
  • Mixed dementia: This is a combination of two or more types of dementia. The most common combination is Alzheimer’s disease with vascular dementia. It’s most common in people 80 years of age and over. It’s often hard to diagnose because symptoms of one dementia may be more obvious and/or many symptoms of each type overlap. The decline is faster in people who have mixed dementia compared with those who only have one type.

Dementia due to other diseases and conditions

Other causes of dementia include:

  • Huntington’s disease: A single defective gene causes this brain disorder. The disease causes a breakdown in your brain’s nerve cells, which causes body movement control problems, as well as thinking, decision-making and memory trouble, and personality changes.
  • Parkinson’s disease: Many people in the later stages of Parkinson’s disease develop dementia. Symptoms include trouble with thinking and memory, hallucinations and delusions, depression and trouble with speech.
  • Creutzfeldt-Jakob disease: This rare infective brain disease affects about only 1 in 1 million people. An abnormal protein in your brain called prions causes the disease. These prions clump together and cause nerve cell death in your brain. Symptoms include problems with thinking, memory, communication, planning and/or judgment, confusion, behavior changes, agitation and depression.
  • Wernicke-Korsakoff syndrome: This brain disorder is caused by a severe thiamine (vitamin B1) deficiency. This can result in bleeding in key areas related to memory in your brain. It’s most commonly caused by alcohol use disorder but can also be due to malnutrition and chronic infection. Symptoms include double vision, loss of muscle coordination, and difficulty processing information, learning new skills and remembering things.
  • Traumatic brain injury: Repeated blows to your head can cause this injury. It’s most often seen in football players, boxers, soldiers and people who’ve had a vehicle accident. Dementia symptoms, which appear years later, include memory loss, behavior or mood changes, slurred speech and headaches.

Dementias due to reversible causes

Some conditions can cause dementia-like symptoms that can be reversed with treatment, including:

  • Normal pressure hydrocephalus (NPH): This condition happens when cerebrospinal fluid (CSF) builds up in your brain’s spaces (ventricles). The excess buildup harms your brain. NPH can be caused by a brain infection, brain injury, brain bleed or previous brain surgery. Symptoms include poor balance, forgetfulness, trouble paying attention, mood swings, frequent falls and loss of bladder control. Your healthcare provider can drain excess fluid through the surgical placement of a shunt (tube).
  • Vitamin deficiency: Not getting enough vitamin B1, B6, B12 cooper and vitamin E in your diet can cause dementia-like symptoms.
  • Infections: Infections that can cause dementia-like symptoms include HIV infection, syphilis and Lyme disease. Symptoms reported with COVID-19 infection include “brain fog” and acute delirium. Because of the inflammation and stroke risk seen with COVID-19 infection, both short- and long-term cognitive effects are being investigated. Urinary tract infections (UTIs) and infections in your lungs in the elderly can also result in dementia-like symptoms. Other central nervous system infections and brain infections caused by fungi, bacteria and parasites can also cause cognitive symptoms.
  • Metabolic and endocrine conditions: Conditions that can mimic dementia include Addison’s disease, Cushing’s disease, low blood sugar (hypoglycemia) exposure to heavy metals (like arsenic or mercury), high calcium levels (hypercalcemia, often due to hyperparathyroidism), liver cirrhosis and thyroid problems.
  • Medication side effects: Some medications, in some people, can mimic dementia symptoms. These include sleeping pills, anti-anxiety drugs, antidepressants, anti-seizure drugs, antiparkinson drugs, nonbenzodiazepine sedatives, narcotic pain relievers, statins and others. Ask your healthcare provider to review your medications if you have any dementia-like symptoms.
  • Other causes: Other causes of dementia-like symptoms include brain tumors and

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