Experts estimate that Alzheimer's disease is the underlying cause of -- of all dementia cases. However, there are many other conditions which can also cause dementia, which makes it vital for the patient to obtain accurate diagnosing of dementia early on in order to get proper treatment. Following are some of the most common types of dementia and their causes.
1. Vascular Dementia
The second most common form of dementia, vascular dementia is caused by poor blood flow to the brain, which deprives brain cells of the nutrients and oxygen they need to function normally. One of the ten different dementia types, vascular dementia can result from any number of conditions which narrow the blood vessels, including stroke, diabetes and hypertension.
2. Mixed Dementia
Sometimes dementia is caused by more than one medical condition. This is called mixed dementia. The most common form of mixed dementia is caused by both Alzheimer's and vascular disease.
3. Dementia with Lewy Bodies (DLB)
Sometimes referred to as Lewy Body Disease, this type of dementia is characterized by abnormal protein deposits called Lewy bodies which appear in nerve cells in the brain stem. These deposits disrupt the brain's normal functioning, impairing cognition and behavior and can also cause tremors. DLB is not reversible and has no known cure.
4. Parkinson's Disease Dementia (PDD)
Parkinson's disease is a chronic, progressive neurological condition, and in its advanced stages, the disease can affect cognitive functioning. Not all people with Parkinson's disease will develop dementia, however. Dementia due to Parkinson's is also a Lewy body dementia. Symptoms include tremors, muscle stiffness and speech problems. Reasoning, memory, speech, and judgment are usually affected.
5. Frontotemporal Dementia
Pick's disease, the most common of the frontotemporal dementia types, is a rare disorder which causes damage to brain cells in the frontal and temporal lobes. Pick's disease affects the individual's personality significantly, usually resulting in a decline in social skills, coupled with emotional apathy. Unlike other types of dementia, Pick's disease typically results in behavior and personality changes manifesting before memory loss and speech problems.
6. Creutzfeldt-Jacob Dementia (CJD)
CJD is a degenerative neurological disorder, which is also known as mad cow disease. The incidence is very low, occurring in about one in one million people. There is no cure. Caused by viruses that interfere with the brain's normal functioning, dementia due to CJD progresses rapidly, usually over a period of several months. Symptoms include memory loss, speech impairment, confusion, muscle stiffness and twitching, and general lack of coordination, making the individual susceptible to falls. Occasionally, blurred vision and hallucinations are also associated with the condition.
7. Normal Pressure Hydrocephalus (NPH)
Normal pressure hydrocephalus involves an accumulation of cerebrospinal fluid in the brain's cavities. Impaired drainage of this fluid leads to the build-up and results in added pressure on the brain, interfering with the brain's ability to function normally. Individuals with dementia caused by normal pressure hydrocephalus often experience problems with ambulation, balance and bladder control, in addition to cognitive impairments involving speech, problem-solving abilities and memory.
8. Huntington's Disease
Huntington's disease is an inherited progressive dementia that affects the individual's cognition, behavior and movement. The cognitive and behavioral symptoms of dementia due to Huntington's include memory problems, impaired judgment, mood swings, depression and speech problems (especially slurred speech). Delusions and hallucinations may occur. In addition, the individual may experience difficulty ambulating, and uncontrollable jerking movements of the face and body.
9. Wernicke-Korsakoff Syndrome
Wernicke-Korsakoff syndrome is caused by a deficiency in thiamine (Vitamin B1) and often occurs in alcoholics, although it can also result from malnutrition, cancer which have spread in the body, abnormally high thyroid hormone levels, long-term dialysis and long-term diuretic therapy (used to treat congestive heart failure). The symptoms of dementia caused by Wernicke-Korsakoff syndrome include confusion, permanent gaps in memory, and impaired short-term memory. Hallucinations may also occur.
10. Mild Cognitive Impairment (MCI)
Dementia can be due to medical illness, medications and a host of other treatable causes. With mild cognitive impairment, an individual will experience memory loss, and sometimes impaired judgment and speech, but is usually aware of the decline. These problems usually don't interfere with the normal activities of daily living. Individuals with mild cognitive impairment may also experience behavioral changes that involve depression, anxiety, aggression and emotional apathy; these can be due to the awareness of and frustration related to his or her condition.