From: olivercranglejr@gmail.com   
      
   Skip to main navigation   
   Skip to main content   
    mayo-mobile-logo-image MenuSearch   
   Appointments at Mayo Clinic   
      
   Request Appointment   
   Diseases and Conditions   
   Dementia   
   SECTIONS   
   Causes   
   By Mayo Clinic Staff   
   Dementia involves damage of nerve cells in the brain, which may occur in   
   several areas of the brain. Dementia may affect people differently, depending   
   on the area of the brain affected.   
      
   Dementias can be classified in a variety of ways and are often grouped by what   
   they have in common, such as what part of the brain is affected, or whether   
   they worsen over time (progressive dementias).   
      
   Some dementias, such as those caused by a reaction to medications or an   
   infection, are reversible with treatment.   
      
   Progressive dementias   
      
   Types of dementias that worsen over time include:   
      
   Alzheimer's disease. In people age 65 and older, Alzheimer's disease is the   
   most common cause of dementia. People generally may develop symptoms after age   
   60, but some people may have early-onset forms of the disease, often as the   
   result of a defective    
   gene.   
      
   Although in most cases the exact cause of Alzheimer's disease isn't known,   
   plaques and tangles are often found in the brains of people with Alzheimer's.   
   Plaques are clumps of a protein called beta-amyloid, and tangles are fibrous   
   tangles made up of tau    
   protein.   
      
   Certain genetic factors also may make it more likely that people will develop   
   Alzheimer's.   
      
   Alzheimer's disease usually progresses slowly over seven to 10 years. Your   
   cognitive abilities slowly decline. Eventually, the affected areas of your   
   brain don't work properly, including parts of your brain that control memory,   
   language, judgment and    
   spatial abilities.   
      
   Lewy body dementia. Lewy body dementia affects approximately 10 to 22 percent   
   of people with dementia, making it one of the most common types of dementia.   
   Lewy body dementia becomes more common with age.   
      
   Lewy bodies are abnormal clumps of protein that have been found in the brains   
   of people with Lewy body dementia, Alzheimer's disease and Parkinson's disease.   
      
   Lewy body dementia symptoms are similar to symptoms of Alzheimer's disease.   
   Its unique features include fluctuations between confusion and clear thinking   
   (lucidity), visual hallucinations, and tremor and rigidity (parkinsonism).   
      
   People with Lewy body dementia often have a condition called rapid eye   
   movement (REM) sleep behavior disorder that involves acting out dreams.   
      
   Vascular dementia. Vascular dementia, the second most common type of dementia,   
   occurs as a result of brain damage due to reduced or blocked blood flow in   
   blood vessels leading to your brain.   
      
   Blood vessel problems may be caused by stroke, infection of a heart valve   
   (endocarditis) or other blood vessel (vascular) conditions.   
      
   Symptoms usually start suddenly and often occur in people with high blood   
   pressure or people who have had strokes or heart attacks in the past.   
      
   Several different types of vascular dementia exist, and the types have   
   different causes and symptoms. Alzheimer's disease and other dementias also   
   may be present at the same time as this dementia.   
      
   Frontotemporal dementia. This less common cause of dementia tends to occur at   
   a younger age than does Alzheimer's disease, generally between the ages of 40   
   and 65.   
      
   This is a group of diseases characterized by the breakdown (degeneration) of   
   nerve cells in the frontal and temporal lobes of the brain, the areas   
   generally associated with personality, behavior and language.   
      
   Signs and symptoms of frontotemporal dementia can include inappropriate   
   behaviors, language problems, difficulty with thinking and concentration, and   
   movement problems.   
      
   As with other dementias, the cause isn't known, although in some cases this   
   dementia is related to certain genetic mutations.   
      
   Other disorders linked to dementia   
      
   Huntington's disease. This inherited disease causes certain nerve cells in   
   your brain and spinal cord to waste away.   
      
   Signs and symptoms usually appear during your 30s or 40s. People may   
   experience personality changes, such as irritability or anxiety. The condition   
   causes a severe decline in thinking (cognitive) skills over time. Huntington's   
   disease also causes    
   weakness and difficulty with walking and movement.   
      
   Traumatic brain injury. This condition is caused by repetitive head trauma,   
   such as experienced by boxers, football players or soldiers.   
      
   Depending on the part of the brain injured, this condition can cause dementia   
   signs and symptoms such as uncoordinated movement and impaired speech, as well   
   as slow movement, tremors and rigidity (parkinsonism). Symptoms may not appear   
   until many years    
   after the actual trauma.   
      
   A person who has experienced a single traumatic head injury could develop a   
   similar condition called post-traumatic dementia, which may cause symptoms   
   such as long-term memory problems.   
      
   HIV-associated dementia. Infection with the human immunodeficiency virus   
   (HIV), which causes AIDS, destroys brain matter and may cause memory problems,   
   withdrawal from social situations, concentration problems or movement problems.   
   Creutzfeldt-Jakob disease. This rare brain disorder usually occurs in people   
   without risk factors. This condition may be due to an abnormal form of a   
   protein. Creutzfeldt-Jakob disease sometimes may be inherited or caused by   
   exposure to diseased brain or    
   nervous system tissue.   
      
   Signs and symptoms of this fatal condition usually appear around age 60 and   
   initially include problems with coordination, memory, thinking and vision.   
   Symptoms worsen over time and may include the inability to move or talk,   
   blindness, or infections.   
      
   Secondary dementias. People with movement disorders and other conditions may   
   develop dementia. For example, many people with Parkinson's disease eventually   
   develop dementia symptoms (Parkinson's disease dementia).   
   The relationship between these disorders and dementia isn't completely   
   understood.   
      
   Dementia causes that can be reversed   
      
   Some causes of dementia or dementia-like symptoms can be reversed. Your doctor   
   may identify and treat these causes:   
      
   Infections and immune disorders. Dementia can result from fever or other side   
   effects of your body's attempt to fight off an infection. People may develop   
   dementia or thinking difficulties if they have brain infections like   
   meningitis and encephalitis,    
   untreated syphilis, Lyme disease, or conditions that cause a completely   
   compromised immune system, such as leukemia.   
      
      
   [continued in next message]   
      
   --- SoupGate-Win32 v1.05   
    * Origin: you cannot sedate... all the things you hate (1:229/2)