Different kinds of dementia present different warning signs and symptoms. Here are the symptoms of the four most common kinds of dementia and what to be on the lookout for.
1. Alzheimer's disease
Alzheimer's disease is the most frequent type of dementia in adults. Scientists are not sure whether the accumulation of tangled proteins around neurons in the brain results from the disease or causes the disease, but the accumulation of these proteins occurs in nearly all cases. Tangled fibers of protein, overproduction of toxic free radicals, inflammation, and oxidation lead to brain cell death.
The cardinal symptoms of Alzheimer's disease are that it:
- Produces early memory loss.
- Begins in an insidious fashion; it's not traumatic.
- Always progresses, either slowly or rapidly but without improvement.
Also, every Alzheimer's patient displays at least one but possibly more or all of the following symptoms:
- Agnosia (inability to recognize things, inability to interpret sensations).
- Apraxia (difficulty planning motor functions).
- Executive dysfunction (bad judgment).
- Language dysfunction (difficulties with speech, reading, writing, listening).
- Visuospatial disorder (inability to judge the relationships of objects in three-dimensional space).
Short-term memory declines first. Then long-term memories are lost, too. Difficulties with motor motion don't show up for a few years. Difficulties with gait and tendencies to get lost and wander around are part of the later phases of the disease. Loss of inhibitions. aggression, depression, and anxiety are also more common in the later stages of the condition.
2. Lewy body disease
Lewy body disease is the second most common form of dementia. It produces many of the same symptoms as Parkinson's disease, but like Parkinson's patients, people with Lewy body dementia almost never experience all of the possible symptoms of the disease.
- About 25 to 50 percent of Lewy body disease patients experience hallucinations.
- About 25 to 50 percent of Lewy body disease patients experience Parkinson's symptoms such as rigidity, tremors on one side of the body, These symptoms come along after the patient begins to experience delusions and hallucinations.
- Eventually 50 to 75 percent of Lewy body disease patients experience fluctuating cognitive impairment. They have better periods and worse periods.
Symptoms that distinguish Lewy body dementia from Alzheimer's disease include:
- Nonvisual hallucinations rather than solely visual hallucinations.
- Unexplained fainting spells.
- Rapid eye movement sleep disorders.
- Depression in response to stress.
People who have Lewy body dementia may have long periods of clarity. There may be other times that they seem to be cognitively impaired. This places them at special risk for suicide, because there are time they realize how bad their situation is.
3. Vascular dementia
Vascular dementia is not so much a single disease as it is a collection of diseases. The most common form of vascular dementia is multi-infarct dementia, an accumulation of damage from "mini-strokes" across brain tissue. However, there is also single-infarct dementia, in which a single blood clot destroys a critical portion of the brain. In Binswanger's disease, damage to small blood vessels destroys the white matter of the brain. Lacunar dementia results from obstructions to smaller arteries inside the brain.
Vascular dementia is usually accompanied by high blood pressure, coronary artery disease, peripheral artery disease, and/or type 2 diabetes. People who have vascular dementia may simply "slow down." They may suffer poor executive judgment. They make bad decisions. They may have specific kinds of difficulties with movements. Symptoms may come on abruptly or they may come on slowly, but there are usually symptoms within three months of the vascular event in the brain. You don't wait decades for symptoms to appear.
4. Frontotemporal Dementia
Regina (not her real name) seemed to undergo some kind of pervasive personality change. Always fastidious about her appearance, she stopped bathing and began to reek strongly enough that coworkers complained. A devoutly religious person, she started telling dirty jokes and propositioning coworkers of both sexes. She was fired from her job when she stole $2.25 from petty cash to buy a Diet Coke.
The kinds of mental changes that occur in frontotemporal dementia, a condition caused by shrinkage of the brain's frontotemporal lobes, often overlap with personality disorders, at least at first. People may eat too much, or drink too much. They may start telling lies compulsively. They may start talking louder or softer. They may start repeating what other people say, or lose a large part of their normal vocabulary. This condition always causes profound personality change.