Although Alzheimer's Disease is the most commonly known cause of dementia in the elderly, accounting for about 50% of all dementias, Dementia With Lewy Bodies accounts for somewhere between 20 and 35% of dementias worldwide. Treatment options are sometimes wildly different, and what works for one can cause serious problems in the other, so it's very important to know what's causing dementia symptoms.

Dementia with Lewy Bodies (the more or less official name of this kind of dementia) has the dementia characteristics of Alzheimer's Disease and the deteriorating motor control characteristics of Parkinson's Disease. Because the symptoms overlap, diagnosing dementia with Lewy bodies can be difficult. In its earlier stages it is often confused with Alzheimer's disease or vascular dementia, which is caused by stroke (CVA or cerebral vascular accident).

While both are progressive in nature, one of the major differentiators between Alzheimer's Disease and Lewy Body Dementia is that Alzheimer's Disease usually progresses quite slowly, while LBD tends to move much more quickly. LBD differs from Parkinson's Disease in that dementia symptoms in Parkinson's Disease usually appear more than a year after Parkinson's symptoms first appear (if they appear at all). In Dementia with Lewy Bodies, dementia symptoms usually arise at the same time Parkinson's-like motor symptoms appear, or shortly thereafter.

In spite of the fact that it may be difficult to diagnose, it's important to make every effort to do so. "Dementia is dementia" does not apply, because the treatment options are so different.

The symptoms and brain destruction seen in Lewy Body Dementia is caused by the buildup of a particular protein, alpha-synuclein protein, in the brain neurons responsible for motor control, memory, emotions and behavior.

The most significant Lewy Body symptoms to be aware of at the outset are:

1. Cognitive symptoms can vary. Attention and alertness can swing wildly from day to day, and even hourly. While those with Alzheimer's disease also experience "good" days and "bad" days, their swings tend to be much less intense. LBD patients frequently experience sudden drowsiness or loss of alertness, trouble finding the "right" words, and lack of judgment. In the early stages they are more likely than someone with Alzheimer's to spend unusual amount of time staring blankly. Symptoms usually appear quite suddenly in LBD patients.

2. Those with LBD often experience hallucinations, particularly visual hallucinations (people and animals in particular), although hearing, smell and taste hallucinations have also been reported. These are not always disturbing, depending on the individual. In the early stages of Alzheimer's disease, hallucinations are rare. As many as 75% of people with Lewy Body Dementia experience vivid hallucinations in the early stages. While hallucinations can also occur in Parkinson's Disease and Alzheimer's, they are not usually present in the early stages.

3. Parkinson's-like motor symptoms: slow movement, shuffling gait, reduced armswing, frequent falls and even fainting from a sudden drop in blood pressure (orthostasis), reduced arm-swing during walking, blank expression (reduced range of facial expression), stiffness of movements, "cogwheeling" type movement; low speech volume, drooling, and difficulty swallowing. Tremors, however, are less common in Dementia with Lewy bodies than in Parkinson's disease.

For many families one of the first indicators that their loved one may have Dementia with Lewy Bodies is the sudden onset of balance difficulties and frequent falls. Falling frequently is not typical of early Alzheimer's Disease.

4. A hypersensitivity to certain anti-psychotic (neuroleptic) and anti-nausea (antiemetic) drugs. Individuals with LBD have been reported to have lost significant cognitive function, develop life-threatening muscle rigidity, or even become catatonic when given these medications. Chlorpromazine, haloperidol, and thioridazine, which are used to treat agitation, paranoia and other psychiatric symptoms have been especially identified as very risky for anyone with Lewy Body dementia. Unfortunately, if it has not been diagnosed, the first indicator may be a very bad reaction to one of these drugs.

Dementia with Lewy Bodies can overlap, or exist concurrently, with either Alzheimer's Disease and Parkinson's, which makes it even more difficult to diagnose. Diagnosis requires medical, neurological and neuropsychological testing.

As in the case of Alzheimer's Disease and Parkinson's Disease, there is no cure for Dementia with Lewy bodies. The currently available treatments can sometimes provide some symptom relief. However, it remains very tricky to balance treating the Parkinson's-like symptoms and the cognitive/emotional symptoms, as treatment for one often causes unwelcome side effects in the other. Treatment of the movement portion of the disease can worsen hallucinations and psychosis, while treatment of hallucinations and psychosis can worsen parkinsonian symptoms.

Similar to Alzheimer's Disease, the average length of life after diagnosis is approximately 8 years.