Definition
Dementia with Lewy bodies, the second most frequent cause of
dementia in elderly adults, is a neurodegenerative disorder
associated with abnormal structures (Lewy bodies) found in certain
areas of the brain. Because these structures and many of the
symptoms of dementia with Lewy bodies are associated with
Parkinson's and Alzheimer's diseases, researchers do not yet
understand whether dementia with Lewy bodies is a distinct clinical
entity or perhaps a variant of Alzheimer's or Parkinson's disease.
Recent research has revealed that Lewy bodies contain deposits of a
protein called alpha-synuclein that is also linked to Parkinson's
disease and multiple system atrophy.
Symptoms
Symptoms can range from traditional parkinsonian effects, such
as loss of spontaneous movement (bradykinesia), rigidity (muscles
feel stiff and resist movement), tremor, and shuffling gait, to
effects similar to those of Alzheimer's disease, such as acute
confusion, loss of memory, and loss of, or fluctuating, cognition.
Visual hallucinations may be one of the first symptoms noted, and
patients may suffer from other psychiatric disturbances such as
delusions and depression. Onset of the disorder usually occurs in
older adults, although younger people can be affected as well. In
1996 scientists published guidelines for the diagnosis of dementia
with Lewy bodies (McKeith IG, et al, Neurology, vol 47, pp
1113-1114, Nov 1996).
Treatments
Scientists continue to search for a specific course of therapy for
people with dementia with Lewy bodies. Treatment is symptomatic,
often involving the use of medication to control the parkinsonian
and psychiatric symptoms. However, patients should be aware that
antiparkinsonian medication that may help to reduce tremor and loss
of muscle movement may actually worsen such symptoms as
hallucinations and delusions. Similarly, neuroleptic drugs
prescribed for psychiatric symptoms may in fact markedly worsen the
movement symptoms. In general atypical antipsychotic medications are
more successful than older drugs such as haloperidol.
Prognosis
Dementia with Lewy bodies is a slowly progressive condition for
which there is no cure.
