Lewy Body Dementia
Overview
Lewy Body Dementia (LBD) is a type of progressive dementia that leads to a decline in thinking, reasoning and independent function due to abnormal microscopic deposits that damage brain cells over time. These deposits, called Lewy bodies, contain a protein associated with Parkinson's disease and are also found in several other brain disorders.
Etiology
The exact cause of LBD is unknown. The disorder is characterized by the presence of Lewy bodies, abnormal aggregates of the protein alpha-synuclein. These are found in regions of the brain that control particular aspects of memory and motor control. The presence of Lewy bodies is linked to degeneration of nerve cells and a deficiency in the neurotransmitters acetylcholine and dopamine.
Symptoms
The symptoms of LBD include cognitive problems similar to those of Alzheimer's disease, as well as hallucinations, fluctuations in alertness and attention, and parkinsonian motor symptoms, such as slowness of movement, difficulty walking, or rigidity. People with LBD may also suffer from depression and sleep disturbances, such as acting out dreams during REM sleep, a disorder known as REM sleep behavior disorder.
Diagnosis
Diagnosis of LBD is based on the presence of characteristic symptoms and ruling out other possible causes. Neurological examination, brain imaging, and assessment of cognitive function are commonly used. However, definitive diagnosis can only be made by autopsy, through examination of brain tissue for the presence of Lewy bodies.
Treatment
There is currently no cure for LBD, but some symptoms can be managed with medication or other interventions. For example, cholinesterase inhibitors may be used to improve cognitive symptoms, while Parkinson's medications may help manage motor symptoms. Non-drug approaches, such as physical therapy, can also be beneficial.
Prognosis
The course of LBD varies, but the disease typically progresses over several years. Life expectancy after onset of symptoms is roughly similar to that in Alzheimer's disease. However, the presence of parkinsonian symptoms and hallucinations early in the disease course is associated with a poorer prognosis.
Epidemiology
LBD is the third most common cause of dementia, after Alzheimer's disease and vascular dementia. It accounts for 5-10% of all dementia cases. The disease typically begins in people over 50 years of age.
Research
Research into LBD is ongoing, with efforts focused on understanding the genetic and environmental factors that contribute to the disease, as well as developing better diagnostic tools and treatments.