Lewy Body Dementia

Excerpt

Lewy Body Dementia (LBD) encompasses two clinical entities, namely dementia with Lewy bodies and Parkinson disease dementia. It is a progressive degenerative brain disorder characterized by dementia, psychosis, and features of parkinsonism. Symptoms fluctuate with time and vary among different individuals. Diagnosis of LBD requires thorough clinical examination as many of its features overlap with other dementia disorders. It is the third most common type of dementia after Alzheimer disease and Vascular dementia. It characterizes by the deposition of Lewy bodies in the brain that are intraneuronal cytoplasmic inclusion bodies having aggregates of alpha-synuclein and ubiquitin.

There continues to be a debate between the relationship between Parkinson disease and LBD. The latest LBD consortium has set an arbitrary 12-month rule to differentiate LBD from Parkinson disease with dementia. If the patient has Parkinson disease for 12 months or longer before any cognitive impairment is noticed, then the disorder is most likely Parkinson disease with dementia, if the time period is shorter then the disorder is LBD. In most cases of LBD, dementia precedes the motor signs, particularly episodes of diminished responsiveness and visual hallucinations.