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Lewy Body Dementia


Dementia caused by the formation of Lewy Bodies. OK, you probably could have figured that out yourself.


10-15% of dementias are caused by Lewy bodies, making it the second/third most common cause of dementia, after Alzheimers and vascular[1]. Most common around the age of 67.


Lewy bodies are abnormal aggregates of protein which develop inside nerve cells. This causes a loss of dopamine-producing neurons (in the substantia nigra as in Parkinson's Disease), acetylcholine-producing neurons (as in Alzheimer's disease) and causes cerebral atrophy as the cerebral cortex degenerates.

Clinical Features

  • Visual hallucinations (particularly in early disease)
  • Parkinsonian symptoms
  • Fluctuating cognition (attention and alertness)



Treatment of Lewy Body dementia depends on which of the visual hallucinations and the Parkinsonian symptoms are worse. Treating the hallucinations with antipsychotics will likely exacerbate the Parkinsonian symptoms whilst treating the Parkinsonian symptoms with L-dopa will exacerbate the hallucinations[2].


Average survival after diagnosis is 5 years. The more psychosis present, the worse the survival, the more parkinsonion symptoms, the better[3].


  1. "Motor and cognitive function in Lewy body dementia: comparison with Alzheimer's and Parkinson's diseases" by KK Gnanalingham, et al. - Journal of Neurology, Neurosurgery, and Psychiatry 1997;62:243-252
  2. "Lewy body dementia" by G Lennox - Baillieres Clin Neurol. 1992 Nov;1(3):653-76
  3. "Predictors of Survival in Dementia with Lewy Bodies and Parkinson Dementia" by KA Jellinger et al. - Neurodegenerative Dis 2007;4:428-430