Edison P et al. (2008) Amyloid load in Parkinson's disease dementia and Lewy body dementia measured with [11C]PIB-PET. J Neurol Neurosurg Psychiatry [doi: 10.1136/jnnp.2007.127878]

In a new study, dementia with Lewy bodies (DLB) has been associated with the deposition of amyloid-β in the brain. According to Edison and colleagues, these results indicate that most patients with DLB could benefit from therapy with anti-amyloid agents.

The PET radiotracer 11C-labeled Pittsburgh Compound B (11C-PIB) binds to amyloid-β deposits in the cortex and striatum and is used to measure in vivo amyloid load in patients with Alzheimer disease. Edison et al. have now used 11C-PIB PET to assess amyloid load in patients with DLB or Parkinson disease dementia (PDD; n = 13 and n = 12, respectively), comparing findings with those from 10 patients with Parkinson disease without dementia and 41 age-matched healthy controls. Of the 13 patients with DLB, 11 (85%) had a significantly increased amyloid load (indicated by increased 11C-PIB uptake) in at least one cortical region in comparison with that observed in the control group. By comparison, only 2 (15%) patients with PDD demonstrated increased uptake of 11C-PIB, and none of the patients with Parkinson disease without dementia showed an increase in uptake of the marker compared with controls.

The authors conclude that assessment of amyloid load can be used to differentiate between PDD and DLB and that 11C-PIB PET can help to target novel anti-amyloid agents to patients with DLB. Some patients with PDD might also benefit from such strategies.