The new study, available online inAnnals of Neurology, still implicates amyloid beta in causing Alzheimer's dementia, but not necessarily in the form of plaques. Instead, smaller molecules of amyloid beta dissolved in the brain fluid appear more closely correlated with whether a person develops symptoms of dementia. Called amyloid beta "oligomers," they contain more than a single molecule of amyloid beta but not so many that they form a plaque.
Science Daily, Oct 22, 2012
Esparza TJ et al.
Amyloid-beta oligomerization in Alzheimer dementia versus high-pathology controls.