研究发现，乙型淀粉样蛋白（amyloid-beta，这种物质会结团形成淀粉样斑块）会在痴呆症状出现前25年就消失于大脑周边的脑脊液中。
The research found that amyloid-beta – the substance that clumps together and forms amyloid plaques – becomes depleted in the cerebrospinal fluid around the brain as long as 25 years before the onset of dementia.