Abstract: A method for assisting the diagnosis of Alzheimer's disease, comprising: measuring an amount of extracellular vesicles having phosphatidylserine and tetraspanin, or the amount of extracellular vesicles having phosphatidylserine and tetraspanin and an amount of extracellular vesicles having tetraspanin, in a biological specimen derived from a subject; and determining that the subject has Alzheimer's disease using the amount of extracellular vesicles having phosphatidylserine and tetraspanin, or a ratio of the amount of extracellular vesicles having phosphatidylserine and tetraspanin to the amount of extracellular vesicles having tetraspanin as an indicator.

Abstract: A method for assisting the diagnosis of Parkinson's disease, including: measuring an amount of extracellular vesicles having phosphatidylserine and tetraspanin, or the amount of extracellular vesicles having phosphatidylserine and tetraspanin and an amount of extracellular vesicles having tetraspanin, in a biological specimen derived from a subject; and determining that the subject has Parkinson's disease using the amount of extracellular vesicles having phosphatidylserine and tetraspanin, or a ratio of the amount of extracellular vesicles having phosphatidylserine and tetraspanin to the amount of extracellular vesicles having tetraspanin as an indicator.