Biomarkers and diagnostic methods for Alzheimer's disease and other neurodegenerative disorders

1. A method of analyzing a sample from a subject comprising the steps of: (i) obtaining a biological sample comprising exosomes from a subject, (ii) isolating exosomes from the biological sample comprising: contacting the biological sample with an antibody under conditions wherein the exosomes present in the biological sample bind to the antibody to form an exosome-antibody complex, thereby isolating the exosomes from the sample, and (iii) detecting one or more proteins or phosphorylated proteins from the isolated exosomes with an immunoassay, wherein the biological sample is whole blood, serum, or plasma, and wherein the exosomes are selected from the group consisting of neuron-derived exosomes, astrocyte-derived exosomes, oliogodendrocyte-derived exosomes, and microglia-derived exosomes, wherein the antibody is an anti-NCAM antibody, an anti-CD171 antibody; an anti-CD9 antibody; and/or an anti-CD81 antibody.

2. The method of claim 1 , wherein the subject is selected from the group consisting of a human, a monkey, a dog, a pig, a bovine, a rabbit, a guinea pig, and a rodent.