Patent ID: 7713962

Claim:
A method for determining the Braak stage of neurofibrillary degeneration associated with a tauopathy in a subject having neurofibrillary degeneration, which method comprises the steps of: (i) administering to the subject a ligand that labels aggregated paired helical filament (PHF) tau protein, wherein the ligand is capable of crossing the blood brain barrier, wherein the ligand is conjugated, chelated, or otherwise associated, with a detectable chemical group, and wherein the ligand is a compound of the formula: wherein: W is S, O, or NH; exactly one of X, Y, and Z is CH or N; the others of X, Y, and Z are CH; M 1 is an alkali metal cation selected from: Li, Na, K, or Cs; RL is a rigid linker group; Ar 1 is a C 5-20 aryl group; n is an integer from 0 to 3; and, each R BT is independently a core substituent selected from: C 1-4 alkyl, hydroxy, C 1-4 alkoxy, nitro, cyano, halo, or amino, (ii) determining the presence and\or amount of ligand bound to extracellular aggregated PHF tau in the medial temporal lobe of the brain of the subject, and (iii) correlating the result of the determination made in (ii) with the extent of neurofibrillary degeneration in the subject.