TH and Parkinson disease: They are found in ~10% of clinically unimpaired subjects over the age of 60 with a distribution similar to PD, but showing lesser density of inclusions and a lesser degree of tyrosine hydroxylase (TH) reduction, as compared to what observed in PD, suggesting that p‐Syn immunoreactivity and LB formation are already detectable at preclinical stages, before the onset of motor symptoms (Dickson et al., 2008; Forno, 1969; Fumimura et al., 2007).