NEFL and Parkinson disease: When looking at the model including only the diseased groups (PD + PDD + DLB) (R2 = 61%), the results did not change: the negative predictors were again LB density (β = -0.130, p < 0.001), NfL immunoreactivity (β = -0.006, p = 0.003), and age (β = -0.004, p < 0.001), and the only positive predictor amyloid-β load (β = 0.210, p < 0.001).