RT Journal Article SR Electronic T1 Cholinergic forebrain density loss in Parkinson disease JF Neurology JO Neurology FD Lippincott Williams & Wilkins SP 823 OP 824 DO 10.1212/WNL.0000000000005408 VO 90 IS 18 A1 Nicolaas I. Bohnen A1 Stefan J. Teipel YR 2018 UL http://n.neurology.org/content/90/18/823.abstract AB