We found that nucleus basalis of Meynert grey matter mean voxel value remained a predictor of cognitive impairment when adjusted for UPSIT, RBDSQ, Geriatric Depression Scale, MDS-UPDRS-III, APOE, amyloid-β:tau, axial gait score, and white matter lesions volume (Supplementary Table 2). The gene discussed is APOE; the disease is depressive symptom measurement.