Parkinsonian signs were related to AD pathology, cerebrovascular disease, Lewy bodies and nigral degeneration [160]. Physical frailty was also directly related to AD pathology and the association was similar in persons both with and without dementia [161]. Further, among those without cognitive impairment, impaired odor identification was related to both AD pathology and Lewy bodies [162,163]. Unlike APOE and other polymorphisms for which there is considerable evidence suggesting that it leads to the accumulation of AD pathology, the findings with parkinsonian signs, frailty and odor identification suggest that these clinical findings may be early signs of disease [164].
