Affiliations: [a] Department of Psychiatry, Philadelphia, PA, USA
| [b] Department of Neurology, Philadelphia, PA, USA
| [c] Alzheimer’s Disease Center of the University of Pennsylvania Perelman School of Medicine, Philadelphia, PA, USA
| [d] Department of Neurology of Massachusetts General Hospital, Harvard University, Boston, MA, USA
Correspondence:
[*]
Correspondence to: David R. Roalf, PhD, University of Pennsylvania Department of Psychiatry, Neuropsychiatry, 3400 Spruce Street, Gates Building 10th Floor, Philadelphia, PA 19104, USA. Tel.: +1 215 662 7559; E-mail: roalf@upenn.edu.
Abstract: Background: Measurements of olfaction may serve as useful biomarkers of incipient dementia. Here we examine the improvement in diagnostic accuracy of Alzheimer’s disease (AD) and mild cognitive impairment (MCI) when assessing both cognitive functioning and odor identification. Objective: To determine the utility of odor identification as a supplementary screening test in incipient AD. Methods: Sniffin’ Sticks Odor Identification Test (SS-OIT) and the Montreal Cognitive Assessment (MoCA) were administered in 262 AD, 174 MCI [150 amnestic (aMCI), and 24 non-amnestic (naMCI)], and 292 healthy older adults (HOA). Results: Odor identification scores were higher in HOA relative to MCI or AD groups, and MCI outperformed AD. Odor identification scores were higher in aMCI single domain than aMCI multiple domain. Complementing MoCA scores with the SS-OIT significantly improved diagnostic accuracy of individuals with AD and MCI, including within MCI subgroups. Discussion: Odor identification is a useful supplementary screening tool that provides additional information relevant for clinical categorization of AD and MCI, including those who are at highest risk to convert to AD.
Keywords: Alzheimer’s disease, mild cognitive impairment, Montreal Cognitive
Assessment, odor identification, smell, Sniffin’ Sticks Olfactory Identification Test
