title: Olfactory thresholds of the U.S. Population of home-dwelling older adults: development and validation of a short, reliable measure.
abstract: Current methods of olfactory sensitivity testing are logistically challenging and therefore infeasible for use in in-home surveys and other field settings. We developed a fast, easy and reliable method of assessing olfactory thresholds, and used it in the first study of olfactory sensitivity in a nationally representative sample of U.S. home-dwelling older adults. We validated our method via computer simulation together with a model estimated from 590 normosmics. Simulated subjects were assigned n-butanol thresholds drawn from the estimated normosmic distribution and based on these and the model, we simulated administration of both the staircase and constant stimuli methods. Our results replicate both the correlation between the two methods and their reliability as previously reported by studies using human subjects. Further simulations evaluated the reliability of different constant stimuli protocols, varying both the range of dilutions and number of stimuli (6-16). Six appropriately chosen dilutions were sufficient for good reliability (0.67) in normosmic subjects. Finally, we applied our method to design a 5-minute, in-home assessment of older adults (National Social Life, Health and Aging Project, or NSHAP), which had comparable reliability (0.56), despite many subjects having estimated thresholds above the strongest dilution. Thus, testing with a fast, 6-item constant stimuli protocol is informative, and permits olfactory testing in previously inaccessible research settings.
authors.affiliation: Institute for Mind and Biology and Department of Comparative Human Development, The University of Chicago, Chicago, IL, United States of America.
authors.forename: David W
authors.initials: DW
authors.lastname: Kern
authors.affiliation: Department of Public Health Sciences, The University of Chicago, Chicago, IL, United States of America.
authors.forename: L Philip
authors.initials: LP
authors.lastname: Schumm
authors.affiliation: Department of Public Health Sciences, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Kristen E
authors.initials: KE
authors.lastname: Wroblewski
authors.affiliation: Section of Otolaryngology-Head and Neck Surgery, Department of Surgery, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Jayant M
authors.initials: JM
authors.lastname: Pinto
authors.affiliation: Interdisciplinary Center Smell & Taste, ENT Clinic, TU Dresden, Germany.
authors.forename: Thomas
authors.initials: T
authors.lastname: Hummel
authors.affiliation: Institute for Mind and Biology and Department of Comparative Human Development, The University of Chicago, Chicago, IL, United States of America.
authors.forename: Martha K
authors.initials: MK
authors.lastname: McClintock
mesh_terms: D000368:Aged; D000369:Aged, 80 and over; D000375:Aging / Q000502:physiology; D016208:Databases, Factual; D005260:Female; D006798:Housing; D006801:Humans; D008297:Male; D008875:Middle Aged; D008954:Models, Biological; D010812:Physical Stimulation; D011930:Reaction Time; D015203:Reproducibility of Results; D012684:Sensory Thresholds; D012903:Smell / Q000502:physiology*; D012984:Software; D014481:United States