Odor threshold, recognition, discrimination and identification in centenarians.

Abstract

The main purpose of this study was to learn the use of select measures that are relevant to olfactory discrimination, identification and recognition and to ascertain the appropriateness of extant methods and procedures for adaptation for use with the oldest-old. A second purpose of this study was to attempt initial examination of the relationship of different memorial systems in the oldest old through an atypical sensory modality. Twenty-one centenarians (mean=105.1 years) were tested on odor thresholds for phenethyl alcohol (PEA) and menthol, recognition and discrimination of lexically challenging odors, and identification of common odors. Chronological age was not found to be a significant predictor of abilities for any of the tasks. Thresholds for PEA and menthol were found to be better than anticipated levels and were associated with odor recognition and certainty of response. Mini Mental State Examination scores were not found to be associated with olfactory measures, contrary to expectations. Findings suggest much of the previous research into olfactorial abilities of older adults may have failed to account for the influence of illness, trauma, dementia and pathologies typically associated with age. In light of their performance on the tasks, the relative good health and cognitive status of the participants strengthens the idea that olfaction is an appropriate addition to diagnostic tests of Alzheimer's and other diseases.