Odor identification, consistency of label use, olfactory threshold and their relationships to odor memory over the human lifespan

The purpose of this study was to investigate olfactory threshold, odor iden tification, consistency of label use and their relationships to odor memory in the context of semantic/episodic memory across the human lifespan. A to tal of 137 subjects aged 4-90 years were tested with several olfactory test procedures. We found that olfactory sensitivity was well developed in chil dren despite the finding that their odor naming and odor memory were inferi or to that of adults. In the elderly population, olfactory functions gradua lly declined, with odor memory and odor identification demonstrating the mo st significant decline. Semantic encoding was differentially related to odo r memory over the human age span. Whereas consistency of label use was the main predictor for odor memory in child ren and you ng adults, olfactory id entification ability was the main predictor in the elderly study group. We also calculated response bias for the separate age groups and found no diff erences between children, young adults and elderly. However, with age false alarm rates increased. We conclude that children possess equal olfactory s ensitivity compared with adults; however, due to limitations in linguistic capabilities and familiarity to odorants, odor memory and odor identificati on performance was limited. Additionally, our data indicate major alteratio ns of olfactory processing in advanced age with substantial losses in odor memory and odor identification performance.