Odor Identification, Consistency of Label Use, Olfactory Threshold and their Relationships to Odor Memory over the Human Lifespan

Abstract

The purpose of this study was to investigate olfactory threshold, odor identification, consistency of label use and their relationships to odor memory in the context of semantic/episodic memory across the human lifespan. A total of 137 subjects aged 4-90 years were tested with several olfactory test procedures. We found that olfactory sensitivity was well developed in children despite the finding that their odor naming and odor memory were inferior to that of adults. In the elderly population, olfactory functions gradually declined, with odor memory and odor identification demonstrating the most significant decline. Semantic encoding was differentially related to odor memory over the human age span. Whereas consistency of label use was the main predictor for odor memory in children and young adults, olfactory identification ability was the main predictor in the elderly study group. We also calculated response bias for the separate age groups and found no differences between children, young adults and elderly. However, with age false alarm rates increased. We conclude that children possess equal olfactory sensitivity compared with adults; however, due to limitations in linguistic capabilities and familiarity to odorants, odor memory and odor identification performance was limited. Additionally, our data indicate major alterations of olfactory processing in advanced age with substantial losses in odor memory and odor identification performance.

Identification of odors of edible and nonedible stimuli as affected by age and gender

“…Other researchers have tried to explain differences between cultures in terms of olfactory ability and odor preferences. However, learning may also play an important role in olfactory performance (Alaoui-Ismaïli, VernetMaury, Dittmar, Delhomme, & Chanel, 1997;Engen, 1988;Lehrner, Glück, & Laska, 1999).…”

Intranasal trigeminal function in children

“…Cain et al 7 reported that the sensitivity of children (aged 8-14y) was equivalent to that of young adults (aged 18-24y). Similarly, Lehrner et al 8 observed comparable results for butanol thresholds of children (aged 4-11y) and young adults (aged 18-30y). However, there is also research suggesting that children aged 5 to 9 years are less successful in an odour discrimination task than older children.…”

Olfactory Function: The Influence of Demographic, Cognitive, and Genetic factors

“…Likewise, both odor identification and odor recognition are negatively affected by aging (Larsson, 1997;Larsson & Bäckman, 1993;Larsson et al, 2004;Lehrner et al, 1999;Murphy et al, 1991;Ship & Weiffenbach, 1993). A vast majority of findings report of age-related impairments in odor identification ability (Doty et al, 1984;Dulay et al, 2008;Larsson et al, 2000).…”

“…However, other work did not find an interaction between sex and age in either odor identification or odor detection . Lehrner et al, (1999) reported that elderly subjects exhibited a detection impairment and that the detection thresholds were correlated with episodic odor memory, suggesting that a primary sensory impairment may be responsible for the odor recognition impairment observed in old age. Also, older subjects were impaired in remembering odors that had been identified correctly in an earlier task.…”