Lateralization of odor identification in right-handers

Background: Odor identification is related to odor naming, which is more of a verbal than an olfactory sensory task. Linguistic functions in right-handers are typically lateralized to the left hemisphere of the brain and the olfactory processing happens predominantly ipsilaterally to the stimulated side.Aims: Re-investigate side-related effect in healthy right-handed people with a larger sample size and investigate the influence of age or gender on the odor identification lateralization effect.Material and methods: The 'Sniffin' Sticks' odor identification test on a single nostril (either left or right side) was conducted in four hundred and thirty-eight right-handed participants. Among those one hundred and ninety-nine participants were tested on the left-side nostril and two hundred and thirty-nine on the right-side nostril. They were divided into two groups based on the age (18 years) or sex, in the older group (18 years) and the younger group (18 years) we had subgroups based on the sex.Results: In adults (age >18 years), the left-nostril odor identification score was significantly higher than the right-nostril odor identification score (t₂₅₆ = 2.21, p = .03), in the male participants, the left-nostril odor identification score was also significantly higher than the right-nostril odor identification score (t₁₄₇ = 2.01, p = 0.04).Conclusions and significance: The present study found that the in adult group (age >18 years), the odor identification performed better on the left-side nostril than the right-side nostril compared to the younger group (age ≤18 years); The males performed better on the left-side nostril than the right-side nostril compared to the females. In the adults (age >18 years) group, the males subgroup played a more important role on the lateralization of odor identification. Gender and age seem to have a large influence on the lateralization of odor identification.