Lateralization of odor identification in right-handers

Abstract

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.

Chinese abstract

背景：气味识别与气味命名有关, 它更多是语言上的而不是嗅觉上的任务。惯用右手者的语言功能通常横向联系大脑的左半球, 而嗅觉处理主要发生在受刺激的一侧。

目的：重新研究样本量较大的健康右撇子的侧向相关作用, 并调查年龄或性别对气味识别偏侧效应的影响。

材料和方法：对438名右撇子参与者的单个鼻孔（左侧或右侧）进行了“嗅探棒”气味识别测试。对其中199位参与者进行了左侧鼻孔测试, 而对239位参与者进行了右侧鼻孔测试。根据年龄（18岁）或性别将他们分为两组。在较大年龄组（大于18岁）和较年轻组（小于18岁）中, 我们根据性别划分了亚组。

结果：在成年人（大于18岁）中, 左鼻孔气味识别评分显著高于右鼻孔气味识别评分（t₂₅₆ = 2.21, p = .03）, 在男性参与者中, 左鼻孔异味识别评分鉴别分数也明显高于右鼻孔气味鉴别分数（t₁₄₇ = 2.01, p = 0.04）。

结论和意义：本研究发现, 在成年组（年龄大于18岁）中, 左侧鼻孔的气味识别效果比年轻组（小于等于18岁）要好。与女性相比, 男性左侧鼻孔的表现要好于右侧鼻孔。在成年人（年龄大于 18岁）组中, 男性亚组在气味识别的侧向化方面起着更重要的作用。性别和年龄因素似乎对气味识别的影响很大。

Keywords:

• Handedness
• olfactory lateralization
• identification

Acknowledgements

We would like to thank Marie Gottschlich for her help with data acquisition.

Disclosure statement

No potential conflict of interest was reported by the author(s).

Authorship contribution

Zang Y, Pengfei H contributed to the analysis of the results and to the writing of the manuscript, Zang Y, Hummel T contributed to the design and implementation of the research.