The Association Between Depth of the Olfactory Sulcus, Age, Gender and Olfactory Function: An MRI-based Investigation in More Than 1000 Participants

The present study aimed to investigate the relationship between olfactory sulcus (OS) depth and olfactory function considering age and gen-der and to provide normative data on OS depth in a population with normal olfactory function. Materials and methods: OS depth was obtained using T1 magnetic resonance imaging scans. Participants (mean age +/- sd = 57 +/- 16 years, ranging from 20 to 80 years) were screened for olfactory function using the Sniffin' Sticks Screening 12 test. They were divided into an olfactory dysfunction group (n = 604) and a normosmia group (n = 493). Participants also completed questionnaires measuring depression, anxiety and quality of life. Results: The right OS was deeper than the left side in all age groups. On the left side, women had deeper OS com-pared with men, exhibiting a higher degree of symmetry in left and right OS depth in women. Variance of olfactory function was largely determined by age, OS depth explained only minor portions of this variance. Normative data for minimum OS depth was 7.55 mm on the left and 8.78 mm on the right for participants aged between 18 and 35 years (n = 144), 6.47 mm on the left and 6.99 mm on the right for those aged 36-55 years (n = 120), and 5.28 mm on the left and 6.19 mm on the right for participants older than 55 years (n = 222). Conclusion: Considering the limited resolution of the presently used T1 weighted MR scans and the nature of the olfactory screening test, OS depth explained only minor portions of the variance of olfactory function, which was largely determined by age. Age-related normative data of OS depth are presented as a reference for future work.(c) 2023 IBRO. Published by Elsevier Ltd. All rights reserved.

Automated summary

The study investigated the relationship between olfactory sulcus (OS) depth and olfactory function, considering age and gender. Normative data on OS depth were provided for a population with normal olfactory function. Results showed that the right OS was deeper than the left side in all age groups. Women had deeper OS on the left side compared to men. OS depth explained only minor portions of the variance in olfactory function, which was largely determined by age. Age-related normative data on OS depth were presented.