Age-related differences in olfactory cleft volume in adults: A computational volumetric study

OBJECTIVES/HYPOTHESIS There is a growing need to understand the underlying mechanisms of age-related olfactory dysfunction with the increasing proportion of older adults over the next 20 years. Despite the importance of olfactory cleft (OC) volumes on odorant deposition and olfactory function, little is known about age-related changes to OC volume. The goal of this study was to use automated techniques in a cross-sectional design to investigate the extent to which OC volumes vary with age and determine the spatial specificity of any age-related effects. STUDY DESIGN Retrospective cross-sectional study. METHODS Deformation-based morphometry was utilized to measure OC and sinus volumes in two independent samples of 101 (Medical University of South Carolina [MUSC] sample) and 95 (Hammersmith sample) healthy adults who underwent T1-weighted magnetic resonance imaging, with the Hammersmith sample serving as a replication sample. RESULTS The mean age of the MUSC and Hammersmith samples were 54.9 ± 17.0 years and 52.1 years ± 15.7 years, respectively. In both samples, there was a significant positive association between age and OC volume that occurred at a constant rate across the lifespan (Cohen's f2 of 0.065 in the MUSC sample and 0.110 in the Hammersmith sample). Age-associated OC volume increases occurred in conjunction with decreases in sinus volumes as well as increases in non-OC nasal cavity volumes. CONCLUSIONS In this cross-sectional study, there is an increase in OC volume with increasing age that occurs in the context of broad age-associated differences in sinonasal anatomy. Future studies should investigate the impact of age-associated differences in intranasal anatomy on nasal airflow, odorant deposition, and olfactory function. LEVEL OF EVIDENCE 4 Laryngoscope, 129:E55-E60, 2019.