This longitudinal prospective study was the first to examine the cessation of olfactory stimulation in olfactory deficiency resulting from OB functional and structural changes.

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Objectives: The olfactory bulb (OB) is a remarkably plastic structure with highly active afferent neurons, which is partly reflected by its volume. Although deterioration of olfaction after total laryngectomy is reported by many patients, this problem has not received widespread attention. There has been no study that had addresses this loss olfactory ability as a function of OB volume. The aim of this study was to determine OB volume changes after laryngectomy. Study design: Twenty one patients post-total laryngectomy and 17 subjects with normal olfactory function underwent magnetic resonance imaging (MRI) for volumetric measurement of the OB. The history of all participants was taken in detail to exclude other possible causes of smell dysfunction. Volumetric measurement of the OB was performed by manual segmentation of the OB into coronal slices. Olfactory function was assessed with the orthonasal olfaction test. Results: There was no statistically significant difference in volume between the right and left sides of the OB in the study and control groups. However, the study group had smaller OB volumes than the control group. In our assessment of orthonasal olfaction, patients who were post-total laryngectomy had worse orthonasal olfactory function than the control group. There were significant correlations between OB volumes and orthonasal test scores. Conclusions: Our MRI study showed that post-total laryngectomy patients had higher rates of olfactory bulb atrophy than the control subjects. Laryngectomy is associated with measurable decreases in olfactory function and this study hopes to further clarify this association by demonstrating that patients with total laryngectomy have reduced OB volumes when compared to the normal population.

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To ascertain the level and rate of olfactory dysfunction in patients with leprosy and to determine whether olfactory bulb volume is affected by the pathophysiology. Olfactory bulb (OB) volume, measured using magnetic resonance imaging (MRI), was compared in 15 patients with leprosy and 15 healthy controls. All of the participants were evaluated using a detailed history to identify the probable causes of the smell dysfunction. Those who had a disease other than leprosy that may have caused the smell dysfunction were excluded from the study. OB volumes were calculated by manually tracing the OB on coronal sections. Orthonasal olfaction testing was used to assess smell function. The orthonasal olfaction testing indicated that all patients with leprosy were anosmic or severely hyposmic. The smell function test indicated that the OB volume of the patient group was significantly lower than that of the control group. No within-group difference was detected between right and left OB volume in either group. The patients in the leprosy group were severely hyposmic or anosmic and their olfactory bulb volume was significantly lower than that of the control group. To our knowledge, this study is the first to show a reduction in olfactory bulb volume among leprosy patients.