Structural Correlates of Taste and Smell Loss in Encephalitis Disseminata

BACKGROUND: Olfactory dysfunction in MS patients is reported in the literature. MRI of the olfactory bulb (OB) is discussed as a promising new testing method for measuring olfactory function (OF). Aim of this study was to explore reasons for and optimize the detection of olfactory dysfunction in MS patients with MRI. MATERIALS AND METHODS: OB and olfactory brain volume was assessed within 34 MS patients by manual segmentation. Olfactory function was tested using the Threshold-Discrimination-Identification-Test (TDI), gustatory function was tested using Taste Strips (TST). RESULTS: 41% of the MS patients displayed olfactory dysfunction (8% of the control group), 16% displayed gustatory dysfunction (5% of the control group). There was a correlation between the OB volume and the number and volume of MS lesions in the olfactory brain. Olfactory brain volume correlated with the volume of lesions in the olfactory brain and the EDSS score. The TST score correlated with the number and volume of lesions in the olfactory brain. CONCLUSION: The correlation between a higher number and volume of MS lesions with a decreased OB and olfactory brain volume could help to explain olfactory dysfunction

Increasing olfactory bulb volume due to treatment of chronic rhinosinusitis--a longitudinal study.

Differentiation of progenitor cells into neurons in the olfactory bulb depends on olfactory stimulation that can lead to an increase in olfactory bulb volume. In this study, we investigated whether the human olfactory bulb volume increases with increasing olfactory function due to treatment of chronic rhinosinusitis. Nineteen patients with chronic rhinosinusitis were investigated before and after treatment. For comparison, additional measurements were performed in 18 healthy volunteers. Volumetric measurements of the olfactory bulb were based on planimetric manual contouring of magnetic resonance scans. Olfactory function was evaluated separately for each nostril using tests for odour threshold, odour discrimination and odour identification. Measurements were performed on two occasions, 3 months apart. In healthy controls, the olfactory bulb volume did not change significantly between the two measurements. In contrast, the olfactory bulb volume in patients increased significantly from the initial 64.5 +/- 3.2 to 70.0 +/- 3.5 mm(3) on the left side (P = 0.02) and from 60.9 +/- 3.5 to 72.4 +/- 2.8 mm(3) on the right side (P < 0.001). The increase in olfactory bulb volume correlated significantly with an increase in odour thresholds (r = 0.60, P = 0.006, left side; r = 0.49, P = 0.03, right side), but not with changes in odour discrimination or odour identification. Results of this study support the idea that stimulation of olfactory receptor neurons impacts on the cell death in the olfactory bulb, not only in rodents but also in humans. To our knowledge, this is the first longitudinal study that describes an enlargement of the human olfactory bulb due to improvement of peripheral olfactory function

Correlation between olfactory bulb volume and olfactory function in children and adolescents.

WOS:000295171300011International audienceThe olfactory bulb (OB) is considered to be the most important relay station in odor processing. The present study aimed to investigate the volumetric development of the human bulb and the olfactory function during childhood and youth. Furthermore, the present study aimed to investigate a possible correlation between OB volume and specific olfactory functions including odor threshold, odor discrimination and odor identification. A total of 87 subjects (46 boys, 41 girls), aged 1-17 years (mean age 8 years), participated in this study. None of them reported olfactory dysfunction or had signs of a dysfunctional sense of smell. Whenever possible, participants received a volumetric scan of the brain and lateralized olfactory tests. Volumetric measurements of the right and left OB were taken by manual segmentation of the coronal slices through the OB. Significant correlations between OB volumes and olfactory function were observed. Both, OB volumes and olfactory function increased with age, although the correlation between structure and function was not mediated by the subjects' age. In conclusion, for the first time, the present study showed a correlation between OB volume and olfactory functions in children