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Background: Individuals with hyposmia, or the partial loss of smell, represent a large sector (15 %) of the population that is likely to grow with the current aging population; however, our understanding to how hyposmics centrally process odors is still not clear. One popular non-invasive tool for in vivo imaging of biological activity among human brains has been function magnetic resonance imaging (fMRI) which uses blood-oxygenation level dependent (BOLD) signal as an indirect measurement. Therefore, the aim of this study was to understand differences in olfaction processing between patients with hyposmia and healthy controls using functional magnetic resonance imaging (fMRI)., Methodology: Eleven hyposmic and 12 healthy, normosmic subjects were exposed to two different food-related odors (coffee and peach) during a block-designed fMRI session. Additionally, odor perception qualities were rated for each odor throughout the scanning session., Results: The activations of the normosmic group were localized in typical olfactory areas (insula, orbitofrontal cortex [OFC], limbic system and amygdala). The hyposmic group showed similar regions of activation (insula, OFC, limbic system), however, less activation was found in the amygdala, left anterior cingulate and right OFC, but higher activation was shown in the right parahippocampal and both the left and right posterior cingulate gyrus which are assumed to play an important role in the processing and remembrance of memories., Conclusions: These results indicate similar central olfactory processing among groups, yet subjects with partial loss may attempt to compensate smell impairment with odor memory or higher motivation to smell.

Olfactory function influences social behavior. For instance, olfaction seems to play a key role in mate choice and helps detecting emotions in other people. In a previous study, we showed that people who were born without a sense of smell exhibit enhanced social insecurity. Based on the comments to this article we decided to have a closer look to whether the absence of the sense of smell affects men and women differently. Under this focus questionnaire data of 32 patients, diagnosed with isolated congenital anosmia (10 men, 22 women) and 36 age-matched healthy controls (15 men, 21 women) was reanalyzed. In result, men and women without a sense of smell reported enhanced social insecurity, but with different consequences: Men who were born without a sense of smell exhibit a strongly reduced number of sexual relationships and women are affected such that they feel less secure about their partner. This emphasizes the importance of the sense of smell for intimate relationships., (Copyright © 2012 Elsevier B.V. All rights reserved.)

Background: Isolated congenital anosmia is a disorder (ICA) characterized by not or only rudimentary developed central olfactory structures. This results in the lack of the sense of smell since birth. Although this phenomenon is known among clinicians almost no knowledge exists on how those people cope with the disorder., Material and Methods: 43 people with ICA were asked with a standardised questionnaire about when they fi rst noticed their disorder, how they experience the lack of smelling ability and about different aspects of daily life., Results: ICA is detected by the patients self or by their parents at the age of 10 in average. However about 13 years pass, until the right diagnosis is confirmed. In contrast to people with acquired olfactory loos ICA patients have developed strategies to adapt to the deficit in daily life. Nevertheless they report increased social insecurity and more hazardous events., Conclusion: The results can be of advantage for clinicians and patients to get a better understanding of the disorder., (© Georg Thieme Verlag KG Stuttgart · New York.)

The aim of this pilot study was to investigate olfactory function in unselected, cooperative patients with ischemic stroke and to gain information about olfactory perception in patients with distinct stroke localizations. Three ischemic stroke patients underwent olfactory testing using the Sniffin' Sticks test and olfactory event-related potentials recording. All stroke patients were found to be normosmic or only slightly hyposmic when using a psychophysical testing device with age-adjusted norms. No responses or longer latencies on the affected side were found, however, when recording evoked potentials. This seems to argue for the idea that on the affected side it is often possible to document the objective lesion although the subjective perception of the patient appears normal.

Food is evaluated for various attributes. One of the key food evaluation domains is hedonicity. As food is consumed, its hedonic valence decreases (due to prolonged sensory stimulation) and hedonic habituation results. The aim of the present study was to investigate changes in food pleasantness ratings during consumption of a simple food by individuals without olfactory experience with food as compared to normosmics. 15 congenital anosmics and 15 normosmic controls were each presented with ten 10 g banana slices. Each was visually inspected, then smelled and chewed for ten seconds and subsequently rated for hedonicity on a 21-point scale. There was a significant difference in pleasantness ratings between congenital anosmics and controls (F(1, 26) = 6.71, p = .02) with the anosmics exhibiting higher ratings than the controls, a significant main repeated-measures effect on the ratings (F(1.85, 48) = 12.15, p<.001), which showed a decreasing trend over the course of consumption, as well as a significant portion*group interaction (F(1.85, 48) = 3.54, p = .04), with the anosmic participants experiencing a less pronounced decline. The results of the present explorative study suggest that over the course of consumption of a simple food, congenitally anosmic individuals experience differential patterns of appreciation of food as compared to normosmics. In this particular case, the decrease of hedonic valence was less pronounced in congenital anosmics.