No abstract

Clinical experience shows that the individual significance of olfactory function varies between subjects. In order to estimate these individual differences we developed a questionnaire to study the subjective importance of the sense of smell. Questions were arranged within three subscales: association with olfactory sensations, application of the sense of smell, and the readiness to draw consequences from the olfactory perception. The questionnaire was shown to be time efficient, suitable for normosmic subjects and patients with hyposmia or anosmia. It exhibited a good internal reliability (Cronbach's Alpha = 0.77). First results in 123 subjects indicate that the subjective importance of the sense of smell stays at the same level throughout life-span despite of a decreased olfactory sensitivity. Furthermore, women reported a higher importance of olfaction. It is hoped that this questionnaire will contribute to clarify, for example, cross-cultural differences in the perception of odours.

The currently presented large dataset (n = 1,422) consists of results that have been assembled over the last 8 years at science fairs using the 16-item odor identification part of the “Sniffin’ Sticks”. In this context, the focus was on olfactory function in children; in addition before testing, we asked participants to rate their olfactory abilities and the patency of the nasal airways. We reinvestigated some simple questions, e.g., differences in olfactory odor identification abilities in relation to age, sex, self-ratings of olfactory function and nasal patency. Three major results evolved: first, consistent with previously published reports, we found that identification scores of the youngest and the oldest participants were lower than the scores obtained by people aged 20–60. Second, we observed an age-related increase in the olfactory abilities of children. Moreover, the self-assessed olfactory abilities were related to actual performance in the smell test, but only in adults, and self-assessed nasal patency was not related to the “Sniffin’ Sticks” identification score.

The olfactory system provides numerous functions to humans, influencing ingestive behavior, awareness of environmental hazards and social communication. Approximately ⅕ of the general population exhibit an impaired sense of smell. However, in contrast to the many affected, only few patients complain of their impairment. So how important is it for humans to have an intact sense of smell? Or is it even dispensable, at least in the Western world? To investigate this, we compared 32 patients, who were born without a sense of smell (isolated congenital anosmia - ICA) with 36 age-matched controls. A broad questionnaire was used, containing domains relevant to olfaction in daily life, along with a questionnaire about social relationships and the BDI-questionnaire. ICA-patients differed only slightly from controls in functions of daily life related to olfaction. These differences included enhanced social insecurity, increased risk for depressive symptoms and increased risk for household accidents. In these domains the sense of olfaction seems to play a key role.

No abstract

The results indicate that threshold testing with PEA is an alternative to butanol. The wide step method provided similar results as the narrow step method but required less time.

Repeated exposure to odors modifies olfactory function. Consequently, "olfactory training" plays a significant role in hyposmia treatment. In addition, numerous studies show that the olfactory bulb (OB) volume changes in disorders associated with olfactory dysfunction. Aim of this study was to investigate whether and how olfactory bulb volume changes in relation to lateralized olfactory training in healthy people. Over a period of 4 months, 97 healthy participants (63 females and 34 males, mean age: 23.74 ± 4.16 years, age range: 19-43 years) performed olfactory training by exposing the same nostril twice a day to 4 odors (lemon, rose, eucalyptus and cloves) while closing the other nostril. Before and after olfactory training, magnetic resonance imaging (MRI) scans were performed to measure OB volume. Furthermore, participants underwent lateralized odor threshold and odor identification testing using the "Sniffin' Sticks" test battery.OB volume increased significantly after olfactory training (11.3 % and 13.1 % respectively) for both trained and untrained nostril. No significant effects of sex, duration and frequency of training or age of the subjects were seen. Interestingly, PEA odor thresholds worsened after training, while olfactory identification remained unchanged.These data show for the first time in humans that olfactory training may involve top-down process, which ultimately lead to a bilateral increase in olfactory bulb volume.

The study was designed to provide a topographical map of the sensitivity of the human nasal respiratory epithelium towards trigeminal chemosensory stimuli. As an electrophysiological measure of intranasal trigeminal activation at the level of the epithelium, we used the so-called negative mucosa potential (NMP), a measure that represents the sum of generator potentials of trigeminal receptor neurons after chemical stimulation. Sixty subjects participated (30 men and 30 women; mean age 23.5 years). Measurements were made in response to stimulation with menthol, CO(2), ethanol, and cinnamaldehyde, which are known to activate trigeminal receptors to various degrees. Recordings of the NMP were made from five intranasal sites: the anterior septum, the posterior septum, the tip of the middle turbinate, the tip of the lower turbinate, and the lateral side wall of the posterior nasal cavity. The recording electrode was positioned under endoscopic control. The largest NMP amplitudes were recorded at the anterior septum in response to stimulation with CO(2). Comparing all recording sites, significant differences were observed between responses at the posterior septum and the lateral side wall of the posterior nasal cavity in response to stimulation by ethanol, menthol, and CO(2). These findings suggest that the presence of topographical and chemosensory differences in the responsiveness of the nasal mucosa to irritants.