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At least 1,243 records · Page 69Linked to original sources
PubMed1990

A method of assessment in cases of lingual nerve injury.

A method for assessing lingual sensation is described, comprising sensory testing, using touch and moving two-point discrimination and patient subjective reporting. The clinical application is seen to be the evaluation of lingual nerve injury consequent upon lower third molar surgery. Using this method it is considered possible to identify many of those patients unlikely to make full spontaneous recovery at the stage of 3 months following injury, with a view to achieving an earlier timing of surgical repair than that which prevails at present.

Adolescent↗
PubMed1996

The Merkel cell as a possible mechanoreceptor cell.

Merkel cells (MCs) are abundant at the basal layer of various skin in vertebrates, and make synaptic contacts with nerve endings to form the Merkel cell-neurite complex (MCN-complex). It has been established that the MCN-complex is involved in slowly adapting mechanoreception, cutaneous afferents of which are called SAI units in mammals or Ft-I units in frogs. However, the MC function has been the focus of attention, and some hypotheses propose that the site of mechanoreception is at the nerve terminals but not at the MC. In the present review, the possibility that MCs are the mechanoreceptors was focused on recent findings. Irradiation of quinacrine-loaded MCs in the rat hairy skin using excitation light degenerates the MCs selectively with the nerve terminals left intact. Correspondingly, SAI units decrease tonic discharges rapidly, but phasic responses remain intact. Blocking synaptic transmission in the MCN-complexes by divalent or alkyl Ca antagonists in mammals or frogs heavily decreases the tonic mechanical responses of the afferent units, but the phasic responses are rather resistant. Application of anodal current on the Ft-I receptive spots produces tonic discharges as in hair cells or taste cells, while the threshold to elicit the first spike is lower with cathodal than anodal stimulation, in contrast with other secondary sensory cells. These findings indicate that MCs are mechanoreceptors to yield tonic responses, while the nerve terminals may transduce the transient phase. Further studies, particularly on mechanically-gated ionic channels in the MC membrane and on transmitters between the MCs and nerve terminal, are necessary to establish the MC as mechanoreceptors.

Animals↗
PubMed1997

Perceptual learning in olfaction: professional wine tasters versus controls.

By having professional wine tasters and controls perform olfactory tasks of absolute detection (1-butanol), discrimination (lemon and cloves), and identification (common household odors), the present two experiments studied (a) if perceptual odor learning takes place from odor experience acquired under nonlaboratory conditions, (b) if this learning generalizes to odors for which experience is limited, and (c) if generalized learning can be referred to increased general interest for odors that increases attention to odorous features. The results showed that whereas wine tasters were not better than controls on detection, they were superior to controls on discrimination and identification, the latter due to only a few odors. Ratings of experience with certain odors during professional evaluation suggest that generalized perceptual learning may take place in discrimination but not in identification. Wine tasters did not show more general interest for odorous features than did controls. The nonsuperiority in detection may be explained by the fact wine tasters have no professional experience of a detection task per se, implying that perceptual odor learning does not generalize from the olfactory tasks of discrimination and identification to detection.

Adult↗
PubMed2002

Freundlich adsorption isotherms of agricultural by-product-based powdered activated carbons in a geosmin-water system.

The present study was designed to model the adsorption of geosmin from water under laboratory conditions using the Freundlich isotherm model. This model was used to compare the efficiency of sugarcane bagasse and pecan shell-based powdered activated carbon to the efficiency of a coal-based commercial activated carbon (Calgon Filtrasorb 400). When data were generated from Freundlich isotherms, Calgon Filtrasorb 400 had greater geosmin adsorption at all geosmin concentrations studied than the laboratory produced steam-activated pecan shell carbon, steam-activated bagasse carbon, and the CO2-activated pecan shell carbon. At geosmin concentrations < 0.07 microg/l for the phosphoric acid-activated pecan shell carbon and below 0.08 microg/l for a commercially produced steam-activated pecan shell carbon obtained from Scientific Carbons, these two carbons had a higher calculated geosmin adsorption than Filtrasorb 400. While the commercial carbon was more efficient than some laboratory prepared carbons at most geosmin concentrations, the results indicate that when the amount of geosmin was below the threshold level of human taste (about 0.10 microg/l), the phosphoric acid-activated pecan shell carbon and the Scientific Carbons sample were more efficient than Filtrasorb 400 at geosmin removal.

Adsorption↗
PubMed1990

Color affects perceived odor intensity.

In Experiment 1, some odorous solutions (e.g., strawberry) were rated as smelling stronger when colored (e.g., red) than when colorless. Experiment 2 showed this effect to be due to a perceptual change rather than a response to experimental demand characteristics. Experiment 3 showed that the color-induced increase in odor intensity is not due to subjects' preexperimental experience with particular color-odor combinations, because the increase occurred with novel ones. We conclude that color induces a weak olfactory percept that combines with odorant-induced percepts. The effect may be due to conditioning or may be the result of residual intersensory neural connections left over from infancy.

Adult↗
PubMed1985

Effect of color on judgments of food aroma and flavour intensity in young and elderly adults.

The hypothesis was tested that subjects' judgments of food aroma and flavour strength will be increasingly influenced by food color as the chemosensory differences between foods become less apparent. Elderly (n = 24) and young (n = 22) adults were presented with pairs of food samples and instructed to indicate which sample had the more intense aroma or flavor. The chemosensory discriminations varied in difficulty, and the color of the food pairs was also manipulated so that either they were similarly colored, or the color strength differed so that it was either positively or inversely correlated with flavour strength. Overall, the results failed to support the hypothesis that color alters the perceived intensity of the food aroma or flavor. There was a weak trend toward a greater number of errors among sample pairs that varied in color, especially when color strength was inversely related to flavor strength. Elderly and young adult groups did not differ in chemosensory ability or in their responses to food color differences, although the elderly adults were significantly more certain of the accuracy of their chemosensory judgments.

Adult↗
PubMed1996

Prevalence and assessment of qualitative olfactory dysfunction in different age groups.

The prevalence of parosmia and phantosmia among 363 chemosensory and nasal/sinus patients was studied, as was the accuracy with which our clinical questionnaire could assess these dysfunctions. We then investigated whether patients with parosmia or phantosmia, matched for odor intensity, perform poorer on odor identification than do patients with no dysosmia. More than 40% of the study group evidenced either parosmia (18.7%) and/or phantosmia (25.6%), a finding that suggests that more attention should be paid by the medical practitioner in addressing qualitative olfactory dysfunction. Furthermore, it appears that assessment of these dysfunctions may aid in differential diagnosis, and that questionnaires can be used with reasonable validity irrespective of the patient's age. Finally, the results imply that parosmia may be reflected in a discrepancy between odor identification and detection.

Adult↗
PubMedDate not supplied

Quantitative assessment of olfactory experience during pregnancy.

Results of the National Geographic Smell Survey were used to investigate the effects of pregnancy on olfactory perception and odor-related behavior. The responses to test odors and survey questions of 13,610 pregnant and 277,228 nonpregnant U.S. women between 20 and 40 years of age were analyzed. In comparison to nonpregnant women, pregnant women rated their own sense of smell lower, more often rated the test odors less pleasant smelling, more often classified the test odors as inedible, were less likely to report odor-evoked memories, and used perfume and cologne less frequently. Differences in odor detection and intensity rating did not favor either group.

Adult↗
PubMed2006

Multihormonal resistance to parathyroid hormone, thyroid stimulating hormone, and other hormonal and neurosensory stimuli in patients with pseudohypoparathyroidism.

In patients with pseudohypoparathyroidism, hormonal resistance first affects parathyroid hormone (PTH), which leads to calcipenia, a decrease in renal vitamin D activation, and a tendency to bone receptor remodeling. However, because G proteins are ubiquitously distributed, multiple hormonal resistance occurs in pseudohypoparathyroidism type Ia and type Ic, impairing responses to other calciotropic hormones (PTHrP, calcitonin), TSH, and also pituitary and hypothalamic hormones, and to neurosensory stimuli. The diversity of multihormonal resistance contributes to the various phenotypes of the disease. Some clinical discomfort and medical consequences of the disease can be treated or prevented with hormone supplementation or modulation.

Hearing↗
PubMed1991

Influence of color on odor identification and liking ratings.

The effects of color on odor identification were tested under color appropriate, inappropriate, and blindfolded conditions. Subjects made fewer errors in identifying solutions that were colored appropriately (e.g., red-cherry) than in either the blindfolded condition, where there were no color cues, or the inappropriate color condition (e.g., red-lemon). Identification accuracy was greatest for typical odor-color combinations (e.g., red-cherry) compared with appropriate but nontypical odor-color combinations (e.g., red-watermelon). Response latencies were fastest for odors in the appropriately colored solutions. Subjects also rated appropriate color-odor combinations as most pleasant. However, this effect is probably due to the increase in identification accuracy of the appropriately colored solutions. In all three conditions, correctly identified odors were liked more than odors that were not correctly identified. Thus, color is an important perceptual variable in odor identification because it biases subjects toward a color category that facilitates identification if the color is "correct". This ability to identify an odor in turn influences the affective response to the odor.

Adult↗
PubMed1990

Congenital anosmia.

Seven patients with congenital anosmia underwent detailed chemosensory evaluation, followed by the performance of biopsies of the olfactory region. Olfactory epithelium was not found in any of the biopsy specimens. It appears therefore that patients with congenital anosmia lack any olfactory epithelium. Several possible explanations for this finding are discussed. The most attractive hypothesis is that the olfactory placode forms either normally or abnormally during development but later degenerates and is replaced with respiratory epithelium. Only one patient in our series had congenital anosmia in association with a syndrome (Kallmann's syndrome), indicating that congenital anosmia is found more often as an isolated symptom.

Adolescent↗