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At least 19 recordsLinked to original sources
PubMed1991

Smell and taste disorders, a study of 750 patients from the University of Pennsylvania Smell and Taste Center.

Smell and taste disorders are common in the general population, yet little is known about their nature or cause. This article describes a study of 750 patients with complaints of abnormal smell or taste perception from the University of Pennsylvania Smell and Taste Center, Philadelphia. Major findings suggest that: chemosensory dysfunction influences quality of life; complaints of taste loss usually reflect loss of smell function; upper respiratory infection, head trauma, and chronic nasal and paranasal sinus disease are the most common causes of the diminution of the sense of smell, with head trauma having the greatest loss; depression frequently accompanies chemosensory distortion; low body weight accompanies burning mouth syndrome; estrogens protect against loss of the sense of smell in postmenopausal women; zinc therapy may provide no benefit to patients with chemosensory dysfunction; and thyroid hormone function is associated with oral sensory distortion. The findings are discussed in relation to management of patients with chemosensory disturbances.

Burning Mouth Syndrome↗
PubMed1995

Unawareness of smell loss in normal aging and Alzheimer's disease: discrepancy between self-reported and diagnosed smell sensitivity.

Awareness of loss in smell sensitivity was assessed in 80 normal elderly subjects, 80 patients with probable Alzheimer's disease (AD), and 80 patients with sinusitis by comparing measured smell sensitivity to questionnaire-based, self-reported sensitivity. Both AD patients and sinusitis patients had significantly poorer diagnosed smell sensitivity than the normal elderly. Both patient groups had thresholds which on average were about nine times more concentrated than those of the normal elderly. However, 74% of the AD patients and 77% of the normal elderly with smell loss reported normal smell sensitivity. In contrast, only 8% of the sinusitis patients with loss reported normal smell sensitivity.

Adolescent↗
PubMed1975

[Functional investigation of the sense of smell and its role in the diagnosis of sense of smell disorders].

The authors deal in turn with: -- the anatomical classification of disorders of the sense of smell, -- the various clinical and instrumental methods used to investigate the sense of smell, -- a practical method of investigation enabling the topography and the nature of the lesion to be found when a patient presents with a disorders involving the sense of smell. Finally, a classification of the various disorders which may be observed is suggested based on the topography of the lesion in the olfactory system.

Humans↗
PubMed1995

Cross-adaptation of sweaty-smelling 3-methyl-2-hexenoic acid by a structurally-similar, pleasant-smelling odorant.

Cross-adaptation has been interpreted as a measure of the degree to which odors share common sensory channels. How structural similarity, in the absence of perceptual similarity, influences cross-adaptation is unknown. The present study assessed cross-adaptation by structurally similar, but perceptually different, odorants. Magnitude estimates for a 10:1 mixture of (E)- and (Z)-3-methyl-2-hexenoic acid (3M2H), a principal component of human underarm odor, decreased following adaptation to a mixture of (E)- and (Z)-ethyl esters of 3M2H (EE3M2H), which possess a pleasant, fruity odor. Cross-adaptation was asymmetric; adaptation to 3M2H did not significantly affect the perceived intensity of EE3M2H. By contrast, there was no significant cross-adaptation between 3M2H and the fruity-smelling ethyl esters of its homologues, 3-methyl-2-octenoic acid (EE3M20) and 3-methyl-2-pentenoic acid (EE3M2P). Similarity ratings revealed no differences among the three ethyl esters in their perceptual similarity to 3M2H (i.e. all were rated equally dissimilar to 3M2H). Molecular modeling studies revealed no difference in the charge distribution of these molecules. Rather, differences in the shape and size of the hydrophobic part of the molecule may determine the extent of cross-adaptation. These results demonstrate that structurally-similar, yet perceptually-distinct, odorants may cross-adapt and suggest that the extent of cross-adaptation may be affected by the degree of structural, as well as perceptual, similarity.

Adaptation, Physiological↗
PubMedDate not supplied

[The chemical senses of smell and taste in the course of life - changes of smell and taste perception].

Based on own experiments and on the results of other laboratories changes of olfactory and gustatory perception throughout the life span are discussed. Similar to other modalities gustatory and olfactory thresholds generally rise while age increases. Certain gustatory substances (amino acids), however, show a decrease of thresholds if 70 years old subjects are compared with 20 years old ones. Preference for certain odorants (strawberry, vanillin) are reported to increase in higher age (after initial higher peaks in young age).

Adolescent↗
PubMedDate not supplied

Lateralization of brain activation to imagination and smell of odors using functional magnetic resonance imaging (fMRI): left hemispheric localization of pleasant and right hemispheric localization of unpleasant odors.

PURPOSE: Our goal was to use functional MRI (fMRI) of brain to reveal activation in each cerebral hemisphere in response to imagination and smell of odors. METHOD: FMRI brain scans were obtained in 24 normal subjects using multislice fast low angle shot (FLASH) MRI in response to imagination of banana and peppermint odors and in response to smell of corresponding odors of amyl acetate and menthone, respectively, and of pyridine. Three coronal sections selected from anterior to posterior brain regions were used. Similar studies were obtained in two patients with hyposmia using FLASH MRI and in one patient with hyposmia using echo planar imaging (EPI) both before and after theophylline treatment that returned smell function to or toward normal in each patient and in two patients with birhinal phantosmia (persistent foul odor) and global phantogeusia (persistent foul taste) with FLASH and EPI fMRI before and after treatment with neuroleptic drugs that inhibited their phantosmia and phantogeusia. Activation images were derived using correlation analysis. Ratios of hemispheric areas of brain activation to total hemispheric brain areas were calculated for FLASH fMRI, and numerical counts of pixel clusters in each hemisphere were made for EPI studies. Total pixel cluster counts in localized regions of each hemispheric section were also obtained. RESULTS: In normal subjects, activation generally occurred in left (L) > right (R) brain hemisphere in response to banana and peppermint odor imagination and to smell of corresponding odors of amyl acetate and menthone. Whereas there were no overall hemispheric differences for pyridine odor, activation in men was R > L hemisphere. Although absolute activation in both L and R hemispheres in response to banana odor imagination and amyl acetate smell was men > women, the ratio of L to R activation was women > men. In hyposmic patients studied by FLASH fMRI, activation to banana odor imagination and amyl acetate smell was L > R hemisphere both before and after theophylline treatment. In the hyposmic patient studied with EPI before theophylline treatment, activation to banana and peppermint odor imagination and to amyl acetate, menthone, and pyridine smell was R > L hemisphere; after theophylline treatment restored normal smell function, activation shifted completely with banana and peppermint odor imagination and amyl acetate and menthone smell to L > R hemisphere, consistent with responses in normal subjects. However, this shift also occurred for pyridine smell, which is opposite to responses in normal control subjects. In patients with phantosmia and phantogeusia, activation to phantosmia and phantogeusia before treatment was R > L hemisphere; after treatment inhibited phantosmia and phantogeusia, activation shifted with a slight L > R hemispheric lateralization. Localization of all lateralized responses indicated that anterior frontal and temporal cortices were brain regions most involved with imagination and smell of odors and with phantosmia and phantogeusia presence. CONCLUSION: Imagination and smell of odors perceived as pleasant generally activated the dominant or L > R brain hemisphere. Smell of odors perceived as unpleasant and unpleasant phantosmia and phantogeusia generally activated the contralateral or R > L brain hemisphere. With remission of phantosmia and phantogeusia, hemispheric activation was not only inhibited, but also there was a slight shift to L > R hemispheric predominance. Predominant L > R hemispheric differences in brain activation in normal subjects occurred in the order amyl acetate > menthone > pyridine, consistent with the hypothesis that pleasant odors are more appreciated in L hemisphere and unpleasant odors more in R hemisphere. Anterior frontal and temporal cortex regions previously found activated by imagination and smell of odors and phantosmia and phantogeusia perception accounted for most hemispheric differences.

Adult↗
PubMed1985

The occupational meaning of smell.

The sense of smell has its meaning for a successful performance of certain occupations. It has further a protective meaning. The acuity of smell often changes for different reasons. The prolonged or repeated smelling is combined with the process of smell adaptation, fatigue and habituation. They diminish the flavour sensations and increase the risk of work accidents. Some chemical compounds are characterized by a quick and high adaptation. The occupational changes of smell can be peripheral or central. The qualitative changes of the smell perception are numerous, but they have little sense in industrial hygiene. The hypersensibilisation can be temporal or lasting, where a change of profession is sometimes inevitable. The values of smell thresholds (detection, recognition, distinction) of 25 substances are given. The sensitivity of smell is greater at the smell threshold concentrations. The smell thresholds are put among the main basic properties of chemical compounds which decide about the values of MAC and about the possibilities of their passing over. 68 substances ranged according to their basic characteristics in three groups were studied. There was statistical dependence between the molecular weight, the boiling point, smell thresholds of detection and recognition. In two groups of matters there was a dependence between the threshold of irritation and the smell threshold of recognition and distinction. The regression was linear with the majority of dependencies.

Dose-Response Relationship, Drug↗
PubMed1995

Taste and smell losses in HIV infected patients.

Human immunodeficiency virus (HIV-1) associated wasting is an increasingly common clinical manifestation of AIDS. The pathogenesis of wasting is multifactorial and includes reduced caloric intake as a major contributing mechanism. The perceptions of taste and smell play an important role in stimulating caloric intake and in optimizing nutrient absorption through cephalic phase reflexes. The purpose of this study was to evaluate the degree of losses in taste and smell function that occur in subjects infected with HIV. Taste and smell function was evaluated in 40 HIV infected individuals and 40 healthy control subjects matched for age, sex, race, smoking behavior, and number of years of education. Chemosensory tests administered to subjects included taste and smell detection thresholds, taste and smell memory tests, taste and smell discrimination tests, and taste and smell identification tasks. Significant differences were observed between experimental and control subjects in glutamic acid taste detection threshold (p < 0.001), quinine hydrochloride taste detection threshold (p < 0.001), menthol smell detection threshold (p < 0.001) and in the taste identification task (p = 0.006). Overall the results suggest abnormalities in the peripheral and central nervous systems, and subjective distortion of taste and smell. A significant correlation was not established between CDC classification of HIV infection and taste and smell function, although trends were observed suggesting worsening function with progression of HIV disease. These results document significant taste and smell losses in HIV infected subjects which may be of clinical significance in the development or progression of HIV associated wasting.

Acquired Immunodeficiency Syndrome↗
PubMedDate not supplied

Taste and smell phantoms revealed by brain functional MRI (fMRI).

PURPOSE: Our goal was to demonstrate the appearance of phantom tastes and smells (phantageusia and phantosmia, respectively) by use of functional MRI (fMRI) of the brain and to demonstrate the efficacy of drug treatment that inhibited both the subjective presence of these phantoms and the fMRI brain activation initiated by these phantoms. METHOD: Multislice FLASH MR or echo planar MR brain scans were obtained in two patients with phantageusia and phantosmia in response to memory of two tastants (salt and sweet); memory of two odors (banana and peppermint); actual smell of amyl acetate, menthone, and pyridine; and memory of phantom tastes and smells before and after treatment with thioridazine and haloperidol. Activation images were derived using correlation analysis, and ratios of brain area activated to total brain area were obtained. RESULTS: Prior to treatment, both patients experienced persistent birhinal and global oral obnoxious tastes and smells in the absence of any external stimulus. The fMRI response to memory of phantoms was activation in sensory-specific brain regions for taste and smell, respectively. fMRI activation was greater than for memory of any tastant or odorant or for actual smell of any odor. After treatment with thioridazine or haloperidol, which successfully inhibited each phantom in each patient, fMRI response to phantom memory was significantly inhibited and was significantly lower than for memory of any tastant or odorant or actual smell of any odorant. CONCLUSION: These results demonstrate that (a) phantom taste and smell can be revealed by fMRI brain activation, (b) brain activation in response to taste and smell phantoms is localized in sensory-specific brain regions for taste and smell, respectively, (c) brain activation in response to memory of each phantom initiated the greatest degree of activation we had previously measured, and (d) treatment with thioridazine or haloperidol inhibited both the presence of each phantom and its associated fMRI brain activation. This is the first study in which phantom tastes and smells have been demonstrated by an objective technique and treatment that inhibited the phantoms was characterized by objective inhibition of fMRI activation. These two patients represent a relatively common group that may be classified as having primary phantageusia and phantosmia distinct from those with phantoms or auras secondary to neurological, migrainous, psychiatric, or other causes.

Brain Mapping↗
PubMed1997

Sensation of smell does not determine nutritional status in patients with cystic fibrosis.

Poor nutritional status in patients with cystic fibrosis (CF) is associated with increased mortality. Patients with CF often have a decreased sensation of smell secondary to recurrent sinus infections or sinus surgery; in other CF populations, a decreased sensation of smell has been associated with poor nutritional status. We hypothesized that a decreased sensation of smell would be associated with worse nutritional status in patients with CF. We studied 50 (26 F and 24 M) of 58 consecutive patients with CF (86%) aged 14-53 years (28 +/- 8; mean +/- SD) who attended the University of Washington Medical Center from June 1994 to March 1995 and who agreed to participate. Demographic information was obtained, and nutritional status was assessed by ideal body weight, arm muscle area, arm fat area, pancreatic sufficiency, insulin-requiring diabetes, vitamins A and E levels, albumin, iron, iron binding capacity, ferritin, cholesterol, and zinc levels. Objective sensation of small was examined (Sensonics, Philadelphia, PA), a sinus compacted tomogram (CT) was performed, and a questionnaire for prior sinus symptoms, sinus surgery, medications, and subjective sensation of smell was administered. Twenty-seven of 49 subjects (55%) had an objective decrease in sensation of smell, 23/50 (46%) had had prior sinus surgery. 46/50 (92%) were pancreatic insufficient, and 8/50 (16%) were insulin-requiring diabetics. Weight for height ranged from the 38th to 157th percentile (100 +/- 18; mean +/- SD). Arm muscle area ranged from the < 5th to the 75th percentile (25 +/- 23; mean +/- SD). Arm fat area ranged from the < 5th to the 95th percentile (45 +/- 39; mean +/- SD). Sinus CT scans were abnormal in all patients (100%). Patients with anosmia were more likely to have had sinus surgery, but their nutritional status was no different from that of patients with a normal sensation of smell. We conclude that decreased sensation of smell is common in patients with CF, especially those with prior sinus surgery. Subjective sensation of smell and sinus CT scans were unreliable indicators of a decreased objective sensation of smell. In this pilot study, no association was found between sensation of smell and nutritional status.

Adolescent↗
PubMed1975

Defects of taste and smell in patients with hypothyroidism.

Taste and smell functions were measured in 18 unselected patients with untreated primary hypothyroidism, and in 15 of the 18 patients after treatment with thyroid hormones. Before treatment, 9 of the 18 patients (50 per cent) were aware of some alteration in their sense of taste, and 7 of the 18 patients (39 per cent) were aware of some alteration in their sense of smell. Distoritions of tase (dysgeusia) and smell (dysosmia) were frequent complaints among the untreated patients; dysgeusia was observed by 7 patients (39 per cent) and dysosmia by 3 patients (17 per cent). Median detection and recognition thresholds for four taste stimuli salt (sodium chloride), sweet (sucrose), sour (hydrochloric acid) and bitter (urea), and for two smell stimuli (pyridine and nitrobenzene), were determined in each patient before and after treatment with thyroid hormones. Before treatment, decreased taste acuity (hypogeusia) for at least one stimulus was observed in 14 of the patients (83 per cent); the most common abnormalities were in the detection and recognition of bitter stimuli. Median detection thresholds for both smell stimuli were also markedly elevated (hyposmia) before therapy. Treatment with throid hormones largely reversed both the taste and smell defects. In one patient, taste and smell abnormalities were completely corrected after 16 days of treatment with thyroxine. This study indicates that taste and smell defects are common clinical abnormalities in primary hypothyroidism, and suggests that these defects may contribute to the anorexia and lack of interest in eating which are frequently observed.

Adult↗
PubMed1986

Role of thought, sight, smell, and taste of food in the cephalic phase of gastric acid secretion in humans.

The relative importance of thought, sight, smell, and taste of food in the cephalic phase of gastric acid secretion has not been studied systematically. We found that discussing appetizing food for 30 min (without sight, smell, or taste) increased acid secretion from 4 to 13 mmol/h in healthy human subjects (p less than 0.001) and also increased serum gastrin concentrations significantly (p less than 0.02). Discussing food resulted in an acid secretory response that averaged 66% +/- 10% of the response to modified sham feeding, which activates thought, sight, smell, and taste. Discussing topics other than food (e.g., current events, sports) did not increase acid secretion significantly. The sight of appetizing food (without smell or taste), the smell of appetizing food (without sight or taste), or the combination of sight and smell (without taste) also increased acid secretion and serum gastrin concentrations significantly. However, sight and smell were significantly less potent stimulants of acid secretion than sham feeding, with responses averaging only 23%-46% of the response to sham feeding. These studies indicate that thinking about food is a potent stimulant of gastric secretion in healthy humans. Moreover, the sight and smell of food increase gastric acid secretion and serum gastrin concentrations, probably by provoking thoughts related to food.

Adult↗
PubMed1986

[Role of smell in the food-seeking activity of newborn puppies].

In 36 newborn puppies, positive responses to the mother hair smell appear immediately after birth which indicates emanation of a corresponding pheromone. Within 6 hrs after isolation from the mother, the preference for her smell is reduced and substituted with a response to hair smell of other females. Learning of the motor to the mother smell seems to occur yet in prenatal period. The inherent negative response to cat's smell does not depend on the duration of the puppy isolation from the mother. During first 3 days of life (the 1st period), learning of the food-seeking response to an artificial smell is possible (imprinting). Starting from the 4th-5th day of life, the ability to form a food-seeking response to smell disappears. In 11-12 day old puppies, a conditioning can be achieved by means of combining smell with feeding 5-6 times. The role of olfaction in the puppy food-seeking behaviour during ontogenesis, is discussed.

Animals↗
PubMed1989

Characteristics of rat lateral hypothalamic neuron responses to smell and taste in emotional behavior.

Single unit activity in the lateral hypothalamus (LHA) of the rat was recorded while the animal learned to discriminate cue signals. Normally preferred potables (glucose, orange, or grape solution) or intracranial self-stimulation (ICSS) were used as rewards. Electric shock or tail pinch were used as aversive stimuli. The same behavior, licking, was the response required to either obtain the rewarding stimuli or avoid the aversive ones. For positive reinforcement a rat was rewarded with fluid or ICSS upon licking a spout presented in front of its mouth. In negative reinforcement experiments, an aversive stimulus, electric shock or tail pinch, was applied if the rat did not lick the spout. Solutions having smell only, taste only, or smell-plus-taste, were prepared from oranges or grape extract. Of 392 neurons analyzed, 256 responded differentially to rewarding and aversive stimuli, and 138 of these were tested with the 3 different solutions. Similar LHA neural responses occurred during actual drinking of the 3 kinds of solutions, as well as on recognition of the cue signal. Responses to smell only had shorter latency than responses to taste only. Neural activity in response to solutions that could be both smelled and tasted was the sum of activity in response to taste-only solutions plus that in response to smell-only solutions. Cue signal responses were rapidly acquired, usually within 2-5 trials, for both taste-only and smell-only solutions. The results indicate the integration of both taste and olfactory information by the same LHA neurons, and these neurons are involved in cue signal learning. Present results of LHA neuronal responses to taste and smell suggest that the intensity of gustation and olfaction may add together to enhance instinctive hedonic sensations. These neurons are involved in the formation of stimulus-reinforcement association in learning, and in elicitation of conditioned emotional responses.

Action Potentials↗