Olfactory disturbances as the initial or most prominent symptom of multiple sclerosis.
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Adult↗
Biomedical subjects
R L Doty
Publications and source records attributed to R L Doty.
Olfactory function in Parkinson's disease subtypes.
Decreased olfactory function commonly occurs in idiopathic Parkinson's disease (PD), regardless of stage, treatment, or duration of disease. In the present study, we sought to determine whether different subtypes of PD, categorized according to well-defined clinical criteria, evidence different degrees of olfactory dysfunction. Significantly different scores on the University of Pennsylvania Smell Identification Test (UPSIT) were present between patients with benign PD and malignant PD (respective means [SD] = 22.51 [8.50] and 17.38 [6.29]) and between tremor-predominant PD and postural instability-gait disorder (PIGD)-predominant PD (23.43 [8.18] versus 17.35 [6.00]). No statistically significant differences in UPSIT scores were observed between young-onset and older-onset PD patients. Women outperformed men in most subtypes examined.
Adult↗
The effect of human olfactory biopsy on olfaction: a preliminary report.
Normal human olfactory function is subject to a wide variety of factors. Although biopsy of human olfactory neuroepithelium has been reported by several researchers, there are no studies which have evaluated the effect of this procedure on olfactory function. In this retrospective study, we sought to determine if tissue removal from the olfactory cleft has an adverse influence on the sense of smell. Nineteen subjects underwent bilateral olfactory testing and subsequent endoscopic olfactory mucosal biopsy. All subjects were retested 6 weeks to 1 year after olfactory neuroepithelial biopsy. No statistical difference was found between olfactory tests performed before or after biopsy. These data suggest that biopsy of human olfactory neuroepithelium has no discernible adverse effect on the ability to smell.
Alzheimer Disease↗
Neuroimaging in patients with olfactory dysfunction.
This review summarizes neuroimaging findings in patients with olfactory dysfunction. Neuroimaging techniques offer a valuable means for evaluating and distinguishing disorders of olfaction. The new or refined techniques make it possible to pinpoint the anatomic and pathologic changes of many disorders of the sinonasal cavity and brain that cause olfactory deficits. From an anatomic point of view, the causes of olfactory deficits generally can be classified as peripheral or central (intracranial). In the assessment of the peripheral causes, CT and MR imaging reveal anatomic information and structural changes, enable a differential diagnosis, and provide a road map for surgical intervention. In the evaluation of the central causes, MR imaging, positron emission tomography, or single-photon emission computed tomography can provide the links between olfactory dysfunction and structural or functional changes in the brain.
Brain Diseases↗
Tests of human olfactory function: principal components analysis suggests that most measure a common source of variance.
It is not known whether nominally different olfactory tests actually measure dissimilar perceptual attributes. In this study, we administered nine olfactory tests, including tests of odor identification, discrimination, detection, memory, and suprathreshold intensity and pleasantness perception, to 97 healthy subjects. A principal components analysis performed on the intercorrelation matrix revealed four meaningful components. The first was comprised of strong primary loadings from most of the olfactory test measures, whereas the second was comprised of primary loadings from intensity ratings given to a set of suprathreshold odorant concentrations. The third and fourth components had primary loadings that reflected, respectively, mean suprathreshold pleasantness ratings and a response bias measure derived from a yes/no odor identification signal detection task. In an effort to adjust for potential confounding influences of age, gender, smoking, and years of schooling on the component structure, a matrix of residuals from a multiple regression analysis, which included these variables, was also analyzed. A similar component pattern emerged. Overall, these findings suggest, in healthy subjects spanning a wide range, that (1) a number of nominally distinct tests of olfactory function are measuring a common source of variance, and (2) some suprathreshold odor intensity and pleasantness rating tests may be measuring sources of variance different from this common source.
Adult↗
Olfactory testing differentiates between progressive supranuclear palsy and idiopathic Parkinson's disease.
Olfactory dysfunction occurs in most patients with idiopathic Parkinson's disease (PD). In this study, we sought to determine whether such dysfunction is also present in progressive supranuclear palsy (PSP), a condition which shares a number of motor symptoms with PD and is commonly misdiagnosed as PD. We administered the University of Pennsylvania Smell Identification Test, a standardized test of odor identification ability, to 21 PSP patients; 17 also received a forced-choice odor detection threshold test. We compared the olfactory test scores to those obtained from PD patients and normal controls matched to the PSP patients on the basis of age, sex, and smoking habits. Overall, the olfactory function of the PSP patients was markedly superior to that of the PD patients and did not differ significantly from that of the normal controls. There was no association in either the PSP or PD patient groups between (1) the olfactory test scores and (2) measures of motor symptom severity, disease stage, and medication usage. These findings demonstrate that patients with PSP and PD differ markedly in their ability to smell and suggest that olfactory testing may be useful in their differential diagnosis.
Aged↗
Endoscopic human olfactory biopsy technique: a preliminary report.
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Biopsy↗
Smell and taste function in the visually impaired.
Surprisingly few quantitative studies have addressed the question of whether visually impaired individuals evidence, perhaps in compensation for their loss of vision, increased acuteness in their other senses. In this experiment we sought to determine whether blind subjects outperform sighted subjects on a number of basic tests of chemosensory function. Over 50 blind and 75 sighted subjects were administered the following olfactory and gustatory tests: the University of Pennsylvania Smell Identification Test (UPSIT); a 16-item odor discrimination test; and a suprathreshold taste test in which measures of taste-quality identification and ratings of the perceived intensity and pleasantness of sucrose, citric acid, sodium chloride, and caffeine were obtained. In addition, 39 blind subjects and 77 sighted subjects were administered a single staircase phenyl ethyl alcohol (PEA) odor detection threshold test. Twenty-three of the sighted subjects were employed by the Philadelphia Water Department and trained to serve on its water quality evaluation panel. The primary findings of the study were that (a) the blind subjects did not outperform sighted subjects on any test of chemosensory function and (b) the trained subjects significantly outperformed the other two groups on the odor detection, odor discrimination, and taste identification tests, and nearly outperformed the blind subjects on the UPSIT. The citric acid concentrations received larger pleasantness ratings from the trained panel members than from the blind subjects, whose ratings did not differ significantly from those of the untrained sighted subjects. Overall, the data imply that blindness, per se, has little influence on chemosensory function and add further support to the notion that specialized training enhances performance on a number of chemosensory tasks.
Blindness↗
Lack of major olfactory dysfunction in MPTP-induced parkinsonism.
The olfactory function of 6 patients whose parkinsonism was the result of intravenous administration of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP) was compared to that of 12 age-matched patients with idiopathic Parkinson's disease (PD) and 10 age-matched normal control subjects. Unlike their PD counterparts, the olfactory test scores of patients with MPTP-induced parkinsonism did not differ significantly from those of control subjects. These findings suggest that MPTP-induced parkinsonism, unlike idiopathic PD, is unaccompanied, on average, by major alterations in the ability to smell.
1-Methyl-4-phenyl-1,2,3,6-tetrahydropyridine↗
Influences of hypothyroidism on the taste detection performance of rats: a signal detection analysis.
The influences of hypothyroidism on behavioral measures of the taste function in male and female Long-Evans rats were determined. Experimental rats' preferences for and ability to detect NaCl, HCl, sucrose, and quinine sulfate were examined before, during, and after 9 weeks of maintenance on 0.1% propylthiouracil (PTU), an agent that produces marked hypothyroidism, with similar determinations made for control animals. Despite significant decreases in PTU-treated rats' serum triiodothyronine (T3) and thyroxin (T4), there were no changes in sensitivity or responsivity to the target tastants. However, altered preferences for NaCl, HCl, and quinine sulfate were observed for PTU-treated rats; elevated consumption of HCl and quinine sulfate was present at the end of the study when serum T3 and T4 had returned to near-baseline levels. The data confirm observations that PTU-induced hypothyroidism alters rats' taste preference behavior.
Animals↗
Bilateral olfactory dysfunction in early stage treated and untreated idiopathic Parkinson's disease.
Decreased olfactory function is among the first signs of idiopathic Parkinson's disease (PD). Whether such dysfunction is present to the same degree on both sides of the nose, however, is unknown. Furthermore, whether the deficit results from or is influenced by anti-Parkinsonian medications has not been definitely established. Odour identification ability was evaluated on the left and right sides of the nose in 20 early-stage untreated PD patients, 20 early-stage treated PD patients, and 20 controls. In all cases, the PD related olfactory dysfunction was bilateral and no difference was observed between the test scores of patients taking or not taking drugs for PD. Although asymmetries of unsystematic direction were present in the test scores of some PD patients, similar asymmetries were observed in the controls and the asymmetries were not related to the side of the major motor dysfunction. As in earlier work, no relation was present between the olfactory test scores and the degree of tremor, rigidity, bradykinesia, or gait disturbance at the time of testing. These findings indicate that the olfactory dysfunction of early stage PD is robust, typically of the same general magnitude on both sides of the nose, and uninfluenced by anti-Parkinsonian medications.
Age Factors↗
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↗
Influence of adrenalectomy on the odor detection performance of rats.
The influence of adrenalectomy (ADX) on the odor detection performance of male Long-Evans rats was assessed using high-precision olfactometry and a go/no-go operant signal detection task. Nonparametric signal detection measures of sensitivity and responsivity, as well as measures of S+ response latency, the number of aborted trials, and session time, were obtained in daily 250-trial test sessions prior to and after adrenalectomy. Four ADX animals were tested using the odorant pyridine, three using the odorant eugenol, and two using the odorant ethyl acetate. Nine other rats served as sham-operated controls. Neither odor detection nor related nonsensory performance measures were influenced by adrenalectomy or sham-operation procedures. These results imply that adrenalectomy has little or no influence on the odor detection performance of the rat.
Adrenal Cortex↗
Olfactory capacities in aging and Alzheimer's disease. Psychophysical and anatomic considerations.
Age-related alterations in the ability to smell are well documented. For example, more than three-fourths of individuals over the age of 80 have major difficulty detecting and identifying odors. Furthermore, olfactory dysfunction is among the first signs of Alzheimer's disease (AD). Indeed, the olfactory pathways of patients with AD evidence disproportionate numbers of neuritic plaques and neurofibrillary tangles relative to other sensory pathways, suggesting that the olfactory system may be the site of first involvement of the AD process. In this article, the literature related to age- and AD-related alterations in olfactory perception has been briefly reviewed, and several current hypotheses regarding the physiologic basis for these changes discussed.
Aged↗
Odor identification deficit of the parkinsonism-dementia complex of Guam: equivalence to that of Alzheimer's and idiopathic Parkinson's disease.
Olfactory dysfunction is among the first signs of Alzheimer's disease (AD), idiopathic Parkinson's disease (PD), and the parkinsonism-dementia complex (PDC) of Guam. We have recently demonstrated that the odor identification and detection deficits of patients with PD are equivalent to those of patients with mild AD when subtle differences in cognitive function are statistically controlled for by analysis of covariance. In contrast, patients with progressive supranuclear palsy (PSP) and patients with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism evidence olfactory function much more similar to that of normal controls. In the present study, we administered the University of Pennsylvania Smell Identification Test and the Picture Identification Test to 24 patients with early signs of the PDC of Guam and statistically compared their test scores to those of 24 early-stage AD and 24 early-stage PD patients of similar age and gender from the United States mainland. Although the PDC group evidenced slightly more difficulty in identifying pictures than did the other 2 groups, the odor identification deficit associated with this disorder was of the same magnitude as that observed in AD and PD, suggesting that olfactory testing cannot be used to distinguish among these 3 diseases and that the olfactory dysfunction of these disorders may reflect a common neurologic substrate.
Adult↗
Olfactory dysfunction in three neurodegenerative diseases.
Olfactory dysfunction is among the first signs of Alzheimer's disease (AD), idiopathic Parkinson's disease (PD), and the parkinsonism-dementia complex (PDC) of Guam. We have recently demonstrated that the odor identification and detection deficits of patients with PD are equivalent to those of patients with mild AD when subtle differences in cognitive function are statistically controlled for by analysis of covariance. In contrast, patients with progressive supranuclear palsy (PSP) and patients with 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP)-induced parkinsonism evidence olfactory function much more similar to that of normal controls. In the present study, we administered the University of Pennsylvania Smell Identification Test and the Picture Identification Test to 24 patients with early signs of the PDC of Guam and statistically compared their test scores to those of 24 early-stage AD and 24 early-stage PD patients of similar age and gender from the United States mainland. Although the PDC group evidenced slightly more difficulty in identifying pictures than did the other 2 groups, the odor identification deficit associated with this disorder was of the same magnitude as that observed in AD and PD, suggesting that olfactory testing cannot be used to distinguish among these 3 diseases and that the olfactory dysfunction of these disorders may reflect a common neurologic substrate.
Adult↗
Taste responses of dogs to ethylene glycol, propylene glycol, and ethylene glycol-based antifreeze.
Although it is widely believed that ethylene glycol-based antifreeze (AF) is an attractive tastant to dogs and other animals, empirical data on this point are not available. In experiment 1, we examined the propensity of 178 adult mixed-breed dogs to approach, sniff, and lick a concentration of AF commonly used in automotive cooling systems (50%). Despite the fact that most of the dogs approached and sniffed the AF in these 5-minute tests, only 9% initiated lick responses and most of these were brief and not followed by additional licking. In experiment 2, the lick responses of five gastric-cannulated dogs to aqueous solutions of 20% sucrose, 50% ethylene glycol, 50% propylene glycol, water, and 50% AF were examined in 14-minute tests before and after periods of food and water deprivation. Under the latter conditions, 2 of the 5 dogs drank amounts of ethylene glycol that would have been lethal to uncannulated dogs. None of the five dogs drank potentially lethal amounts of AF. The preference order for these tastants was sucrose greater than water greater than ethylene glycol greater than AF = propylene glycol. Although these findings question the general belief that AF is highly palatable to most dogs, they do imply that large individual differences in responsiveness exist and that AF ingestion is likely influenced by motivational state. Furthermore, they suggest the possibility that unpleasant-tasting additives could be successfully developed to eliminate the ingestion of AF, because the initial attractiveness of AF is relatively low. Such additives would have to be stable in vehicular cooling systems and not adversely affect the functional aspects of AF performance.
Animals↗