Examinando por Autor "Doty, Richard L."

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    Dysfunctional chemosensation in myasthenia gravis : A systematic review
    (2013-09) Leon Sarmiento, Fidias E.; Leon Ariza, Daniel S.; Doty, Richard L.
    Myasthenia gravis has traditionally been viewed as a disorder that solely affects the neuromuscular junction within the peripheral nervous system. However, there is now evidence that the cholinergic dysfunction of this disorder may be more widespread than previously believed. This article provides a systematic review of the studies that examined smell and taste function in myasthenia gravis. Methods: We analyzed studies that reported chemosensory function alterations in patients with myasthenia gravis. PubMed, MEDLINE, Web of Science, EMBASE, and SciELO, searched to identify articles published from January 1950 through December 2012, were supplemented by relevant articles. The following information was identified from each article: the number of patients, number of controls (if any), clinical stage of patients, neurological involvement, serological state, taste or smell involvement, chemosensory test used, and country of publication. Results: Ten studies reporting smell and taste function and dysfunction in patients with myasthenia gravis were identified, most of which were case reports commenting on apparent abnormalities in the taste system. The sole empirical study that investigated taste function, however, was negative, suggesting that some reports of taste loss may reflect olfactory loss. One study clearly documented olfactory dysfunction in patients with myasthenia gravis, dysfunction most likely attributable to altered central nervous system cholinergic function. Conclusions: Chemosensory dysfunction has been reported in a number of patients with myasthenia gravis. Given the close association between complaints of taste dysfunction and loss of flavor sensations secondary to olfactory system damage, quantitative testing should be used to accurately assess the nature and degree of the dysfunction present in this debilitating disorder.
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    The lateralized smell test for detecting Alzheimer's disease : Failure to replicate
    (2014-05-15) Doty, Richard L.; Bayona, Edgardo A.; Leon Ariza, Daniel S.; Cuadros, Juan; Chung, Inna; Vazquez, Britney; Leon Sarmiento, Fidias E.
    Objectives A widely publicized study by Stamps, Bartoshuk and Heilman (2013) reported that a simple measure of left:right naris differences in the ability to detect the odor of peanut butter is a sensitive marker of Alzheimer's disease (AD). AD patients were said to have abnormal smell function on the left side of the nose and normal function on right side of the nose. In light of its implications for medical practice and the world-wide publicity that it engendered, we sought to replicate and expand this work. Methods Two studies were performed. In the first, 15 AD patients were tested according to the procedures described by Stamps et al. in which the nostril contralateral to the tested side was occluded by the patient using lateral pressure from the index finger. Since this can potentially distort the contralateral naris, we repeated the testing using tape for naris occlusion. In the second, 20 AD patients were administered 20 odors of the University of Pennsylvania Smell Identification Test (UPSIT) to each side of the nose, with the contralateral naris being closed with tape. In both studies, the order of the side of testing was systematically counterbalanced. Results No evidence of a left:right asymmetry on any test measure was observed. Conclusion Although hyposmia is well-established in AD, no meaningful asymmetry in smell perception is apparent. If olfactory function on the right side of the nose was normal as claimed, then AD patients should exhibit normal function when tested bilaterally, a phenomenon not seen in dozens of AD-related olfactory studies.
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    Smell status in functional movement disorders : New clues for diagnosis and underlying mechanisms
    (2019) Leon Sarmiento, Fidias E.; Bayona Prieto, Jaime; Leon Ariza, Juan S.; Leon Ariza, Daniel S.; Jacob, Alexandra E.; LaFaver, Kathrin; Doty, Richard L.
    Objective: Functional movement disorders (FMDs) mimic a range of movements, neuropsychiatric and neurodegenerative disorders known to have smell dysfunction, which has been neglected in terms of its application to FMD. We aim to determine the smell status in FMD patients tested by a non-invasive, reliable and validated olfactory test. Patients and methods: We quantitatively assessed in thirty-five FMD patients their smell status and compared it to that of healthy age- and sex-matched controls, and of patients with Parkinson’s disease (PD). All participants were administered the Brief Smell Identification Test (B-SIT), a standardized short version of the University of Pennsylvania Smell Identification Test (UPSIT). The Picture Identification Test (PIT), a visual test analogous in content and form to the UPSIT designed to control for non-olfactory cognitive confounds, was also administered. Results: The B-SIT scores of the FMD patients were higher than those from PD patients [respective means (standard deviations: SDs) = FMD, 9.54 (1.57); PD, 4.64 (1.05), p < 0.01)] but similar to the smell scores from healthy controls [9.97 (1.77), p=0.35]. Gender, age, time of disease onset, smoking status, and phenotypic expression did not influence the test scores. Fourteen FMD patients who mentioned having olfactory dysfunction before smell testing have their test results within normal range. PIT scores from patients and healthy controls were within normal range. Conclusions: These findings indicate that FMD patients have normal olfactory function. Olfactory testing may be helpful in identifying and differentiating FMD from other movement, neurodegenerative and neuropsychiatric diseases for which smell function is altered.