Examinando por Autor "Leon Sarmiento, Fidias E."

Mostrando 1 - 8 de 8
  • Publicación
    Acceso abierto
    Chemosensory disturbances-associated nanocholinergic dysfunction : The case of, not only, myasthenia gravis
    (2015-09-01) Leon Sarmiento, Fidias E.; Leon-Ariza, Juan S.; Prada, Diddier G.; Leon-Ariza, Daniel S.
  • Publicación
    Acceso abierto
    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.
  • Publicación
    Acceso abierto
    Evaluación neurofuncional del tallo cerebral. Parte I : Reflejo del parpadeo
    (2009-10) Leon Sarmiento, Fidias E.; Gutiérrez, Claudia; Bayona Prieto, Jaime
    The blink reflex is the neural response elicited in the orbicular oculi muscle after single or paired supraorbital nerve stimulation, by either electrical, mechanical, acoustic, thermal, chemical or magnetic stimulation. It is made up of three responses called R1, R2 and R3. R1 is an early response that follows A beta fibers, and does not habituate. R2 is a middle-latency response that follows A beta and A delta fibers, tends to habituate and is modulated by sensorimotor suprasegmental structures. R3 is a long-latency response, generated by stimulation of a multisynaptic chain of neurons that involve type C fibers belonging to a complex pontothalamic-amigdalo-cerebellar pathway. It is also possible to record three silent periods if the blink reflex is obtained while the subject makes a voluntary facial muscle effort. The functional study of this reflex allows to define with certainty whether the lesion is in afferent or efferent pathways or if it involves an abnormal sensorimotor integration due to disorders of the central, autonomic or peripheral nervous systems. A correct execution of these studies, and their appropriate interpretation, based on the underlying mechanisms of neural plasticity, will guide toward better neurorehabilitation protocols.
  • Publicación
    Acceso abierto
    Evidences in Neurological Surgery and a Cutting Edge Classification of the Trigeminocardiac Reflex : A Systematic Review
    (2018-08) Leon Ariza, Daniel S.; Leon Ariza, Juan S.; Nangiana, Jasvinder; Vargas Grau, Gabriel; Leon Sarmiento, Fidias E.; Quiñones Hinojosa, Alfredo
    The trigeminocardiac reflex (TCR) is characterized by bradycardia, decrease of mean arterial blood pressure, and sometimes, asystole during surgery. We critically reviewed TCR studies and devised a novel classification scheme for assessing the reflex. Methods A comprehensive systematic literature review was performed using PubMed, MEDLINE, Web of Science, EMBASE, and Scielo databases. Eligible studies were extracted based on stringent inclusion and exclusion criteria. Statistical analyses were used to assess cardiovascular variables. TCR was classified according to morphophysiologic aspects involved with reflex elicitation. Results A total of 575 patients were included in this study. TCR was found in 8.9% of patients. The reflex was more often triggered by interventions made within the anterior cranial fossa. The maxillary branch (type II in the new classification) was the most prevalent nerve branch found to trigger the TCR. Heart rate and mean arterial blood pressure were similarly altered (P = 0.06; F = 0.3912809), covaried with age (P = 0.012; F = 9.302), and inversely correlated to each other (r = −0.27). Conclusions TCR is a critical cardiovascular phenomenon that must be quickly identified and efficiently classified and should trigger vigilance. Prompt therapeutic measures during neurosurgical procedures should be carefully addressed to avoid unwanted complications. Accurate categorization using the new classification scheme will help to improve understanding and guide the management of TCR in the perioperative period.
  • Publicación
    Acceso abierto
  • Publicación
    Acceso abierto
    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.
  • Publicación
    Acceso abierto
    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.
  • Publicación
    Acceso abierto
    The Three Nociceptive Responses of the Orbicularis Oculi Reflex in Alzheimer’s Disease : State of the Evidence and Meta-analysis
    (2019-01) Leon Ariza, Daniel S.; Leon Ariza, Juan S.; Prada, Diddier G.; Castillo, Camilo; Leon Sarmiento, Fidias E.
    There is an emerging belief that electrically elicited blink reflexes (BR) may distinguish Alzheimer’s disease (AD) from other disorders characterized by memory dysfunction. To qualitatively and quantitatively distinguish the effects that electrical stimulation has over the blink reflex (eBR) recorded from patients with AD and healthy controls (HCs), we did a systematic review of the literature, and conducted a meta-analysis. Following our selected criteria, 94 AD patients and 97 HCs were identified from articles published in English between 1950 and 2017. Although the 3 responses (R1, R2 and R3) of the eBR were studied in a number of patients, only the R2 response was quantified in all studies. Thresholds and stimulation intensities parameters were found to be used in a miscellaneous form, and the majority of times, such parameters deviated from validated guidelines. The stimulation frequencies used to elicit the BR responses ranged between 0.14 and 0.2 Hz. These frequencies favored HCs compared with AD patients (odds ratio = 1.08; 95% CI = 0.30-1.85), I2 = 0% [P = .99]; Q = 271.89 [df = 7, P < .000]). Egger’s regression test suggested publication bias (intercept = 32.38; 95% CI = −8.98 to −3.2; P = .001). Our results unveiled key shortcomings in the data reported; such shortcomings need to be corrected in future AD research looking for obtaining more reliable and reproducible eBR studies; otherwise, interventions may be misleading.