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Neurology India 2023
Topics: Humans; Urination; Epilepsy, Reflex; Reflex
PubMed: 38174496
DOI: 10.4103/0028-3886.391379 -
Physiological Research Dec 2023Cough is one of the most important airway defensive reflexes aimed at removing foreign particles or endogenously produced materials from the airways and provides... (Review)
Review
Cough is one of the most important airway defensive reflexes aimed at removing foreign particles or endogenously produced materials from the airways and provides protection against aspiration. Generally considered, cough is a vital physiological defensive mechanism for lung health. However, in case of cough dysregulation this reflex can become pathological and leads to an adverse influence on daily life. Therefore, it is necessary to effectively evaluate the severity of cough for its diagnosis and treatment. There are subjective and objective methods for assessing cough. These methods should help describe the heterogeneity of cough phenotypes and may establish better treatment by monitoring response to nonpharmacological or pharmacological therapies. It is important to keep in mind that the clinical assessment of cough should include both tools that measure the amount and severity of the cough. The importance of a combined subjective and objective evaluation for a comprehensive assessment of cough has been advocated in the guidelines of the European Respiratory Society on cough evaluation. This review article provides an overview of subjective and objective methods for assessing and monitoring cough in children and adults comparing to animal models. Key words Cough frequency; Cough intensity; Cough reflex sensitivity; Cough monitors; Cough assessment.
Topics: Animals; Adult; Child; Humans; Cough; Lung; Reflex
PubMed: 38215057
DOI: 10.33549/physiolres.935062 -
Canadian Journal of Anaesthesia =... Apr 2021Pupillometry is a technique for objective quantification of nociception that takes into account the central processing of noxious stimuli and its sympathetic response.... (Review)
Review
PURPOSE
Pupillometry is a technique for objective quantification of nociception that takes into account the central processing of noxious stimuli and its sympathetic response. This narrative review provides an overview of the physiology of the pupil, the principles of pupillometry, and its potential application in the perioperative environment, especially in nociception monitoring and quantifying responses to opioids.
SOURCE
Relevant articles, including reports of original investigation, review articles, and meta-analyses were identified from searches of PubMed and Google Scholar databases. Articles that described pupillary physiology and pupillometry, along with original research reports of the application of pupillometry in perioperative and critical care environment were used to synthesize a narrative review.
PRINCIPAL FINDINGS
Pupillometry is emerging as an objective measure of nociception, especially in patients under general anesthesia, children, non-verbal patients, and critically ill patients who cannot effectively communicate ongoing pain. Portable automated pupillometers have made accurate quantification of pupillary reflexes, including light reflex and dilatation reflex, possible. This technique has been successfully studied in the perioperative setting for a number of applications, including quantification of nociception, response to analgesia, and assessing efficacy of regional blocks. Pupillary oscillations have shown promise in assessing central opioid effects. Pupillometers can also accurately quantify light reflexes during the neurologic evaluation of critically ill patients.
CONCLUSIONS
Pupillometry is an easy to use non-invasive bedside technique to quantify nociception and monitor opioid effects. It has the potential to personalize pain management in perioperative and intensive care unit environments. Additional studies are needed to further understand the utility of pupillometry in this context.
Topics: Analgesia; Child; Critical Care; Humans; Perioperative Medicine; Pupil; Reflex, Pupillary
PubMed: 33432497
DOI: 10.1007/s12630-020-01905-z -
Handbook of Clinical Neurology 2022This chapter reviews cardiorespiratory adaptations to chronic hypoxia (CH) experienced at high altitude and cardiorespiratory pathologies elicited by chronic... (Review)
Review
This chapter reviews cardiorespiratory adaptations to chronic hypoxia (CH) experienced at high altitude and cardiorespiratory pathologies elicited by chronic intermittent hypoxia (CIH) occurring with obstructive sleep apnea (OSA). Short-term CH increases breathing (ventilatory acclimatization to hypoxia) and blood pressure (BP) through carotid body (CB) chemo reflex. Hyperplasia of glomus cells, alterations in ion channels, and recruitment of additional excitatory molecules are implicated in the heightened CB chemo reflex by CH. Transcriptional activation of hypoxia-inducible factors (HIF-1 and 2) is a major molecular mechanism underlying respiratory adaptations to short-term CH. High-altitude natives experiencing long-term CH exhibit blunted hypoxic ventilatory response (HVR) and reduced BP due to desensitization of CB response to hypoxia and impaired processing of CB sensory information at the central nervous system. Ventilatory changes evoked by long-term CH are not readily reversed after return to sea level. OSA patients and rodents subjected to CIH exhibit heightened CB chemo reflex, increased hypoxic ventilatory response, and hypertension. Increased generation of reactive oxygen species (ROS) is a major cellular mechanism underlying CIH-induced enhanced CB chemo reflex and the ensuing cardiorespiratory pathologies. ROS generation by CIH is mediated by nontranscriptional, disrupted HIF-1 and HIF-2-dependent transcriptions as well as epigenetic mechanisms.
Topics: Humans; Hypoxia; Reactive Oxygen Species; Reflex; Respiration; Sleep Apnea, Obstructive
PubMed: 35965023
DOI: 10.1016/B978-0-323-91534-2.00009-6 -
Dysphagia Feb 2023This literature review explores a wide range of themes addressing the links between swallowing and consciousness. Signs of consciousness are historically based on the... (Review)
Review
This literature review explores a wide range of themes addressing the links between swallowing and consciousness. Signs of consciousness are historically based on the principle of differentiating reflexive from volitional behaviors. We show that the sequencing of the components of swallowing falls on a continuum of voluntary to reflex behaviors and we describe several types of volitional and non-volitional swallowing tasks. The frequency, speed of initiation of the swallowing reflex, efficacy of the pharyngeal phase of swallowing and coordination between respiration and swallowing are influenced by the level of consciousness during non-pathological modifications of consciousness such as sleep and general anesthesia. In patients with severe brain injury, the level of consciousness is associated with several components related to swallowing, such as the possibility of extubation, risk of pneumonia, type of feeding or components directly related to swallowing such as oral or pharyngeal abnormalities. Based on our theoretical and empirical analysis, the efficacy of the oral phase and the ability to receive exclusive oral feeding seem to be the most robust signs of consciousness related to swallowing in patients with disorders of consciousness. Components of the pharyngeal phase (in terms of abilities of saliva management) and evoked cough may be influenced by consciousness, but further studies are necessary to determine if they constitute signs of consciousness as such or only cortically mediated behaviors. This review also highlights the critical lack of tools and techniques to assess and treat dysphagia in patients with disorders of consciousness.
Topics: Humans; Deglutition; Consciousness; Consciousness Disorders; Deglutition Disorders; Reflex
PubMed: 35773497
DOI: 10.1007/s00455-022-10452-2 -
Otolaryngologic Clinics of North America Aug 2020Animal models have significantly contributed to understanding the pathophysiology of chronic subjective tinnitus. They are useful because they control etiology, which in... (Review)
Review
Animal models have significantly contributed to understanding the pathophysiology of chronic subjective tinnitus. They are useful because they control etiology, which in humans is heterogeneous; employ random group assignment; and often use methods not permissible in human studies. Animal models can be broadly categorized as either operant or reflexive, based on methodology. Operant methods use variants of established psychophysical procedures to reveal what an animal hears. Reflexive methods do the same using elicited behavior, for example, the acoustic startle reflex. All methods contrast the absence of sound and presence of sound, because tinnitus cannot by definition be perceived as silence.
Topics: Acoustic Stimulation; Animals; Behavior, Animal; Disease Models, Animal; Hearing; Hearing Loss; Humans; Reflex; Reflex, Startle; Reproducibility of Results; Sound; Tinnitus
PubMed: 32327193
DOI: 10.1016/j.otc.2020.03.001 -
Nature Mar 2024Airway integrity must be continuously maintained throughout life. Sensory neurons guard against airway obstruction and, on a moment-by-moment basis, enact vital reflexes...
Airway integrity must be continuously maintained throughout life. Sensory neurons guard against airway obstruction and, on a moment-by-moment basis, enact vital reflexes to maintain respiratory function. Decreased lung capacity is common and life-threatening across many respiratory diseases, and lung collapse can be acutely evoked by chest wall trauma, pneumothorax or airway compression. Here we characterize a neuronal reflex of the vagus nerve evoked by airway closure that leads to gasping. In vivo vagal ganglion imaging revealed dedicated sensory neurons that detect airway compression but not airway stretch. Vagal neurons expressing PVALB mediate airway closure responses and innervate clusters of lung epithelial cells called neuroepithelial bodies (NEBs). Stimulating NEBs or vagal PVALB neurons evoked gasping in the absence of airway threats, whereas ablating NEBs or vagal PVALB neurons eliminated gasping in response to airway closure. Single-cell RNA sequencing revealed that NEBs uniformly express the mechanoreceptor PIEZO2, and targeted knockout of Piezo2 in NEBs eliminated responses to airway closure. NEBs were dispensable for the Hering-Breuer inspiratory reflex, which indicated that discrete terminal structures detect airway closure and inflation. Similar to the involvement of Merkel cells in touch sensation, NEBs are PIEZO2-expressing epithelial cells and, moreover, are crucial for an aspect of lung mechanosensation. These findings expand our understanding of neuronal diversity in the airways and reveal a dedicated vagal pathway that detects airway closure to help preserve respiratory function.
Topics: Animals; Female; Male; Mice; Epithelial Cells; Lung; Mechanoreceptors; Parvalbumins; Reflex; Respiration; Sensory Receptor Cells; Vagus Nerve; Lung Compliance; Respiratory Mechanics
PubMed: 38448588
DOI: 10.1038/s41586-024-07144-2 -
Journal of Neuroengineering and... Dec 2022Spasticity is defined as "a motor disorder characterised by a velocity dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks". It is a... (Review)
Review
BACKGROUND
Spasticity is defined as "a motor disorder characterised by a velocity dependent increase in tonic stretch reflexes (muscle tone) with exaggerated tendon jerks". It is a highly prevalent condition following stroke and other neurological conditions. Clinical assessment of spasticity relies predominantly on manual, non-instrumented, clinical scales. Technology based solutions have been developed in the last decades to offer more specific, sensitive and accurate alternatives but no consensus exists on these different approaches.
METHOD
A systematic review of literature of technology-based methods aiming at the assessment of spasticity was performed. The approaches taken in the studies were classified based on the method used as well as their outcome measures. The psychometric properties and usability of the methods and outcome measures reported were evaluated.
RESULTS
124 studies were included in the analysis. 78 different outcome measures were identified, among which seven were used in more than 10 different studies each. The different methods rely on a wide range of different equipment (from robotic systems to simple goniometers) affecting their cost and usability. Studies equivalently applied to the lower and upper limbs (48% and 52%, respectively). A majority of studies applied to a stroke population (N = 79). More than half the papers did not report thoroughly the psychometric properties of the measures. Analysis identified that only 54 studies used measures specific to spasticity. Repeatability and discriminant validity were found to be of good quality in respectively 25 and 42 studies but were most often not evaluated (N = 95 and N = 78). Clinical validity was commonly assessed only against clinical scales (N = 33). Sensitivity of the measure was assessed in only three studies.
CONCLUSION
The development of a large diversity of assessment approaches appears to be done at the expense of their careful evaluation. Still, among the well validated approaches, the ones based on manual stretching and measuring a muscle activity reaction and the ones leveraging controlled stretches while isolating the stretch-reflex torque component appear as the two promising practical alternatives to clinical scales. These methods should be further evaluated, including on their sensitivity, to fully inform on their potential.
Topics: Humans; Muscle Spasticity; Reflex, Stretch; Stroke Rehabilitation; Stroke; Technology
PubMed: 36494721
DOI: 10.1186/s12984-022-01115-2 -
Arquivos de Neuro-psiquiatria Apr 2023Percussion is an important part of the neurological examination and reflex hammers are necessary to obtain it properly. (Review)
Review
BACKGROUND
Percussion is an important part of the neurological examination and reflex hammers are necessary to obtain it properly.
OBJECTIVE
We aimed to review the historical aspects of the main reflex hammers and to define the favorite one of Brazilian neurologists.
METHODS
We searched original and review articles about historical aspects of the reflex hammers in Scielo and Pubmed and conducted an online survey to investigate the favorite reflex hammer of Brazilian neurologists.
RESULTS
In the first part, we describe the major milestones in the creation of the reflex hammers. Following, we exhibit the results of the online survey: Babinski-Rabiner was the most voted.
CONCLUSIONS
The origins of the reflex hammers goes back long before their creation, from a basic clinical examination method: percussion. Since the description of deep tendon reflexes and the creation of percussion hammers, much has been improved in this technique. Among all the hammers surveyed, the Babinski-Rabiner was the chosen one by a significant portion of Brazilian neurologists.
Topics: Humans; Brazil; Neurologic Examination; Neurologists; Reflex
PubMed: 37160138
DOI: 10.1055/s-0043-1768697 -
Neuron Oct 2019The ability to establish behaviorally what psychological capacity an animal is deploying-to discern accurately what an animal is doing-is key to functional analyses of... (Review)
Review
The ability to establish behaviorally what psychological capacity an animal is deploying-to discern accurately what an animal is doing-is key to functional analyses of the brain. Our current understanding of these capacities suggests, however, that this task is complex; there is evidence that multiple capacities are engaged simultaneously and contribute independently to the control of behavior. As such, establishing the contribution of a cell, circuit, or neural system to any one function requires careful dissection of that role from its influence on other functions and, therefore, the careful selection and design of behavioral tasks fit for that purpose. Here I describe recent research that has sought to utilize behavioral tools to investigate the neural bases of instrumental conditioning, particularly the circuits and systems supporting the capacity for goal-directed action, as opposed to conditioned reflexes and habits, and how these sources of action control interact to generate adaptive behavior.
Topics: Adaptation, Psychological; Animals; Behavior Therapy; Behavior, Animal; Brain; Goals; Reflex; Volition
PubMed: 31600515
DOI: 10.1016/j.neuron.2019.09.024