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72 active trials for Cognitive Dysfunction

Effect of Propfol Versus Sevoflurane on Auditory and Cognitive Function

Perioperative hearing loss is a rarely reported phenomenon. However, it occurs more frequently than most anaesthesiologists suspect. Perioperative hearing impairment is often subclinical and may go unnoticed unless audiometry is performed. It can be conductive or sensorineural, unilateral or bilateral, and transient or permanent. Hearing loss has been reported following virtually every type of anaesthetic technique. The hearing mechanism may be less susceptible to acoustic trauma during general anaaesthesia. But other mechanisms are capable of causing both conductive and sensorineural hearing losses (SNHL) in the perioperative period. The aetiologies include mechanical, traumatic, noise-induced, changes in cerebrospinal fluid (CSF) pressure, embolism, pharmacologic, and other miscellaneous causes. Stress may influence central vestibular function in health and disease either directly through the actions of glucocorticoids (cortisol and corticosterone) on ion channels and neurotransmission in the brain, or indirectly through the effects of stress-related neuroactive substances (e.g., histamine, neurosteroids) on these structures. The auditory brainstem response (ABR) provides a good estimate of the shape of the behavioral audiogram [and is thus an extremely useful tool for studying hearing sensitivity as well as the functionality of the auditory system. An awareness of the potential for and the causes of hearing loss during anesthesia may permit the anesthesiologist to prevent or minimize the risk of significant hearing deficit. The suggestion that this risk be discussed in the preoperative period with patients who are at high risk for perioperative hearing loss may be good medical-legal advice. Better understanding of the incidence, causes, and prognoses for perioperative hearing loss is essential for the anesthesiologist. Much Concern has been raised about the effects of anaesthetic drugs on cognition. Postoperative cognitive dysfunction may manifest as impairment in attention, memory, language or executive functions following surgery, and can persist for weeks, months, or more with varying severity. Such post-operative cognitive dysfunction can be quite mild and only diagnosed through psychometric assessment using specific neuropsychological tests. AIM OF THE STUDY The aim of this work is to study the possible deleterious effect of propfol versus sevoflurane on auditory and cognitive function.

Start: January 2021
Probing Cortical Excitability and Cognitive Function With TMS

The overarching purpose of this study is to develop a technique that is capable of identifying neurophysiological biomarkers sensitive enough to detect preclinical dementia by integrating Transcranial Magnetic Stimulation (TMS) and Functional Magnetic Resonance Imaging (fMRI). More specifically, this project has two specific aims: 1. To characterize cortical excitability and its relation to cognitive function using single-pulse TMS paradigm in Mild Cognitive Impairment (MCI) and healthy older adults. 2. To delineate cortical plasticity and its association to cognitive function using repetitive TMS paradigm and resting-state fMRI in MCI and healthy older adults. Techniques to artificially and precisely stimulate brain tissue are increasingly recognized as valuable tools both in clinical practice and in cognitive neuroscience studies among healthy individuals. Transcranial magnetic stimulation (TMS) is a non-invasive approach to stimulate the brain. Importantly, unlike other invasive brain stimulation techniques (e.g., surgical deep brain stimulation), no surgery, anesthesia, or sedation is involved. Instead, TMS involves placing a magnetic coil on the surface of the head. This coil then generates a magnetic field that is about the same strength as the magnetic field used by MRI machines, and when this magnetic field rapidly alternates, the neurons under the coil are excited. Extensive guidelines have been published by experts in the field to ensure safe use, and the thousands of patients & research participants who have received TMS in compliance with these guidelines demonstrate the safety of this practice. Depending on the method of use, TMS is very versatile -- it can be used to study research questions pertaining to the neural circuitry of the brain, it can be used as a diagnostic device, and it can be used therapeutically to treat various neurological conditions. In this study, the investigators intend to further study the potential for diagnostic applications of TMS. More specifically, TMS and brain imaging techniques will be used in combination in order to more sensitively diagnose dementia - perhaps even before symptoms emerge. Right now, there is no reliable method for doing so and it is difficult to distinguish between the forgetfulness of healthy aging and the early signs of disease. Our approach may provide a more sensitive diagnostic tool, which is likely to improve clinical outcomes.

Start: April 2018
Characteristics and Outcomes of a Capacity-to-Consent Assessment Service

Background: Many medical conditions such as Alzheimer s disease limit the ability of people to think clearly. For medical scientists to best study these medical conditions, they need to enroll some people who may not be able to consent to participate in research on their own. Before these individuals enroll in research it is important to assess whether they are able to consent or whether someone else will need to consent for them. The NIH Clinical Center has a team that performs these assessments. A team like this can be useful for two reasons. First, it helps to protect the rights of research participants. Second, it makes it possible to study medical conditions that could not be studied otherwise. In this study we will look back at the records of the NIH Clinical Center team to review the process and results of these assessments. We expect to learn how the capacity assessments were done. We will learn what factors make people more or less able to consent. We will learn who consented for the research participants when they could not consent on their own, for example a spouse or an adult child. These results are likely to be useful to other researchers who wish to study diseases that limit cognitive ability. Objective: To study the process and outcomes of capacity assessments of people who may not be able to consent to research. Eligibility: People of all ages, genders, races, ethnicities, and languages whose ability to consent was assessed at the NIH Clinical Center at some time during the years 1999-2016. Design: This study will only review existing records. There will not be any active participants. Records will be reviewed for research only. This will take place in the Clinical Center. It will be done by staff of the Department of Bioethics and the Human Subjects Protection Unit (HSPU). The study will collect data from the Bioethics Consult database. It will also collect data from HSPU records. Researchers will look at demographic data. They will look at details of capacity evaluations. Personal data will not be extracted from existing records.

Start: June 2017