Active clinical trials for "Hypoxia, Brain"

The investigators will investigate the effect of hypobaria and hypoxia on physiological responses such as: oxygen saturation, heart rate, cerebral blood flow, cerebral oxygenation, brain's activity and concentration performance.

The investigators will conduct a non-randomized clinical trial to examine the effect of pure oxygen breathing on the brain. The study will compare cerebral blood flow, cortical electrical activity, and cognitive performance in 32 persons during room air (21% oxygen) breathing and pure oxygen (100% oxygen) breathing. Subjects will be used as their own controls. The investigators aim to: Determine whether breathing 100% oxygen changes blood flow through the brain. The investigators will learn whether brain blood flow is increased, decreased or stays the same. Determine if changes that might occur in brain blood flow are also accompanied by changes in the brain's electrical activity (EEG). Learn whether changes in the speed at which the brain processes information (cognitive function) accompany changes in brain blood flow and electrical activity that may be seen.

Objectives: Resveratrol, a non-flavonoid polyphenol, has been found to consistently modulate cerebral blood flow (CBF) following oral supplementation. Although, this has not resulted in subsequent predicted benefits to cognitive performance in young healthy populations. However, it is argued that those who suffer a reduction in CBF and cognition, such as aging populations, may benefit more from resveratrol administration. Hypothesis: The current investigation aimed to employ a mild hypoxia as an experimental model of aging in a young healthy population, to assess if resveratrol can attenuate the deficits elicited by the reduction in oxygen supply. It was hypothesized resveratrol would module CBF, to provide a more efficient supply of oxygen to overcome any associated decreases to performance caused by the hypoxic model. Design: This repeated measures, double blind, placebo controlled, balanced design assessed the cognitive and CBF effects of resveratrol in hypoxia (equivalent to ~2000m above sea level) and normoxia (sea level). Methods: 24 participants arrived fully fasted (except water) for 12 hrs before completing a baseline measure of a cognitive task battery, and taking the treatment for the day. Following a 45 min absorption period, participants completed 3 full repetitions of the cognitive test battery and, if appropriate, the oxygen level was altered. Changes in CBF were measured by near-infrared spectroscopy throughout the full testing session.

The primary objective of this research is to measure changes in neurochemical concentrations during stimulation of the primary visual cortex, in both conditions of normoxia (normal oxygen availability) and induced mild hypoxia (reduced oxygen availability).

While the exercise responses are classically described at the cardiorespiratory and muscle levels, recent data suggest that the brain is also significantly stressed by exercise and may even participate to performance limitation. In hypoxia in particular, cerebral responses to exercise may be altered and promote performance reduction during endurance exercise. In the present study, the investigators used innovative approaches to assess cerebral perturbations associated with exercise in hypoxia.

In response to "conscious" EEG findings related to detectable cognitive function that reliably denote awareness in vegetative state patients, in the current study, we will assess the covert conscious EEG activity (as well as standard clinical overt measures) and neuroplasctic propensity (i.e., changes in EEG spectral power synchronization values following tDCS intervention) in vegetative-state patients receiving repetitive transcranial direct current stimulation (tDCS) treatment over frontal motor areas for a period of two weeks. In support of this approach, a recent tDCS study with vegetative and minimally conscious patients implied that a twenty minutes anodal stimulation (i.e., excitatory stimulation) to the left dorsolateral prefrontal cortex (DLPFC) significantly increased CRS-R scores versus sham (placebo: non-active stimulation) stimulation condition. It was noted that this tDCS effect was more pronounced in minimally conscious state patients versus vegetative state patients excluding effects of chronicity or etiology. Thus, the investigators in this study suggested that tDCS could be effective in improving cognitive recovery in severely brain-injured patients. However, their findings would benefit neural activation correlates that could support their conclusion regarding the effectiveness of this type of non-invasive intervention in promoting neurocognitive recovery. Most importantly, tDCS is safe for use in humans, has no adverse effects, is considered the most non-invasive transcranial stimulation method because it uses extremely weak currents (0.5 to 2 mA), and, is known to only temporarily shift the neuron's membrane potential towards excitation/inhibition. In regard to the method's potential to induce functional recovery in vegetative state patients, recent clinical studies indicate that tDCS could counteract the negative effects of brain damage by influencing neurophysiological mechanisms, and is likely to contribute to the "formation of functionally meaningful connections and the maintenance of existing pathways" .

This study aimed to investigate the efficacy and safety of extracorporeal shockwave therapy (ESWT) for upper extremity pain related to spasticity in patients with spinal cord injury.

The aim of this study is to evaluate the clinical feasibility of the angiographic Flat Detector CT perfusion imaging (6s PBV) technique. The investigators will examine the specific vessel distribution of patients with steno-occlusive disease, treated with a surgical extracranial-intracranial bypass and assess the cerebral perfusion during test occlusion upon a neurovascular treatment and in intracranial tumor patients referred for potential pre-operative embolization. This study encompasses three scientific objectives: What is the selective contribution of an individual bypass artery to the brain perfusion? Is a selective intra-arterial angiographic perfusion examination useful in the decision-making of performing pre-operative embolization of intracranial tumors? What is the usefulness of performing additive 6s PBV images compared to classical 2D angiography and/or clinical neurological evaluation in case of test occlusion in the evaluation of possible mother vessel occlusion in treatment of complex neurovascular diseases?

the purpose of this study is to investigate whether propofol and sevoflurane have difference effect on cerebral oxygenation .

When patients survive a severe brain injury but fail to fully recover, they often enter a Disorder of Consciousness (DoC) --that is, a set of related conditions of decreased awareness and arousal including the Vegetative State (VS) and the Minimally Conscious State (MCS). When these conditions become chronic, there are no approved treatments to help bolster any further recovery. In prior work, we have shown the clinical feasibility and potential of Low Intensity Focused Ultrasound Pulsation (LIFUP) as a remarkably safe form of non-invasive brain stimulation in these conditions.