Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology
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Switching from maintenance of general anesthesia with an ether anesthetic to maintenance with high-dose (concentration >50% and total gas flow rate >4 liters per minute) nitrous oxide is a common practice used to facilitate emergence from general anesthesia. The transition from the ether anesthetic to nitrous oxide is associated with a switch in the putative mechanisms and sites of anesthetic action. We investigated whether there is an electroencephalogram (EEG) marker of this transition. ⋯ We postulate that these slow-delta oscillations may result from nitrous oxide-induced blockade of major excitatory inputs (NMDA glutamate projections) from the brainstem (parabrachial nucleus and medial pontine reticular formation) to the thalamus and cortex. This EEG signature of high-dose nitrous oxide may offer new insights into brain states during general anesthesia.
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Lack of habituation is considered a neurophysiological hallmark of migraine. However, the results of visual evoked potential (VEP) studies have been discrepant, possibly because of different stimulation parameters and lack of blinding. Hence, there is a need for independent confirmation of lack of VEP habituation in migraine. In this blinded study we applied 16' checks to supplement our previous findings with 8', 31', 62' and 65' checks. ⋯ Lack of VEP habituation cannot be considered a reliable neurophysiological hallmark in migraine.
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In this review, we recommend means to enhance the evidence-base for intraoperative neurophysiological monitoring (IONM). We address two preliminary issues: (1) whether IONM should be evaluated as a diagnostic test or an intervention, and (2) the state of the evidence for IONM (as presented in systematic reviews, for example). Three reasons may be suggested to evaluate at least some IONM applications as interventions (or as part of an "interventional cascade"). ⋯ Observational evidence for IONM is growing yet more is required to understand the conditions under which IONM, in its variety of settings, can benefit patients. A multi-center observational cohort study would represent an important initial compromise between the pragmatic difficulties with conducting controlled trials in IONM and the Evidence-Based Medicine (EBM) view that large scale randomized trials are required. Such a cohort study would improve the evidence base and (if justified) provide the rationale for controlled trials.
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Controlled Clinical Trial
A transcranial direct current stimulation over the sensorimotor cortex modulates the itch sensation induced by histamine.
Itching can be suppressed by scratching. However, scratching may aggravate itch symptoms by damaging the skin. Therefore, identifying an alternative approach to suppress itching is of clinical importance. The aim of the present study was to determine whether a transcranial direct current stimulation (tDCS) was useful for itch relief. ⋯ The present study demonstrated that a tDCS intervention may be an alternative approach for suppressing unpleasant itch sensations in healthy participants. Since tDCS has some advantages, namely, its easy application and safety in a clinical setting, it may become a useful method for the treatment of itching.
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Randomized Controlled Trial
Modulation of temporal summation threshold of the nociceptive withdrawal reflex by transcutaneous spinal direct current stimulation in humans.
Transcutaneous spinal direct current stimulation (tsDCS) modulates spinal cord pain pathways. The study is aimed to clarify the neurophysiology of the tsDCS-induced modulation of the spinal cord pain processing by evaluating the effect of the tsDCS on temporal summation threshold (TST) of the nociceptive withdrawal reflex (NWR). ⋯ The modulation of the temporal processing of nociceptive stimuli could be effective in treating clinical pain conditions in which pain is generated by spinal cord structures.