Clinical neurophysiology : official journal of the International Federation of Clinical Neurophysiology
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The anatomy, pathophysiology, and clinical evaluation of radiculopathies are discussed. Defining whether root injury is present and which roots are involved can be difficult but critical for patient management. In conjunction with clinical and radiological information, studies that establish physiological abnormalities of roots should be helpful and important. ⋯ Available information does not necessarily answer critical questions about the role of electrophysiology in patients with radiculopathies. This cannot be done using analyses based on current ideas about evidence based medicine given the absence of a 'gold standard' for defining radiculopathies as well the absence of blinded studies. The available information provides strong arguments for further investigations evaluating different clinical neurophysiological techniques in the same patient, and for evaluating the value of these techniques by concentrating on their clinical import.
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The relationship between the masseter inhibitory reflex (MIR) and nociceptive processing in the trigeminal region was studied in 10 healthy subjects. Based on the known increase in perceived sensory intensity following repetitive stimulation of the nociceptive system, we examined the hypothesis that the MIR reflects noxious activity in the trigeminal system by determining the possible relation between changes in MIR and perceived sensory intensity. ⋯ The observed reduction of the magnitude of ES2 suppression is not specifically related to nociceptive processing. Habituation or net inhibitory effects on inhibitory pre-motor neurones (i.e. disinhibition) are possible mechanisms for the observed reduction of the magnitude of ES2 suppression after repetitive stimulation.
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Clinical Trial Controlled Clinical Trial
Corticospinal volleys and compound muscle action potentials produced by repetitive transcranial stimulation during spinal surgery.
To report our experience with neurophysiological monitoring of corticospinal function using compound muscle action potentials (CMAPs) produced by repetitive transcranial electrical stimulation in a large series of patients, after defining optimal stimulus parameters in a small group of patients. ⋯ When epidural recordings can be made, direct recordings of corticospinal activity are probably more reliable than recordings of CMAPs. However, epidural recordings are not suitable under all circumstances, and the ability to record CMAPs reliably represents an advance in intraoperative monitoring. Under the anaesthetic conditions used in the present study, the optimal stimulus parameters consist of a train of 5 stimuli of 50 micros duration at an interstimulus interval of 5 ms and an intensity of 500 V.
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The aim of the present study was to analyze in detail the relationship of two newly introduced measures, related to the Beta and Gamma EEG bands during REM sleep, with Delta and Sigma activity at REM sleep onset and REM sleep end, in order to understand their eventual role in the sleep modulation mechanism. ⋯ The results of the present study show a different time synchronization of the changes in the Delta band and in Beta and Gamma ratios, at around REM sleep onset, and seem to suggest that the oscillations of these parameters might be modulated by mechanisms more complex than a simple reciprocity. All these considerations point to the fact that REM sleep can be considered as a complex phenomenon and the analysis of high-frequency EEG bands and of our Beta and Gamma ratios represent an additional important element to include in the study of this sleep stage.
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Clinical Trial
Somatosensory event-related potential and autonomic activity to varying pain reduction cognitive strategies in hypnosis.
The issues of differential effects among cognitive strategies during hypnosis in the control of human pain are under active debate. This study, which employs measures of pain perception, electrocortical and autonomic responses, was aimed at determining these pain-related modulations. ⋯ The effect of pain modulation is limited to high hypnotizable subjects rather than low hypnotizable ones. Higher frontal-temporal N2 and smaller posterior parietal P3 may indicate active inhibitory processes during cognitive strategies in hypnotic analgesia. These inhibitory processes also regulate the autonomic activities in pain perception.