Search results for "NERVE"
showing 10 items of 1683 documents
Influence of vagus nerve stimulation on histamine-induced itching
2002
To investigate whether vagus nerve stimulation (VNS) reduces pruritus in humans.Recently, it has been shown that VNS has antinociceptive and antidepressant effects in humans.Eleven patients were investigated before (baseline) and during chronic VNS treatment. The experiments were performed at two different stimulation intensities: 2 to 5 days after implantation at a low stimulation intensity (mean intensity 0.7 +/- 0.2 mA, second session) and after 8 to 14 weeks of VNS therapy (mean intensity 1.4 +/- 0.3 mA, third session). Twelve healthy age- and sex-matched subjects were investigated using the same experimental protocol. Itch was induced by histamine-iontophoresis and quantified on a visu…
EMG power spectrum and features of the superimposed M-wave during voluntary eccentric and concentric actions at different activation levels.
2001
Muscle fiber conduction velocity (CV) may be affected by the level of voluntary activation and by the diameter of the fiber. Both the frequency component of the electromyography (EMG) power spectrum, such the as median frequency (MF) or mean power frequency, and the duration of muscle compound action potential to single supramaximal electrical impulse (maximal M-wave) may be related to CV. The aim of the present study was to examine how changes in the activation level in lengthening and in shortening conditions would affect the EMG power spectrum during voluntary effort, and compare them to changes in M-wave shape in similar conditions. Ten male subjects performed eccentric and concentric k…
Specific modulation of spinal and cortical excitabilities during lengthening and shortening submaximal and maximal contractions in plantar flexor mus…
2014
This study investigated the influence of the torque produced by plantar flexor muscles on cortical and spinal excitability during lengthening and shortening voluntary contractions. To that purpose, modulations of motor-evoked potential (MEP) and Hoffmann (H) reflex were compared in the soleus (SOL) and medial gastrocnemius (MG) during anisometric submaximal and maximal voluntary contraction (MVC) of the plantar flexor muscles. For the submaximal shortening and lengthening contractions, the target torque was set at 50% of their respective MVC force. The results indicate that the amplitudes of both MEP and H-reflex responses, normalized to the maximal M wave, were significantly ( P < 0.05…
Increased risk of sensory neuropathy in workers with chloracne after exposure to 2,3,7,8-polychlorinated dioxins and furans
1999
Objective - The existence of a peripheral neuropathy after exposure to polychlorinated dioxins (PCDD) is still discussed, as studies concerning dioxin effects on the peripheral nervous system are rare and contradictory. Material and methods - Clinical and neurophysiological examinations (motor conduction velocity of the peroneal nerve, sensory conduction velocities of the sural and ulnar nerves) were made in 156 dioxin exposed workers (42 with, 114 without cloracne) from one pesticide producing plant. Because of known risk factors for peripheral neuropathy, 7 workers with and 28 without cloracne were excluded from further analysis. Results - Workers with chloracne had a significantly higher…
Metabolic and structural connectivity within the default mode network relates to working memory performance in young healthy adults.
2012
Abstract Studies of functional connectivity suggest that the default mode network (DMN) might be relevant for cognitive functions. Here, we examined metabolic and structural connectivity between major DMN nodes, the posterior cingulate (PCC) and medial prefrontal cortex (MPFC), in relation to normal working memory (WM). DMN was captured using independent component analysis of [18F]fluorodeoxyglucose positron emission tomography (FDG-PET) data from 35 young healthy adults (27.1 ± 5.1 years). Metabolic connectivity, a correlation between FDG uptake in PCC and MPFC, was examined in groups of subjects with (relative to median) low (n = 18) and high (n = 17) performance on digit span backward te…
Posterior interosseous nerve of the elbow at the arcade of Frohse: Ultrasound appearance in asymptomatic subjects
2019
PURPOSE To assess the normal values of the antero-posterior (AP) diameter of the posterior interosseous nerve (PIN) of the elbow as it passes beneath the arcade of Frohse and to search for PIN-diameter differences between the upstream, entry point and downstream of the arcade. MATERIAL AND METHODS Thirty asymptomatic patients prospectively underwent bilateral B-mode ultrasound of the PIN of the elbow. There were 15 men and 15 women with a mean age of 30.2±5.31 (SD) years (range: 26-43 years). Of these, 23 patients were right-handers (23/30; 77%) and 7 were left handers (7/30; 23%). AP diameter of the PIN was measured in long axis at three different locations including the entry point of the…
Central and peripheral fatigue of the knee extensor muscles induced by electromyostimulation.
2005
The main purpose of this study was to characterise neuromuscular fatigue induced by 30 contractions of the knee extensor muscles evoked by electromyostimulation (EMS). Twelve healthy subjects were tested before and after a typical EMS session (frequency: 75 Hz, on-off ratio: 6.25 s on-20 s off) used for quadriceps femoris muscle strengthening. Surface electromyographic (EMG) activity and torque obtained during maximal voluntary and electrically evoked contractions were analysed to distinguish peripheral from central fatigue. Maximal voluntary torque of the knee extensor muscles decreased approximately 20 % (p < 0.001) following EMS. In the same way, peak torque associated to single (p < 0.0…
Patterned functional network disruption in amyotrophic lateral sclerosis
2019
Abstract Amyotrophic lateral sclerosis (ALS) is a progressive neurodegenerative disease primarily affecting motor function, with additional evidence of extensive nonmotor involvement. Despite increasing recognition of the disease as a multisystem network disorder characterised by impaired connectivity, the precise neuroelectric characteristics of impaired cortical communication remain to be fully elucidated. Here, we characterise changes in functional connectivity using beamformer source analysis on resting‐state electroencephalography recordings from 74 ALS patients and 47 age‐matched healthy controls. Spatiospectral characteristics of network changes in the ALS patient group were quantifi…
Dissociated secondary hyperalgesia in a subject with a large-fibre sensory neuropathy
1993
In the skin surrounding a site of injury, hyperalgesia develops to mechanical stimuli. Two types of secondary hyperalgesia (to light touch and punctate stimuli) have recently been differentiated, based on different durations and sizes of the area involved. We studied secondary hyperalgesia in a subject who had a loss of myelinated afferent nerve fibres below the neck that spared the A delta group. Stroking with a cotton swab was not perceived anywhere on affected skin either before or after injection of 60 micrograms of capsaicin. Thus, there was no hyperalgesia to light touch. Capsaicin injection into the volar forearm evoked normal pain and flare. A von Frey probe exerting a force of 40 m…
Subcortical somatosensory evoked potentials after median nerve stimulation in children.
2000
We report our normative data of subcortical somatosensory evoked potentials (SEPs) after median nerve stimulation from a group of 55 children 4–15 years of age and 18 young adults 18–29 years of age. We recorded near-field potentials from the brachial plexus, the cervical cord and the somatosensory cortex. The far-field potentials P13, P14 and N18 from the brainstem were recorded from the scalp electrodes, when a non-cephalic reference at the contralateral Erb's point or an ear reference was used. The N9 (brachial plexus), N13a (dorsal horn), P13 (caudal medulla oblongata), N18 (medulla oblongata) and N20 (somatosensory cortex) were present in all subjects. The N13b (dorsal column near the …