Search results for "FLEX"
showing 10 items of 1677 documents
Reduced stretch-reflex sensitivity after exhausting stretch-shortening cycle exercise.
1996
The stretch-shortening cycle (SSC) is an effective and natural form of muscle function but, when repeated with sufficient intensity or duration, it may lead to muscle damage and functional defects. A reduced tolerance to impact has been reported, which may be partly attributed to a reduced stretch-reflex potentiation. The aim of the present study was to examine the influence of SSC-induced metabolic fatigue and muscle damage on the efficacy of stretch reflexes, as judged by the electromyograph (EMG) response of two shank muscles (lateral gastrocnemius LG, soleus SOL) to controlled ramp stretches. These EMG responses were recorded before and immediately after exhausting SSC-type leg exercise…
Analysis of F response in upper motoneurone lesions
2009
The F response can provide a measure of motoneurone excitability (MNE) and so it may be used to investigate upper motoneurone disorders. This report studies the F-wave configuration in patients with stroke to evaluate the changes of the central excitability of the motoneurones at different times after an acute cerebral insult. Various parameters of the F response, including amplitude (absolute and F%/M), duration, and persistence have been determined in 26 patients with unilateral hemiplegia and in 32 healthy subjects of both sexes in the same age range. The investigation was carried out applying a series of 20 supramaximal stimuli at 0.5 Hz on tibial and ulnar nerves bilaterally. In all pa…
Sacral bladder denervation for treatment of detrusor hyperreflexia and autonomic dysreflexia
2001
Objectives. Detrusor hyperreflexia after spinal cord injury may cause urinary incontinence and chronic renal failure. In patients refractory to conservative treatment and not eligible for ventral sacral root stimulation for electrically induced micturition, we investigated the therapeutic value of sacral bladder denervation as a stand-alone procedure. Methods. Nine patients (8 men and 1 woman) between 21 and 58 years old (mean 30.2) with traumatic suprasacral spinal cord lesions underwent sacral bladder denervation for treatment of detrusor hyperreflexia and/or autonomic dysreflexia. Results. Detrusor hyperreflexia and autonomic dysreflexia were eliminated in all cases. Bladder capacity inc…
Spreading of sudomotor axon reflexes in human skin.
2005
Acetylcholine (ACh) activates both sudomotor fibers and primary afferent nociceptors. This leads to sudomotor and vasodilator axon reflexes, which can be diminished, for example, in neuropathies. In some neuropathies, however, there is increased axon reflex sweating, a response pattern that has never been observed for vasodilator flares.To compare both types of axon reflexes and to elucidate possible differences.In healthy young male subjects, sweat response and flare reaction in response to ACh were quantified. Constant-current iontophoresis (300 mC) of ACh was performed on the lateral lower legs. The sudomotor axon reflex was visualized with iodine starch staining, and the sweat response …
Cardiac modulation of startle is altered in depersonalization-/derealization disorder: Evidence for impaired brainstem representation of baro-afferen…
2016
Patients with depersonalization-/derealization disorder (DPD) show altered heartbeat-evoked brain potentials, which are considered psychophysiological indicators of cortical representation of visceral-afferent neural signals. The aim of the current investigation was to clarify whether the impaired CNS representation of visceral-afferent neural signals in DPD is restricted to the cortical level or is also present in sub-cortical structures. We used cardiac modulation of startle (CMS) to assess baro-afferent signal transmission at brainstem level in 22 DPD and 23 healthy control individuals. The CMS paradigm involved acoustic startle stimuli (105dB(A), 50ms) elicited 0, 100, 200, 300, 400 and…
Mechanisms of causal interaction between short-term RR interval and systolic arterial pressure oscillations during orthostatic challenge
2013
The transition from the supine to the upright position requires a reorganization of the mechanisms of cardiovascular control that, if not properly accomplished, may lead to neurally mediated syncope. We investigated how the patterns of causality between systolic arterial pressure (SAP) and cardiac RR interval were modified by prolonged head-up tilt using a novel nonlinear approach based on corrected conditional entropy (CCE) compared with the standard approach exploiting the cross-correlation function (CCF). Measures of coupling strength and delay of the causal interactions from SAP to RR and from RR to SAP were obtained in 10 patients with recurrent, neurally mediated syncope (RNMS) and 10…
Somatotopic arrangement of sudomotor axon reflex sweating in humans
2005
Impaired sweating may be one of the first symptoms in neuropathies, and therefore the evaluation of sweating might facilitate their early detection. Sudomotor axon reflexes can be quantified by two different methods: quantitative sudomotor axon reflex testing (QSART) measures the amount of local sweating, whereas staining with the iodine starch reaction assesses the extension of the sudomotor axon reflex area. The aim of our study was to compare both tests at three different sites on the leg: foot, lower leg and thigh.QSART and iodine starch staining after iontophoretic stimulation with acetylcholine were performed on 15 male volunteers (mean age: 25; range 24-27 years) on the left resp. th…
Topical prazosin attenuates sensitivity to tactile stimuli in patients with complex regional pain syndrome
2015
Background The sympathetic nervous system may play an important role in certain forms of chronic pain. The main aim of this study was to determine whether functional blockade of α1-adrenoceptors would alter sensitivity to cutaneous stimulation in patients with complex regional pain syndrome (CRPS). Methods and Results In an initial study, high-performance liquid chromatography-mass spectrometry of intradermal interstitial fluid collected from the forearms of three healthy individuals established that the α1-adrenoceptor antagonist prazosin penetrated the skin barrier when mixed in Lipoderm® cream base. Next, we found that application of this cream to the forearm of 10 healthy participants a…
Mental load during cognitive performance in complex regional pain syndrome I.
2018
Background Complex regional pain syndrome (CRPS) is associated with deficits in limb recognition. The purpose of our study was to determine whether mental load during this task affected performance, sympathetic nervous system activity or pain in CRPS patients. Methods We investigated twenty CRPS‐I patients with pain in the upper extremity and twenty age‐ and sex‐matched healthy controls. Each participant completed a limb recognition task. To experimentally manipulate mental load, the presentation time for each picture varied from 2 s (greatest mental load), 4, 6 to 10 s (least mental load). Before and after each run, pain intensity was assessed. Skin conductance was recorded continuously. R…
Does a Mental Training Session Induce Neuromuscular Fatigue?
2014
ROZAND, V., F. LEBON, C. PAPAXANTHIS, and R. LEPERS. Does a Mental Training Session Induce Neuromuscular Fatigue? Med. Sci. Sports Exerc., Vol. 46, No. 10, pp. 1981–1989, 2014. Mental training, as physical training, enhances muscle strength. Whereas the repetition of maximal voluntary contractions (MVC) induces neuromuscular fatigue, the effect of maximal imagined contractions (MIC) on neuromuscular fatigue remains unknown. Here, we investigated neuromuscular alterations after a mental training session including MIC, a physical training session including MVC, and a combined training session including both MIC and MVC of the elbow flexor muscles. Methods: Ten participants performed 80 MIC (d…