Search results for "reflex"
showing 10 items of 622 documents
Synchronization index for quantifying nonlinear causal coupling between RR interval and systolic arterial pressure after myocardial infarction
2002
The analysis of nonlinear couplings among cardiovascular variability series can improve the knowledge of the cardioregulatory mechanism and help to understand how it can be affected by pathologies. In this study, the influences of acute myocardial infarction (AMI) on the causal relationships between the heart period and the arterial pressure were investigated by a nonlinear dynamic approach based on the corrected cross-conditional entropy. Whereas the global synchronization index did not differentiate the post-AMI patients from the young and old control groups, the causal indexes evidenced the impairment of the baroreflex control and showed an increase of the mechanical driving of the RR in…
Arteriovenous fistula of the vertebral artery in a female infant with hypotonia and cephalocorporal disproportion
2010
Background: Congenital arteriovenous fistulas are exceptional in childhood and imply a therapeutic challenge. Case report: A 9-month-old female infant was studied for cephalocorporal disproportion, hypotonia, progressive muscular atrophy and hyperreflexia. Computed tomography of the brain and electroencephalography were normal. Electromyographic patterns suggested proximal myopathic involvement. A continuous murmur with systolic reinforcement was audible in the neck. Angioresonance detected intracranial aneurysmal dilatations behind the bulbo-medullary junction and cerebral panangiography evidenced a direct vertebrovertebral fistula with extra- and intra-cranial varices and extreme medulla…
Effects of power training on neuromuscular performance and mechanical efficiency
2007
Effects of power training with stretch-shortening cycle (SSC) exercises on mechanical efficiency (ME) were investigated with 9 young women who trained 3 times a week for 4 months. The training included various types of jumping exercises. Before and after the training as well as after the detraining (2 months) the subjects performed 6 different submaximal exercises with a special sledge apparatus. Each exercise involved 60 muscle actions lasting for a total of 3 min per testing condition. The work intensities were determined individually according to the recordings of distance obtained during the single maximal concentric exercises. The training caused the greatest changes of ME in condition…
About the Trigemino-cardiac reflex, their association with sleep bruxism and the reason why clinicians treating Sb should consider a careful examinat…
2018
This work is licensed under Creative Commons Attribution 4.0 License.
Effects of rectilinear acceleration and optokinetic and caloric stimulations in space.
1984
During the flight of Spacelab 1 the crew performed a number of experiments to explore changes in vestibular function and visual-vestibular interactions on exposure to microgravity. Measurements were made on the threshold for detection of linear oscillation, vestibulo-ocular reflexes elicited by angular and linear movements, oculomotor and posture responses to optokinetic stimulations, and responses to caloric stimulation. Tests were also conducted on the ground, during the 4 months before and on days 1 to 6 after flight. The most significant result was that caloric mystagmus of the same direction as on the earth could also be evoked in the weightless environment.
European vestibular experiments on the Spacelab-1 mission: 1. Overview.
1986
During the flight of Spacelab-1 a series of vestibular experiments was performed on the crew by a group of European investigators. Control experiments were carried out on the same subjects pre- and postflight. The tests included caloric stimulation of the ears, threshold measurements of response to linear acceleration, motion sickness provocative stimuli, vestibulo-ocular reflexes during linear and angular stimulation, estimation of the subjective vertical (luminous line measurements) and static ocular counterrotation at various tilt angles. The caloric experiment proved the existence of a nonthermoconvective mechanism of caloric nystagmus in space. Most of the other test results point to a…
Electronystagmography in the diagnosis of central vertigo.
2011
Objective: Determine the efficacy and applicability of electronystagmography (ENG) testing in the differential diagnosis between peripheral and central vertigo, through the visual-vestibular interaction test, in patients with vertigo.Method: Patients were submitted to ENG recording. Patients sat on a rotatory chair, which was placed in the middle of a rotary rotatory cylindrical chamber. The rotatory chamber was driven by a direct current engine, which turned it clockwise and counterclockwise, and its internal area was covered with 32 black vertical contrast.Results: All patients underwent rotatory vestibular stimulation by Stop test (VOR), optokinetic stimulation (OKN), and contemporary ro…
Cranial nerve function in workers exposed to polychlorinated dioxins and furans
2002
OBJECTIVE: To look for possible effects of polychlorinated dioxins and furans (PCDD/F) on cranial nerve function. MATERIAL AND METHODS: Clinical and neurophysiological examinations [visual and brainstem auditory evoked potentials (VEP and BAEP), blink reflex] in 121 PCDD/F exposed workers of one pesticide producing plant. RESULTS: BAEP abnormalities were more frequent in workers with chloracne (6 of 33 workers, 18.2%) than in those without chloracne (7 of 84, 8.3%), but this was not statistically significant (chi2: 2.33). VEP abnormalities were seen in one worker with and two without chloracne. Clinically visual functions were normal except in one worker, who was amaurotic since birth. Blin…
Interaction between muscle stiffness and stretch reflex sensitivity after long-term stretch-shortening cycle exercise
1998
The short latency stretch-reflex component (M1) and its interactions with muscle stiffness and with muscle performance were investigated before and after long-term stretch-shortening cycle (SSC) exercise. Dramatic fatigue induced reduction in maximal SSC performance capability, and electromyographic activity was accompanied by a consistent decrease in the M1 reflex component and eccentric peak stiffness of the muscle. It can be suggested, therefore, that the decreased muscle performance is not simply a direct effect of central or peripheral fatigue, but is partly due to impairment of the ability to utilize stiffness-related elastic energy.
Cerebrovascular Brainstem Diseases with Isolated Cranial Nerve Palsies
2002
There is a significant number of individual patients with cranial nerve palsies as the sole manifestation of MRI- and, less frequently, CT-documented small brainstem infarctions or hemorrhages. The 3rd and 6th nerves are most commonly involved and, less frequently, the 4th, 5th, 7th, and 8th nerves. An intra-axial basis for such lesions may be underestimated if the diagnosis is based solely on MRI. The electrophysiologic abnormalities indicating brainstem lesions may be independent of MRI-documented morphological lesions. This paper reviews the literature on cerebrovascular brainstem diseases manifesting as isolated cranial nerve palsies. It supports the concept that small pontine and mesen…