Search results for "reflex"
showing 10 items of 622 documents
Postural equilibrium: functional system and its stabilization by means of osteoreflexotherapy.
1998
Our investigations have confirmed that the osteoreceptive sensory system participates in the polysensoric regulation of animal and human posture. Experiments with animals have demonstrated that the irritation of osteoreceptors by electric pulses leads to osteoreceptive response potentials of the same parts of the brain (Deiter's nuclei, cerebellum, caudate nucleus, cortical motor centre etc.) which participate in the regulation of animal and human posture and other motion acts. Close functional relations have been established between the skin, bone, vestibular and muscle sensory systems in the brain structures where the osteoreceptive excitation converges. The studies of osteoreceptive sens…
Characterization of human reflex tear proteome reveals high expression of lacrimal proline-rich protein 4 (PRR4).
2014
In-depth studies on the proteome of reflex tears are still inadequate. Hence, further studies on this subject will unravel the key proteins which are conjectured to possess vital functions in the protection of the ocular surface. Therefore, this study investigated the differences in the expression levels in proteome of reflex compared to basal tears. Basal (n = 10) and reflex (n = 10) tear samples from healthy subjects were collected employing the capillary method, subsequently pooled and the proteomes were characterized employing 1DE combined with LC-ESI-MS/MS strategy for label-free quantitative (LFQ) analysis. The differentially expressed proteins were validated by 2DE combined with LC-E…
The Primitive Palmomental Reflex in Amyotrophic Lateral Sclerosis
2017
<b><i>Background and Purpose:</i></b> The palmomental reflex (PMR) is a primitive reflex that might be released due to inhibition in adulthood. It has been associated with several neurodegenerative conditions. The aim of the present study was to evaluate the frequency of PMR in amyotrophic lateral sclerosis (ALS). <b><i>Patients and Methods:</i></b> Non-demented ALS patients (<i>n</i> = 179) were recruited. Two groups of disease controls were enrolled: (a) non-demented patients with other neurological disorders (NC;<i> n</i> = 86, mean age 60 ± 14 years); (b) healthy subjects, healthy controls (HC; <i>n</i> …
Effects of a vestibular physiotherapy protocol on adults with intellectual disability in the prevention of falls: A multi-centre clinical trial
2018
Background Balance alterations are one of the main problems in people with intellectual disabilities (ID), increasing their risk of falls and impacting their life. Aims To describe a vestibular rehabilitation programme (VRP) and evaluate its effects on the ability to maintain balance and risk of suffering a fall. Methods Forty-seven adults with mild to moderate ID were randomly assigned to two groups: a control group (CG, N = 24), which performed a general physical exercise only, and an experimental group (EG, N = 23) which also completed a VRP. The variables, used pre- and post-training and 1 month after the intervention, were as follows: Center of Pressure Displacement, Berg Scale, Timed …
The relative contribution to the plantar-flexor torque of the soleus motor units activated by the H reflex and M response in humans.
2000
Abstract This study proposes a method of quantifying the relative contribution to the plantar-flexor torque of soleus H and M responses evoked by tibial nerve stimulation. For ten subjects, the amplitude of the twitch produced by the H wave was plotted against the corresponding potential, for stimuli producing H without M (i.e. in the ascending portion of the H-recruitment curve). It was then assumed that the contribution of H to twitches produced by M plus H was similar for similar H waves on the curve-descending portion. Hence, the contribution of M was estimated, for the range of M waves including those accompanying H max . The estimated mechanical contributions of H and M wave increase …
Short and long latency reflex responses elicited by electrical and mechanical stimulation in human hand muscle
1986
The relationship between electrically and mechanically induced reflex responses in the rectified, averaged surface electromyogram of the first interosseus dorsalis muscle was examined in 18 healthy human subjects. Both methods evoked identifiable short and long latency reflex responses. The onset latencies for short latency reflexes with electrical and mechanical stimulations were 30.6 ms (+/- 2.2 ms) and 28.9 ms (+/- 2.2 ms) and for long latency reflexes 50.0 ms (+/- 2.8 ms) and 51.2 ms (+/- 5.2 ms), respectively. The correlation of the onset latencies of the reflexes revealed significant correspondence between the electrical and mechanical methods implying at least partly mutual mechanism…
Influence of aging on the mechanical behavior of leg extensor muscles.
1980
Age dependence of the mechanical behavior of leg extensor muscle was investigated using vertical jumps with and without a stretch-shortening cycle on the force-platform. A total 226 subjects (113 females and 113 males) ranging in age from 4--73 years were examined. The results indicated in general that performance in males was better than that in females. This difference was reduced when body weight was taken into consideration. The peak performance of the various parameters, such as average force, height of rise of center of gravity, net impulse, and also the average power output, was reached in both sexes between the ages of 20 and 30 years. For example, the average vertical force in squa…
Heat-evoked vasodilatation in human hairy skin: axon reflexes due to low-level activity of nociceptive afferents.
1996
1. Spreading vasodilatation of the axon reflex type was evoked by contact heat stimulation of the hairy skin in the human forearm (13.3 cm2 stimulus area) and was detected by laser Doppler flowmetry at 8, 19 and 30 mm distance. 2. From a base temperature of 35 degrees C, rapidly rising short heat stimuli (4 degrees C s-1, 2 s plateau) elicited vasodilatation at an average threshold of 39.4 degrees C. For slowly rising sustained heat stimuli (64 s duration) the average threshold was 39.6 degrees C (n.s.) Laser Doppler flowmetry revealed a rapid onset within about 4 s, a long duration of several minutes beyond the end of the stimulus, and a rapid spread of vasodilatation to remote skin areas.…
Neuromuscular function during drop jumps in young and elderly males
2011
The Hoffman reflex (H-reflex), indicating alpha-motoneuron pool activity, has been shown to be task - and in resting conditions - age dependent. How aging affects H-reflex activity during explosive movements is not clear at present. The purpose of this study was to examine the effects of aging on H-reflexes during drop jumps, and its possible role in drop jump performance. Ten young (26.8 ± 2.7 years) and twenty elderly (64.2 ± 2.7 years) subjects participated in the study. Maximal drop jump performance and soleus H-reflex response (H/M jump) 20 ms after ground contact were measured in a sledge ergometer. Maximal H-reflex, maximal M-wave, Hmax/Mmax-ratio and H-reflex excitability curves wer…
Application of intermittent galvanic vestibular stimulation reveals age-related constraints in the multisensory reweighting of posture
2014
In this study we examined the effects of intermittent short-duration Galvanic Vestibular Stimulation (GVS) during a multisensory perturbation of posture in young and elderly adults. Twelve young (24.91 +/- 6.44 years) and eleven elderly (74.8 +/- 6.42 years) participants stood upright under two task conditions: (a) quiet standing and (b) standing while receiving pseudo-randomly presented bipolar 2 s GVS pulses. In both conditions, sensory reweighting was evoked by visual surround oscillations (20 cm, 0.3 Hz) and Achilles tendon vibration (3 mm, 80 Hz), concurrently delivered during the middle 60 s of standing. Intermittent GVS decreased the excessive postural sway induced by the concurrent …