Search Results
Results 601 - 650 of 681
< 4 5 6 7 8 9 10 11 12 13 14 >
Carlton M J - - 1985
A detailed kinematic and electromyographic (EMG) analysis of single degree of freedom timing responses is reported to (a) determine the coherence of kinematic and EMG variability to the reduced timing error variability exhibited with amplitude increments within a given criterion movement time and (b) understand the temporal organization of various ...
Sieck G C - - 1985
Changes in electromyographic (EMG) activity of the diaphragm were examined in human subjects during different levels of voluntary hyperpnea. Diaphragmatic EMG was recorded using both surface and esophageal electrodes. The power spectra density (PSD) of the EMG signal was calculated and characterized by the high frequency to low frequency (H/L) ...
Haagh S A - - 1985
The present experiment was aimed at whether subjects, performing a forewarned simple reaction time (RT) task, do voluntarily tense agonist and antagonist muscles during the foreperiod; if so, would such muscle tension co-vary with CNV amplitude or RT? Although excessive eye movements caused 30% of the subjects to be removed ...
d'Ascanio P - - 1985
The main aim of the present study was to find out whether the dynamic characteristics of responses of limb extensor muscles to labyrinth stimulation were modified by the proprioceptive input elicited by appropriate displacements of the corresponding limb extremity. In cats decerebrated at precollicular or intercollicular level, the multiunit EMG ...
Siegler S - - 1985
The relationship between the force generated by an isometrically contracting muscle and the associated myoelectric signal has been the subject of extensive investigation in the past and conflicting results were reported regarding this relationship. The objective of the present study was to investigate some of the sources that may lead ...
Yaar I - - 1985
Twenty patients with myasthenia gravis were studied. Needle interference patterns at maximal isometric contractions were recorded from the biceps brachii muscles. Each recording lasted for 30 seconds and induced some fatigue. The EMG signals were transformed into power spectra and were analyzed for differences between control and myasthenic fatigue trends ...
Solomonow M - - 1985
A technique for recording the myoelectric activity of electrically stimulated muscle through its motor nerve without the interference of stimuli artifacts has been developed and tested. The technique consists of a wide band differential amplifier with fine intramuscular wire electrodes. The amplified signal is passed through a Chebyshev low pass ...
Kawasaki K - - 1985
This study characterizes the inhibiting effect of diltiazem and nitroglycerin on periodic contractions of isolated human coronary arteries. Isometric force of coronary ring segments from sixty-nine cadavers was recorded in a muscle bath. To quantify the experimental results, we used 3 X 10(-6) M prostaglandin F2 alpha to induce the ...
Zahalak G I - - 1985
The dynamic relations between the surface myoelectric activity in tonically contracting triceps brachii and the forearm rotation (proportional to triceps stretch) were measured by imposing small, sinusoidal, displacement-controlled perturbations on the forearm position. Three normal, adult, male subjects participated in these experiments. The amplitude of the forearm rotation, the driving ...
Pfeiffer C - - 1985
The maximal post-pause contraction has been measured in random bred albino rats by varying the contraction interval preceding this event. The amplitude of the maximal post-pause contraction as well as the duration of the pause interval corresponding to this contraction depend on the driving frequency applied just prior to this ...
Boylls C C - - 1984
Strong 'neural constraints' synchronizing the step cycles of bilaterally paired limbs in decerebrate cats have been revealed by forcing those limbs to step at different speeds. To determine if humans operate under similar restrictions, we studied subjects pedaling a bicycle ergometer whose coupled cranks imposed continuous change upon interlimb phasing. ...
Gielen C C - - 1984
Nonlinear viscous properties of stretch and unloading reflexes in the human wrist were examined using constant-velocity ramp stretches and releases in the range between 5 and 500 mm/s. Subjects were asked to oppose an initial flexor preload and were instructed not to intervene voluntarily when the changes in position were ...
Zecker S G - - 1984
Twenty male and female subjects listened for mispronounced words while minimizing either subvocal or frontalis electromyographic activity. Stimuli were varied on size of the distortion, lexical constraint, and contextual constraint, all known to influence detections. Analysis of both the reaction time and detection data indicated that the minimization of subvocal ...
Bedingham W - - 1984
The relationship between the segmented EMG activity in flexor carpi radialis evoked by imposed angular wrist displacement was studied with respect to the level of pre-existing background activity in 30 normal human subjects. Input-output response planes demonstrate that the magnitude of the M1 & M2-3 segments is dependent on both ...
Yaar I - - 1984
The motor unit potential shape, mainly its duration and frequency spectra, and the EMG IP crispiness and its frequency spectra are affected by the muscle fiber conduction velocities (MFCVs). Present techniques are somewhat deficient in that they are not adaptable to measure MFCVs continuously and intramuscularly in the presence of ...
Arvidsson A - - 1984
An automatic procedure for detecting artifacts in the electromyogram (EMG) has been developed and applied to a study of respiratory muscle fatigue. Signal segments are characterized by a set of features, the normal variations of which have been estimated in a training session. From the features are calculated a classification ...
Sugarbaker D J - - 1984
Mechanical events and membrane potential changes in response to evoked swallows and cervical vagal stimulation (10 and 40 Hz) were recorded in anesthetized opossums. Miniature strain-gauge transducers monitored the mechanical activity of the two layers. A suction electrode recorded from the intact esophagus, from a proximally based pedicle flap of ...
Crist J - - 1984
The prevalence, amplitude, and latency periods of "on," "off," and "intermediate" contractions in response to transmural stimulation were recorded in transverse rings of circular muscle from different levels of the opossum esophagus. Ten-second train stimuli consistently produced off contractions. On contractions were not seen at lower stimulus frequencies (2 and ...
Greeley H P - - 1984
The decision making process by a human observer during visual observation of an EMG waveform has been modelled by electronic methods. EMG onset times were detected with greater precision than is possible with simple threshold voltage comparison, since the threshold voltage detection levels can be set below peak background and ...
van der Glas H W - - 1984
Standardized mechanical taps were delivered on an upper central incisor, while the nine subjects investigated maintained constant clenching levels of 5, 10, 20, 40 and 60 per cent of their maximal EMG outputs. Using statistical criteria, a computer program enabled an objective determination of the interaction between the clenching level ...
Winkel J - - 1984
A method for evaluation of muscular contraction frequencies during prolonged work is presented. It is based upon computer-aided electromyographic (EMG) analyses. Variations in muscular tension, expressed as the relative force of contraction or torque in the joint, are followed using previously described EMG techniques. The number of times muscular tension ...
Wolpaw J R - - 1983
Description of the neuronal and synaptic bases of memory in the vertebrate central nervous system (CNS) requires a CNS stimulus-response pathway that is defined and accessible, has the capacity for adaptive change, and clearly contains the responsible substrates. This study was an attempt to determine whether the spinal stretch reflex ...
van der Schee E J - - 1983
Interdigestive gastric contraction-related phenomena were studied in four healthy conscious dogs by running-spectrum analysis of signals derived from the abdominal surface. When groups of contractions occur irregularly spaced in time, low frequencies (in the range below 0.085 Hz) show up in the power spectra of the electrogastrograms. It has been ...
Sandrini G - - 1983
An electromyographic (EMG) investigation was performed on 216 workers of a viscose rayon plant with different degrees of exposure to CS2. In the light of the data supplied by the survey the AA. maintain that meedle EMG is able to detect, probably better than other test, changes of PNS even ...
Yang J F - - 1983
The purpose of this study was to determine the reliability of average surface electromyography (EMG) within and between days. Nine subjects were tested on three different days. Five maximum and 10 submaximum (five at each of two different levels) isometric contractions were performed each day. The submaximum levels were determined ...
Ackerson L M - - 1983
Bilaterally synchronized high-frequency oscillations have been found in recordings of human diaphragm and intercostal EMGs during spontaneous breathing (SB). Correlated frequencies (28-52 and/or 68-88 Hz) in the left and right diaphragm EMGs during SB: (1) are at similar values, but not as broad-band, as those found during voluntary breathing maneuvers; ...
Bruce E N - - 1983
Electromyograms (EMGs) from respiratory muscles were obtained from human subjects during voluntarily controlled breathing. In 10 studies on 6 subjects EMGs were recorded from the right and left lower ventrolateral surface of the rib cage while the subject emphasized the use of his diaphragm for breathing. Simultaneous samples of the ...
Hulliger M - - 1983
Direct recordings from identified and classified fusimotor gamma-motoneurons in freely moving animals have not so far been achieved, and present knowledge on fusimotor activity during natural movements is based on qualitative inferences made from spindle afferent discharge. In order to put such deductions on a firmer basis, a simulation method ...
Rossi G - - 1983
The data were gathered by connecting the output from a middle ear impedance meter (Amplaid 702) to the computer and averaging section of the Amplaid MK VI which was also used as an acoustic stimuli generator. The stimuli consisted of white noise bursts having different peak equivalent sound pressures (115, ...
Tümer A - - 1983
In this study the spontaneous activities of prescapular lymph nodes, which were isolated from calves, goats and sheep and mesenteric lymph nodes of guinea-pigs were recorded and analysed in the frequency domain. Stretch-evoked contractions of the mesenteric lymph nodes were also recorded and their frequency characteristics analysed. The preparations were ...
Sakitt B - - 1983
Visually triggered forearm movements were analyzed by an Information Theory approach. Human subjects made smooth movements which were characterized by moderate speeds, ranging about 100 degrees per second, by continuity in the position and velocity traces, and attainment of final average EMG levels before completion of the movement. We calculated ...
Kearney R E - - 1983
The interpretation of stretch-evoked reflex responses is complicated by the fact that the pattern of response will depend upon both the underlying reflex mechanisms and the time course of the stretch used to evoke the response. The objective of the present study was to use engineering systems analysis techniques to ...
Bach T M - - 1983
Viscoelastic models of the musculoskeletal system suggest resonant frequencies of oscillatory movement at which maximal output is realized with minimal energy expenditure. To investigate this, resonance at the human ankle joint was explored by comparing predicted and experimental gain/frequency and phase frequency functions. These functions were predicted from viscous (B) ...
Wallace S A - - 1982
The experiment examined the effects of movement time (MT) and distance on the timing at electromyographic (EMG) activity from an agonist and antagonist muscle during rapid, discrete elbow movements in the horizontal plane. According to impulse-timing theory (Wallace, 1981) MT, not distance moved, should have a pronounced effect on the ...
Partanen J - - 1982
A multidimensional quantitative EMG analysis method with averaged motor unit potentials (MUPs) was applied to a study of different stages of polymyositis. The duration parameters had a general tendency to increase in polymyositis. The only exception was the total MUP duration, which decreased in the onset stage of acute polymyositis. ...
Moxham J - - 1982
During and following high-load fatiguing voluntary contractions, the force response of skeletal muscle to electrical stimulation is altered so that the frequency-force curve is moved to the right. Fatiguing contractions also result in a shift to the left of the electromyographic (EMG) power spectrum. In the quadriceps muscle and the ...
Brown T I - - 1982
1. The interphalangeal joint of the thumb was driven through sinusoidal flexion-extension movements while electromyograms were recorded from over the flexor pollicis longus muscle. 2. When the subject relaxed his thumb the movement generated no detectable e.m.g. response. When, however, he exerted a voluntary flexing force electrical activity could be ...
Bellemare F - - 1982
The time course of the frequency content of the electromyogram (EMG) was studied in the diaphragm of five normal subjects breathing through high inspiratory resistance. The ratio between the power content of a high-frequency band (150-350 Hz) (H) and a low-frequency band (20-40 Hz) (L) was calculated for each breath ...
Hary D - - 1982
EMG and bandlimited noise (BLN) signals of comparable spectra were processed to compute the centroid and median frequencies and the high/low ratio for different record lengths, signal amplitudes, and noise bandwidths. The spectral moments of EMG and BLN showed similar statistical properties, independent of record length and amplitude. The signal-to-noise ...
Jaeger R J - - 1982
1. Torque-step perturbations were applied to flex or extend the wrists of normal human subjects. The electromyographic activity (EMG) of two of the stretched muscles, flexor carpi radialis and extensor carpi radialis, was monitored. 2. Based on functional characteristics and temporal bursting patterns, the EMG responses were partitioned into four ...
Eklund G - - 1982
1. Brisk joint displacements and tendon taps were applied to voluntarily contracting wrist flexor muscles in subjects who did not attempt to react to them. Different types of mechanotransducers, some of them attached to an intramuscular needle, were used to detect mechanical oscillations in the wrist flexors, resulting from the ...
Chan C W - - 1982
Recent findings in humans and primates suggest that the long latency electromyographic (EMG) responses, evoked by opposing sudden limb displacements, might be mediated via a transcortical pathway. However, it is not clear whether these "late" responses are servo controlled or preprogrammed. We have addressed these questions in two interrelated experimental ...
Nakamura R - - 1982
The effect of passive movements of the elbow on biceps EMG reaction time (RT) was studied in 10 normal subjects. Each subject was required to perform a simple RT task, flexing the left elbow to a tone stimulus, under three different conditions: (a) during passive flexion (PFLX) of the elbow, ...
Graupe D - - 1982
The paper discusses results of on-line tests on amputees and hemiplegics of multifunctional prostheses and orthoses control by identifying the parameters of single-site temporal EMG signal signatures. The results relate to tests on above-elbow amputees, on shoulder-disarticulation amputees (including a congenital disarticulation amputee) and on hemiplegics, varying from 5 to ...
Wicke R W - - 1982
Human subjects were suspended in a safety harness 28 cm above the floor by a steel cable connected to a computer controlled force generator (electromagnetic brake). After the subjects were unexpectedly released, various controlled patterns of downward acceleration (less than 1 g) could be produced. During the falls, EMG activity ...
Wetzel M C - - 1981
Cats were trained to walk and trot on a motor-driven treadmill such that mean kinematic timings were highly uniform. Evidence was sought that variations in electromyographic activity in individual muscles was due to separate sources of control. EMGs were recorded on magnetic tape from a knee extensor, vastus lateralis (VL), ...
Grebecki A - - 1981
The uroids, the posterior, middle and anterior segments of the intermediate body regions, and the frontal zones of Amoeba proteus were exposed, separately or in different combinations, to local increases or decreases of light intensity. In general, an increase of luminosity promotes contraction, and its decrease induces relaxation in any ...
Lacour M - - 1981
In the present investigation, we have analysed the visually induced modulations of muscular responses during falls at different rates of acceleration and performed in five different visual conditions: Normal vision (NV), Darkness (D), Stabilized vision (SV), with visual motion cues being enhanced (EV), or reduced (RV). This study was conducted ...
Perry J - - 1981
This article reviews the history of attempts to define in quantitative terms the relationship between a processed electromyographic signal and the corresponding force produced by skeletal muscle. Numerous reports have indicated a linear relationship between isometric force and rectified, integrated EMG. These reports, the nature of their experiments, and the ...
Shanks C A - - 1980
Electromyographic and mechanical evoked twitch responses at the hand were observed simultaneously following suxamethonium. The intensity of neuromuscular blockade was assessed by comparison with their control heights of the responses obtained from both the force of thumb adduction and from the compound electromyogram (EMG). Surface electrodes placed dorsally over the ...
< 4 5 6 7 8 9 10 11 12 13 14 >