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At least 37 records · Page 2Linked to original sources
PubMed1986

EMG-biofeedback therapy for rupture of the extensor pollicis longus tendon.

EMG-biofeedback therapy was attempted in five cases of EPL tendon rupture with residual postoperative functional disabilities such as weakness of extension or extension lag of the thumb, and improvement was obtained in muscle strength, range of motion, and performance of daily activities. EMG-biofeedback therapy is a method which, utilizing visual or auditory information, supplements and facilitates the intrinsic feedback mechanism in the human body. This method is applied as a treatment to improve motor dysfunction. The effectiveness of the therapy is elucidated by a neural motor control theory based on the sensory-motor feedback loop.

Adolescent↗
PubMed1980

Electromyographic feedback: effect on voluntary muscle contractions in paretic subjects.

To evaluate the efficacy and function of emg feedback (emgFB) in muscle reeducation, skeletal muscle contractions with and without emgFB were compared under controlled experimental conditions in human subjects with paresis due to brain damage (n=6) or peripheral nervous system damage (n=6). Each subject was instructed to produce 12 sustained 30-second contractions of a muscle below functional strength, 6 contractions in each of 2 sessions. EmgFB was provided in half the trials, alternating with nonfeedback trials. Emg activity during each trial was quantitified and the data analyzed statistically. By the 2nd session, emg activity was significantly greater during voluntary muscle contractions attempted with emgFB for both subject categories. This differential developed over the 1st 10 seconds of the muscle contraction and remained relatively constant until the end of the 30-second trial period. Response to emgFB was not closely linked to type of injury, duration of injury, or age. These results indicated a substantial and positive response to such feedback.

Adult↗
PubMed1981

[Electromyographic feedback for cerebral children (adults): on the residual tension of muscle (author's transl)].

In order to investigate the residual tension of muscle in cerebral palsied (CP) children (adults) and the effect of EMG feedback on its relaxation processes, 5 normal children and 15 CP children, including one adult, were asked to flex their elbows gradually, then increase the tension with full flexion, and finally relax as quickly as possible under three conditions: pre-feedback, feedback, and post-feedback. Under the feedback condition, a meter display was provided. Results were as follows: (1) All except one in the CP group showed more residual tension than the normals at the pre-feedback condition. (2) Under the feedback condition, the time to relax was shortened significantly in the CP group. (3) The CPs could be classified into following four types by the influence of EMG feedback. (a) Type A (N = 2) showed no change. (b) Type B (N = 9) improved. (c) Type C (N = 1) improved in the latter half of the feedback condition, though it increased tension in the first half. (d) Type D (N = 2) increased conversely under the feedback condition.

Adolescent↗
PubMed2006

Evidence for positive force feedback during involuntary aftercontractions.

We examined the involuntary isotonic muscle aftercontraction which follows a 1-min voluntary contraction at 60% of maximum voluntary force. Aftercontractions provide a unique paradigm for investigating the automatic postural control of the upper limb in man. Previous work has shown that the strength of these contractions in m. deltoid is linearly dependent on the inclination of the subject's body in the gravitational field. The current experiments were designed to test if this was due to the gravitational loading on the arm as this also changes with body inclination. The subject sat with the head stationary to prevent changes in vestibular orientation. Aftercontractions in m. deltoid were evoked with the normal weight of the arm present and also with arm loadings equal to 0, 25, 50 and 75% of this value. These reductions were produced by a counter lever apparatus. The results showed that the EMG amplitude of this involuntary contraction depended linearly on the loading of the arm. This is interpreted as being the result of positive load feedback. Aftercontraction EMG amplitude at 100% load was 2.7 times greater than at 0% load. The results are discussed in the context of recent work on positive load feedback in man and animals.

Adult↗
PubMed2006

Synchrony of hand-foot coupled movements: is it attained by mutual feedback entrainment or by independent linkage of each limb to a common rhythm generator?

BACKGROUND: Synchrony of coupled oscillations of ipsilateral hand and foot may be achieved by controlling the interlimb phase difference through a crossed kinaesthetic feedback between the two limbs, or by an independent linkage of each limb cycle to a common clock signal. These alternative models may be experimentally challenged by comparing the behaviour of the two limbs when they oscillate following an external time giver, either alone or coupled together. RESULTS: Ten subjects oscillated their right hand and foot both alone and coupled (iso- or antidirectionally), paced by a metronome. Wrist and ankle angular position and Electromyograms (EMG) from the respective flexor and extensor muscles were recorded. Three phase delays were measured: i) the clk-mov delay, between the clock (metronome beat) and the oscillation peak; ii) the neur (neural) delay, between the clock and the motoneurone excitatory input, as inferred from the EMG onset; and iii) the mech (mechanical) delay between the EMG onset and the corresponding point of the limb oscillation. During uncoupled oscillations (0.4 Hz to 3.0 Hz), the mech delay increased from -7 degrees to -111 degrees (hand) and from -4 degrees to -83 degrees (foot). In contrast, the clk-mov delay remained constant and close to zero in either limb since a progressive advance of the motoneurone activation on the pacing beat (neur advance) compensated for the increasing mech delay. Adding an inertial load to either extremity induced a frequency dependent increase of the limb mechanical delay that could not be completely compensated by the increase of the neural phase advance, resulting in a frequency dependent increment of clk-mov delay of the hampered limb. When limb oscillations were iso- or antidirectionally coupled, either in the loaded or unloaded condition, the three delays did not significantly change with respect to values measured when limbs were moved separately. CONCLUSION: The absence of any significant effect of limb coupling on the measured delays suggests that during hand-foot oscillations, both iso- and antidirectionally coupled, each limb is synchronised to the common rhythm generator by a "private" position control, with no need for a crossed feedback interaction between limbs.

Adult↗
PubMed1993

Effects of oral sensory afferents on mastication in the miniature pig.

The performance of mastication is presumed to be influenced by afferent stimulation, but little information is available from awake, intact animals. Thirteen experiments were carried out with four miniature pigs. Electromyographic signals from the jaw muscles were recorded simultaneously with jaw movements during natural chewing of foods of differing hardnesses. Harder foods were found to be associated with higher activity levels of jaw-closing muscles and greater lateral deviation, but reduced jaw opening. The sensory supply from one side of the oral cavity was then removed by injected local anesthetic, and the recordings repeated. In addition to decreased activity levels, the jaw-closing muscles showed reduced ability to adjust to different foods. The frequency of mastication fell slightly, and the animals preferred to chew on the uninjected side. Lateral deviation was reduced, but at the same time the jaw-opening muscles usually became more active and accordingly the jaw opened more widely. These findings provide new information on the role of oral sensory afferents in regulating natural chewing patterns. The decreased activities of the jaw-closing muscles are consistent with, although they do not demonstrate, the existence of a positive feedback from periodontal afferents.

Afferent Pathways↗
PubMed2000

Rapid correction of aimed movements by summation of force-field primitives.

Spinal circuits form building blocks for movement construction. In the frog, such building blocks have been described as isometric force fields. Microstimulation studies showed that individual force fields can be combined by vector summation. Summation and scaling of a few force-field types can, in theory, produce a large range of dynamic force-field structures associated with limb behaviors. We tested for the first time whether force-field summation underlies the construction of real limb behavior in the frog. We examined the organization of correction responses that circumvent path obstacles during hindlimb wiping trajectories. Correction responses were triggered on-line during wiping by cutaneous feedback signaling obstacle collision. The correction response activated a force field that summed with an ongoing sequence of force fields activated during wiping. Both impact force and time of impact within the wiping motor pattern scaled the evoked correction response amplitude. However, the duration of the correction response was constant and similar to the duration of other muscles activated in different phases of wiping. Thus, our results confirm that both force-field summation and scaling occur during real limb behavior, that force fields represent fixed-timing motor elements, and that these motor elements are combined in chains and in combination contingent on the interaction of feedback and central motor programs.

Animals↗