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1.
E. Lorenc-Koci S. Wolfarth K. Ossowska 《Experimental brain research. Experimentelle Hirnforschung. Expérimentation cérébrale》1996,109(2):268-276
The aim of the present study was to find out whether haloperidol-induced rigidity was similar to that seen in parkinsonism. Simultaneous measurements of the muscle resistance (mechanomyogram, MMG) of the hind foot to passive flexion and extension in the ankle joint, as well as determination of the electromyographic (EMG) activity of the gastrocnemius and tibialis anterior muscles of rats were carried out. Haloperidol was injected in doses of 0.5–10 mg/kg 1 h before the start of measurements. Haloperidol increased, in a dose-dependent manner, the muscle resistance of the rat's hind leg to passive movements. Muscle rigidity was accompanied with an increase resting, as well as in the stretch-induced long-latency EMG activity (in which supraspinal reflexes are most probably involved) in both those muscles, whereas the short-latency EMG activity (first large bursts of EMG activity, beginning ca. 9 ms after the start of a movement, probably of a spinal origin) was significantly decreased. The obtained results suggest that the haloperidol-increased MMG/EMG activity might be a good model of parkinsonian rigidity. 相似文献
2.
Kawakami S Kodama N Maeda N Sakamoto S Oki K Yanagi Y Asaumi J Maeda T Minagi S 《Journal of neuroscience methods》2012,203(1):157-162
The activity of the lateral pterygoid muscle has been regarded to be related to the pathological condition of the temporomandibular joint (TMJ) in the craniomandibular disorders. Because the lateral pterygoid muscle is a deep muscle, a needle electrode is necessary for EMG recordings. The purpose of this study was to establish a non-invasive method for the evaluation of muscle activity of the lateral pterygoid muscle using mechanomyogram (MMG). In three male subjects, surface electromyogram (EMG) in the left masseter muscle, left anterior and posterior belly of the temporal muscle, left anterior belly of the digastric muscle and needle EMG of the inferior head of the lateral pterygoid were recorded during mandibular movement tasks simultaneously with the MMG derived from a condenser microphone in the external ear canal. There were significant positive correlations between the needle EMG signal of the lateral pterygoid muscle and the MMG signal for the tasks of static jaw opened position of 30 mm of interincisal distance (p = 0.000, R2 = 0.725), static jaw opened position of 40 mm of interincisal distance (p = 0.000, R2 = 0.753), 5 mm protruded mandibular position (p = 0.000, R2 = 0.653), the most protruded mandibular position (p = 0.000, R2 = 0803). On the contrary, for the task of maximal clenching, there was no significant correlation between the EMG signal of the lateral pterygoid muscle and the MMG signal. These results suggest that the activity of the lateral pterygoid muscle could be evaluated by the MMG signals recorded in the external ear canal, unless jaw closing major muscles show active contraction. 相似文献
3.
Kimura T Hamada T Watanabe T Maeda A Oya T Moritani T 《European journal of applied physiology》2004,92(4-5):533-539
The purpose of this study was to elucidate the responses of the mechanomyogram (MMG) from two apparently different muscles (biceps brachii and soleus) during a sustained voluntary contraction at 50% maximum voluntary contraction. The MMG and surface electromyogram (EMG) were recorded from human biceps brachii and soleus during sustained elbow flexion and plantar flexion, respectively. Results indicated that the slope coefficient of rise in EMG amplitude as a function of time for the biceps was significantly greater than that for the soleus (P<0.001). On the contrary, the MMG amplitude of the biceps showed a significant increase during the initial phase of sustained contraction (P<0.05); however, when exhaustion was approached the amplitude declined significantly (P<0.05). In the soleus muscle the decrease in MMG amplitude toward exhaustion occurred to a much lesser extent than that observed in the biceps. This difference could be attributed to the nature of the fusion state of the underlying muscle fibers. That is, the great extent of fusion observed in the biceps may be as a result of a greater quantity of fatigable motor units. In addition, the absence of MMG reduction in the soleus would indicate the absence of fatigue-induced slowing of contractile machinery and/or the lack of full activation (tetanus) of muscle fibers even at the exhaustion phase of plantar flexion. 相似文献
4.
The objective of the study was to develop a new surface probe for differential mechanomyographic (MMG) and electromyographic
(EMG) recording. Differential amplification is commonly used in electromyography to improve the signal-to-noise ratio. A new
composite probe was developed with two electrodes (EMG) and two identical piezo-electric membranes (MMG) to be positioned
on muscle. The probe had two built-in fixed-gain differential amplifiers: one to amplify the electric signal and the other
to amplify the vibration signal. A similar non-differential MMG probe was used for comparisons. Burst muscular activity was
recorded using the non-differential and differential probes and was used to test the performance of the two probes in suppressing
artifacts of non-muscular origin. Power spectrum analysis of signals from the two probes showed that differential amplification
significantly improved the signal-to-noise ratio in MMG recordings and significantly suppressed artifacts (power difference>90%).
The composite probe allowed simultaneous differential recording of MMG and EMG signals from the same muscular site. It recorded
muscular activity more efficiently than the non-differential probe and could therefore be useful in studying fatigue and neuromuscular
diseases. 相似文献
5.
A moving magnet galvanometer equipped with lever and indentor was evaluated for mechanomyography (MMG). First, the precision
of the galvanometer was tested on a piezo-electric disc actuator. Using a 50mm lever, synthesised micromotions with an amplitude
of 1 μm could be detected (noise level<0.2μm) at static indentation forces ranging from 0.1 to 2N. Then the galvanometer was
mounted on an isometric ankle dynamometer to sense calf-muscle responses (N=6). In the first protocol, twitch contractions
were elicited by electrical stimulation while the indentation force was increased. Twitch amplitudes, twitch contraction times
and twitch halfrelaxation times were analysed from the surface and contraction responses. With indentation force (0.1–0.5N),
the amplitude of the surface responses increased (+61%), contraction and half-relaxation times, however, were not influenced.
The mean twitch contraction time from the surface responses (60±11 ms) was shorter than that from the contraction responses
(115±7 ms), indicating more fast-contracting fibres under the indented area. In the second protocol, voluntary target contractions
were produced, and the surface responses were simultaneously recorded on an accelerometer. After double differentiation of
the galvanometer signal, both acceleration MMGs showed a high coincidence in the time and frequency domains. With an indentation
force of 2N applied on the accelerometer, the signal amplitude (−10%) and the mean frequency (−19%) decreased. A specific
application of this galvanometer-dynamometer test system is the assessment of regeneration processes in paraplegics with long-term
denervated muscles. 相似文献
6.
Cescon C Farina D Gobbo M Merletti R Orizio C 《Medical & biological engineering & computing》2004,42(1):121-127
To understand better the features of the mechanomyogram (MMG) with different force levels and muscle architectures, the MMG
signals detected at many points along three muscles were analysed by the application of a linear array of MMG sensors (up
to eight) over the skin. MMG signals were recorded from the biceps brachii, tibialis anterior and upper trapezius muscles
of the dominant side of ten healthy male subjects. The accelerometers were aligned along the direction of the muscle fibres.
One accelerometer was located over the distal muscle innervation zone, and the other six or seven accelerometers were placed
over the muscle, forming an array of sensors with fixed distances between them. The array covered almost the entire muscle
length in all cases. MMG signals detected from adjacent accelerometers had similar shapes, with correlation coefficients ranging
from about 0.5 to about 0.9. MMG amplitude and characteristic spectral frequencies significantly depended on accelerometer
location. The MMG amplitude was maximum at the muscle belly for the biceps brachii and the tibialis anterior. Higher MMG characteristic
spectral frequencies were associated with higher amplitudes in the case of the biceps brachii, whereas the opposite was observed
for the tibialis anterior muscle. In the upper trapezius, the relationship between characteristic spectral frequencies, MMG
amplitude and contraction force depended on the accelerometer location. This suggested that MMG spectral features do not only
reflect the mechanical properties of the recruited muscle fibres but depend on muscle architecture and motor unit territorial
distribution. It was concluded that the location of the accelerometer can have an influence on both amplitude and spectral
MMG features, and this dependence should be considered when MMG signals are used for muscle assessment. 相似文献
7.
Mechanomyogram and force relationship during voluntary isometric ramp contractions of the biceps brachii muscle 总被引:1,自引:0,他引:1
The aim of the present study was to examine the non-stationary mechanomyogram (MMG) during voluntary isometric ramp contractions
of the biceps brachii muscles using the short-time Fourier transform, and to obtain more detailed information on the motor
unit (MU) activation strategy underlying in the continuous MMG/force relationship. The subjects were asked to exert ramp contractions
from 5% to 80% of the maximal voluntary contraction (MVC) at a constant rate of 10% MVC/s. The root mean squared (RMS) amplitude
of the MMG began to increase slowly at low levels of force, then there was a slight reduction between 12% and 20% MVC. After
that, a progressive increase was followed by a decrease beyond 60% MVC. As to the mean power frequency (MPF), a relatively
rapid increase up to 30% MVC was followed by a period of slow increment between 30% and 50% MVC. Then temporary reduction
at around 50% MVC and a further rapid increase above 60% MVC was observed. The interaction between amplitude and MPF of the
MMG in relation to the MU activation strategy is discussed for five force regions defined on the basis of their inflection
points in the RMS-amplitude/force and MPF/force relationships. It was found that the MMG during ramp contractions enables
deeper insights into the MU activation strategy than those determined during traditional separate contractions. In addition,
this contraction protocol is useful not only to ensure higher force resolution in the MMG/force relationship, but also to
markedly shorten the time taken for data acquisition and to reduce the risk of fatigue.
Accepted: 31 August 2000 相似文献
8.
Kimura T Fujibayashi M Tanaka S Moritani T 《European journal of applied physiology》2008,104(4):651-656
The present study examined whether the mechanomyogram (MMG) could assess the fatigue-related changes in muscle mechanical
properties during cycle exercise. In eight male subjects, the MMG signals were measured in vastus lateralis and rectus femoris
by electret condenser microphones. It was found that the integrated MMG (iMMG) showed non linear increase against workload
during continuous, incremental cycle exercise and the onset of abrupt changes in iMMG coincided with the ventilatory threshold
(VT). Specifically, iMMG in vastus lateralis showed a significant decrement in the rate of increase against workload above
VT, reflecting the fatigue-induced impairment of contractile properties of the fibers of active motor units. These results
suggest that the MMG measured by electret condenser microphone could be practically used to retrieve the fatigue-related changes
in muscle mechanical properties during cycle exercise. 相似文献
9.
The electromyogram (EMG) and intramuscular pressure (IMP) increase linearly with force during voluntary static contractions,
while the surface mechanomyogram (MMG) increases linearly only up to approximately 70% of the maximal voluntary contraction
(MVC) and then levels off. The aim of this study was to investigate the possible influence of IMP on the non-linear MMG increase
with force and hence on the signal generation process. Seven subjects performed static contractions of the elbow flexors during:
(1) ramp contractions from 0 to 60% of the MVC, and (2) steps at 10, 20 and 40% of the MVC. An external pressure of 0 and
50 mmHg for the ramps or 0, 20, 40, 60, 80 and 100 mmHg for the steps was applied by means of a sphygmomanometer cuff in separate
trials. The EMG and the MMG were detected in the biceps brachii by means of a pair of surface electrodes and an accelerometer.
The IMP was measured using a Millar tipped pressure transducer, and the data was presented as the mean and standard deviation
in each case. The IMP was strongly and linearly related to the external pressure and contraction force both during ramps and
steps. The EMGrms and MMGrms were never reduced as a consequence of the IMP increments. In contrast, a steeper MMGrms versus %MVC relationship during ramps at 50 mmHg cuff pressure, and an influence of the cuff pressure at 40% of MVC on MMGrms were evident. We conclude that IMP per se does not attenuate the MMG generation process during voluntary contraction, suggesting
that the previously described MMGrms decrease at near maximal static efforts must be attributed to other determinants, such as a fusion-like situation due to
the high motor unit firing rate. 相似文献
10.
Morufu Olusola Ibitoye Nur Azah Hamzaid Jorge M. Zuniga Ahmad Khairi Abdul Wahab 《Clinical biomechanics (Bristol, Avon)》2014
Previous studies have explored to saturation the efficacy of the conventional signal (such as electromyogram) for muscle function assessment and found its clinical impact limited. Increasing demand for reliable muscle function assessment modalities continues to prompt further investigation into other complementary alternatives. Application of mechanomyographic signal to quantify muscle performance has been proposed due to its inherent mechanical nature and ability to assess muscle function non-invasively while preserving muscular neurophysiologic information. Mechanomyogram is gaining accelerated applications in evaluating the properties of muscle under voluntary and evoked muscle contraction with prospects in clinical practices. As a complementary modality and the mechanical counterpart to electromyogram; mechanomyogram has gained significant acceptance in analysis of isometric and dynamic muscle actions. Substantial studies have also documented the effectiveness of mechanomyographic signal to assess muscle performance but none involved comprehensive appraisal of the state of the art applications with highlights on the future prospect and potential integration into the clinical practices. Motivated by the dearth of such critical review, we assessed the literature to investigate its principle of acquisition, current applications, challenges and future directions. Based on our findings, the importance of rigorous scientific and clinical validation of the signal is highlighted. It is also evident that as a robust complement to electromyogram, mechanomyographic signal may possess unprecedented potentials and further investigation will be enlightening. 相似文献