Varied morphology of spontaneous single muscle fiber discharges
Varied morphology of spontaneous single muscle fiber discharges
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DOI：
10.1097/00002060-199803000-00009
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发表时间：
1998-03-01
影响因子：
3
通讯作者：
King, JC
中科院分区：
文献类型：
--
作者：
Dumitru, D;King, JC
纤颤电位和正尖波具有相当典型的形态，通常分别符合三相初始正波形和两相初始正波形。然而，在对静息膜电位不稳定的肌肉组织进行针肌电图检查时，如果仔细观察，往往会发现自发电位的外观不仅符合上述要求，而且其波形的形态最好表征为纤颤电位和正尖波的混合。这些“混合”或复合波形被假设为产生于两个单一的肌肉纤维以时间锁定的方式重复放电的电总和。五个人与下运动神经元疾病显示自发放电在休息期间针肌电图进行了检查。根据其形态学对自发放电进行分类。对这些患者的典型阳性和阴性房颤发作电位和阳性尖波进行数字化。计算机模拟总结数字化波形成功地再现了所有观察到的“混合”波形记录在患者。两个单个肌纤维在有助于电求和的时域内放电的假设是包括运动单元的肌纤维的电求和求和以生成该运动单元的电表示的概念的扩展。
Fibrillation potentials and positive sharp waves have rather stereotypical morphologies generally conforming to a triphasic initially positive and biphasic initially positive waveform, respectively. Careful attention during the needle electromyographic examination of muscle tissue with unstable resting membrane potentials, however, frequently reveals spontaneous potentials with appearances conforming to not only those described above but also waveforms with morphologies that can best be characterized as a blend of both a fibrillation potential and positive sharp wave. These "hybrid" or composite waveforms are hypothesized to arise from an electrical summation of two single muscle fibers repetitively discharging in a time-locked manner. Five individuals with lower motor neuron disorders displaying spontaneous discharges at rest during the needle electromyographic were examined. The spontaneous discharges were categorized according to their morphology. Stereotypical positive and negative onset fibrillation potentials and positive sharp waves from these patients were digitized. Computer simulations summating the digitized waveforms were successful in reproducing all of the observed "hybrid" waveforms documented in the patients. The supposition of two single muscle fibers discharging within a temporal domain conducive to electrical summation is an extension of the concept that electrical summation of muscle fibers comprising a motor unit summate to generate an electrical representation of that motor unit.