Dumitru D, Walsh N E
Dept. of Physical Medicine and Rehabilitation, University of Texas Health Sciences Center, San Antonio 78284-7798.
Am J Phys Med Rehabil. 1988 Apr;67(2):55-65. doi: 10.1097/00002060-198804000-00005.
A thorough comprehension of electrodiagnostic equipment is essential to consistently obtain accurate and reproducible data. Unreliable waveform latencies or morphologies may result from inappropriate filter settings, sensitivity comparisons, sweep speeds, interelectrode separation, cathode/anode reversals and stimulus artifact. A low frequency filter with too high a frequency limit may decrease amplitude, shorten peak latency, decrease the negative spike duration, add a phase and increase total waveform duration. A high frequency filter with too low a cut-off may decrease amplitude and prolong onset and peak latencies. Increasing the amplifier's sensitivity may shorten the onset latency of a response. Sweep speeds that are too slow may omit phases, turns or entire potentials when using digital equipment. If the interelectrode separation is inadequate, waveform morphology and amplitude can be altered. Reversing cathode and anode placement affects latency and velocity determinations. Stimulus artifact may obscure a response and its reduction must be understood. Comparing latencies and amplitudes at different instrument settings is never appropriate and can lead to serious errors and misdiagnoses. A naive approach to instrumentation, therefore, is indefensible.
全面理解电诊断设备对于持续获取准确且可重复的数据至关重要。不适当的滤波设置、灵敏度比较、扫描速度、电极间距、阴极/阳极反转以及刺激伪迹可能导致波形潜伏期或形态不可靠。低频滤波器的频率上限过高可能会降低振幅、缩短峰潜伏期、减少负尖峰持续时间、增加相位并延长总波形持续时间。高频滤波器的截止频率过低可能会降低振幅并延长起始和峰潜伏期。增加放大器的灵敏度可能会缩短反应的起始潜伏期。使用数字设备时，扫描速度过慢可能会遗漏相位、转折或整个电位。如果电极间距不足，波形形态和振幅可能会改变。阴极和阳极放置的反转会影响潜伏期和速度的测定。刺激伪迹可能会掩盖反应，必须了解如何减少它。在不同仪器设置下比较潜伏期和振幅是不合适的，可能会导致严重错误和误诊。因此，对仪器使用的天真方法是站不住脚的。
