A correlation technique for muscle fibre action potential conduction velocity measurement using a single acquisition channel

Abstract

Muscle fibre conduction velocity is an important parameter in electrophysiology and also for patient rehabilitation. Its measurement is usually made by placing electrodes spaced at known distances and, somehow, estimating the action potential conduction time. The problem, common to all methods, is how to as accurately as possible estimate the latter, i.e., the time delay. Several procedures have been proposed, both in the time and frequency domains. Time domain strategies usually require two acquisition channels, while frequency-domain based methods use a single one. The method described herein operates in the time domain, producing a conduction delay estimate by means of the autocorrelation of the signal obtained from a single acquisition channel. As with other time domain methods, it does not require long records. Experimental results are shown using the spontaneous electric activity of the muscle under contraction. It yields satisfactory results even with records as short as 0.2 s.