A NEW METHOD OF ESTIMATING THE DISTRIBUTION OF MUSCLE-FIBER CONDUCTION VELOCITIES

A computer-assisted method of estimating the distribution of muscle fi ber conduction velocities is described. An electrode array composed of 2 stimulating and 4 recording electrodes is used to record surface mu scle action potentials (MAPs) in response to diner muscle stimulation. The velocity distribution and the single muscle fiber action potentia l (SFAP) are calculated from the recorded MAPs by an iterative method of estimation. The estimation is based on the assumption that the spat ial orientation of each muscle fiber viewed from the recording electro des is the same along the muscle fibers and a MAP is recorded as a lin ear summation of all SFAPs. The accuracy of this estimation is demonst rated using simulated MAPs. The method is also tested on MAPs containi ng simulated amplifier noise, stimulus artifact, and errors in distanc e between electrodes. Finally we applied this method to MAP recordings of the biceps brachii in 23 healthy subjects. The velocity distributi on was successfully estimated in 20 cases. The average of the estimate d distributions was smaller than that described by previous workers. T he reasons for the difference are discussed.