Computer simulation of jitter phenomenon in neuromuscular transmission disorders

Neuromuscular jitter is a sensitive measure of the safety factor of neuromuscular transmission. Nevertheless, the actual relationship between jitter and the safety factor is unknown because these parameters have not been simultaneously measured. In order to explore the theoretical relationship between them, a computer model of mammalian neuromuscular transmission has been developed. If the safety factor is expressed as the absolute value of the natural logarithm of the probability of a block, the model predicts a double exponential relationship between the safety factor and jitter, except when the percentage of blocks is greater than 90%. In that case, the jitter value decreases. Simulation of acetylcholinesterase inhibition shows that this treatment decreases the neuromuscular transmission blocks more effectively in postsynaptic than in presynaptic disorders. In contrast, when the percentage of blocks is greater than 60%, the jitter value increases in both conditions. (C) 2001 John Wiley & Sons, Inc.