Changes in the histograms of nerves resulting from growth and various modalities of damage. A computer simulation.

A computer program simulates the changes in a nerve's histogram during normal growth and from various neuropathies. The program shows how a nerve's histogram will change from various percentages of fiber damage or from preferential damage to either thick or thin fibers, or from various degrees of fiber restitution, or from single-event or repetitive damage. In single-event damage, the main alteration is a preponderance of thin (regenerating) fibers. Patterns of selective fiber vulnerability are difficult to deduce from the shape of the histogram. Repetitive damage remodels the histogram to a broad unimodal fiber distribution at reduced mean caliber. Comparison of simulated changes with data from an experimental isoniazid neuropathy yielded a close match between observed changes and simulation.