Probability of conduction deficit as related to fiber length in random-distribution models of peripheral neuropathies.

This paper presents a set of probabilistic models which reproduce the proximodistal gradient of sensory deficit in peripheral neuropathies, on the basis of the occurrence of axonal dysfunction as a result of randomly distributed abnormalities. The models, which are based on conduction block, loss of temporal coherence, and weak interactions between nerve fibers, demonstrate that randomly distributed axonal dysfunction provides a sufficient condition for distal sensory deficit. The models predict a marked reduction in the length for normal sensory conduction with small increases in the probability of axomal dysfunction, providing a possible correlate for the rapid clinical progression of some neuropathies. The hypothesis that weak interactions between fibers result in paresthesiae in peripheral neuropathies is also discussed.