Early appearance of aging phenomenon in the interdigital nerves of the foot.

To test the hypothesis that the interdigital nerves of the foot are the first to be affected by aging, we studied sensory nerve conduction in the nerves of normal subjects between the ages of 10 and 79, using the near-nerve needle technique. In normal individuals up to the seventh decade we could get sensory CNAPs without any difficulty by 256 averagings. In 10% of the 70-79-year-old group we could not obtain those potentials in some digital or interdigital nerves. Between the 10-49-year-old and 50-79-year-old groups, there was a significant slowing in the sensory NCVs, a significant decline in the amplitude of the sensory CNAPs, and a significant prolongation of the duration of sensory CNAPs for the various interdigital nerves. Thus, our study documented the earlier presence of aging phenomenon in the sensory nerve conduction of the interdigital nerves of the foot compared with the previously reported sensory nerve conduction change with age in the other nerves. We conclude that the "degeneration" of various interdigital nerves of the foot is accelerated from the early 50s on, possibly resulting from the normal aging process.