Age-related change in peripheral nerve conduction: Compound muscle action potential duration and dispersion

Background: We investigated the effect of age on nerve conduction parameters with special reference to the compound muscle action potential (CMAP) duration and duration ratio. Method: We examined 295 subjects (aged 15-85 years old) with no previous history or present signs of peripheral neuropathy. The subjects were divided into 3 groups: young (15-34 years old); intermediate (35-64 years old), and old (65-85 years old), Results: CMAP amplitude was lower in the old group than in the young group; however, the CMAP ratio (proximal CMAP/distal CMAP) did not change with age. The CMAP duration and duration ratio did not differ among the 3 groups, The CMAP area was smaller in the old group, but the area ratio was almost constant among the 3 groups. Conclusion: We suggest that age-related changes in CMAP amplitude, duration or area may occur uniformly, at least in the forearm and the calf segment, in routine nerve conduction studies, The present findings also provide useful a nd reliable information, regardless of age, in diagnosing peripheral neuropathy.