Muscle fiber conduction velocity in situ (MFCV) in denervation, reinnervation and disuse atrophy

OBJECTIVES: Muscle fiber conduction velocity (MFCV) was performed in disuse atrophy, in denervated muscle and during reinnervation as a possible index of muscle atrophy, and to clarify the evolution of the fiber size. MATERIAL AND METHODS: MFCV was performed in 12 patients with complete denervation of biceps brachii muscle and during various stages of reinnervation. Twenty-one patients with disuse quadriceps atrophy were also tested. Invasive MFCV was performed according to the method reported elsewhere (2). RESULTS: MFCV decreased significantly in denervated muscles. Reduction of MFCV was found during the first weeks and was progressive. Peak frequency in histograms decreased and the normal Gaussian distribution was lost. MFCV increased progressively after reinnervation with coexistence of slow and significant increase of faster MFCV. MFCV decreased significantly also during the first weeks after immobilization and improved by rehabilitation therapy. CONCLUSION: MFCV is a reliable method to test the muscle fiber size after denervation and immobilization, and its evolution by reinnervation and therapy.