Study of the dispersion of motor nerve conduction velocity in charcot-marie-tooth-hoffmann disease and in steinert's syndrome

A study of the maximum and minimum motor conduction velocity by techniques for measuring the dispersion (Hopf, desynchronisation) was made in clinical cases of Charcot-Marie-Tooth-Hoffmann disease and in their healthy relatives, and in cases of Steinert's syndrome. It revealed an initial elective involvement of the fibers with a higher motor conduction velocity and only secondarily (in the more advanced cases of C.M.T.H.) involvement of the slower conducting fibers, both in distal neural atrophy and in Steinert's syndrome. The data are discussed in the light of current thinking on the neurophysiology and histoenzymology of motor unit impairment in these two diseases.