DETERIORATION OF MOTOR FUNCTION IN MYOTONIC-DYSTROPHY AND HEREDITARY MOTOR AND SENSORY NEUROPATHY

In order to obtain more information about the deterioration of motor f unction in patients with myotonic dystrophy and in patients with hered itary motor and sensory neuropathy, changes in strength and functional ity were determined at one year intervals, over a follow-up period of 1 to 5 years. Twenty-five myotonic dystrophy patients and 16 hereditar y motor and sensory neuropathy patients participated. Strength measure ments were restricted to knee extension and flexion torques measured i sokinetically on a dynamometer at two velocities (120 and 60 degrees/s ). Functionality was measured as scaled time scores for rising from si tting, rising from supine, walking and stair climbing. Myotonic dystro phy patients showed a reduction of knee extension torques at 60 degree s/sec (mean decrease per year 5.7 Nm, or 9%) as well as a decrease in functionality. Hereditary motor and sensory neuropathy patients showed no statistically significant changes in torques or functionality. The correlation between isokinetically measured knee extension torques an d functional scores was statistically significant in myotonic dystroph y but not in hereditary motor and sensory neuropathy. No correlation w as found between changes in torques and changes in functional scores.