[Analysis of tracking behavior in patients with muscular dystrophy]

A compensatory tracking experiment was performed to investigate, on the basis of control theory, the dynamic characteristics of control movement in patients with progressive muscular dystrophy (limb-girdle type) and with myotonic dystrophy. Error scores and operator's transfer functions were estimated from the tracking data. The latter were approximated by a model which was composed of a gain constant, a delayed time constant and a dead time. The results showed that error scores for the muscular dystrophy patients and for the myotonic dystrophy patients were, in this order, greater than those for the normal subjects; the dynamic characteristics described by the transfer functions of the three groups were different from each other in terms of gain, phase lag and linearity of their operation. These results were discussed in terms of the stage of disability of motor function and the deterioration of intelligence with disease.