On cerebral motor control: The recovery from experimentally produced hemiplegia.

Attention has recently been directed to the possibility of recovery of voluntary muscular control in human cases of cerebral hemiplegia. The results which have been reported are so different from those which have been predicted by neurologists that the whole matter of cerebral control again comes to the fore as a problem of intense practical as well as theoretical interest. It has long been believed that if improvement in motor ability does not occur in man within a period of two years following the cerebral accident the paralysis is permanent. The series of cases which have been reported show that this is not true, because even in cases of paralysis of eight or more years' duration, considerable improvement follows suitable remedial measures of the nature of exercise, including massage. It is well known that an animal which has had its so-called motor cortex destroyed or the pyramidal fibers cut on one side shows a condition similar to that of the human apoplectic hemiplegia. It is also known that, even though the hemiplegia be complete, recovery of (voluntary) motor function takes place. The beginning of this recovery in the dog comes in a day or two, and after a few weeks the dog can use the legs on the paralyzed side apparently as well as those on the non-paralyzed side. The animal does, however, use the legs of the non-paralyzed side in preference to those of the paralyzed side even though the latter be " recovered ". And also, when the animal is under the influence of certain toxic agents, such as alcohol or ether the previously paralyzed limbs exhibit motor disturbances even though prior to the administration of the alcohol or ether the animal appeared to be perfectly normal in a motor way. The recovery in the monkey and ape is less rapid than in the dog, although after nine to twelve months it may not be possible on casual inspection to notice any motor disturbances. The effect of suitable exercises in the long-standing human hemiplegics suggested that if the paralyzed segments of an animal with an experimentally produced hemiplegia were adequately dealt with the recovery would be more rapid and more complete than if the animal were permitted to recover by itself. The suggestion was tested and the results of the observations are given in the subsequent paragraphs. Four male monkeys (macacus rhesus) about a year and a half …