脳性麻痺者の把持制御動作の観察

POLYGRAPHICAL OBSERVATION OF GRIPPING MECHANISM IN CEREBRAL PALSIED CHILDREN

I．はじめに

　脳性麻痺者の把持制御動作の機序をうかがい知り，あわせて随意運動の一面を明らかにするために，われわれは硬軟両質のコップを把持することを命じたときの長母指屈筋筋電図，短母指外転筋筋電図，同積分図，歪記録計による栂指頭における把持圧記録，などの多描記同時観察を行ない．その把持動作を過渡状態と定常状態とについて検索し，正常者と比較検討した。

Subjects were asked to grip two kinds of cups with or without load in successive ten trials. Multi-channel equipment made it possible to observe the actual pressure and electrical muscular activities in-volved in grasping act. This led us to explain some aspects of servomechanism in cerebral palsied pa-tients in comparison with normal persons.

Inactivity period was longer than in normal subjects due to either prolonged latency between the instruc-tion and the onset of innervation, prologned interval between this and the beginning of actual grasping, or combined delay in both periods. The duration of the electrical event in musclue from its onset to the peak was lengthened as compared with normal per-sons. Unlike transient response in normal persons, the onset of the actual grasping coincided with the peak of electrical muscular activity and was not pre-ceded by silent period or diminution in electrical ac-tivity of prime mover. As a consequence excessive overshooting took place inevitably.

Some patients with heavy involuntary movement disclosed oscillating grasp performances which follo-wed an irregular muscular activities associated with high amplitude.

In striking contrast with the constant figure obtain-ed from normal persons grasping pressure varied in extent from trial to trial and from case to case, being as high as 4000 g.