Effect of the Stimulation of Touch and Proprioceptive Sensation on Protective Reaction against the Wall

In order to investigate the mechanism of the development of the parachute reaction, the authors tried to analyze the effect of the stimulation of touch and proprioceptive sensation on the reaction which was elicited with quick approach of child vertically held in space to the surface of the wall.<BR>The subjects were divided into 3 groups, and each group consisted of 34 normal children from 12 to 15 month of age. The reaction was elicited with quick approach of children vertically held in space to the surface of the wall. In group 1 the reaction was elicited two times continuously on each child. Then the armes of the child were pushed against the wall. Again the reaction was elicited two times continuously. In group 2 the reaction was elicited four times continuously after pushing technique. In group 3 the reaction was elicited four times continuously without pushing technique. The responses of shoulder joint, elbow joint and finger joint were scored respectively as follows: 1; no response, 2; slight response, 3; moderate response, 4; almost complete response, 5; complete response. The average score of each time was compared among each groups.<BR>In group 1 the score significantly increased after pushing technique. The score of first trial of group 2 or second trial of group 2 was significantly higher than that of first trial of group 1 or second trial of group 1 respectively. The score of third trial of group 1 or fourth trial of group 1 was significantly higher than that of third trial of group 3 or fourth trial of group 3 respectively.<BR>The reaction against the wall is not and the same with the parachute reaction, but has the same nature in protective reaction and visual and vestibular stimulation as the parachute reaction. The results indicate that the response of the arm is more facilitated after the stimulation of touch and proprioceptive sensation than only with visual and horizontal vestibular stimulation. Kitahara reported that the positive parachute reaction appeared when children could push themselves circularly or backward in prone position. So we consider the stimulation of touch and proprioceptive sensation on arm as well as visual and vestibular stimulation play the important role in the developmental course of the parachute reaction.