Influence of Dry Immersion on the Characteristics of Cyclic Precise Hand Movements

Abstract

The characteristics of precise hand movements in Dry Immersion (DI) have been studied. Motor tasks were cyclic single-joint hand movements corresponding to the length and orientation of the presented horizontal or vertical segment and carried out for 5 s with or without visual feedback. The studies were carried out with the participation of 35 test healthy volunteers divided into three groups: control (n = 10), 6-hour DI (n = 11), and 5-day DI (n = 14). In the control group, the test was carried out three times, lying on the couch, imitating the cyclogram of a 6-hour DI—once before DI, in the morning on the day of DI, and in the evening 2 h after the end of exposure. In the 5-day DI, tests were performed once before the start of the DI, on the 1st, 3rd, and 5th days of the DI, and also once after its completion. It is shown that the accuracy of movements in the control group does not depend on the measurement number, while in the experimental groups on the first day of DI there is an increase in the overestimation of the length of horizontal segments and an increase in the error in estimating the direction of vertical segments. The data indicate that DI affects the hand movement control system and can be considered as a suitable Earth model for studying fine movement disorders observed in microgravity.