Effects of Long-duration Microgravity and Gravitational Transitions on Fine Motor Skills

Abstract

Objective Assess the effects of long-duration microgravity and gravitational transitions on fine motor skills using a tablet-based test battery of four fine motor tasks: Pointing, Dragging, Shape Tracing, and Pinch-Rotate. Background While there have been some studies on fine motor skills in microgravity, few have measured the fine motor skills that are core components of interaction with computer-based devices, and none have measured performance systematically, to include preflight, inflight, and postflight space mission time periods. Methods Seven astronauts completed the Fine Motor Skills test battery 30–40 times before, during, and up to 30 days after standard duration International Space Station missions, while a matching set of seven ground-based control participants also completed the battery over a comparable period of time. Response time and accuracy were the primary outcome measures. Results Relative to controls, astronauts experienced fine motor skill decrements at gravitational transitions (first week on orbit, and first month post landing). No decrements were found inflight after the first week of adaptation. Conclusion Gravitational transitions appear to negatively impact fine motor skills needed to operate small controls with accuracy, such as those on touchscreen interfaces. This raises concerns for future long-duration crewmembers who will land on a planetary surface and need to perform critical tasks accurately, such as configuring spacesuits, powering up a habitat, or teleoperating rovers. Application Results from this study highlight the need for confirmatory research, and the possible need for countermeasure development. The Fine Motor Skills test battery may have application outside of NASA as a fine motor skills diagnostic screening, rehabilitation, or readiness-to-perform tool.

Postural adaptation to microgravity underlies fine motor impairment in astronauts' speech

“…Therefore, while no direct observations can be made in the present study regarding long-term effects, Holden's work suggests that fine motor skills may be subject to long-term changes with sufficient exposure to microgravity. The present findings also suggest that gravitational transitions have the potential to affect speech communication in astronauts, similar concerns were recently raised by [11] regarding manual fine motor skills and the control of computer systems.…”

“…While the current study does not evaluate readaptation to 1g, and thus cannot infer the longevity of the observed changes, recent work on manual fine motor skills in astronauts following longterm adaptation to microgravity and subsequent gravitational transition to 1g, demonstrates that some level of impairment can still be observed after 30 days 11 . However, note that the astronauts in Holden's work remained on the ISS for six months, thus achieving "deep adaptation" to microgravity 11 . In the present study, astronauts spent between 10-14 days aboard the ISS, much lower than the 90 day threshold necessary to achieve deep adaptation.…”

“…This reflects both human's sophisticated internal model of gravity 5 and the adaptability of that internal model to changing gravity conditions 6 . Considering mechanical alteration to the speech production system is known to affect speech perception as well 20 , it stands to reason that the ability to both send and receive spoken information may be compromised during transitions in gravity, which are often critical to the mission, and provides further support for observations that gravitational transitions may broadly impair fine motor skills in astronauts 11 .…”

“…Alterations to gross motor skills such as gait and limb control observed in astronauts following gravitational change are taken to represent changes to anti-gravity behaviour [4][5][6] . While antigravity posture is understood to play a critical role in gross motor skills, its role in fine motor skills is not often discussed despite evidence of gravity-related adaptation during fine motor control [7][8][9][10][11] , highlighting a significant point of divergence across different domains of motor control. Clarifying the role of anti-gravity posture in fine motor skills is a missing key in achieving a unified theory of movement control.…”

Human Factors in Spaceflight: New Progress on a Long Journey

“…The wide-spread adoption of touchscreens and other advances in human-computer understanding and technology has opened up new avenues of research. Holden and colleagues (2023) describe multiple effects of microgravity on fine motor skills. There will be transitions to different gravity environments during different phases of future missions (e.g.…”