Study protocol to examine the effects of spaceflight and a spaceflight analog on neurocognitive performance: extent, longevity, and neural bases

Abstract

BackgroundLong duration spaceflight (i.e., 22 days or longer) has been associated with changes in sensorimotor systems, resulting in difficulties that astronauts experience with posture control, locomotion, and manual control. The microgravity environment is an important causal factor for spaceflight induced sensorimotor changes. Whether spaceflight also affects other central nervous system functions such as cognition is yet largely unknown, but of importance in consideration of the health and performance of crewmembers both in- and post-flight. We are therefore conducting a controlled prospective longitudinal study to investigate the effects of spaceflight on the extent, longevity and neural bases of sensorimotor and cognitive performance changes. Here we present the protocol of our study.Methods/designThis study includes three groups (astronauts, bed rest subjects, ground-based control subjects) for which each the design is single group with repeated measures. The effects of spaceflight on the brain will be investigated in astronauts who will be assessed at two time points pre-, at three time points during-, and at four time points following a spaceflight mission of six months. To parse out the effect of microgravity from the overall effects of spaceflight, we investigate the effects of seventy days head-down tilted bed rest. Bed rest subjects will be assessed at two time points before-, two time points during-, and three time points post-bed rest. A third group of ground based controls will be measured at four time points to assess reliability of our measures over time. For all participants and at all time points, except in flight, measures of neurocognitive performance, fine motor control, gait, balance, structural MRI (T1, DTI), task fMRI, and functional connectivity MRI will be obtained. In flight, astronauts will complete some of the tasks that they complete pre- and post flight, including tasks measuring spatial working memory, sensorimotor adaptation, and fine motor performance. Potential changes over time and associations between cognition, motor-behavior, and brain structure and function will be analyzed.DiscussionThis study explores how spaceflight induced brain changes impact functional performance. This understanding could aid in the design of targeted countermeasures to mitigate the negative effects of long-duration spaceflight.

The contributions of occupational science to the readiness of long duration deep space exploration

“…For example, a decreased number of synapses and degeneration of axon terminals have also been identified [4]. De La Torre [3] suggest that the following neurocognitive deficits may occur: somatosensory problems, selfposition accuracy problems, color perception and loss of acuity, sound localization and binaural hearing, impaired executive functioning, concentration problems, difficulty acquiring targets in voluntary movements, visual attention problems, irritability, and lack of motivation.…”

“…Researchers have found that changes in the sensorimotor system occur during space travel [8]. These impairments include: diminished control of movement, reduced ability to see and interpret information from the eyes, impaired spatial orientation, and difficulty walking [4]. Alterations in the sensorimotor system can contribute to impaired postural control, locomotion, gait and manual control [4,8].…”

“…Specifically, skeletal muscle atrophy is a major concern [4]. Research indicates that long-term missions could reduce overall muscle function by nearly half [2].…”

“…microgravity, radiation, isolation), there is degradation in many health domains that will influence well-being and occupational performance [1][2][3][4][5][6][7][8]. Occupational therapy practitioners are uniquely qualified to examine the intersection of person, environment, occupation, and performance during long duration space exploration through current practice models and frames of reference such as psychodynamic, cognitive behavioral, neurodevelopmental, biomechanical and sensory integration.…”

“…A significant body of research currently exists describing the various health effects of space travel on astronauts. Scientific knowledge and technology such as magnetic resonance imaging (MRI), computed tomography (CT) scans and positron emission tomography (PET) scans of focal areas in the body have allowed researchers to distribute the body into subcomponents to study the effects of space exploration on human health [1][2][3][4][5][6][7][8]. Unfortunately, space travel is not commonly viewed from a holistic and occupation-based perspective.…”