While the effect of long-duration spaceflight has been extensively studied with respect to bone loss, muscle atrophy as well as several other physiological systems, the existence of an effect on the brain has been reported only very recently. We performed a prospective study using MRI scans pre and post flight to investigate the impact of prolonged microgravity on the human brain. Part of that study was to look at the cerebrospinal fluid (CSF) volume of the brain ventricular regions in space crew by means of a region of interest analysis on structural brain scans. Cosmonaut MRI data were investigated preflight (n = 11), postflight (n = 11), and at long-term follow-up 7 months after return to Earth (n = 7). We observed a significant increase from preflight to postflight values of 11.6 % ± 1.5 % (SE) (p < 0.0001). Seven months after return to Earth the mean total ventricular volume increase was still 6.4 % ± 1.3 % (SE), (p = 0.0008). Although the visual acuity early postflight appeared to be only subclinically altered, there was a trending but not significant correlation between the lateral ventricular volume and the visual acuity change for the left eye. Although multifactorial in origin, we hypothesize that the increase in ventricular volume could be the result of a hampered CSF circulation and resorption in microgravity. In addition we speculate that the increased volume of the ventricle can also be considered as a buffering mechanism to deal with the reduced CSF resorption in long-duration space flight. Although the cosmonauts did not show clear clinical signs of SANS (Spaceflight Associated Neuro-ocular Syndrome), we hypothesize a link between the increased ventricular volume and SANS, and suggest that intracranial temperature, ventricular wall elasticity as well as optic sheath compliance, countermeasure regime, forced breathing and other factors play an important role in this phenomenon. Hence, a holistic and interdisciplinary approach is necessary to better understand the development of the ventricular volume increase in long-duration space flyers.
|Journal||Proceedings of the International Astronautical Congress, IAC|
|Publication status||Published - 1 Jan 2019|
|Event||70th International Astronautical Congress, IAC 2019 - Washington, United States|
Duration: 21 Oct 2019 → 25 Oct 2019