Between the Ears: International Space Station Examines the Human Brain

The International Space Station (ISS) is a unique laboratory enabling advances in science that simply would not be possible on the ground. The new ISS Benefits for Humanity 2015 book highlights some of the pioneering science that benefits the citizens of Earth, including probing the biological marvel of the human brain.

“Among the many problems that have challenged astronauts since humans first began exploring space is adapting to it,” said Dr. Kirt Costello, ISS deputy chief scientist.

“When arriving in microgravity, and often when returning to the ground, astronauts frequently have trouble with vertigo and dizziness, possibly experiencing motion sickness or visual problems. The space station provides us with a platform to conduct long-duration experiments that help us find treatments for these and other conditions that also occur on Earth.”

Microgravity causes the vestibular functions of the body, which is the balance and coordination controlled in the inner ear or brain, to not easily align with information received by the other senses. The brain cannot correctly interpret incoming signals, leading to development of motion sickness or problems focusing the eyes that could cause health problems for crew members and delays in conducting scientific investigations in orbit.

Analysis of data collected in space has resulted in new diagnostic methods to accurately assess vestibular function, while offering a faster and less expensive initial differential diagnosis of dizziness and balance disturbances compared to traditional clinical testing.

Data collected for decades in Russia lead to the development of the OculoStim-CM, a system used in clinical studies on patients with vertigo, dizziness and equilibrium disturbances. The method evaluates eye movement reactions to various stimuli.

Computers conduct visual tracking tests using targets on a clean (black) field on the screen, as well as targets on a background that includes other obstructions that are aimed at distracting peripheral vision . Movements of the eyes and head are recorded during testing. These studies have been particularly useful in experiments simulating bed rest and evaluating the effectiveness of various medications.

The OculoStim-CM has been actively used during the preflight and postflight clinical and physiological examinations of space station crew members in experiments called Virtual and Slezheniye (Pursuit), and after crew members return to Earth during the experiments Sensory Adaptation and Gaze-Spin.

While some medications currently eliminate the symptoms of motion sickness in space, they can have unwanted side effects. This is leading to innovative methods of preventing or correcting neurovestibular problems with biofeedback. Depending on the nature of the problem, the patient is exposed to a series of unique visual stimuli on the computer, recording eye and head movement, to learn the most effective way to treat the condition.

The study showed that patients were able to maintain their focus on all targets, which resulted in suppressing a variety of vertigo or equilibrium disturbances. Training effectiveness depended not only on the disorder, but also on the type of training selected.

Because this non-pharmacological computerized method of treatment had successful results, it has shown itself to be a viable tool to use for space station crew members during their pre-flight training, as well as for use in orbit if they suffer symptoms of space motion sickness.

Thanks to the microgravity environment of the space station, we have new insights into multiple scientific disciplines. By investigating neurovestibular problems in space, discoveries are improving the quality of life for millions of people on Earth.