Wearable Vibrotactors Fight Astronaut Disorientation

In the realm beyond Earth’s atmosphere, spatial orientation becomes a critical challenge for astronauts. The absence of familiar cues poses a risk, underscoring the importance of intensive training to combat spatial disorientation.

Researchers have now discovered that wearable devices employing vibrations to provide orientation cues could significantly enhance the effectiveness of astronaut training, offering a potential safety boost for spaceflight.

Dr. Vivekanand P. Vimal from Brandeis University, lead author of the study published in Frontiers in Physiology, highlighted that extended space missions subject astronauts to various physiological and psychological stressors, making them highly vulnerable to spatial disorientation. When disoriented, astronauts lose their reliance on internal sensors they’ve depended on throughout their lives.

To investigate this challenge, researchers utilized sensory deprivation and a multi-axis rotation device to evaluate their vibrotactors in simulated spaceflight conditions, rendering participants’ usual sensory cues ineffective. The study aimed to determine if vibrotactors could counteract misleading cues from participants’ vestibular systems and if participants could be trained to trust them.

The study involved 30 participants divided into three groups: one received training on the rotation device, another received vibrotactors, and the third received both. Participants familiarized themselves with the rotation device’s operation, which mimicked an inverted pendulum movement stabilized by a joystick-controlled operator.

Additional training for some participants focused on detaching from their natural gravitational cues and relying on vibrotactors instead. This involved locating hidden non-upright balance points, challenging participants to prioritize vibrotactors over their inclination to align with gravity.

Participants were equipped with blindfolds, earplugs, and white noise to nullify external sensory input. Those with vibrotactors wore four on each arm, programmed to buzz when they deviated from the balance point. Each participant completed 40 trials, striving to maintain the rotation device close to the balance point.

Half of the trials emulated the Earth’s vertical roll plane, allowing participants to use natural gravitational cues. The second half simulated spaceflight conditions, employing a horizontal roll plane where gravitational cues were irrelevant.

Following each trial block, participants assessed their disorientation and trust in the vibrotactors. Success was gauged by crash frequency and balance control proficiency.

As anticipated, all groups initially experienced disorientation in the spaceflight simulation due to the absence of familiar gravitational cues. Most participants expressed trust in the vibrotactors but also reported conflicts between their internal cues and the device’s vibrations.

Participants wearing vibrotactors outperformed those with training alone. The training-only group experienced more crashes, greater movement around the balance point, and increased accidental destabilization. Combined training and vibrotactors yielded the best results over time.

Despite training, participants didn’t match their performance in Earth analog conditions. This could indicate a need for extended integration time for vibrotactor cues or a potential need for stronger warning signals from the devices.

Dr. Vimal emphasized that cognitive trust in the external device may not suffice, calling for a deeper, nearly sub-cognitive level of trust, necessitating specialized training.

Should further trials prove successful, the vibrotactors hold promise for diverse applications in spaceflight, ranging from aiding safe planetary landings to supporting extravehicular activities.

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