Using Galvanic Vestibular Stimulation to Induce Post-Roll Illusion in a Fixed-Base Flight Simulator.

Area of Science:

• Aerospace Medicine
• Human Factors Engineering
• Neuroscience

Background:

• Galvanic vestibular stimulation (GVS) can induce illusory head motion, potentially impacting pilot performance in simulators.
• Existing GVS research often fails to replicate realistic flight disorientation because stimuli are not synchronized with simulated aircraft motion.
• The 'post-roll illusion' is a specific vestibular spatial disorientation experienced during flight.

Purpose of the Study:

• To investigate if bilateral-bipolar GVS, synchronized with aircraft roll in a fixed-base simulator, can mimic the 'post-roll illusion'.
• To assess the potential of GVS to recreate vestibular spatial disorientation relevant to flight.

Main Methods:

• Fourteen nonpilot subjects were exposed to simulated aircraft roll in a fixed-base simulator.
• Bilateral-bipolar GVS was applied via mastoid electrodes, with the electrical stimulus driven by high-pass filtered aircraft roll rate.
• Post-roll tests involved maintaining a constant bank angle after a roll maneuver, without visual cues, to observe GVS-induced roll overshoot.

Main Results:

• Subject responses showed significant variability, with fewer than one-third experiencing effects consistent with the post-roll illusion.
• Subjective feedback indicated that the GVS stimuli were mild and did not clearly convey roll direction.
• Uncontrolled head movements during stimulation may have interfered with the intended GVS effects on illusory head motion.

Conclusions:

• The GVS stimuli used were too mild and transient to convincingly replicate the post-roll illusion.
• Uncontrolled head movements further complicated the assessment of GVS-induced illusions in this simulator study.
• Further research is needed to refine GVS parameters for effectively simulating vestibular spatial disorientation in flight.