Prolonged reduction of motion sickness sensitivity by visual-vestibular interaction

Area of Science:

• Neuroscience
• Vestibular System Physiology
• Human Motion Sickness

Background:

• The vestibular system, responsible for balance and spatial orientation, plays a crucial role in motion sickness.
• Habituation, a form of learning, can alter vestibular system responses.
• Understanding the effects of habituation on vestibular time constants is key to mitigating motion sickness.

Purpose of the Study:

• To investigate the impact of visual-vestibular habituation on motion sickness susceptibility.
• To determine if habituating the velocity storage time constant in the vestibular system can reduce motion sickness.
• To evaluate a novel method of opposing angular vestibulo-ocular reflex (aVOR) and optokinetic nystagmus (OKN) for habituation.

Main Methods:

• Twenty-nine subjects underwent 5 days of habituation using sinusoidal rotation (0.017 Hz) and a full-field optokinetic nystagmus (OKN) stimulus with opposing directions.
• Motion sickness sensitivity was assessed using off-vertical axis rotation (OVAR) and real-world transportation before and after habituation.
• Vestibular time constants and aVOR gains were measured.

Main Results:

• Habituation significantly shortened vestibular time constants in all subjects.
• Motion sickness susceptibility, evaluated by OVAR and transportation, was greatly reduced in susceptible individuals.
• The reduction in motion sickness persisted for up to 18 weeks, and habituation did not induce motion sickness or alter aVOR gains.

Conclusions:

• Opposing aVOR/OKN stimulation is a well-tolerated and effective technique for rapid and prolonged habituation of motion sickness.
• This non-pharmacological method offers a novel approach to treating motion sickness without relying on drugs or other nauseating stimuli.
• Habituation of the vestibular system's velocity storage mechanism provides lasting relief from motion sickness.