A healthy inner ear supplies the brain with constant information about movement. That information changes with movement. The inner ears could be described as generators producing electrical current. When the head is still, the “power” supplied by the two generators (the two inner ears) is equal. Whenever the brain receives a signal from the inner ears, the eyes reflexively respond to these changes in power. This is known as the Vestibular Ocular Reflex or VOR.
For example, when the head is rotated to the right, the right generator distributes more power, while simultaneously, the left generator distributes less power. This makes the eyes move exactly opposite of the head movement, essentially visually cancelling out that head movement and allowing the eyes to stay stable and focused on the outside world.
The key point here is that the “power” generated from the inner ears can be substituted by an external electricity source. If you electrically stimulate the nerve that connects the ear to the brain, the brain will interpret that electrical impulse as movement. This concept has been explored as a treatment for people with dysfunctional inner ears, and manufacturers have designed and developed technology for this use.
Most recently, this concept has been considered as a potential additional benefit for gamers or virtual reality seekers. Early visual reality involved visual surrounds or goggles that presented visual scenes that would adapt to your movement. As this technology developed, it was only natural that designers would look for ways to make the experience more realistic. If the vestibular system could be electrically stimulated, it could result in the viewer feeling a sense of movement even though they were sitting still in a chair. Click here to see the Mayo Clinic animation.
Obviously, my interest is to see improvements in technology to benefit people with vestibular dysfunction. Interest and funding triggered by gaming and virtual reality applications may be just the ticket we need.
Photo courtesy of SoterixMedical