Mother Nature has given humans several sensory systems to detect the effects of gravity and to allow us to remain upright when we move through the environment. These symptoms include the proprioceptive or somatosensory system (muscle and tendon senses), the vestibular system, and the visual system - specifically the part of the visual system that senses the periphery. For most of us, these systems work well together and allow us to engage in tasks ranging from simply sitting in a chair without falling over, to skiing at high speed. The systems help us to know "where we are in space," which is somewhat the same concept as "where we are with respect to the pull of gravity."
Unfortunately, sometimes these systems deliver information that is in conflict with reality or information that is not internally consistent between systems. For example, in an airplane the vestibular and proprioceptive systems might indicate that you are moving up and down, tipping over, hitting severe turbulence, etc., but at the same time your visual system says that the walls of the airplane are not moving and neither is the seat in front of you. This sets up a conflict, which can result in dizziness, motion sickness, vertigo, nausea, panic, and other unpleasant sensations.
In an aircraft, we can understand why these sensations occur, but for some patients, the sensations occur during their daily activities either continuously or episodically without an apparent external cause. Because conflicts typically involve visual system information as part of the conflict (even though vision might be contributing normal information), sensory conflicts are of interest to vision care specialists.
This course will demonstrate that mismatches must occur between visual, vestibular, and/or proprioceptive inputs (or stored memories of these inputs) for a person to experience motion sickness. In turn, mismatches produce symptoms that can be aggravated by patient anxiety, and significant, sometimes debilitating motion sickness can occur.
Robert L. Yolton, PhD, OD; Karl Citek, OD, PhD; Bradley Coffey, OD; Hannu Laukkanen, OD, MEd
Company: Pacific University
CE Credits: 3
CE Format: Online text/photos
COPE ID: 13459-GO