Everyone has free flowing crystals in their ears. Their purpose is to be in a particular position to give the brain key information about the body's position in space. When crystals detach and float, it causes issues. As a result, Positional Vertigo tends to last only a few seconds and is triggered by certain head positions.
Meniere's Disease, on the other hand, does not relate to the crystals. It is caused by pressure in the ear and can be marked by a loss of hearing. Meniere's Disease lasts minutes to hours and can occur anytime and anywhere. Dr. Jack J. Wazen explains a few of the key differences between Positional Vertigo and Meniere's Disease and what can be done as treatment for each in the video below.
Related Blog: Do I Have to Live with Vertigo?