Capital Region Special Surgery Blog

Think way back to those college days. You went on a long night out with your friends at the local watering hole. You open your eyes at the first ray of light and all of a sudden the whole world is spinnning faster than Dorothy Gale’s house.

It turns out that there is a very real physiologic reason why this happens and it is directly related to a very common nonalchohol related problem called Benign Paraxysmal Positional Vertigo.

In order to understand why this occurs you must understand how your ear helps you maintain balance. Each ear has a set of three balance canals called the semicircular canals.

These three canals are set at right angles to one another corresponding to three dimensional space. They are made up of a hollow tube filled with a fluid. At one end of that tube is a dilated space that houses a pice of jellatenous material called the cupula that literally floats in its surrounding fluid. There is a delicate balance between the density (weight) of the cupula and the fluid. When we move our heads the cupula gets difflected by innertia which in tern triggers nerve endings. This “tells” our ears that our head is moving. This system is designed to be insensitive to gravity and only sense angular acceleration (how quickly you move your head in one plane). Any change in the density of the Cupula or surrounding will cause the jelly to float or sink in resonse to gravity.

Alchohol (ethanol) is lighter than water. During your night of revelry the ethanol that you drink quickly creeps into fluid within the balance canals. This causes a difference in the “weight” of the fluid relative to the cupula and causes the cupula to rise or sink relative to gravity. Over time (as you sleep) this process reverses. The ethanol leaves the fluid and creeps into the cupula. As you wake up the cupula is becoming lighter than it surrounding fluid due to the ethanol getting into it. When you roll over in bed the cupula starts to float up activating the nerve endings telling your brain that you are moving. All of a sudden your head is spinning.

Benign Paroxysmal Positional Vertigo is very similar but in reverse. In this disorder calcium particles get stuck within the semicircular canal disrupting the delicate balance of cupula and fluid. The same thing happens in this disorder as in a hangover, only in reverse. You roll over, the calcium pushes on the nerve endings causing a sensation of spinning.

This entry was posted on Thursday, October 16th, 2008 at 10:13 am and is filed under Announcement. You can follow any responses to this entry through the RSS 2.0 feed. You can leave a response, or trackback from your own site.