What is dizziness and can it be harmful?

[PretentiousMan]

What states in the brain are associated with being dizzy and can spinning yourself dizzy too much cause any harm?

[Richard_Pearse]

From How Stuff Works:

Here is how the vestibular system senses motion:

1. There are three semicircular canals for sensing motion.
2. They are at right angles to one another.
3. They contain fluid called endolymph and hair-like sensory nerve cells.
4. As your head moves in a given direction, the endolymph lags behind because it resists a change in motion (the principle of inertia).

So far so good?

When you spin, the endolymph slowly moves in the direction you are spinning. The movement of the endolymph signals the brain that the head is spinning. The brain quickly adapts to the signal because the endolymph begins to move at the same rate that you are spinning and no longer stimulates the hair cells. However, when you stop spinning, the endolymph continues to move and stimulate hair cells in the opposite direction. These hair cells send signals to the brain. The brain determines that the head is still spinning, even though you have stopped. This is where the dizzy feeling comes from. Eventually, the endolymph stops moving, no signals are sent to the brain, your brain determines that your motion has stopped, and you no longer feel dizzy.

[Ringo]

Hooboy! Besides the potential danger from just falling down or bumping into things as a result of being dizzy, which I suspect are the primary dangers from self-induced dizziness (which I think is vertigo), this page indicates dizziness is a symptom associated with many conditions, including vestibular neuritis, acute otitis media, chronic otitis media, late stage syphilis, trauma, tumors…, too much to list - click the link.

[Ringo]

What Skogcat’s post describes is, I believe, vestibular nystagmus. Besides the contribution from the vestibular system, I seem to recall an ocular component that has to do with temporary exhaustion of visual receptors, but I’m obviously not searching the right things. The phenomenon would be related to that wherein you stare at an object, then look away, preferably at a white wall, and continue to see the object in its opposite colors.

Anybody want to take a shot?

[KarlGauss]

*Originally posted by Ringo *
**What Skogcat’s post describes is, I believe, vestibular nystagmus. Besides the contribution from the vestibular system, I seem to recall an ocular component that has to do with temporary exhaustion of visual receptors, but I’m obviously not searching the right things. The phenomenon would be related to that wherein you stare at an object, then look away, preferably at a white wall, and continue to see the object in its opposite colors.

Anybody want to take a shot? **

Oculokinetic Nystagmus

[KarlGauss]

First, different people mean things when they report being dizzy. Some mean true nystagmus, i.e. a feeling of the room (or themself) spinning. Some people are referring to light-headedness, and some to other things such as difficulty walking or with their balance.

True vertigo is usually from one of two major categories of causes:

1. Central - due to a problem in the brain itself
2. Peripheral - due to a problem in the semicircular canals or the nerve controlling equillibrium (which lies outside the brain)

Central causes are almost associated with other neurological problems such as double vision, slurred speech, or trouble swallowing.

Peripheral causes have vertigo but no other neurological symptoms. However, there may be associated symptoms such as ear pain, ringing of the ears, discharge from the ears, or hearing loss.

Statistically speaking, most isolated vertigo is due to a peripheral cause. In particular vestibular neuronitis, an inflammation of the nerve ccntrolling balance that may follow a viral infection OR so-called benign positional vertigo, where vertigo predictably occurs with head movement, are both relatively common (and benign).

[KarlGauss]

First, different people mean things when they report being dizzy. Some mean true nystagmus, i.e. a feeling of the room (or themself) spinning. Some people are referring to light-headedness, and some to other things such as difficulty walking or with their balance.

True vertigo is usually from one of two major categories of causes:

1. Central - due to a problem in the brain itself
2. Peripheral - due to a problem in the semicircular canals or the nerve controlling equillibrium (which lies outside the brain)

Central causes are almost associated with other neurological problems such as double vision, slurred speech, or trouble swallowing.

Peripheral causes have vertigo but no other neurological symptoms. However, there may be associated symptoms such as ear pain, ringing of the ears, discharge from the ears, or hearing loss.

Statistically speaking, most isolated vertigo is due to a peripheral cause. In particular vestibular neuronitis, an inflammation of the nerve ccntrolling balance that may follow a viral infection OR so-called benign positional vertigo, where vertigo predictably occurs with head movement, are both relatively common (and benign).

[KarlGauss]

I double posted and still screwed up.

The second sentence above should say "Some mean true vertigo, i.e. a feeling of the room (or themself) spinning.

And, BTW, oculokinetic nystagmus is also known as optokinetic nystagmus.