+1 for what Dr. Mitchell said. A few thoughts about the other points mentioned here...
1) I believe that IEDC is underdiagnosed. For a number of reasons, the inner ear seems to be more susceptible to decompression injury than other tissues. The mechanisms of this are not completely understood.
Basically there are two ways for bubbles to get into any tissue - they can form there on ascent or they can be carried there. In the second scenario, they form in other tissues, and then move from the veins (where they would normally be taken to the lungs and cleared) to the arteries (bypassing the lungs, by a PFO or other shunt). Once in the arteries, they "embolize", which means that they are carried into smaller and smaller blood vessels until they eventually block the vessel and deprive the downstream tissue of blood and oxygen. This second mechanism is how an embolic stroke happens in the brain, although this is with pieces of clot rather than bubbles in the non-diving population.
So IEDCS could either be caused by embolized bubbles or bubbles forming in the inner ear. These potential mechanisms are discussed in Dr. Mitchell's excellent article, and elsewhere. Since the brain is better perfused than the inner ear, that might explain why people who bubble and shunt (a large number of divers overall) don't all get strokes.
2) MdDS (Mal de Debarquement Syndrome) is probably not an inner ear problem at all, but a poorly understood phenomenon of the brain. Vestibular testing in these patients is usually normal. As was described above, this can be a potentially debilitating condition, especially since it doesn't go away right away, and stopping diving can't help. As stillswimmingingcircles alluded to, it is more of a feeling of imbalance than true vertigo (with a sensation of environmental rotation).
3) MdDS is not thought to be related to the otoliths. Displacement of these crystals in the inner ear is a separate phenomenon, benign paroxysmal positional vertigo (BPPV). Certain maneuvers can help reposition these dislodged crystals.
4) Residual balance symptoms after IEDC may be helped by vestibular rehab. This is much like physical rehab after an joint or muscle injury. It's hard to give a prediction as to how soon the symptoms will go away, but it's not uncommon for them to last even if hearing is recovered after recompression therapy.
5) The brain and vestibular system does have the ability to recover and compensate over time, so don't give up!
1) I believe that IEDC is underdiagnosed. For a number of reasons, the inner ear seems to be more susceptible to decompression injury than other tissues. The mechanisms of this are not completely understood.
Basically there are two ways for bubbles to get into any tissue - they can form there on ascent or they can be carried there. In the second scenario, they form in other tissues, and then move from the veins (where they would normally be taken to the lungs and cleared) to the arteries (bypassing the lungs, by a PFO or other shunt). Once in the arteries, they "embolize", which means that they are carried into smaller and smaller blood vessels until they eventually block the vessel and deprive the downstream tissue of blood and oxygen. This second mechanism is how an embolic stroke happens in the brain, although this is with pieces of clot rather than bubbles in the non-diving population.
So IEDCS could either be caused by embolized bubbles or bubbles forming in the inner ear. These potential mechanisms are discussed in Dr. Mitchell's excellent article, and elsewhere. Since the brain is better perfused than the inner ear, that might explain why people who bubble and shunt (a large number of divers overall) don't all get strokes.
2) MdDS (Mal de Debarquement Syndrome) is probably not an inner ear problem at all, but a poorly understood phenomenon of the brain. Vestibular testing in these patients is usually normal. As was described above, this can be a potentially debilitating condition, especially since it doesn't go away right away, and stopping diving can't help. As stillswimmingingcircles alluded to, it is more of a feeling of imbalance than true vertigo (with a sensation of environmental rotation).
3) MdDS is not thought to be related to the otoliths. Displacement of these crystals in the inner ear is a separate phenomenon, benign paroxysmal positional vertigo (BPPV). Certain maneuvers can help reposition these dislodged crystals.
4) Residual balance symptoms after IEDC may be helped by vestibular rehab. This is much like physical rehab after an joint or muscle injury. It's hard to give a prediction as to how soon the symptoms will go away, but it's not uncommon for them to last even if hearing is recovered after recompression therapy.
5) The brain and vestibular system does have the ability to recover and compensate over time, so don't give up!
