Facial baroparesis is a reversible paralysis of the facial nerve due to increased pressure in the middle ear while diving.
The facial nerve is a cranial nerve that controls the muscles of the face. On its way from the muscle to the brain it passes through a channel in the wall of the middle-ear space. Barometric changes in that space normally have little or no effect on the nerve. However, in some people, the facial nerve canal is missing the bony wall that normally separates it from the middle-ear cavity. This “bone dehiscense” leaves the nerve exposed to the middle ear cavity, protected only by a thin membrane. If such a person were to experience overpressurization in their middle ear — equal to or greater than the capillary pressure — circulation to the facial nerve would stop. The facial nerve’s functionality would be impaired and facial muscles may become paralyzed (i.e., facial baroparesis). Fortunately, pressure in the middle ear generally returns to normal soon after the exposure, restoring the circulation to the nerve and re-enabling its normal functionality. Facial baroparesis tends to recur with repeated diving.
Symptoms include numbness, paresthesia, weakness and even paralysis of the face. Decreased sensation and facial droop may be noted, usually on one side of the face.
Facial baroparesis typically occurs soon after surfacing, as it results from a reverse block.
Facial baroparesis is usually discovered postdive. Even when its duration is brief and it resolves spontaneously, the diver should be evaluated by a physician to exclude other possible causes such as stroke, infection, trauma or decompression sickness. In rare instances of protracted facial baroparesis, treatment may be necessary. There is experimental evidence that overpressurization lasting more than 3.5 hours may cause permanent damage. Divers who continue to experience facial numbness and drooping should see a physician as soon as possible (within three hours).
Fitness to Dive
This condition is usually self-limiting, resolving spontaneously within hours. Because it is caused by an anatomical variation, further exposure to diving (or other significant barometric changes such as flying or other ascent to elevation) can cause recurrence of symptoms. Returning to diving may be considered when symptoms have completely resolved and have been determined to be the result of facial nerve baroparesis rather than a stroke.
- Learn gentle but effective equalization techniques.
- Do not dive while congested.