Sleep apnea can cause brain dysfunction

Symptoms of sleep apnea indicate that there is something more here than just sleep deprivation. Losing a couple of nights sleep does not lead to much impairment, but apnea may. This may be the first evidence of brain dysfunction.

Fourteen men in a recent study were asked to place small pegs into a board, recall lists of numbers and copy designs on pieces of paper. All of the men suffer from sleep apnea, a disorder that caused them to wake repeatedly during the night, starved for oxygen and with air passageways blocked.

None of them could complete the tasks as well as a control group of men who suffer from other problems that prevented them from getting a good night's sleep.

We know people are able to perform well on stimulating tasks when they have been deprived of sleep, but have problems on boring or repetitive tasks. here have been studies to find the mechanisms -- what biochemical changes occur in the body -- but the results are not clear.

Doctors say it is important to differentiate between sleep apnea, a chronic and potentially life-threatening disorder, and simply losing a few nights of sleep. In apnea, the brain is deprived of oxygen periodically as airway passages become blocked. The patient will awaken momentarily in order to start breathing again, then drift back into sleep.

Studies show that a real impairment in concentration, memory and psychomotor skills in people with apnea that was not seen in people who had simply been deprived of sleep. In sleep apnea, all respiratory effort ceases suddenly as a result of a predisposing disorder.

It is not clear what the cause might be. Some chronic lung diseases show similar types of impairment. It might be due to a reduction of oxygen to the brain. Sleep apnea is estimated to lower a patient's IQ approximately 10%.

Normally, people sleep between seven and eight hours out of every 24, although individuals may need more or less. When deprived of sleep for a cycle, they function well -- as long as the work is stimulating.

If they are deprived of sleep for several days, they may have trouble with such tasks as driving or operating machinery, but they can still rise to the occasion if necessary.

Studies have also shown that stimulants, such as amphetamines and caffeine, have less and less of an effect on people who have gone without sleep for long periods.

Next: Sleep apnea in children