The medical community has long considered children aged five or six who are persistent bed-wetters also suffer from a sleep disorder. Recent studies seem to show that this is not always the case and that typically these children sleep deeply and fail to rouse when the brain sends the message that the bladder needs to be emptied. Controlled laboratory studies indicate that deep sleeping is responsible in part for bed-wetting, but is not the chief cause. A study at Albert Einstein College of Medicine recorded the electroencephalography (EEG) of the children participating. The EEG monitors the brain’s electrical activity throughout sleep.
Children suffering from a variety of sleep disorders were recorded by the EEG as having abnormal electrical patterns. Children who suffered from enuresis, but no known sleep disorder, showed expected brain activity throughout sleep. These results support the idea that sleep disorders and bed-wetting are not linked. The medical community do not know just what causes nocturnal enuresis, though total bladder control is known to be a gradual process that takes time, with no definitive age of mastery for all children. Some children master their bladder at night at a very early age while others take considerably more time. Daytime bladder control is normally achieved first while children are awake and alert, able to immediately respond to a full bladder.
Many aspects of the body must work together in regulating bladder function and urine control including the muscles, nerves, brain and spinal chord. The bladder sends a message to the brain to wake up when the bladder is full. A deep sleeper does not respond to the brain's message and attempts to contain the urine in the bladder until the sleeper awakes. Typically, where nocturnal enuresis is concerned, the body is not coordinated enough yet to control the urine. Some children have a smaller than average bladder, or one that is not yet matured enough to make nighttime bladder control happen regularly. Other children create a higher volume of urine in which case the bladder is incapable of containing it throughout the night.
Physical problems such as diabetes and urinary tract infections can also factor in bed-wetting. Studies have shown there may be a genetic link to bed-wetting. According to the National Kidney Foundation, a child with one parent who experienced bed-wetting has a 4 in 10 chance of also suffering with nocturnal enuresis. Having both parents who were bed wetters raises it to a 7 in 10 chance.