Changes in the structure of sleep spindles and delta waves on electroencephalography in patients with nocturnal...

To evaluate the mechanism of the dysfunction of arousal in patients with Type I and Type IIa enuresis.

The numbers of sleep spindles and delta waves were analysed during electroencephalography in 19 patients with enuresis (17 male, two female, mean age 9.7 years, range 8-14).

In four patients with Type I enuresis, who awoke spontaneously and remained dry as a result of urinary sensation, the numbers of sleep spindles and delta waves diminished gradually and finally disappeared just before the patients awoke completely. In the remaining nine patients with Type I enuresis, there was no decrease in the number of sleep spindles and delta waves, and enuresis occurred without the subjects awakening. In the six patients with Type IIa enuresis, there was no arousal reaction or generation of sleep spindles on urination while asleep.

An immaturity in the function of the thalamus might be a cause of the arousal dysfunction in patients with Type I enuresis. In Type IIa enuresis, a possible abnormal or immature arousal mechanism in the pons or the lower tract may be responsible.