Sleep in the Down syndrome.

Polysomnographic recordings were obtained for 10 Down syndrome (DS) children (6 males and 4 females, 9 months to 7 years old) and 16 age-matched normal controls. The present study was conducted to study the sleep characteristics of DS patients of this age group. The percentage of each sleep stage, rapid eye movements (REMs)/min, time intervals between REMs(I)/min, times of awakening in the middle of sleep, body movements (BMs) and twitch movements (TMs) were studied. I/min was divided into three frequencies: I less than 1 sec, l less than or equal to I less than 2 sec and I greater than or equal to 2 sec. Two of the 10 patients showed an increase in the percentage of REM sleep. In the group aged 1 to 5 years old, the REMs/min and I/min (I less than 1 sec) values were higher than those in normal controls (p less than 0.05). Many times of awakening in the middle of sleep (greater than or equal to 5 times and/or greater than or equal to 60 min) were observed in 4 cases. The frequency of BMs in total sleep was higher than that in controls (p less than 0.01). Five of the 10 cases showed an abnormal pattern as to the frequency of BMs during each sleep stage. The frequency of TMs was less than that in controls (total sleep and stage 1, p less than 0.05; stage REM, p less than 0.01). Seven of 9 cases showed an abnormal pattern as to the frequency of TMs during each sleep stage.(ABSTRACT TRUNCATED AT 250 WORDS)