[填空题]Bipolar disorder is characterized by cycling mood changes. Mostly, such changes are gradual.

[填空题]Bipolar disorder is characterized by cycling mood changes. Mostly, such changes are gradual.

[单项选择]Sleepwalking is a disorder characterized by walking or other activities a person engaged in while (62) still asleep. It is especially (63) among children. Each night there are several (64) of non-REM and REM sleep. Sleepwalking most often occurs during deep, non-REM sleep early in the night. It can also occur during REM sleep near morning.
The cause of sleepwalking in children is usually unknown (65) may be related to fatigue, (66) sleep loss, or anxiety. Sleepwalking in adults can be associated with mental disorders, reactions to drugs and alcohol, or disease such as seizures: In the elderly, sleepwalking may be a (67) of an organic brain syndrome(综合病症) or REM behavior disorders.
The sleepwalking activity may include simply sitting (68) and appearing to be awake (69) actually being asleep, getting up and walking around, or (70) activities such as (71) furniture, g
A. circles
B. cycles
C. circulation
D. recurrence