Clinical: 41-year-old man with witnessed apneas and tooth grinding.

Staging: Stage 1 sleep.

Respiratory: Normal respirations.

Behavior: Bruxism. Bursts of EMG activity occur at a rate of about 1 per second in the EEG, chin EMG, and EOG channels.

Clinical: 26-year-old woman with excessive daytime sleepiness, tooth grinding, and morning headache.

Staging: Probable stage 1 sleep but difficult to stage because of artifact.

Respiratory: Normal respirations.

Behavior: Bruxism. Rhythmic bursts of EMG activity occur about every 4 seconds.

Clinical: 47-year-old woman with excessive daytime sleepiness.

Staging: Stage 1 sleep.

Respiratory: Normal respirations.

Behavior: Movements of the left leg (*) occur rhythmically at a rate of about 1 per second, characteristic of rhythmic movement disorder. Movement artifact is evident in the thoracic and abdominal channels.

Clinical: 47-year-old woman with excessive daytime sleepiness.

Staging: Stage wake.

Respiratory: Normal respirations.

Behavior: Movements of the left leg (*) occur rhythmically at a rate of about 1 per second, with a brief period of quiescence between the runs of movement. This pattern is characteristic of rhythmic movement disorder. Movement artifact is evident in the thoracic and abdominal channels.

Clinical: 7-year-old boy with nocturnal episodes of inconsolable fear.

Staging: Stage 3 sleep with an arousal.

Respiratory: Normal respirations.

EEG: Arousal (*) with delta activity associated with screaming and inconsolable fear, characteristic of sleep terrors. The EEG following the arousal consists of a mixture of delta and faster frequencies. This EEG pattern commonly accompanies arousals from slow-wave sleep in children with arousal disorders.