These three video clips demonstrate rhythmic movements of the lower extremities and lower body at a rate of about 1.5Hz. The accompanying polysomnogram shows that the movements occurred during the arousals that separated successive apneas during sleep. E2-M1, electro-oculography, right eye; E1-M2, left eye. Chin1–Chin2, surface EMG of the chin. F4-M1, right frontal EEG (international 10–20 EEG electrode placement system); C4-M1, right central; O2-M1, right occipital. ECG2-ECG1 and ECG2-ECG3, electrocardiographic leads. LAT1–LAT2, left anterior tibialis surface EMG; RAT1–RAT2, right anterior tibialis surface EMG. NPRE, nasal pressure; N/O, oronasal thermocouple. THOR and ABD, thoracic and abdominal excursion (piezo-electric belts). SpO2, oxyhemoglobin saturation (%). Pleth, pulse waveform from oximeter.