Polysomnography (PSG) recordings, including the assessment of continuous Blood Pressure and 12-lead Electrocardiogram (ECG), were obtained on 2 consecutive nights prior to Baseline Visit and prior to End of Maintenance Period (Visit 7) for up to 8 hours per night. Readings from the first night of the PSG were only used for analysis if the PSG from the second night was determined to be not valid for evaluation. Influence of Periodic Limb Movements (PLMs) on sleep is reflected in the Periodic Limb Movement-Related Arousal Index (PLMAI). Arousal is defined as sudden change in the EEG activity and the index illustrates to what degree the PLMs contribute to arousal from sleep. Sleep stages and time spent in each sleep stage were determined from Electroencephalogram (EEG) readings.
A negative value in Change from Baseline indicates an improvement from Baseline. The higher the negative value the better the improvement.