Embla n7000 system

The in-lab polysomnogram for the patients recruited from the sleep center included recordings of C3 and C4 electroencephalograms, right and left electrooculograms, and submental and bilateral anterior tibialis electromyograms. Sleep-stage scoring was performed in 30-second epochs. Respiration was monitored with a nasal pressure transducer, nose and mouth thermocouples, and thoracic and abdominal strain gauges. Recording of the oxyhemoglobin saturation (SpO₂) was obtained with Biox 3700 pulse oximeter (Ohmeda, Englewood, CO) at 10 Hz and averaged over each 30-second epoch. Apneas were identified if airflow was absent in thermocouples and nasal cannula channels for at least 10 seconds. Hypopneas were identified if there was at least 30% reduction in airflow for at least 10 seconds accompanied with at least 4% oxyhemoglobin desaturation. AHI was determined as the frequency of apneas and hypopneas per hour of total sleep time. The in-lab polysomnography was conducted using the Embla N-7000 system (Natus Medical, Pleasanton, CA). Polysomnography for the community participants was performed at home, using the Compumedics P-series recording system (Compumedics, Abbotsford, Victoria, Australia).

The established 10–20 system [61 ] was used for full PSG including F3/F4, C3/C4, O1/O2, bilateral electro-oculogram (EOG) and submental electromyogram (EMG), electrocardiogram (EKG), abdominal and thoracic respiratory belts, an oral/nasal airflow thermistor, a snore sensor, a pulse oximeter, and leg EMG sensors. When the first night of screening indicated no sleep disorders, the participant continued in the study and the next two nights (baseline and sleep fragmentation) included a minimal montage of EEG, EOG, EMG, and EKG. High resolution video monitoring was used for behavioral observation and video recording. Recordings were made with the Embla N7000 system (Natus Neurology, Middleton, WI) and data were analyzed using Rembrandt software (Natus Neurology, Middleton, WI).