Hours of usable carbon dioxide (CO2) signal - requires use of calibrated channel type with upper and lower limits for valid signal

1=Apnea/Hypopnea distinction unreliable (when airflow signal is artifactual or absent for over 20 % of scored respiratory events)

1=Problems with respiratory events (when due to the technical quality of the respiratory signals, distinctions between hypopneas and normal breaths are equivocal in over 20 % of scored events; also when the quality of the oximetry signal raises doubts about actual magnitude of desaturation linked with over 20 % of respiratory events (unstable baseline)

1=Unusual Occurrences - Abnormal EEG

1=Unusual Occurrences - Alpha intrusion

Total minutes of unscorable (artifact) data

1=Arousals unreliable (when the technical quality of the study does not allow one to distinguish discrete increases in EEG frequency from background changes in EEG. EEG still may be of sufficient quality to score stages. Studies with the physiological alpha intrusion will have arousals scored regardless of difficulty)

Hours of usable cap signal - requires use of calibrated channel type with upper and lower limits for valid signal

1=data lost - loss at beginning of study

1=Outlier - other

1=unusual occurrences - periodic breathing > 5 minutes

*All non-compumedics collected studies have position hand scored by scorer from notes supplied by site / none of position signals transfer in European Data Format (EDF) only numbers

Quality of EEG

Quality of EEG

usable mainly artifact free signal

Quality of EEG

Quality of EEG

Quality of EEG

Quality of EEG

Quality of EEG

Quality of EEG

*position for all non-compumedics data hand scored from notes from site tech

Quality of snore microphone

Quality of SUM channel

1=data Lost - recording ended before wake

1=arousals in rapid eye movement sleep (REM) unreliable (when EMG is artifactual or absent during all or rapid eye movement sleep (REM) portion of the study)

1=Study scored sleep wake

1=Sleep staging problem - scoring stage1/stage2 unreliable (when K-complexes and sleep spindles do not have show their classical morphology and distinction between Stage 1 and Stage 2 is doubtful (characteristic for the studies with low voltage EEG))

1=sleep staging problem - scoring stage2/stage3-4 unreliable (when distinction between Stage 2 and Deep Sleep is unreliable because of EEG artifact (usually due to the respiratory or sweat artifact on the EEG, and High Pass filter =1Hz used))

Hours of usable EEG

Hours of usable EEG

1=Sleep staging problem - scoring wake/sleep unreliable (when the clarity of the EEG makes distinguishing the transition unreliable)