See Appendix B for sample QS form
The following are coded on the QS Form during the scoring of each study:
Lights are considered to have been calibrated appropriately if, at any time during the study, there is a clear transition (on recorded lights) from lights on to lights off. Otherwise, lights are considered not appropriate (including a light channel showing: no change throughout the study, reversed calibration and/or constant fluctuation from “on” to “off” throughout the study). On studies with clear, but multiple, light transitions "lights off" will be marked at the first "off" transition that is maintained for at least 30 minutes. Light calibration will be considered reliable, but sleep latency will be unreliable. This method will be employed for all studies with the only exception being when onset of sleep occurs prior to the light change, in which "lights off" will be set at the onset of sleep.
Sleep latency will be considered reliable when a change in lights status (on/off) shows a clear transition (even if reversed- off to on) prior to the onset of sleep.
Position changing during study: This sensor will be considered to have been calibrated appropriately if changes in position are visualized during the recording.
The QA grades of the signal and study are assigned at the time of scoring. It is recognized that the scorer, who spends a longer time with each study, may disagree with the preliminary pass/fail review of the Chief Polysomnologist. This will be re-reviewed with the Chief Polysomnologist and final determination made. Unusual signals, questions not addressed in manual of operations will be addressed at weekly scoring meeting.
Studies with limited sleep data
The following codes and guidelines are used to maximize the use of the respiratory data even when the sleep data are limited. These codes also provide a means for subsetting analyses according to the perceived levels of reliability of the scored data. Some studies will undergo only limited scoring (sleep-wake), as described below.
Study is scored sleep - wake only when the technical quality of the EEG does not allow distinction between sleep stages, but allows a differentiation between sleep and wake. The time considered sleep will be marked as Stage 2. No arousals will be scored for these studies. Respiratory events will be scored as usual. Scoring a study “sleep-wake” requires approval by the CP. Any study scored sleep - wake only will be given grade Fair regardless of the hours of scorable signal.
Arousals are not scored when the technical quality of the EEG does not allow differentiation of background changes in EEG from discrete periods of EEG acceleration. Studies may still be of sufficient quality to stage sleep.
Scoring Limitations or Unreliability
Was the study scored with the minimal problems? The following boxes are checked when the scorer is unsure approximately 20% of the time (1 in 5) about classifying epochs/events when making a decision regarding each of the following:
Unusual occurrences during sleep
The following patterns are also noted on the QS form:
Abnormal Awake EEG: when the waking EEG background rhythm consists of waves in the theta range. This should be distinguished from presence of theta waves as a result of excessive sleepiness, which will disappear after some period of sleep, and may indicate a neurological disorder or toxicity (QSFigure 1a and 1b).
Physiologic alpha intrusion - when alpha rhythm is present in more than 40% of Non-REM sleep, Alpha delta sleep (QSFigure 2a, 2b, and 2c).
Alpha artifact-when alpha range activity is seen throughout all periods of sleep, does not vary with eye closure, may be evident on non-cerebral channels (i.e., EOG) (QSFigure 2d).
Abnormal Eye Movements: presence of the rhythmical lateral eye movements in Non-REM sleep, or asymmetrical or disconjugate movements (QSFigure 3a, 3b, 3c, 3d, 3e, and 3f).
Periodic breathing ≥ 10 minutes: when the airflow or inductance channels are increasing and decreasing at least 50 % from the maximum, in a periodic (cyclic waxing and waning or "sinusoidal") manner, for a consecutive period of at least 10 min. Examples of this pattern will be printed and attached to the scoring form. Periodicity is noted independently from scoring apneas and hypopneas (QSFigures 4a, 4b, 4c, and 4d).
Periodic breathing ≥ 5 minutes only in SHHS2 data): Will be marked when there is a cyclic waxing and waning pattern on the inductance channels for at least 5 minutes.
Periodic large breaths: when very large breaths (one or two) occur periodically (mostly on the inductance channels) between runs of fairly normal breaths for a duration of at least 10 minutes. Examples of this pattern will be printed and attached to the scoring form (QSFigures 5a, 5b, and 5c).
Before the QS form is marked for the presence of abnormal events, such events will be reviewed with the CP and physician investigator (abnormal awake EEG, alpha intrusion) or other scorers (periodicity and periodic large breaths). Any study with abnormal events or problems with scoring will be discussed at the weekly QA meetings.
Any problems with the staging or marking arousals will be marked on the QS scoring notes form by checking appropriate boxes and/or by placing notes in the Notes section. All studies so marked will be reviewed with a physician investigator or other scorers.
Was any data lost?
Some studies do not contain usable signals for the entire recording time or include only a portion of the sleep period.
Will be checked "yes" if any criteria for medical alert as listed below are met:
Study-by-Study Outlier Identification
The Outlier program will be run after each study is scored and a report generated. The presence of the following potential outliers will be identified immediately after each study is scored and a report is generated:
If any of the outliers will be found, the scorer will review the study and identify the source. Any errors in scoring or editing will be corrected. New Short and Full reports will be generated and saved. The identification of outliers and the results of the review process (with corrections) will be noted on the QS Form.
Were respiratory events/RDI reliable: "No" will be checked when, due to the technical quality of the respiratory signals, over 20 % of scored events distinctions are equivocal; also when quality of the oximetry signal raises doubts about the actual magnitude of desaturation linked with over 20 % of respiratory events (unstable baseline).
Was apnea/hypopnea distinction reliable: "No" will be checked when airflow signal is bad or missing for over 20 % of scored respiratory events.
Summary of Procedures to Follow With Problematic Signals:
EMG artifactual (does not show discernible amplitude variations): may result in difficulty distinguishing REM from non-REM and identify REM- associated arousals. Indicate limitations in boxes 32d, 34b.
EEG artifactual: may result in unreliable or impossible staging and/or arousal identification. Indicate limitations and approaches in boxes 31, 32 (a-d), 33, 34 (a,b,).
Airflow signal poor: Results in all respiratory events defaulting to hypopneas (none qualify as apnea). Indicate limitations in box 36.
Thoracic or/and abdominal channel poor: Results in events defaulting to “obstructive” (none qualify as “central”). Indicate in box 35 if indicated.
Situations when staging or scoring respiratory events are impossible during some portion of the study: If this occurs at the beginning or end of the study, this period will be scored as stage Wake and edited lights will be set as “On” during this period (sleep latency will be unreliable if it is on the beginning). This action may result in artificially shortened sleep time. The appropriate box will be checked on PSG scoring form.
If periods of data loss occurs in the middle of the study: