Sleep Heart Health Study

6.7 QS Form - Scoring Notes

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.

• Turning lights off manually. The Compumedics software uses the lights off data to determine time in bed. However, when sleep latency is unreliable, it may be difficult to determine when “lights off” happened (or when the participant went to bed). In these cases, Lights off will be manually marked when the first epoch of sleep occurs. Sometimes even this is complicated by periods of presumed napping that may occur prior to bedtime. Therefore, if periods of 20 minutes or less of sleep occur more than 20 minutes prior to a longer period of sleep, this initial sleep period is considered a nap and not included in sleep/bed time (i.e., “lights off” are marked at the onset of the longer sleep period).

Position changing during study: This sensor will be considered to have been calibrated appropriately if changes in position are visualized during the recording.

QA Grade Review

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.

Limited Scoring:

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:

• Wake - Sleep unreliable: when the amount of the quality or clarity of the EEG makes distinguishing the transition from Stage Wake to sleep uncertain.
• Stage 1/Stage 2 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).
• Stage 2/Deep Sleep unreliable: when distinction between Stage 2 and Deep Sleep is unreliable because of EEG artifact (usually due to the respiratory artifact on the EEG).
• REM/NonREM unreliable: when identification of Stage REM is unreliable (usually due to poor or missing EMG or when both EOGs are absent).
• 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, Checking the “arousal unreliable” box requires approval by the CP.
• Arousals in REM unreliable: when EMG is artifactual or absent during all or REM portion of the study.
• Respiratory events/RDI unreliable: 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).
• Apnea/hypopnea unreliable – when airflow signal is artifactual or absent for over 20 % of scored respiratory events.

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).

  TIP:

  • Alpha artifact was more likely than alpha intrusion when the activity in question:
    • Occurs across most sleep stages, and does not vary by sleep state
    • The activity is fairly similar in amplitude throughout the study
    • Often is superimposed on top of the EEG signal
  • Alpha intrusion is more likely when:
    • Varied by sleep stage
    • Displayed a fluctuating amplitude

• 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.

  NOTE: Records containing periodicity for > 10 minutes will also be coded as containing Periodic breathing for ≥ 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.

• Recording started after sleep onset - first epoch of the study is any sleep stage.
• Recording ended before participant awoke - the last epoch of the study is any stage of sleep; or when an arousal is seen in the last few epochs of the study and there is a question if the participant actually awoke or would have returned to sleep (i.e., lack of sustained activity indicating “out of bed.”).
• Loss of the data at the beginning, end or during study - indicates a loss of the data due to poor technical quality of the signals for >30 minutes.

Medical Alert:

Will be checked "yes" if any criteria for medical alert as listed below are met:

• Heart rate > 150 bpm for ≥ 2 min
• Heart rate < 30 bpm for ≥ 2 min
• Oxygen Saturation < 75% for >10% TST
• RDI > 50

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:

• 0 % of the any sleep stage
• 90 % of any Non-REM sleep stage
• >60 % of Stage REM
• RDI3P = 0 or RDI3P > 160
• Obstructive apnea index > 80
• Central apnea index > 40
• Minimum desaturation < 40 %
• AI (Arousal Index ) < 3
• Apnea or hypopnea duration < 10 s.
• Oxygen saturation = 0.

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.

• Exception to identifying central events when airflow is poor: An exception occurs when both inductance channels (thoracic and abdomen) are flat for ≥ 10 s. Then the event will be marked as a central apnea.

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:

• if periods are < 30 min. long:
  • on the O₂ sat signal: period will be marked as a O₂ sat artifact
  • on airflow and both inductance channels: no respiratory events will be scored during this period
  • on both EEGs: period will be scored as a stage Wake
• if periods are ≥ 30 min. long then period of unscorable data will be marked as Stage Wake and on the PSG scoring form appropriate box (“Intervening period of bad EEG” or “Intervening period of bad Resp/Oximetry”) will be checked. This action may result in artificially shortened sleep time.