Report Sleep cycles

This tool computes and report the sleep cycles.

Definition of Sleep Cycles

Sleep cycles typically last around 90 minutes to 2 hours, during which time the brain cycles from slow-wave sleep to REM sleep. Sleep cycles are succession of NREM-REMs periods.

Definition of NREM Period (NREMP)

  • First NREMP : begins at the first NREM stage of the recording.

  • Central NREMPs : begin at the next NREM stage following a REMP end.

  • The NREMP ends at the start of a REMP.

REM Period (REMP)

  • The REMP ends when there are 15 min without an R stage (except at the last cycle).

  • The end is defined as the last R stage of the REMP or the beginning of the next NREMP.

  • The REMP begins at the first stage R.

The hypnogram below shows six complete sleep cycles (NREMP + REMP) and one incomplete cycle at the end of the night. The Y-axis indicates sleep stages, and the X-axis shows time from recording start (hours). Cycles 1-6 are labeled above the hypnogram (e.g., C1-C6); the final incomplete cycle is unlabeled. NREM periods appear in blue and REM periods in green.

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Steps

1 - Input Files

Start by opening your PSG files (.edf, .sts or .eeg).

  • European Data Format (EDF) :

    The corresponding .tsv file is required with .edf. Both files must be saved in the same directory and share the exact same filename.

  • Stellate format (up to version 6.2) :

    The corresponding .sig file is required with the .sts. Both files must be saved in the same directory and share the exact same filename.

  • NATUS format (version 9.1) :

    (CEAMS users only) The entire NATUS subject folder is required.

2 - Cycle Definition

Select or edit your sleep cycle criteria.

3 - Output Files

Sleep Cycle Cohort file :

  • The start and duration (s) of each NREM and REM period are saved in a .tsv (tab separated values) file defined by the user.

  • The file includes 5 columns : group, name, start_sec, duration_sec and channels.

  • Each row corresponds to a period and the group identifies the PSG recording.

  • New PSG recording are added in the .tsv file if it exists otherwise it is created.

Sleep Cycle specific to each PSG opened:

  • The hypnogram of each PSG is saved in a .png picture file

  • The sleep stages and sleep periods events are saved in a .tsv file

Version History

  • v2.1.0Distributed with CEAMS package version 7.2.0 — Snooz beta 2.0.1

    • Initial release of the tool.

  • v2.4.0Distributed with CEAMS package version 7.3.0 — Snooz beta 3.0.0

    • Refactor hypnogram plotting to use contours instead of filled bars, and add background colors.

    • Fix Aeschebach method to support two REMPs without NREM between.

    • Improve path, filename, and extension handling for sleep cycle warning log file.