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About MASS

The Montreal Archive of Sleep Studies (MASS) is an open-access and collaborative database of laboratory-based polysomnography (PSG) recordings O’Reilly, C., et al. (2014) J Seep Res, 23(6):628-635. Its goal is to provide a standard and easily accessible source of data for benchmarking the various systems developed to help the automation of sleep analysis. It also provides a readily available source of data for fast validation of experimental results and for exploratory analyses. Finally, it is a shared resource that can be used to foster large-scale collaborations in sleep study.

MASS is composed of cohorts themselves comprising subsets. Recordings within subsets is kept as homogeneous as possible, whereas it is more heterogeneous between subsets. To allow inter-study comparisons, researchers validating their results on MASS are encouraged to specify which portion of the database they used in their assessment (e.g., MASS-C1 for the whole cohort 1, MASS-C1/SS1-SS3 for subsets 1, 2 and 3 of cohort 1).

Currently, the first MASS cohort available is described in O’Reilly, C., et al. (2014) J Seep Res, 23(6):628-635. This cohort comprises polysomnograms of 200 complete nights recorded in 97 men and 103 women of age varying between 18 and 76 years (mean: 38.3 years, SD: 18.9 years). It has been split in five different subsets:

MASS: https://borealisdata.ca/dataverse/MASS

For the Biosignals and Sleep stages:

For the Sleep Annotations:

To get access to the MASS database

To allow an access that is as unrestricted as possible while keeping high ethical standards regarding the protection of subject’s privacy, we have separated the information of the database in four kinds of data with appropriate access requirements. 

These types are as follow:

  • Biosignals: Polysomnographic data provided as EDF++ files including only the biosignals (EEG, EKG, EMG, EOG, etc.). Access to these files requires that the investigators submit a copy of their project (as approved by their local ethics board) and a proof of ethical approval. Upon reception of these documents, we will provide to the requesting investigators the whole set of PSG files.
  • Subset-specific annotations: Polysomnographic annotations provided as EDF++ files.
  • Open-access descriptors: Excel .xlsx format file including basic recording and scoring sinformation. In some cases, sleep-related indexes are also included.
  • Restricted-access descriptors: Excel .xlsx format file including further information such as demographic (age, gender, education) variables. Access to this file requires stating the hypotheses that are to be investigated such that we may check that they do not conflict with other studies currently being run.

Access requests can be filed by emailing your request here: mass.cnmtl@ssss.gouv.qc.ca

In your request for access, please state which type of data you need:

  • Biosignals and sleep stages
  • Subset-specific annotations
  • Open-access descriptors
  • Restricted-access descriptors

As stated previously, to give you access to type 1 (Biosignals and sleep stages) and/or type 4 (Restricted-access descriptors) of the MASS database, we need two documents from you:

  • A description of the project in which MASS would be used
  • A copy of the accreditation from your local research ethics board for this project

Furthermore, regarding for the Restricted-access descriptors, a full project description is required to present to the MASS scientific committee before sharing that data. In this project description, please state the research hypotheses that are to be investigated with these data. The MASS scientific committee will verify that these hypotheses are not already being investigated before granting access.

Once your dossier is complete (documents a) and b) referred to above, if required), we will send you the license for use of the MASS database. If you agree to the terms we will send you the Open-access descriptor and the procedure to download the MASS data through the Canadian Dataverse Repository Borealis.

* Please note that the subset-specific annotations are available for download directly on Borealis Repository. Look at the Sleep Annotations links listed above. PSG biosignals will never be available for direct download. You can request access through the Borealis Website.

If you require further information that was found on the old website, please click here.

For any question regarding MASS, please contact the database manager via email.

Please stay tuned for further updates on the MASS database and its website.