File: slpdb.txt MIT-BIH Polysomnographic Database Copyright (C) Massachusetts Institute of Technology 1992. All rights reserved. Overview ======== The MIT-BIH Polysomnographic Database is a collection of recordings of multiple physiologic signals during sleep. Subjects (16 males aged 32 to 56) were monitored in Boston's Beth Israel Hospital Sleep Laboratory for evaluation of chronic obstructive sleep apnea syndrome, and to test the effects of constant positive airway pressure (CPAP), a standard therapeutic intervention that usually prevents or substantially reduces airway obstruction in these subjects. The database contains over 80 hours' worth of four-, six-, and seven-channel polysomnographic recordings, each with an ECG signal annotated beat-by-beat, and an EEG signal annotated with respect to sleep stages. All recordings include an ECG signal, a blood pressure signal (from a radial A-line), an EEG signal, and a respiration signal (in most cases, from a nasal thermistor). The six- and seven-channel recordings also include a respiratory effort signal derived by inductance plethysmography; some include an EOG signal and an EMG signal (from the chin), and the remainder include a cardiac stroke volume signal (see reference below) and an earlobe oximeter signal. Each record includes two annotation files. The `.ecg' files contain beat annotations, and the `.st' files contain sleep stage annotations. The annotation files have been made available in their present form to aid users of the database in locating interesting features of the recordings. The current annotation files, although they have been prepared with care and substantial effort, are likely to contain a small number of errors. Information about types of annotations in the `.ecg' files is included in the ECG Database Programmer's Guide. Annotations in the `.st' files are all NOTE annotations, which contain the sleep staging information in their `aux' fields. Each annotation in the `.st' files applies to the thirty seconds of the record that FOLLOW the annotation. The coding scheme is: `aux' meaning W subject is awake 1 sleep stage 1 2 sleep stage 2 3 sleep stage 3 4 sleep stage 4 R REM sleep M subject moved (sleep stage uncertain) The MIT-BIH Polysomnographic Database CD-ROM contains three directories: slpdb MIT-BIH Polysomnographic Database lib DB library for use with Microsoft C (small memory model) bin MS-DOS executable programs for viewing annotated waveforms, and for extracting data in text format The files on the MIT-BIH Polysomnographic Database CD-ROM are in the same format as those on the MIT-BIH Arrhythmia Database CD-ROM, the European ST-T Database CD-ROM, and the MGH/MF Waveform Database CD-ROMs. Reference --------- Tamaki N, Yasuda T, Moore RH, Gill JB, Boucher CA, Hutter AM, Gold HK, Strauss HW. Continuous monitoring of left ventricular function by an ambulatory radionuclide detector in patients with coronary artery disease. JACC 12(3):669-79 (1988). The sample record ================= This directory contains a ten-minute excerpt (record x_slpdb), taken from record slp67x of the MIT-BIH Polysomnographic Database. The record contains respiratory effort (`Resp (chest)'), stroke volume (`SV'), and earlobe oximeter (`SO2') signals in addition to the standard ECG, blood pressure, EEG, and respiration (`Resp (nasal)') signals. The blood pressure and oximeter signals are accurately calibrated; calibrations for the other signals are estimates. Two annotation files (`x_slpdb.ecg' and `x_slpdb.st') are provided, to document the ECG and the sleep stages respectively. Periodic apneas occur throughout the excerpt. Additional information ====================== Additional information about this database is available from: George B. Moody Harvard-MIT Division of Health Sciences and Technology Biomedical Engineering Center MIT Room 20A-113 77 Massachusetts Avenue Cambridge, MA 02139 USA Telephone: +1(617) 253-7424 Telefax: +1(617) 253-2514 E-mail: george@hstbme.mit.edu