PPG Diary 1 Dataset

Table of contents

  1. Overview
  2. Dataset contents
    1. Details of the data file
  3. Replicating the analysis
    1. Steps
    2. Output files

Overview

Item Details
Links Dataset, Publication
Signals Dual-wavelength PPG
No. Subjs 1
Protocol PPG signal measured at the thumb from a single participant for 28 days. The participant recorded their activities of daily living, and any technical problems

Dataset contents

The dataset is presented in Matlab format. It contains:

  • ppg_diary_pilot_conv_data.mat: The main data file (containing 4 weeks of data)
  • PPGdiary1_1_hour_sample.mat: A 1-hour data sample
  • PPGdiary1_1_min_sample.mat: A 1-minute data sample
  • PPGdiary1_1_pulse_sample.mat: A short data sample of a single PPG pulse wave

The repository also contains the following scripts to process the data:

  • ppg_diary_pilot1_analysis.m: The main Matlab script, used to analyse the data.
  • PulseAnalyse.m: a script called by the main script

Details of the data file

The ppg_diary_pilot_conv_data.mat data file contains two variables:

  • data : a structure containing data recorded from the wearable PPG sensor
  • adl_data : a structure containing participant-reported activities of daily living

The “data” variable contains:

  • fs : the sampling frequency of PPG signals (100 Hz)
  • pr : the pulse rate (in beats per minute) provided by the device (at 1 Hz, see t_sec_rel for associated times)
  • spo2 : the arterial blood oxygen saturation (in %) provided by the device (at 1 Hz, see t_sec_rel for associated times)
  • spo2_status : provided by the device (at 1 Hz, see t_sec_rel for associated times)
  • ppg_red : a vector of red PPG values (at 100 Hz, see t_ms_rel for associated times)
  • ppg_ir : a vector of infrared PPG values (at 100 Hz, see t_ms_rel for associated times)
  • perf : perfusion parameter provided by the device (at 1 Hz, see t_sec_rel for associated times)
  • t_ms_rel : time in milliseconds since the start of the study
  • t_sec_rel : time in seconds since the start of the study

The adl_data variable contains a list of activities of daily living (and sensor maintenance issues) and their associated times:

  • act : a list of activities and sensor maintenance issues. The suffix ‘_fin’ indicates the end of an activity.
  • t_ms_rel : the time in milliseconds since the start of the study.

Replicating the analysis

Steps

The analysis reported in this publication can be replicated as follows:

Output files

The following files are produced during the analysis:

  • filt_data.mat: Contains filtered PPG signal
  • beat_data.mat: Contains annotations of beats detected in PPG signal
  • rec_periods.mat: Contains details of each ‘recording period’ (i.e. each period of data in which the participant was doing a single activity, and the device was either connected or disconnected). The file contains the rec_periods variable, which contains the following fields:
    • deb: the start time of each recording period, measured in milliseconds since the start of the study.
    • fin: the end time of each recording period, measured in milliseconds since the start of the study.
    • act: the activity the participant was doing during each recording period (e.g. ‘desk work’).
    • reason_disconnect: (only populated if the device was disconnected during a period) the reason for device disconnection (e.g. ‘connection dropped’).
    • connected: whether or not the device was connected during each recording period (1 indicates that it was connected)
    • durn: the duration of each recording period (in ms)
    • noted_wearing: whether or not the participant noted that they were wearing the device during each recording period
  • trial_outcomes.mat: contains a variable named ‘endpoints’, which is a structure containing each of the study endpoints.
  • quality_data.mat: contains a variable named ‘qual’, which is a structure containing the following fields:
    • no_onsets: the number of pulse wave onsets detected in each recording period.
    • no_hq_onsets: the number of pulse wave onsets detected in each recording period, whose corresponding pulse waves were deemed to be of high quality (in samples, at 100 Hz).
    • durn_hq_onsets: the total duration of the pulse waves which were deemed to be of high quality during each recording period (in samples, at 100 Hz).
    • durn_lq_onsets: the total duration of the pulse waves which were deemed to be of low quality during each recording period (in samples, at 100 Hz).

For a greater understanding of these files, please see the ppg_diary_pilot1_analysis.m script which generates the files.

Copyright © 2021 Peter Charlton.