The ‘ACT’ Structure

This section provides a detailed overview of all the fields in the ACT Dataset which is a Matlab variable of class struct.

  • ACT.filename, and ACT.filepath [string] specifies the filename and path.
  • ACT.version [string] specifies the Cicada version
  • ACT.info [struct] contains all variables related to the device, subject and study
    • info.device [string] device name
    • info.serial [string] device serial number
    • info.institute [string] institute name
    • info.study [string] study name
    • info.researcher [string] researcher’s name
    • info.subject [string] subject identifier
    • info.group [string] group name this subject is assigned to, e.g. ‘controls’
    • info.condition [string] study condition this subject is assigned to, e.g. ‘placebo’
    • info.session [string] session name or number this recording belongs to, e.g. ‘baseline’
    • info.dob [string] participant’s date of birth
    • info.sex [string] participant’s sex
    • info.height [double] participant’s height in centimeters
    • info.weight [double] participant’s weight in kilograms
    • info.handedness [string] participant’s handedness
    • info.deviceLoc [string] location where the actigraphy device was worn
    • info.phenotype [struct] contains any additional variables from psychometric or clinical surveys
  • ACT.pnts [int] number of data points in Raw actigraphy Data
  • ACT.srate [int] sampling frequency of Raw actigraphy Data
  • ACT.xmin [datenum] start date of the recording
  • ACT.xmax [datenum] end date of the recording
  • ACT.startdate [datenum] start date of the data analysis windows
  • ACT.enddate [datenum] start date of the data analysis windows
  • ACT.ndays [int] number of whole analysis windows
  • ACT.times [double] timeseries vector contains datenum values for each sample
  • ACT.timezone [string] time zone
  • ACT.epoch [int] epoch length in seconds used to transform Raw Data into Metrics
  • ACT.data [struct] contains all Raw Data
    • data.acceleration.x [double] Accelerometry in x-axis
    • data.acceleration.y [double] Accelerometry in y-axis
    • data.acceleration.z [double] Accelerometry in z-axis
    • data.(measurement).(datatype) [double] e.g. data.temperature.wrist, to store temperature data obtained from the wrist; or data.light.wideSpec, to store wide-spectrum light exposure
  • ACT.metric [struct] contains all (derived) Metrics, in common Epochs of length ACT.epoch
    • metric.acceleration.euclNormMinOne [timeseries] Euclidean normal of the vector [x, y, z] minus 1 to account for static gravity
    • metric.acceleration.bpFiltEuclNorm [timeseries] Euclidean normal bandpass filtered between 0.2 and 15 Hz using a 4th order Butterworth filter
    • metric.acceleration.angle_z [timeseries] angle of the Accelerometry device in the z-axis, given by atan(z / sqrt(x^2 + y^2)) / (pi/180), where x, y and z are median acceleration values obtained in moving windows of length ACT.epoch
  • ACT.analysis [struct] contains all Annotation and Events
    • analysis.annotate [struct] contains all Annotatation timeseries
      • annotate.acceleration [timeseries] contains Annotation of ‘acceleration’ Metrics
      • annotate.(measurement) [timeseries] e.g. analysis.annotate.light contains Annotation of ‘light’ Metrics
    • analysis.events [table] contains all events
      • events.id [int] unique identifier
      • events.onset [datenum] onset of event
      • events.duration [double] duration of event in days
      • events.label [cell] event label
      • events.type [cell] event type
    • analysis.settings [struct] contains all parameter values used in the analysis
  • ACT.stats [struct] contains all output from statistics
    • stats.average [struct] contains all average statistics
      • average.all [table] contains average statistics across all days
      • average.week [table] contains average statistics across weekdays
      • average.weekend [table] contains average statistics across weekend days
    • stats.daily [table] contains daily statistics
    • stats.sleep [struct] contains statistics for Sleep Window and Sleep Period Events
      • sleep.actigraphy [table] contains statistics for Sleep Window and Sleep Period Events of type actigraphy
      • sleep.sleepDiary [table] contains statistics for Sleep Window and Sleep Period Events of type sleepDiary
    • stats.custom [struct] contains statistics for Custom Events
      • custom.(label) [table] contains statistics for Custom Events identified by label
  • ACT.display [struct] contains all display settings
  • ACT.etc [struct] ‘etcetera’ contains all other non-essential variables
  • ACT.saved [bool] indicates whether file is saved or not
  • ACT.pipe [cell] keeps track of pipeline stages, load, preproc, analysis and statistics
  • ACT.history [char] stores all steps executed by the user interface as Matlab code to reproduce the exact same data processing