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Extract Counts from .agd Data

Source: R/read_agd.R
agd.counts.Rd

Extracts activity counts, timestamps, steps, and inclinometer data (if available) from AGD file data. Inclinometer data can be used to enhance sleep detection for AGD files that lack raw acceleration.

Usage

agd.counts(agd_data, convert.timestamps = TRUE, include_inclinometer = TRUE)

Arguments

agd_data

List returned from read.agd()

convert.timestamps

Logical. Convert ActiGraph timestamps to POSIXct (default: TRUE)

include_inclinometer

Logical. Include inclinometer data if available? (default: TRUE)

Value

Data frame with counts per minute, timestamps, and optional inclinometer data:

  • timestamp - POSIXct timestamp (if convert.timestamps = TRUE)

  • axis1 - Vertical axis counts (Y-axis)

  • axis2 - Horizontal axis counts (X-axis)

  • axis3 - Anterior-posterior axis counts (Z-axis)

  • steps - Step counts

  • lux - Light intensity (if available)

  • inclineOff - Off-body indicator (if available)

  • inclineStanding - Standing indicator (if available)

  • inclineSitting - Sitting indicator (if available)

  • inclineLying - Lying indicator (if available)

Details

Inclinometer data is particularly useful for sleep detection in AGD files:

  • inclineLying = 1 indicates the device detected lying posture

  • Combined with low activity (Cole-Kripke sleep), this sharpens specificity

  • Not all AGD files contain inclinometer data (depends on ActiLife processing settings)