nparACT_flex: Compute non-parametric actigraphy measures with a flexible...

In nparACT: Non-Parametric Measures of Actigraphy Data

Compute non-parametric actigraphy measures with a flexible low-activity window

Description

Computes the classic non-parametric actigraphy measures interdaily stability (IS), intradaily variability (IV), and relative amplitude (RA), as well as the L5 and M10 values and their respective start times. In addition, the function computes a flexible low-activity period (Lflex) of user-defined duration and its start time for a single actigraphy file.

Usage

nparACT_flex(name, SR, cutoff = 1, minutes, plot = T, fulldays = T)

Arguments

name	Character string giving the name of the object in the workspace that contains the actigraphy data.
SR	Numeric. Sampling rate in Hertz (samples per second).
cutoff	Numeric. Activity threshold used to classify movement. Defaults to 1.
minutes	Numeric. Length of the flexible low-activity window (Lflex) in minutes.
plot	Logical. If TRUE, diagnostic plots of the hourly and minute-wise activity profiles are generated. Defaults to TRUE.
fulldays	Logical. If TRUE, data are truncated to include only complete 24-hour periods. Defaults to TRUE.

Details

The function expects the actigraphy data to be available in the workspace under the name provided via name. Data are internally pre-processed, optionally restricted to complete 24-hour periods, and analysed using standard non-parametric actigraphy algorithms.

The input data may contain either two columns (time, activity) or three columns (date, time, activity). Time variables are internally converted to POSIXct. Missing values in the activity signal are not permitted.

Interdaily stability (IS) and intradaily variability (IV) are computed from hourly averaged activity data. Relative amplitude (RA) is derived from the difference between the most active 10-hour period (M10) and the least active 5-hour period (L5). The flexible low-activity measure (Lflex) represents the least active contiguous period of the duration specified by minutes.

Value

A data frame with one row and the following columns:

IS

Interdaily stability

IV

Intradaily variability

RA

Relative amplitude

L5

Mean activity during the least active 5-hour period

L5_starttime

Start time of the L5 period

M10

Mean activity during the most active 10-hour period

M10_starttime

Start time of the M10 period

Lflex

Mean activity during the least active flexible period

Lflex_starttime

Start time of the Lflex period

nparACT documentation built on Dec. 16, 2025, 5:09 p.m.