nparACT_flex_loop: 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 for multiple files

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, looping over all actigraphy files contained in a specified directory.

Usage

nparACT_flex_loop(path, SR, cutoff = 1, minutes, plot = T, fulldays = T)

Arguments

path	Character string specifying the path to a directory containing the actigraphy files to be analysed.
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, group-level diagnostic plots of hourly 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

Each file in the directory is processed independently using the same parameters. Results are returned as one row per file.

Files in path are expected to be plain text or CSV files with 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.

If plot = TRUE, an aggregated (grand average) hourly activity profile across all files is generated.

Value

A data frame with one row per processed file 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.