g.IVIS: Calculates IV and IS

In GGIR: Raw Accelerometer Data Analysis

Calculates IV and IS

Description

To extract interdaily stability and interdaily variability as originally proposed by van Someren.

Usage

  g.IVIS(Xi, epochsizesecondsXi = 5, IVIS_epochsize_seconds = c(),
    IVIS_windowsize_minutes = 60, IVIS.activity.metric = 1,
    IVIS_acc_threshold = 20, IVIS_per_daypair = FALSE)

Arguments

Xi	Vector with acceleration values, e.g. ENMO metric.
epochsizesecondsXi	Epoch size of the values in Xi expressed in seconds.
IVIS_epochsize_seconds	This argument has been depricated.
IVIS_windowsize_minutes	Window size of the Intradaily Variability (IV) and Interdaily Stability (IS) metrics in minutes, needs to be able to add up to 24 hours.
IVIS.activity.metric	Metric used for activity calculation. Value = 1, uses continuous scaled acceleration. Value = 2, tries to collapse acceleration into a binary score of rest versus active to try to simulate the original approach.
IVIS_acc_threshold	Acceleration threshold to distinguish inactive from active
IVIS_per_daypair	Boolean to indicate whether IVIS should be calculated per day pair and then aggregated across day pairs weighted by day completeness (default FALSE).

Value

InterdailyStability
IntradailyVariability

Author(s)

Vincent T van Hees <[e-mail]>

References

• Eus J. W. Van Someren, Dick F. Swaab, Christopher C. Colenda, Wayne Cohen, W. Vaughn McCall & Peter B. Rosenquist. Bright Light Therapy: Improved Sensitivity to Its Effects on Rest-Activity Rhythms in Alzheimer Patients by Application of Nonparametric Methods Chronobiology International. 1999. Volume 16, issue 4.

Examples

  Xi = abs(rnorm(n = 10000,mean = 0.2))
  IVISvariables = g.IVIS(Xi=Xi)

GGIR documentation built on Sept. 11, 2024, 8:59 p.m.