GGIR (version 2.6-0)

g.IVIS: 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)

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 acce;eration into a binary score of rest versus active to try to similate the original approach.

Value

InterdailyStability

IntradailyVariability

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

# NOT RUN {
  Xi = abs(rnorm(n = 10000,mean = 0.2))
  IVISvariables = g.IVIS(Xi=Xi)
# }