nparACT - Non-Parametric Measures of Actigraphy Data
Computes interdaily stability (IS), intradaily variability
(IV) & the relative amplitude (RA) from actigraphy data as
described in Blume et al. (2016) <doi:
10.1016/j.mex.2016.05.006> and van Someren et al. (1999) <doi:
10.3109/07420529908998724>. Additionally, it also computes L5
(i.e. the 5 hours with lowest average actigraphy amplitude) and
M10 (the 10 hours with highest average amplitude) as well as
the respective start times. The flex versions will also compute
the L-value for a user-defined number of minutes. IS describes
the strength of coupling of a rhythm to supposedly stable
zeitgebers. It varies between 0 (Gaussian Noise) and 1 for
perfect IS. IV describes the fragmentation of a rhythm, i.e.
the frequency and extent of transitions between rest and
activity. It is near 0 for a perfect sine wave, about 2 for
Gaussian noise and may be even higher when a definite ultradian
period of about 2 hrs is present. RA is the relative amplitude
of a rhythm. Note that to obtain reliable results, actigraphy
data should cover a reasonable number of days.
