MW8 & MotionWare User Guide: Issue 1.2.1
Page 43
7.4 Non-
Parametric
Variables
The NPCRA window provides a table of resulting Non-
Parametric variables with the following meanings:
IS (Interdaily Stability):
quantifies the degree of regularity
in the Activity-Rest pattern with a range of 0 to 1 where a
value of 0 indicates a total lack of rhythm and a value of 1
indicates a perfectly stable rhythm.
IV (Intra-Daily Variability):
quantifies the degree of
fragmentation of activity-rest periods. Typical healthy
subjects will show a single prolonged activity period and a
single prolonged rest period per 24 hour cycle. Certain
physiological conditions may lead to multiple short-length
periods of activity-rest within any 24 hour period. The
variable has a theoretical range of 0 to 2 with higher values
indicating higher fragmentation. Typical values for healthy
subjects will be below 1.
L5 (Least 5) Average:
all days of data are overlaid and
averaged in 24-hour periods. The L5 average provides the
average activity level for the sequence of the least five
active hours. This value provides an indication of how
restful (inactive) and regular the sleep periods are.
L5 Start Hour:
Indicates the onset of the L5 sequence and
provides an indication of the phase of the most restful
hours.
M10 (Most 10) Average:
all days of data are overlaid and
averaged in 24-hour periods. The M10 average provides
the average activity level for the sequence of the highest
(most) ten active hours. This value provides an indication
of how active and regular the wake periods are.
