User's Manual
B-2 Statistic Definitions
Total Invalid Time (Activity)
(The total number of epochs between the Start Time and the End Time of the
given interval in which the physical activity count was found to exceed the
maximum possible value from a properly functioning Actiwatch [i.e., invalid data
due to rare hardware error, communication error, or data corruption] plus the total
number of epochs with valid physical activity counts manually excluded from
the data set by the practitioner using Actiware) software multiplied by the Epoch
Length in minutes (so the Total Invalid Time is in minutes).
Percent Invalid (Activity)
a) The percentage of Total Invalid Time (Activity) [see above] to the Interval
Duration [see above]. b) (Total Invalid Time (Activity) divided by Interval
Duration) multiplied by 100.
Total Invalid Time (Sleep/Wake)
(The total number of epochs between the Start Time and the End Time of the
given interval for which the sleep/wake scoring algorithm did not have enough
data to determine a SLEEP or WAKE score) multiplied by the Epoch Length in
minutes (so the Total Invalid Time is in minutes). Note: The insufficient data
condition can be caused by invalid or manually excluded physical activity data
at the epoch, and/or immediately before the epoch, and/or immediately after the
epoch – how much before and after being a function of the Epoch Length.
Percent Invalid (Sleep/Wake)
a) The percentage of Total Invalid Time (Sleep/Wake) [see above] to the Interval
Duration [see above]. b) (Total Invalid Time (Sleep/Wake) divided by Interval
Duration) multiplied by 100.
Sleep Onset Latency
a) The time elapsed between the Start Time of a given Rest Interval and the
following Sleep Start Time, in minutes. b) The time required for the onset
of sleep after first attempting to get to sleep (i.e, from the “lights out” time).
Calculated using the analysis setting made on Tools > Options > Analysis.
Snooze Time
a) The time elapsed between Sleep End Time and the End Time of a given Rest
Interval, in minutes. b) The time elapsed between the end of sleep and the time
lightsareswitchedonorthesubjectgetsoutofbed.
Sleep Efficiency
a) The percentage of Scored Total Sleep Time [see below] to (Interval Duration
[see above] minus Total Invalid Time (Sleep/Wake)), for the given Rest Interval.
b) (Scored Total Sleep Time divided by (Interval Duration minus Total Invalid
Time (Sleep/Wake)) of the given Rest Interval) multiplied by 100.
Wake After Sleep Onset (WASO)
The total number of epochs between the Start Time and the End Time of the
given Sleep Interval scored as WAKE by Actiware software (or manually set as
WAKE by the practitioner using Actiware software) multiplied by the Epoch
Length in minutes (so the Wake After Sleep Onset is in minutes). Note: Wake
After Sleep Onset is identical to Scored Total Wake Time [see below] when the
given interval is a Sleep Interval.