User's Manual

A-3
For instance, assume a 1-minute sampling epoch and the following activity
values on/and surrounding the time 12:00.
Time Corresponding
Activity Data
11:58 100
11:59 42
12:00 20
12:01 13
12:02 67
The total activity value for the 12:00 epoch would be:
100
*
(1/25) + 42
*
(1/5) +20 + 13
*
(1/5) + 67
*
(1/25) = 37.68.
If this value is less than or equal to the wake threshold value (next paragraph)
then the epoch would be scored as sleep.
Wake
Threshold
Values
The total number of activity counts calculated above is compared to the wake
threshold value selected by the researcher. These thresholds are listed in the table
below.
Wake Threshold Selection Wake Threshold Value*
Low 20
Medium 40
High 80
Automatic Computed automatically based on activity
data
Custom User-selectable value
*The Automatic Wake Threshold Value calculation is this:
1. Sum the activity counts for all epochs of the data set;
2. Count the number of epochs scored as MOBILE for the data set (see below
for definition of MOBILE);
3. Compute the MOBILE TIME (number of epochs scored as MOBILE from
step 2 multiplied by the Epoch Length) in minutes;
4. Compute the Auto Wake Threshold = ( (sum of activity counts from step 1)
divided by (MOBILE TIME from step 3) ) multiplied by 0.88888
Definition of MOBILE:
An epoch is scored as MOBILE if the number of activity counts recorded in that
epoch is greater than or equal to the epoch length in 15-second intervals. For
example, there are four 15-second intervals for a 1-minute epoch length; hence,
the activity value in an epoch would have to be greater than or equal to four to be
scored as MOBILE.