Software
© 2016 Pulsar Informatics, Inc.
Page 24 of 26
Daily sleep metrics
For the purpose of visualizing sleep patterns, and calculating daily metrics, a 24-hour
day is defined as a 24-hour period starting at a specified hour. The ‘day’
corresponding to a given date is defined as the period from the Day Start Time on
the given date, to the Day Start Time of the next date. For example, with a Day Start
Time of 8:00am, the ‘day’ corresponding to Aug 17 spans from Aug 17, 8:00am to
Aug 18, 8:00am, as shown in Figure 2.
Daily sleep metrics are calculated based on the set of In Bed Intervals associated
with each day. Each interval is
associated to the day in which the In Bed interval
starts.
The interval associations corresponding to Figure 2 are listed in Table 1.
Example in-bed intervals on a 24-hour raster plot with a Day Start Time of 8:00am
Example association of In-bed intervals to days.
Day
Associated intervals
Aug 17
A
Aug 18
B, C
Aug 19
D
The daily metrics are calculated as follows:
Sleep Onset Latency
– The sum of sleep onset latency for all intervals
associated with the day. A value of NaN if there are no intervals.
Wake after sleep onset (WASO)
– The sum of WASO for all intervals
associated with the day. A value of NaN if there are no intervals.
Wake after sleep period (WASP)
– The sum of WASP for all intervals
associated with the day. A value of NaN if there are no intervals.
Total Sleep Time (TST)
– The sum of TST for all intervals associated with
the day. A value of 0 if there are no intervals.
