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. Author manuscript; available in PMC: 2013 Jun 1.
Published in final edited form as: Sleep Med. 2012 Mar 22;13(6):703–706. doi: 10.1016/j.sleep.2011.11.008

Table 1.

Demographic information and results from the overall group of participants, as well as from the two sub-groups (young adults with a complaint of difficulty falling asleep and/or difficulty waking, and older adults with a complaint of difficulty falling asleep too early and/or waking too early).

Overall Group N Mean Standard Deviation
   Age 24 38.13 16.71
   Male/Female 8/16
   PSQI 24 9.00 2.69
   ESS 24 7.75 5.10
   MEQ 23 48.78 9.69
   Average bed time 24 23:39 1:18
   Variability of bed time 24 0:45 0:20
   Home DLMO 3pg/mL 18 21:48 1:21
   Home DLMO 2SD 21 21:00 1:29
   Lab DLMO 3pg/mL 21 22:01 1:19
   Lab DLMO 2SD 22 21:12 1:17
Trouble Falling Asleep / Trouble Waking Up Group N Mean Standard Deviation
   Age 15 26.07 3.03
   Male/Female 3/12
   PSQI 15 8.73 3.03
   ESS 15 6.60 4.52
   MEQ 14 43.50 8.10
   Average bed time 15 0:15 1:05
   Variability of bed time 15 0:45 0:20
   Home DLMO 3pg/mL 13 22:03 1:24
   Home DLMO 2SD 13 21:20 1:31
   Lab DLMO 3pg/mL 15 22:16 1:17
   Lab DLMO 2SD 15 21:33 1:16
Falling Asleep Too Early / Waking Too Early Group
   Age 9 58.22 7.71
   Male/Female 5/4
   PSQI 9 9.44 2.07
   ESS 9 9.67 5.70
   MEQ 9 57.00 5.19
   Average bed time 9 22:39 1:00
   Variability of bed time 9 0:42 0:21
   Home DLMO 3pg/mL 5 21:07 1:05
   Home DLMO 2SD 6 20:27 1:19
   Lab DLMO 3pg/mL 6 21:24 1:18
   Lab DLMO 2SD 7 20:27 1:00

PSQI=Pittsburgh Sleep Quality Index score; ESS=Epworth Sleepiness Scale score; MEQ=Morningness-Eveningness Questionnaire score; DLMO=dim light melatonin onset; DLMO 3pg/mL=DLMO determined by the time at which melatonin levels exceeded 3pg/mL; DLMO 2SD= DLMO determined by the time at which melatonin levels exceeded 2 standard deviations of the average of 3 baseline values.