Volume 11, Issue 1, Pages 56-64 (January 2010) Night-to-night sleep variability in older adults with and without chronic insomnia  Daniel J. Buysse, Yu Cheng, Anne Germain, Douglas E. Moul, Peter L. Franzen, Mary Fletcher, Timothy H. Monk  Sleep Medicine  Volume 11, Issue 1, Pages 56-64 (January 2010) DOI: 10.1016/j.sleep.2009.02.010 Copyright © 2009 Elsevier B.V. Terms and Conditions

Fig. 1 Variability across 14days for sleep diary-assessed time in bed is shown for NI (a) and CI (b). Each individual’s data across 14 nights is represented by a single line. Data from two extreme outlier nights in the NI group were excluded (time in bed>1000min). Sleep Medicine 2010 11, 56-64DOI: (10.1016/j.sleep.2009.02.010) Copyright © 2009 Elsevier B.V. Terms and Conditions

Fig. 2 Variability across 14days for sleep diary-assessed sleep quality is shown for NI (a) and CI (b). Each individual’s data across 14 nights is represented by a single line. Sleep Medicine 2010 11, 56-64DOI: (10.1016/j.sleep.2009.02.010) Copyright © 2009 Elsevier B.V. Terms and Conditions

Fig. 3 Variability across 14days for actigraphy-assessed wake after sleep onset is shown for NI (a) and CI (b). Each individual’s data across 14 nights is represented by a single line. Sleep Medicine 2010 11, 56-64DOI: (10.1016/j.sleep.2009.02.010) Copyright © 2009 Elsevier B.V. Terms and Conditions