Figure 1From: Clinical review: Sleep measurement in critical care patients: research and clinical implicationsScatterplots of the results of four different techniques used to measure nocturnal sleep in our intervention studies: (a) bispectral index (BIS) quantity versus actigraphy, (b) BIS quantity versus patient assessment (Richards-Campbell Sleep Questionnaire), (c) BIS quantity versus nurse assessment, and (d) nurse assessment versus patient assessment.Back to article page