Use of wrist activity for monitoring sleep/wake in demented nursing-home patients

Abstract

Actigraphy is applicable for studying sleep in populations who are unable to tolerate traditional sleep-recording techniques, such as nursing-home patients who are infirm and demented. This study examined whether actigraphy can accurately reflect sleep/wake activity in this population by testing the reliability of a wrist-activity monitor, the Actillume, against traditional sleep measurements and against observations of nursing-home patients. Data from the Actillume are presented as two variables, the sum (total of all activity movements within the prescribed epoch) and the maximum activity (the largest or maximum movement recorded during the prescribed epoch), and by electroencephalogram (EEG). One difficulty in making comparisons was that the EEG records showed diffuse slowing, making it extremely difficult to score sleep/wake activity and making it difficult to use the EEG as a "gold standard". Nevertheless, the correlation for total sleep time from EEG and Actillume was r = 0.91 (p < 0.001) for sum activity and r = 0.81 for maximum activity (p < 0.005). Correlations for percent sleep were r = 0.78 (p < 0.01) for maximum activity and r = 0.61 for sum activity. The comparison of sleep/wake determined by the Actillume vs. observations resulted in a sensitivity of 87% and specificity of 90%. We conclude that the Actillume is the most feasible technique for studying sleep and wake activity in demented nursing-home patients.

Figures

FIG. 1

Scatterplot of percent sleep from EEG and from summary activity.