Katherine E Miller1,2, Linda Bäbler3, Thomas Maillart4, Afik Faerman1,5, Steven H Woodward1. 1. National Center for PTSD, Dissemination and Training Division, VA Palo Alto Healthcare System, Palo Alto, California. 2. Department of Psychiatry and Behavioral Sciences, Stanford University School of Medicine, Stanford, California. 3. Zühlke Engineering AG, Bogenschützenstrasse 9A, Bern, Switzerland. 4. University of Geneva, Geneva School of Economics and Management and Citizen Cyber Lab, Campus Biotech, Geneva, Switzerland. 5. Department of Psychology, Palo Alto University, Palo Alto, California.
Abstract
STUDY OBJECTIVES: Actigraphy, the tool of choice for assessment of sleep phase disorders, is insensitive to movement-free waking. This study aimed to determine whether the detection of waking could be performed by recording instrumental responses to haptic stimuli delivered by a low-cost device. METHODS:Twenty adults underwent 2 nights oflaboratory polysomnography (PSG) while wearing a fingerless glove under which a stimulating actigraph ("Wakemeter") was apposed to the palm. The Wakemeter, controlled by a tablet computer, delivered gentle, haptic stimuli every 10 minutes during the sleep period. If a stimulus was detected, the participant squeezed the Wakemeter. Stimulus times, response times and movements were streamed to the tablet. Concurrent PSG data were scored blind to stimuli and responses. Self-reported sleep quality ratings were collected each morning. RESULTS: The Wakemeter was acceptable to 19 of 20 participants, and effects on self-reported and objective sleep were small. The probability of a response to the stimulus during a wake epoch was high regardless of movement. In contrast, actigraphy magnitude distributions were indistinguishable across epochs scored wake without movement versus sleep, confirming a known limitation of actigraphy. A simple method for calculating sleep efficiency from responses to the stimuli yielded estimates that were highly correlated with PSG-derived estimates (rho = .69, P < .001). CONCLUSIONS: Behavioral responses to haptic stimuli detected epochs of movement-free wake during the sleep period and may augment actigraphy in the low-burden estimation of sleep efficiency. Acceptability of the method over longer recording periods remains to be established.
RCT Entities:
STUDY OBJECTIVES: Actigraphy, the tool of choice for assessment of sleep phase disorders, is insensitive to movement-free waking. This study aimed to determine whether the detection of waking could be performed by recording instrumental responses to haptic stimuli delivered by a low-cost device. METHODS: Twenty adults underwent 2 nights of laboratory polysomnography (PSG) while wearing a fingerless glove under which a stimulating actigraph ("Wakemeter") was apposed to the palm. The Wakemeter, controlled by a tablet computer, delivered gentle, haptic stimuli every 10 minutes during the sleep period. If a stimulus was detected, the participant squeezed the Wakemeter. Stimulus times, response times and movements were streamed to the tablet. Concurrent PSG data were scored blind to stimuli and responses. Self-reported sleep quality ratings were collected each morning. RESULTS: The Wakemeter was acceptable to 19 of 20 participants, and effects on self-reported and objective sleep were small. The probability of a response to the stimulus during a wake epoch was high regardless of movement. In contrast, actigraphy magnitude distributions were indistinguishable across epochs scored wake without movement versus sleep, confirming a known limitation of actigraphy. A simple method for calculating sleep efficiency from responses to the stimuli yielded estimates that were highly correlated with PSG-derived estimates (rho = .69, P < .001). CONCLUSIONS: Behavioral responses to haptic stimuli detected epochs of movement-free wake during the sleep period and may augment actigraphy in the low-burden estimation of sleep efficiency. Acceptability of the method over longer recording periods remains to be established.
Authors: Kenneth L Lichstein; Kristen C Stone; James Donaldson; Sidney D Nau; James P Soeffing; David Murray; Kristin W Lester; R Neal Aguillard Journal: Sleep Date: 2006-02 Impact factor: 5.849