Wrist actigraphic scoring for sleep laboratory patients: algorithm development

Abstract

SUMMARY Wrist actigraphy is employed increasingly in sleep research and clinical sleep medicine.Critical evaluation of the performance of new actigraphs and software is needed. Actigraphic sleep-wake estimation was compared with polysomnographic (PSG) scoring as the standard in a clinical sleep laboratory. A convenience sample of 116 patients undergoing clinical sleep recordings volunteered to participate. Actiwatch-L recordings were obtained from 98 participants, along with 18 recordings using the newer Spectrum model (Philips Electronics), but some of the actigraphic recordings could not be adequately aligned with the simultaneous PSGs. Of satisfactory alignments, 40 Actiwatch recordings were used as a training set to empirically develop a new Scripps Clinic algorithm for sleep-wake scoring. The Scripps Clinic algorithm was then prospectively evaluated in 39 Actiwatch recordings and 16 Spectrum recordings, producing epoch-by-epoch sleep-wake agreements of 85-87% and kappa statistics averaging 0.52 (indicating moderate agreement). Wake was underestimated by the scoring algorithm. The correlations of PSG versus actigraphic wake percentage estimates were r = 0.6690 for the Actiwatch and r = 0.2197 for the Spectrum. In general, using a different weighting of activity counts from previous and subsequent epochs, the Scripps Clinic algorithm discriminated sleep-wake more successfully than the manufacturerÕs Actiware algorithms. Neither algorithm had fully satisfactory agreement with PSG. Further evaluations of algorithms for these actigraphs are needed, along with controlled comparisons of different actigraphic designs and software.

Comparisons of three practical field devices used to measure personal light exposures and activity levels

“…5 All of these devices are designed to measure light exposures and activity levels over extended periods of time while deployed in the field. One study characterized the Actiwatch Spectrum in terms of activity patterns and sleep quality, 6 another study used the device to record personal light exposures, 7 and one recent publication reported on its basic technical characteristics. 8 The technical characteristics of an earlier version of the Daysimeter have been published.…”

Actigraphy and Sleep Diary Measurements in Breast Cancer Survivors: Discrepancy in Selected Sleep Parameters

“…Wrist actigraphs provide high sensitivity (i.e., accuracy in detecting sleep) particularly in normal sleepers (de Souza et al, 2003; Kripke et al, 2010). Yet some studies have raised concerns about the specificity (i.e., accuracy in detecting wakefulness) of actigraphy in some populations or devices (de Souza et al, 2003; Paquet, Kawinska, & Carrier, 2007).…”

Reply: “Obstructive Sleep Apnea, Sleep Duration, and Fasting Glucose” and “The Impact of Obesity on the Association between Obstructive Sleep Apnea and Glucose Metabolism”

“…It is well known that OSA in nonobese individuals is significantly associated with impaired glucose metabolism; however, OSA is not associated with abnormal glucose tolerance categories (2). That is to say, the association of OSA with glucose metabolism is different between obese and nonobese individuals.…”

“…We did use the medium threshold (40 counts per epoch) to differentiate wake from sleep. Prior studies have not found clear benefits in terms of agreement with polysomnography by using either a higher or lower threshold in adults (2,3). Although actigraphy is known to underestimate wake after sleep onset as a result of scoring of quiet wakefulness as sleep, there is little evidence to suggest this offset leads to systematic bias.…”