Limits...
The validity of Actiwatch2 and SenseWear armband compared against polysomnography at different ambient temperature conditions.

Shin M, Swan P, Chow CM - Sleep Sci (2015)

Bottom Line: A linear mixed model indicated that AW2 is valid for sleep onset latency (SOL), total sleep time (TST) and sleep efficiency (SE) but significantly overestimated wake after sleep onset (WASO) at 17 °C and 22 °C.However, at 29 °C, SWA significantly overestimated WASO and underestimated TST and SE.AW2 showed small biases for most of sleep variables at all temperature conditions, except for WASO.

View Article: PubMed Central - PubMed

Affiliation: Delta Sleep Research Unit, Exercise, Heath & Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, NSW, Australia.

ABSTRACT
There were no validation studies on portable sleep devices under different ambient temperature, thus this study evaluated the validity of wrist Actiwatch2 (AW2) or SenseWear armband (SWA) against polysomnography (PSG) in different ambient temperatures. Nine healthy young participants (6 males, aged 23.3±4.1 y) underwent nine nights of study at ambient temperature of 17 °C, 22 °C and 29 °C in random order, after an adaptation night. They wore the AW2 and SWA while being monitored for PSG simultaneously. A linear mixed model indicated that AW2 is valid for sleep onset latency (SOL), total sleep time (TST) and sleep efficiency (SE) but significantly overestimated wake after sleep onset (WASO) at 17 °C and 22 °C. SWA is valid for WASO, TST and SE at these temperatures, but severely underestimates SOL. However, at 29 °C, SWA significantly overestimated WASO and underestimated TST and SE. Bland-Altman plots showed small biases with acceptable limits of agreement (LoA) for AW2 whereas, small biases and relatively wider LoA for most sleep variables were observed in SWA. The kappa statistic showed a moderate sleep-wake epoch agreement, with a high sensitivity but poor specificity; wake detection remains suboptimal. AW2 showed small biases for most of sleep variables at all temperature conditions, except for WASO. SWA is reliable for measures of TST, WASO and SE at 17-22 °C but not at 29 °C, and SOL approximates that of PSG only at 29 °C, thus caution is needed when monitoring sleep at different temperatures, especially in home sleep studies, in which temperature conditions are more variable.

No MeSH data available.


The Bland–Altman plots for SOL, WASO, TST and SE, Left, B–A plots for AW2 and PSG; Right, B–A plots for SWA and PSG, Mean bias, middle horizontal line showing shift from zero; Limits of agreement (2 standard deviations of bias) as indicated by the dotted lines on either side of the mean bias line, SOL, WASO, TST are in minutes, SE in percentages,  17 °C,  22 °C and  29 °C—temperature of the sleeping environment.
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f0005: The Bland–Altman plots for SOL, WASO, TST and SE, Left, B–A plots for AW2 and PSG; Right, B–A plots for SWA and PSG, Mean bias, middle horizontal line showing shift from zero; Limits of agreement (2 standard deviations of bias) as indicated by the dotted lines on either side of the mean bias line, SOL, WASO, TST are in minutes, SE in percentages, 17 °C, 22 °C and  29 °C—temperature of the sleeping environment.

Mentions: Table 1 shows the mean and standard deviations for SOL, WASO, TST and SE for PSG, AW2 and SWA at ambient temperature conditions of 17 °C, 22 °C, 29 °C. The sleep measures of SOL, TST and SE from AW2, at all temperature conditions, were not significantly different from those recorded during PSG. However, WASO was significantly overestimated when compared to PSG at 17 °C and 22 °C (Table 1). The sleep measures recorded from SWA show a significant underestimation of SOL (at 17 °C and 22 °C), and TST and SE (at 29 °C), but an overestimation of WASO (at 29 °C) compared to PSG. Fig. 1, B–A plots for single measurement, has been specifically chosen to display data sets from different ambient temperatures and the spread of data especially those that lie outside of the limits of agreement, i.e., outliers of WASO, TST and SE at 29 °C (Fig. 1F–H). Table 2 presents the differences between AW2/SWA and PSG (mean bias), and LoA from B–A plots with multiple measurements per subject. Consistent with the data presented in Table 1 and Fig. 1, WASO, TST and SE for SWA show larger mean bias and LoA at 29 °C than at 17 °C and 22 °C.


The validity of Actiwatch2 and SenseWear armband compared against polysomnography at different ambient temperature conditions.

Shin M, Swan P, Chow CM - Sleep Sci (2015)

The Bland–Altman plots for SOL, WASO, TST and SE, Left, B–A plots for AW2 and PSG; Right, B–A plots for SWA and PSG, Mean bias, middle horizontal line showing shift from zero; Limits of agreement (2 standard deviations of bias) as indicated by the dotted lines on either side of the mean bias line, SOL, WASO, TST are in minutes, SE in percentages,  17 °C,  22 °C and  29 °C—temperature of the sleeping environment.
© Copyright Policy - CC BY-NC-ND
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4608890&req=5

f0005: The Bland–Altman plots for SOL, WASO, TST and SE, Left, B–A plots for AW2 and PSG; Right, B–A plots for SWA and PSG, Mean bias, middle horizontal line showing shift from zero; Limits of agreement (2 standard deviations of bias) as indicated by the dotted lines on either side of the mean bias line, SOL, WASO, TST are in minutes, SE in percentages, 17 °C, 22 °C and  29 °C—temperature of the sleeping environment.
Mentions: Table 1 shows the mean and standard deviations for SOL, WASO, TST and SE for PSG, AW2 and SWA at ambient temperature conditions of 17 °C, 22 °C, 29 °C. The sleep measures of SOL, TST and SE from AW2, at all temperature conditions, were not significantly different from those recorded during PSG. However, WASO was significantly overestimated when compared to PSG at 17 °C and 22 °C (Table 1). The sleep measures recorded from SWA show a significant underestimation of SOL (at 17 °C and 22 °C), and TST and SE (at 29 °C), but an overestimation of WASO (at 29 °C) compared to PSG. Fig. 1, B–A plots for single measurement, has been specifically chosen to display data sets from different ambient temperatures and the spread of data especially those that lie outside of the limits of agreement, i.e., outliers of WASO, TST and SE at 29 °C (Fig. 1F–H). Table 2 presents the differences between AW2/SWA and PSG (mean bias), and LoA from B–A plots with multiple measurements per subject. Consistent with the data presented in Table 1 and Fig. 1, WASO, TST and SE for SWA show larger mean bias and LoA at 29 °C than at 17 °C and 22 °C.

Bottom Line: A linear mixed model indicated that AW2 is valid for sleep onset latency (SOL), total sleep time (TST) and sleep efficiency (SE) but significantly overestimated wake after sleep onset (WASO) at 17 °C and 22 °C.However, at 29 °C, SWA significantly overestimated WASO and underestimated TST and SE.AW2 showed small biases for most of sleep variables at all temperature conditions, except for WASO.

View Article: PubMed Central - PubMed

Affiliation: Delta Sleep Research Unit, Exercise, Heath & Performance Research Group, Faculty of Health Sciences, The University of Sydney, Lidcombe, NSW, Australia.

ABSTRACT
There were no validation studies on portable sleep devices under different ambient temperature, thus this study evaluated the validity of wrist Actiwatch2 (AW2) or SenseWear armband (SWA) against polysomnography (PSG) in different ambient temperatures. Nine healthy young participants (6 males, aged 23.3±4.1 y) underwent nine nights of study at ambient temperature of 17 °C, 22 °C and 29 °C in random order, after an adaptation night. They wore the AW2 and SWA while being monitored for PSG simultaneously. A linear mixed model indicated that AW2 is valid for sleep onset latency (SOL), total sleep time (TST) and sleep efficiency (SE) but significantly overestimated wake after sleep onset (WASO) at 17 °C and 22 °C. SWA is valid for WASO, TST and SE at these temperatures, but severely underestimates SOL. However, at 29 °C, SWA significantly overestimated WASO and underestimated TST and SE. Bland-Altman plots showed small biases with acceptable limits of agreement (LoA) for AW2 whereas, small biases and relatively wider LoA for most sleep variables were observed in SWA. The kappa statistic showed a moderate sleep-wake epoch agreement, with a high sensitivity but poor specificity; wake detection remains suboptimal. AW2 showed small biases for most of sleep variables at all temperature conditions, except for WASO. SWA is reliable for measures of TST, WASO and SE at 17-22 °C but not at 29 °C, and SOL approximates that of PSG only at 29 °C, thus caution is needed when monitoring sleep at different temperatures, especially in home sleep studies, in which temperature conditions are more variable.

No MeSH data available.