A Protocol for Evaluating Digital Technology for Monitoring Sleep and Circadian Rhythms in Older People and People Living with Dementia in the Community

Abstract

Sleep and circadian rhythm disturbance are predictors of poor physical and mental health, including dementia. Long-term digital technology-enabled monitoring of sleep and circadian rhythms in the community has great potential for early diagnosis, monitoring of disease progression, and assessing the effectiveness of interventions. Before novel digital technology-based monitoring can be implemented at scale, its performance and acceptability need to be evaluated and compared to gold-standard methodology in relevant populations. Here, we describe our protocol for the evaluation of novel sleep and circadian technology which we have applied in cognitively intact older adults and are currently using in people living with dementia (PLWD). In this protocol, we test a range of technologies simultaneously at home (7-14 days) and subsequently in a clinical research facility in which gold standard methodology for assessing sleep and circadian physiology is implemented. We emphasize the importance of assessing both nocturnal and diurnal sleep (naps), valid markers of circadian physiology, and that evaluation of technology is best achieved in protocols in which sleep is mildly disturbed and in populations that are relevant to the intended use-case. We provide details on the design, implementation, challenges, and advantages of this protocol, along with examples of datasets.

Keywords: ageing; circadian; dementia; evaluation; good health; longitudinal; monitoring; sleep; technology; well-being.

Figure 1

Overview of the concept of the protocol and categories of the devices included, the data and application domain, and the study design.

Figure 2

Schematic diagram of the protocol. The people symbol indicates when the telephone pre-screening assessment was conducted. The clipboard symbol indicates completion of questionnaires, the heart symbol when vital signs were measured, and the battery symbol indicates when participants were trained to use the technology. Grey bars indicate sleep periods and white bars indicate wake periods. The black horizontal line indicates the use of wearables and nearables throughout the at-home period. The pink horizontal lines indicate when an EEG device was used at home to measure sleep physiology. The symbol of a hand using an electronic tablet indicates completion of the cognitive test battery, and the questionnaire symbol indicates completion of the sleep diary.

Figure 3

Multiple days of at-home recording (days −14 to −1) and a single overnight laboratory session (day 0) in a male participant in his 60s. The grey bars represent when the participant is out of bed and the purple and green bars represent when the participant is in bed as detected by two different ‘under the mattress’ nearable devices (Nearable 1 = Withings Sleep Analyser, WSA and Nearable 2 = EMFIT-QS, respectively). For Nearable 1, the light pink represents periods of wake, and the darker purple represents sleep; for Nearable 2, the light green represents periods of wake and the darker green represents sleep. The bed entry and bed exit times recorded on the sleep diary are represented by inverted grey and pink triangles, respectively, and the black triangle indicates estimated sleep onset according to the sleep diary. The horizontal magenta lines represent nap times recorded on the sleep diary. The blue bars represent wrist worn actigraphy with dark blue indicating sleep and light blue representing wake.

Figure 4

Hypnograms from a 10-h in-bed period in a laboratory environment in a single participant with simultaneous polysomnography, including video, and three nearable devices (Nearable 1 = Withings Sleep Analyser, Nearable 2 = EMFIT-QS, Nearable 3 = Somnofy) The black vertical dotted line depicts Lights Off and the red vertical dotted line depicts Lights On. The orange horizontal bar represents bed occupancy according to the video, with darker lines indicating when the participant left the bed. For each nearable, the discrepancy between the nearable and the PSG determined sleep is depicted at three different levels of sleep stage classification: (1) wake vs. sleep, (2) wake vs. NREM vs. REM, (3) wake vs. deep sleep vs. light sleep vs. REM. The darker coloured region indicates epochs of discrepancy. BO = bed occupancy, S = Sleep, W = wake, NR = NREM, NP = not present, REM = rapid eye movement sleep, LS = light sleep, DS = deep sleep.

Figure 5

Physiological measures during a 10 h in-bed period in a laboratory environment in a single participant with simultaneous recordings of polysomnography, including video, and from three nearable devices. The black vertical dotted line depicts Lights Off and the red vertical dotted line depicts Lights On. The orange horizontal bar represents bed occupancy according to the video, with darker lines indicating when the participant left the bed. For each nearable device, blue lines represent breathing rate and red lines represent heart rate. Within the PSG hypnogram, BO = bed occupancy, A = artefact, W = wake, R = REM sleep, N1 = stage 1 NREM sleep, N2 = stage 2 NREM sleep, N3 = stage 3 NREM sleep. Devices: Nearable 1 = Withings Sleep Analyser, Nearable 2 = EMFIT QS, Nearable 3 = Somnofy.

Figure 6

Multiple days of at-home recording (days −14 to −1) and a single overnight laboratory session (day 0) from a PLWD and their partner who share a bed. The white bars represent when the participant is out of bed and the purple and red bars represent when the participant is in bed as detected by two different nearable devices (Nearable 1 = Withings Sleep Analyser (WSA) and Nearable 2 = Somnofy, respectively). The purple bars represent an under-mattress sensor and the red bars a bedside sensor; for both, the darker shading indicates sleep and the light shading indicates wake as determined by the devices. The bed entry and bed exit times recorded on the sleep diary are represented by inverted grey and pink triangles, respectively, and the black triangle indicates estimated sleep onset according to the sleep diary.

Figure 7

Percentage error (%) in the all-night sleep measures estimates determined by four devices used in the study protocol. (Wrist-worn wearable = Actiwatch spectrum; Nearable 1 = Withings Sleep Analyser, Nearable 2 = EMFIT QS, Nearable 3 = Somnofy). (Figure adapted from: Ravindran, G.K.K.; della Monica, C.; Atzori, G.; Lambert, D.; Hassanin, H.; Revell, V.; Dijk, D.-J. Three Contactless Sleep Technologies Compared to Actigraphy and Polysomnography in a Heterogenous Group of Older Men and Women in a Model of Mild Sleep Disturbance: A Sleep Laboratory Study. JMIR mHealth and uHealth 2023, 25/08/2023:46338—(forth-coming/in press). URL: https://mhealth.jmir.org/2023/1/e46338. Licensed under Creative Commons Attribution cc-by 4.0) [40].

Figure 8

Light exposure data (plotted on a Log scale) measured over a 24 h period for one participant using three devices: a wrist-worn wearable (blue), a collarbone/lapel worn wearable (green), and a static room device (black) (where the participant spends the majority of their time). Grey shaded areas indicate sleep periods reported in the sleep diary, the vertical red dashed line is sunset, and the vertical pink dashed line is sunrise. The scatter plots indicate the relationship between the light measures obtained by the different devices.

Figure 9

Overview of data acquisition and data management. The two sides of the dotted line on the diagram represent the participant, environment, and paper documentation during the time of the study and the collection of digital representations of these, respectively, from left to right.

Figure 10

Overview of process for evaluating consumer-grade technology against standard device.