Table 2 Summary of sensor technologies, measured data and features used in assessment of social isolation

Motion sensor and actigraphy

Sleep metrics: total sleep time, the sum of all epochs scores as wake during the sleep interval, percent sleep

Goonawardene 2017 [33] Benson 2021 [35]

Physical activity: duration of stay time in each area at home, room-level movement, number of places where the older adult stayed, types of movement (walking, quiet standing, sitting/lying) , Time out of home

De Koning et al. [31], Martinez et al. [28], Schrempft et al. [29], Herbolsheimer et al. [32], Goonawardene et al. [33], Tully et al. [30]

Smartphone

Phone communication (via phone monitor application): number of incoming calls, number of outgoing calls, the average duration of family calls, number of calls from friends, the average duration of outgoing calls to family, average outgoing messages to friends

Martinez et al. [28]

Physiological Sensor

Resting heart rate

McCrory et al. [34]