Table 5.

Activity features extracted from sensor data.

Article	Features Extracted
Goonawardene et al., 2017 [26]	- Sleep - Going out behaviour - Toileting - Time spent in living room - Activity level in kitchen
Huynh et al., 2017 [37]	- In-home mobility patterns - Going out behaviour
Martinez et al., 2017 [27]	- Communication variables from phone - Number of incoming family calls - Average duration of incoming family calls - Number of incoming calls from friends - Average duration of outgoing calls to the family - Number of messages sent to the friends - Number of messages received from the family - Mobility variables from Bluetooth - Average time in the bedroom - Average time in the living room - Average time in the dining room - Average time in the garden - Average time in other area of the home
Austin et al., 2016 [44]	- Daily hours spent outside the home - Number of incoming and outgoing phone calls - In-home walking speed - In-home mobility - Time spent on computer - Number of sessions on computer
Lyons et al., 2015 [47]	- Time spent out of home
Petersen et al., 2015 [48]	- Number and duration of incoming and outgoing calls
Walsh et al., 2014 [45]	- Percentage of time spent in each room/location - Number of transitions between locations - Number of firings from each sensor - Total duration of activity
Petersen et al., 2013 [46]	- Time out of home - Number of sensor firings during each 5 min interval - Entry and exit events - Room from which the sensor events were recorded