Objective Measurement of Sociability and Activity: Mobile Sensing in the Community

Ethan M. Berke; Tanzeem Choudhury; Shahid Ali; Mashfiqui Rabbi

doi:10.1370/afm.1266

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Table 1.

Participant Questionnaire and Sensor Data (N=8)

Assessment	Mean (SD)	Range
CES-D = Center for Epidemiologic Studies–Depression; MCS = mental component score; PCS = physical component score; SF-36 = 36-Item Short Form Health Survey; YPAS = Yale Physical Activity Survey.
^a Scores at the start and end of the study did not differ significantly. Scores shown are from the start of the study.
^b For this activity, n = 7.
Questionnaire^a
SF-36 summary score	77.9 (16)	55–97
SF-36 PCS	68.8 (22.5)	35–92
SF-36 MCS	88.0 (10.9)	64–100
CES-D	7.2 (8.2)	0.5–25.0
YPAS, hr	22.6 (14.4)	1.0–42.5
YPAS, kcal/wk	5,980.5 (4,123.5)	180–13,155
Friendship Scale	20.8 (3.2)	14–24
Sensor
Speaking^b	20.7 (6.1)	9.6–29.1
Stationary	63.2 (5.7)	54.6–73.4
Walking level	7.1 (5.6)	2.7–18.4
Walking up	5.8 (4.9)	0.7–17.5
Walking down	8.1 (5.1)	2.1–17.5

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Table 2.

Correlations Between Questionnaire and Sensor Data

Questionnaire	Speaking^ar²(PValue)	Physical Activity Score^br²(PValue)	Walking Level^ar²(PValue)	Stationary^ar²(PValue)	Walking Up^ar²(PValue)	Walking Down^ar²(PValue)
CES-D = Center for Epidemiologic Studies–Depression; MCS = mental component score; PCS = Physical Component Score; SF-36 = 36-Item Short Form Health Survey; YPAS = Yale Physical Activity Survey.
^a Fraction of time (speaking) or percentage of time (walking, stationary) spent in this activity.
^b Weighted using the following weights: 0.6 for stationary, 3 for walking level, 5 for walking up, 1 for walking down, and −1.5 for unclassified.
SF-36 MCS	0.86 (.03)	–	–	–	–	–
CES-D	−0.75 (.08)	–	–	–	–	–
Friendship Scale	0.97 (.002)	–	–	–	–	–
YPAS hours	–	0.79 (.02)	−0.50 (.21)	−0.68 (.07)	0.80 (.02)	0.72 (.43)
YPAS kcal/week	–	0.82 (.01)	−0.52 (.18)	−0.60 (.12)	0.82 (.01)	0.65 (.08)
SF-36 PCS	–	−0.29 (.49)	0.21 (.62)	0.47 (.24)	−0.56 (.15)	0.18 (.66)

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Table 3.

Associations Between Questionnaire and Sensor Data

Questionnaire	Sensor Measure	Unadjusted β Coefficient (95% CI)	PValue	Adjusted β Coefficient (95% CI)	PValue
CES-D = Center for Epidemiologic Studies–Depression; CI = confidence interval; MCS = mental component score; PCS = physical component score; SF-36 = 36-Item Short Form Health Survey; YPAS = Yale Physical Activity Survey.
Notes: Questionnaire is the dependent variable, and sensor measure is the independent variable. Speaking, stationary, walking flat, walking up, and walking down are percentages of time spent in those activities.
^a Adjusted for age and sex.
^b Adjusted for age, sex, marital status, and pet ownership.
^c Weighted using the following weights: 0.6 for stationary, 3 for walking level, 5 for walking up, 1 for walking down, and −1.5 for unclassified.
Behavior
SF-36 MCS	Speaking	1.29 (−0.46 to 2.62)	.055	1.14 (−0.36 to 2.65)^a	.08
CES-D	Speaking	−1.14 (−2.42 to 0.13)	.07	−1.23 (−2.38 to −0.77)^a	.04
Friendship Scale	Speaking	0.58 (0.44 to 0.72)	<.001	0.49 (0.027 to 0.95)^a	.045
Physical activity
SF-36 PCS	Physical activity score^c	−0.32 (−1.27 to 0.63)	.44	0.71 (−0.60 to 2.02)^b	.14
	Stationary	1.67 (−2.06 to 5.4)	.32	−0.38 (−3.06 to 2.30)^a	.71
	Walking level	0.76 (−2.51 to 4.03)	.59	0.97 (−2.02 to 3.96)^a	.42
	Walking up	−2.31 (−4.48 to −0.13)	.04	1.68 (−7.00 to 10.36)^a	.62
	Walking down	0.73 (−2.36 to 3.81)	.59	−0.37 (−2.32 to 1.59)^a	.63
YPAS total hours	Physical activity score^c	0.57 (0.36 to 0.78)	.001	0.31 (−0.17 to 0.79)^b	.11
	Stationary	−1.57 (−2.68 to −0.47)	.01	−1.30 (−2.52 to −0.07)^a	.04
	Walking level	−1.18 (−2.46 to 0.091)	.06	−0.40 (−3.77 to 2.97)^a	.76
	Walking up	2.12 (1.06 to 3.18)	.003	5.06 (−0.31 to 10.43)^a	.06
	Walking down	1.85 (0.48 to 3.22)	.02	1.98 (0.80 to 3.16)^a	.01
YPAS kcal/week	Physical activity score^c	152.3 (97.8 to 206.8)	<.001	95.7 (50.0 to 141.4)^b	.01
	Stationary	−358.5 (−700.8 to −16.2)	.04	−230.5 (−551.9 to 90.9)^a	.12
	Walking level	−319.5 (−660.9 to 22.0)	.06	−51.3 (−791.3 to 688.7)^a	.86
	Walking up	567.9 (269.8 to 865.9)	.003	1,148.4 (263.9 to 2,032.9)^a	.02
	Walking down	431.9 (37.7 to 826.1)	.04	374.8 (31.3 to 718.3)^c	.04

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The Article in Brief

Objective Measurement of Sociability and Activity: Mobile Sensing in the Community

Ethan M. Berke , and colleagues

Background Health behavior data are often collected in laboratory settings or through surveys or self-reports, but these measures have a number of limitations. Mobile sensing of health behavior in the patient's natural environment over extended periods of time holds promise for clinicians, patients, and researchers. This study tests an automated behavioral monitoring system for sensing, recognizing, and presenting a range of physical, social, and mental indicators of well-being in natural everyday settings in older adults.

What This Study Found The study offers a provocative glimpse into the possibilities of wireless mobile technology to measure elderly patients� physical activity and social interactions and improve detection of changes in their health. Sensors on a waist-mounted wireless mobile device worn by 8 patients aged 65 years and older continuously measured patients� time spent walking level, up or down an elevation, and stationary (sitting or standing), and time spent speaking with one or more other people. Data from the mobile sensors correlated highly with results obtained using four established questionnaires. Moreover, study participants found the device easy to use, comfortable to wear, and more convenient than written questionnaires, which rely on recall and are more prone to biases.

Implications

Automated inference of behavior using commonly available mobile devices is potentially feasible and valid in older populations.
Data obtained through mobile sensing could potentially link to patients� electronic health records, providing clinicians a rich source of information that could alert them of changes in a patient�s behavior before it is identified by family or caregivers.