Table 1.

Studies on virtual coaching applied to clinical or medical contexts included in the analysis as randomized controlled trials.

Paper reference	Clinical field of application	Interface	Subjects enrolled	Subjects (n)	Testing period (in weeks, unless otherwise specified)
Allen et al 2008 [17]	Chronic conditions	Not real-time text message (email)	Chronic pain, depression, or impaired mobility	121	4
Gabriele et al 2011 [18]	Obesity in adults	Not real-time text message (email)	Healthy overweight	104	12
Martorella et al 2012 [19]	Chronic conditions	ECAa (virtual nurse)	Adults scheduled for their first cardiac surgery	60	1 day
Watson et al 2012 [20]	Obesity in adults	ECA with verbal and nonverbal communication	Healthy overweight or obese	70	12
Bickmore et al 2013 [21]	Nutrition and physical activity	ECA (computer-based)	Healthy	122	8
Bickmore et al 2013 [22]	Physical activity	ECA with verbal and nonverbal communication	Healthy elderly	263	8 (follow-up 1 year)
Wijsman et al 2013 [23]	Physical activity	Avatar	Healthy elderly	235	12
Friederichs et al 2014 [24]	Physical activity	Avatar (textual interface)	Healthy	958	8
Vroege et al 2014 [25]	Physical activity	Avatar	Healthy elderly	235	12
Broekhuizen et al 2016 [26]	Physical activity	Avatar	Healthy elderly	235	12
Leahey et al 2016 [27]	Obesity in adults	Periodic email contact	Healthy overweight	75	40
Ritchie et al 2016 [28]	Chronic conditions	Interactive voice and a dashboard for the nurse to review data	Chronic heart failure and COPD	511	12
Gardiner et al 2017 [29]	Health promotion	ECA	Healthy	61	4
King et al 2017 [30]	Physical activity	ECA (computer-based)	Healthy elderly	245	52
Cotè et al 2018 [31]	Chronic conditions	ECA (virtual nurse)	Kidney transplant patients on immunosuppressive medication	70	1 day
Hui et al 2018 [32]	Physical activity	ECA with verbal; face-to-face communication	Healthy	200	12

^aECA: embodied conversational agent.