This chapter is concerned with the use of unobtrusive wearable devices for monitoring health. In this section we define what is meant by an unobtrusive wearable and explain why the criterion of unobtrusiveness is important.
What Is an Unobtrusive Wearable?
A wearable device is one that is designed to be worn on the body by the user, with the implicit assumption that it can be removed easily. This is in contrast to devices that would be considered implantable, such as an intravascular glucose sensor and insulin pump proposed by Renard (2002), or otherwise attachable such as tattoo sensors, as used by Rakibet et al.(2014).
An unobtrusive wearable device is one that blends seamlessly with the user’s day-to-day life and does not make its presence unduly known. This can be achieved through small size, careful design or by masquerading as an every-day object.
Unobtrusive wearable devices do not intrude upon the wearer, through either form or function. That is to say, that the device will be small enough and light enough to not be a physical burden, and attractively designed such that the user is not made socially uncomfortable wearing it. This is sometimes achieved, or enhanced, by adding a ‘secondary’ function to the device that the user finds desirable, a watch screen in the case of a wrist wearable for example.
The function of the device will also not intrude upon the user, with the caveat that this is not always possible to achieve depending on the exact use of the device. In general however, the device will not need the user to interact with it overly much and those interactions will be quick and easy for the user to carry out.
For longitudinal monitoring, the concept of unobtrusiveness is extended to include the long term considerations of the user. The device must be easy to put on and take off and comfortable to wear for extended periods. If it designed to be worn through the night it must not interfere with the user’s sleep – devices which do are quickly put aside.