Fluid Intake Monitoring Systems for the Elderly: A Review of the Literature

Abstract

Fluid intake monitoring is an essential component in preventing dehydration and overhydration, especially for the senior population. Numerous critical health problems are associated with poor or excessive drinking such as swelling of the brain and heart failure. Real-time systems for monitoring fluid intake will not only measure the exact amount consumed by the users, but could also motivate people to maintain a healthy lifestyle by providing feedback to encourage them to hydrate regularly throughout the day. This paper reviews the most recent solutions to automatic fluid intake monitoring both commercially and in the literature. The available technologies are divided into four categories: wearables, surfaces with embedded sensors, vision- and environmental-based solutions, and smart containers. A detailed performance evaluation was carried out considering detection accuracy, usability and availability. It was observed that the most promising results came from studies that used data fusion from multiple technologies, compared to using an individual technology. The areas that need further research and the challenges for each category are discussed in detail.

Keywords: drinking monitoring; fluid intake detection; hydration monitoring; liquid intake.

Figure 1

Number of articles reviewed per year.

Figure 2

Images of the four reviewed categories including (a) wearables, (b) surface-based sensors, (c) vision and environmental based, and (d) smart containers.

Figure 3

Breakdown of liquid intake monitoring approaches based on the technology used. Orange represents wearables, purple is fusion, green is smart containers, blue is surfaces with embedded sensors, and gray is vision- and environmental-based approaches.

Figure 4

Schematic diagram of various sensor layouts for each smart container category, namely (a) inertial [120,121,122,123,124], (b) load and pressure [125], (c) capacitive [126], (d) conductive [127], (e) Wi-Fi [128], (f) vibration [129], (g) acoustic [130], (h) and other level sensor [131].

Figure 5

Images of analyzed commercial bottles: (a) HidrateSpark 3 [153], (b) Hidrate Spark Steel [154], (c) H2OPal [132], (d) Thermos Smart Lid [155], (e) Ozmo Active [156], (f) DrinkUp [158], (g) HydraCoach [159], and (h) Droplet Tumbler [160].