By Anind K. Dey, Carnegie Mellon University, Embedded Assessment Principal Investigator.
In our project, we are focused on sensing activities of daily living from which we want to create measures of observations of daily living. One of the activities we are trying to sense is how well our subjects take their medicine. This involves almost every stage of the process:
- picking up the pillbox
- opening the appropriate slot for the current day of the week
- taking the pills out of the slot
- getting some water
- using the water
We are interested in the quality of the performance of each of these activities. However, it should be pretty obvious that the one thing missing from the list and that we can't sense without using invasive video (which our subjects would not accept) is whether the pills are actually consumed. In searching for a solution, we have discovered some very interesting technologies. While they aren’t available today, one day, in the not-too-distant future...
Proteus Biomedical makes smart pills that are powered by the stomach's gastric juices. Once powered, a digestible microchip embedded inside a pill reports out an id. The id is picked up by a microelectronic receiver that is worn as a skin patch or implanted under the skin. The receiver can then send the information out to a cell phone.
Researchers at the University of Florida have developed a similar system using pills with a microchip and antenna, and created the company eTect. The antenna receives energy from a transmitter worn, say on a wrist, and sends it's unique id, along with data collected from the microchip like the time and the type of pill that was ingested. The transmitter can then communicate that out to an external device for recording.
Researchers at Georgia Tech have developed MagneTrace, a necklace that measures the strength of the magnetic field in the neck area. In this system, tiny magnets are embedded in pills, and when a pill is swallowed and travels down the esophagus, the necklace measures the change in the magnetic field and determines which type of pill was swallowed and how many. The necklace then sends that information to a smart phone or nearby computer. An alternative form factor for the sensing device is a simple patch. It was 94% effective at correctly detecting the magnets in a lab evaluation.
Very cool technology, but they will all require, arguably small but time-consuming changes in the ways that pills are manufactured. In other words, it’s exciting to follow the advances, but they won’t be available for our work. What will we do? Unfortunately, we may just have to skip that aspect of pill taking, as we don't have a solid technology with which to track actual pill ingestion.
