Monitoring Pill Popping

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Ghovanloo says that the device can't be tricked because the algorithms it uses are smart enough to only look for the pill as it passes through the esophagus (and hence through the ring of sensors), rather than just looking somewhere in the vicinity of the sensors.

"We wanted it to be very difficult to cheat," says Ghovanloo. He and Huo have also designed a MagneTrace patch for patients who would rather not wear a necklace.

To test the device, the researchers constructed an artificial neck. They used a length of PVC pipe about the same diameter as an adult neck, packed it with plastic drinking straws, and wrapped the necklace around the pipe. By repeatedly passing a magnetized pill through it at different orientations, they were able to figure out how many sensors were needed to track it, and to refine the algorithm. In tests, the MagneTrace necklace was 94 percent correct in detecting magnets passed through the artificial esophagus, and it produced about 6 percent false positives when pills were passed through areas outside the detection zone.

"We believe we can improve on that," Ghovanloo says.

He feels that MagneTrace could be a boon in clinical trials, which generally rely on patients' own records of their drug compliance, which may not be accurate, and for elderly patients who are forgetful or confused. MagneTrace could also ensure drug compliance in people who have been ordered to take medication for a contagious disease, Ghovanloo says, or a serious psychiatric disorder.

It could also help patients who are reluctant to take the drugs they need because of their unpleasant side effects, or who aren't well educated and hence "don't have the understanding of why they have to take medication at a certain time, or why they can't skip a dose," says Patrice Slojkowski, an informatics nurse at the University of California, San Diego Medical Center. There, a bar-coding system is used to ensure that inpatients are given the correct medication by nurses, and it also records when drugs are administered.

"I think something like this is probably going to be really effective," Slojkowski says.

"It would be great," says Olga Klibanov, a clinical assistant professor in the Temple University School of Pharmacy, who works with inner-city HIV/AIDS patients. Some of them don't really understand the disease or treatment, or have alcohol or drug problems that make them less likely to follow a drug regime. Currently, Klibanov tries to tackle the problem by educating her patients and setting alarms on their watches or cell phones to remind them to take their medication.