It's important for dermatologists to know how itchy a person's skin is, but patients' self-assessments are often quite subjective. A new wearable sensor could help by objectively measuring the frequency and intensity of a user's itch. A team led by Akhil Padmanabha, a doctoral student at Carnegie Mellon University's Robotics Institute, invented the ring-shaped device prototype.
Padmanabha suffered from itching caused by severe eczema throughout his childhood and teenage years, so he was eager to help others with itchy skin. Like other experimental skin itch-detecting wearables before it (yes, there are others, too), Carnegie Mellon University's index-finger-worn device uses accelerometers to detect the distinct finger movements associated with itch scratching.
One thing previous sensors couldn't detect, however, was the intensity of the scratches. In other words, they cannot measure the pressure exerted by the wearer's fingers on the skin.
To obtain this data, Padmanaba equipped his device with a contact microphone. Such microphones do not record sound waves traveling through the air, so there are no privacy concerns, but they can record high-frequency vibrations of solid objects. In this case, the vibrations are generated by the fingernail moving across the skin, and the object is one of the fingers.
Microphone and accelerometer data are processed by a hardwired printed circuit board worn on the patient's forearm.
To develop the software used in the board, Padmanaba asked 20 volunteers to scratch the surface of a pressure-sensitive tablet at varying intensities while wearing the sensor on the same hand. By correlating sensor data from each scratch with pressure readings recorded by the tablet, a machine learning algorithm is able to assign each scratch an intensity rating from 0 to 10.
Even if a commercial version of this wearable device is never used by doctors, Padmanaba and colleagues hope it can be used to test anti-itch drugs or simply as a means for patients to track their own symptoms.
"I've been involved in various technology projects, but now, inspired by my own personal struggles, I wanted to focus on itch, which caused so much pain in my life," he said.
A paper on the research was recently published in the journal Communications Medicine.