While it's important for dermatologists to know just how itchy a person's skin is, patients' self-assessments tend to be quite subjective. A new wearable sensor could help, by objectively measuring the frequency and intensity of its user's scratching sessions.
The prototype ring-style device was invented by a team led by Akhil Padmanabha, who is a PhD student in Carnegie Mellon University's Robotics Institute. Throughout his childhood and adolescence, Padmanabha suffered from itchiness caused by severe eczema, so he was very motivated to help other people with itchy skin.
Like other experimental skin-scratch-detecting wearables before it (yes, there have been others), the index-finger-worn Carnegie Mellon device utilizes an accelerometer to detect the telltale finger movements associated with itch-scratching.
One thing those previous sensors couldn't detect, however, was the intensity of the scratches. In other words, they weren't able to measure the pressure that the wearers' fingers were exerting on their skin.
In order to capture that data, Padmanabha equipped his device with a contact microphone. Such microphones don't record sound waves traveling through the air – so there are no privacy concerns – but they do record high-frequency vibrations traveling through solid objects. In this case, the vibrations are produced by the fingernails moving across the skin, and the object is one of those fingers.
The microphone and accelerometer data is processed by a hardwired printed circuit board worn on the patient's forearm.
To develop the software used by that board, Padmanabha had 20 volunteers scratch the surface of a pressure-sensitive tablet – at various intensities – while wearing the sensor on that same hand. By correlating the sensor data for each scratch with the pressure readings recorded by the tablet, a machine learning algorithm was able to assign each scratch an intensity rating from 0 to 10.
Even if a commercial version of the wearable is never utilized by physicians, Padmanabha and colleagues hope that it may find use in the testing of itch-reducing medications, or simply as a means of allowing patients to track their own symptoms.
"I've worked on various technical projects," he said, "but now, inspired by my personal struggles, I hope to target this thing – itching – that has caused so much suffering in my life."
A paper on the research was recently published in the journal Communications Medicine.
Source: Carnegie Mellon University
