Health.-Develop a wearable sensor to help patients with ALS to communicate

MADRID, 23 (EUROPA PRESS)

A team of researchers from the Massachusetts Institute of Technology (MIT) has designed a device to stretch like the skin that you can connect to the face of a patient with amyotrophic lateral sclerosis (ALS) to help them to communicate by measuring the small facial movements in patients who have lost the ability to speak.

With this system, patients would be able to communicate a variety of feelings, such as “I love You” or “I’m hungry”, with small movements that are measured and interpreted by the device, according to published in the journal ‘Nature Biomedical Engineering’.

The researchers hope that their new device will allow patients to communicate in a more natural way, without having to deal with bulky gear. The portable sensor is fixed and can camouflage with makeup to match any skin tone, which makes it discreet.

“Our devices are not only malleable, soft, disposable and lightweight, but they are also visually invisible –explains Canaan Dagdeviren, assistant professor of career development electronics LG of the Arts and Sciences of the Media in the MIT–. You can camuflarlo and no one would think that you have something in the skin”.

The researchers tested the initial version of its device in two patients with ALS (a man and a woman, for gender balance) and showed that it could precisely distinguish three different facial expressions: smile, open mouth and pursed lips.

The lab, Dagdeviren, the group of decoders conformables, specializes in the development of electronic devices conformables (flexible and stretchable) that may adhere to the body for a variety of medical applications. Interested in working on ways to help patients with neuromuscular disorders to communicate after meeting Stephen Hawking in 2016, when the physicist at Harvard University, and Dagdeviren was a junior member of the Society of Fellows of Harvard.

Hawking, who passed away in 2018, was suffering from a form of ALS slow progression. Was able to communicate using an infrared sensor that could detect twitches in his cheek, which moved a cursor through the rows and columns of letters. While it is effective, this process could take a very long time and require a computer large.

Other ALS patients used similar devices that measure the electrical activity of the nerves that control facial muscles. However, this solution also requires equipment cumbersome and not always accurate. “These devices are very hard, flat and square, and the reliability is a big problem. You may not get consistent results, even of the same patients on the same day,” said Dagdeviren.

The majority of patients with ALS also eventually lose the ability to control your limbs, so that typing is not a viable strategy to help them to communicate. The team from MIT set out to design a portable interface that patients could use to communicate in a more natural way, without the bulky equipment required by current technologies.

The device that created it consists of four piezoelectric sensors embedded in a thin film of silicone. The sensors, which are made of nitride of aluminum, can detect the mechanical deformation of the skin and convert it into an electrical voltage that can be measured easily. All of these components are easy to mass produce, so the researchers estimated that each device would cost around 10 dollars.

The researchers used a process called correlation of digital images in healthy volunteers in order to help them to select the locations most useful to place the sensor. Painted a pattern of speckles in white and black at random in the face and then took many pictures of the area with multiple cameras while the subjects performed facial movements like smiling, moving, cheek, or articulate the form of certain letters. The images were processed by software that analyzes how to move the small points together, in order to determine the amount of stress experienced in a single area.

“We had subjects who performed different movements and create maps of voltage of each part of the face –relates to the degree Rachel McIntosh–. Then we look at our maps of deformation, and determine in what part of the face we were seeing a level of deformation that is correct for our device, and we determined that this was an appropriate place to attach the device to our tests”.

The researchers also used measurements of the deformations of the skin to train an algorithm of machine learning to distinguish between a smile, mouth open and lips pursed. Using this algorithm, tested the devices with two patients with ALS and were able to achieve about a 75 percent accuracy to distinguish between these different movements. The precision rate in healthy subjects was 87 percent.

On the basis of these facial movements are detectable, you could create a library of words or phrases to correspond to different combinations of movements, the researchers say.

“We can create customizable messages based on the movements that you can do –advances Dagdeviren–. Technically, you can create thousands of messages that at this time no other technology is available to do. It all depends on the configuration of your library, which can be designed for a patient or group of patients in particular.”

The sensor information is sent to a processing unit that is portable, that analyzes it using the algorithm that the researchers trained them to distinguish between the facial movements. In the current prototype, this unit is connected to the sensor, but the connection could also be wireless for ease of use, the researchers say.

The researchers have filed a patent on this technology and now plan to try it with more patients. In addition ayudales to communicate, the device could also be used to track the progression of the disease of a patient, or to measure whether the treatments they are receiving are having some effect, say the researchers.