Breaking the Silence

Communication difficulties stemming from strokes and other medical conditions can significantly impact people's ability to express themselves, comprehend language, and engage in social interactions. Strokes, which occur when blood flow to the brain is interrupted, often result in aphasia, a language disorder that affects speech and comprehension. Other conditions such as traumatic brain injury, dementia, and degenerative neurological disorders like Parkinson's disease can also lead to communication impairments.

Millions of people worldwide experience some form of communication difficulty due to medical conditions. Aphasia alone affects at least two million Americans, according to the National Aphasia Association. These challenges can profoundly affect individuals' personal and professional lives, leading to frustration, isolation, and a loss of confidence.

Assistive technologies play a crucial role in eliminating communication barriers for individuals with these conditions. However, despite their utility, these assistive technologies have shortcomings that limit their effectiveness. Using these devices can be challenging for users with motor impairments or cognitive deficits, and they often lack the precision necessary for people to fully express their thoughts. Furthermore, the cost of high-quality assistive technologies can be prohibitive for some individuals, limiting access to those who need them most.

A small team led by a researcher at the Beijing Normal University have taken on the challenge of building an accessible and practical assistive device to help those with difficulty communicating. Built from simple components, their wearable patch is designed to adhere to the skin like a sticker. It is comfortable for long-term use, and has been shown to be very accurate in detecting hand gestures, mouth movements, and more.

The flexible patch is made from a soft material called polydimethylsiloxane (PDMS), a clear, non-toxic, silicone polymer that is considered safe for human use. Tiny optical fibers are embedded within the PDMS, and each fiber is etched with a fiber Bragg grating, which is a type of reflector that changes the way light travels through the fiber. As the sticker is deformed by body movements, the pattern of light traveling through the fibers is also changed. By analyzing these changes, the team showed that they could recognize specific body movements.

When the device is initially attached to a new individual, or a different part of the body, a calibration process involving an inertial measurement unit and a series of body movements must be performed. This is necessary to account for differences between people and also for differences in positioning of the sticker on the body.

Some small-scale studies were conducted to assess how well the device works for different use cases. These experiments demonstrated that the sticker can accurately capture information about, for example, the position of the wrist or the fingers. Using this capability, the researchers showed that a wearer of the device could use it for communication by tapping out letters with their finger in Morse code. More complex hand gestures could also be recognized, which might be utilized in human-computer interactions.

As a next step, the team plans to refine their device by making it smaller and by integrating the processing components into the sticker itself. These updates would go a long way towards making the system practical for real-world use. They also intend to spend some time integrating the device with other electronics, like smartphones, computers, and medical devices.