Wearable gives stroke survivors their voice back

 For dysarthia, not aphasia.

Wearable gives stroke survivors their voice back

A new wearable device named could help stroke survivors communicate, offering speech support without implants.

The device, called Revoice, uses ultra-sensitive sensors and artificial intelligence to decode speech signals and emotional cues so people with post-stroke speech impairment can communicate.

Worn as a soft, flexible choker, it captures heart rate and tiny vibrations from throat muscles, using those signals to reconstruct intended words and sentences in real time.

The development was led by researchers at the University of Cambridge.

Luigi Occhipinti is professor in Cambridge’s Department of Engineering and led the research.

He said: “When people have dysarthria following a stroke, it can be extremely frustrating for them, because they know exactly what they want to say, but physically struggle to say it, because the signals between their brain and their throat have been scrambled by the stroke.

“That frustration can be profound, not just for the patients, but for their caregivers and families as well.”

The signals from the device are processed by two AI agents: one reconstructs words from fragments of silently mouthed speech, while the other interprets emotional state and context, such as time of day or weather, to expand short phrases into full sentences.

In a small trial with five patients with dysarthria, a common post-stroke speech impairment affecting the muscles used for speaking, the device achieved a word error rate of 4.2 per cent and a sentence error rate of 2.9 per cent.

Unlike existing assistive speech technologies, which often require slow letter-by-letter input, eye tracking or brain implants, the Revoice device is claimed to provide seamless real time communication, turning a few mouthed words into full sentences.

The researchers say the technology could aid stroke rehabilitation and could also support people with conditions such as Parkinson’s and motor neurone disease.

They are planning a clinical study in Cambridge for native English-speaking dysarthria patients to assess viability, which they hope to launch this year.

About half of people develop dysarthria, or dysarthria in combination with aphasia, following a stroke.

Dysarthria is a physical condition that weakens the muscles of the face, mouth and vocal cords. Aphasia affects the ability to understand or produce language.

Dysarthria affects people in different ways and can cause unclear, slurred or slow speech, or short, disjointed bursts rather than full sentences.

Most stroke patients with dysarthria work with a speech therapist to regain their ability to communicate, primarily through repetitive word drills, where patients repeat words or phrases back to the speech therapist.

Typical recovery time varies from a few months to a year or more.

Occhipinti said: “Patients can generally perform the repetitive drills after some practice, but they often struggle with open-ended questions and everyday conversation.

“And as many patients do recover most or all of their speech eventually, there is not a need for invasive brain implants, but there is a strong need for speech solutions that are more intuitive and portable.”

The sensors in the Revoice device capture subtle vibrations from the throat to detect speech signals and decode emotional states from pulse signals.

The device also uses an embedded lightweight large language model, a type of AI system, to predict full sentences, so it uses minimal power.

Working with colleagues in China, the researchers carried out a small trial with five stroke patients with dysarthria, as well as 10 healthy controls.

In the study, participants wore the device and mouthed short phrases.

By nodding twice, they could choose to expand those phrases into sentences using the embedded large language model.

Participants reported a 55 per cent increase in satisfaction, suggesting the device could help stroke patients regain their ability to communicate.

Although extensive clinical trials will be required before the device can be made widely available, the researchers hope future versions will include multilingual capabilities, a broader range of emotional states and fully self-contained operation for everyday use.

Occhipinti said: “This is about giving people their independence back. Communication is fundamental to dignity and recovery.”