Project works on restoring speech for stroke patients

A five-year project aims to develop a device that brings back speech functions to people rendered speechless through stroke or other conditions.

Alexander Leonessa, a Virginia Tech College of Engineering researcher, wants to help restore the voice of stroke patients and others who have suffered paralysis of the vocal folds through electrical stimulation.

Leonessa is developing a small device that could use functional electrical stimulation on the paralysed vocal folds of stroke patients or others who have lost the ability to talk, or swallow and breathe properly.

‘The device has the potential of improving the quality of life for patients with vocal paralysis, or neuromuscular disabilities, including traumatic brain injury, multiple sclerosis, cerebral palsy and Parkinson’s disease,’ he said.

Electrical stimulation on muscles is regularly used on legs and arms to prevent muscle atrophy. If the brain can no longer send electrical impulses to move a limb, the muscles and nerves can die off from disuse.

Doctors use an external electrical appendage placed on the exterior skin to provide a small electrical shock that can cause the muscle to contract. The practice exercises the muscles and can save the leg or arm.

Leonessa said that applying the same method to vocal folds can result in re-innervating the muscle, which also affects breathing and swallowing and other functions.

During the study, Leonessa and his research team will work with doctors at the Center for Voice and Swallowing Disorders, part of Wake Forrest University’s Baptist Medical Center in North Carolina. There, patients with paralysed vocal folds will undergo electrical stimulation tests to see if small shocks can reinvigorate their ability to talk through forced contraction.

Leonessa plans to develop a portable, non-invasive device that can be adjusted to each patient. The device itself would be no larger than an iPod, clipped to the belt, and have small wires leading to a patch over the patient’s throat. An Atlanta-based tech company will help develop the device, which will come later in the study if the use of electrical stimulation on the vocal folds holds promise for muscle and nerve rejuvenation.

‘Breathing and swallowing have received much attention for patients with vocal fold paralysis, but vocalisation is still considered an open problem with unresolved issues due to the complexity of the larynx and the difficulties in stimulating the relevant muscles, without invasive surgeries, given their depth in the neck,’ said Leonessa.

‘The proposed development of a robust control strategy in co-operation with voice-driven data acquisition and a novel electrode array for stimulation purposes will provide a solution to these issues.’