In a move that could give a voice to the 300,000 people around the world who have had their larynx removed due to cancer, scientists at the MARCS Institute at Western Sydney University have tested a non-invasive artificial larynx and found it capable of generating a high-quality voice. Unlike existing prosthetics that rely on input from the nerves or muscles of the larynx, the Pneumatic Artificial Larynx (PAL) device uses the patient's respiratory system and doesn't need to be surgically implanted.
"The existing standard of care requires the surgical application of prosthetic devices into the open wound in the neck, known as the 'stoma', which is left after a laryngectomy so that a patient can breathe," says Postdoctoral Research Fellow, Dr Farzaneh Ahmadi. "The surgery is invasive; infections and complications are common; and the resulting voice is often hoarse and whispery."
In a pre-clinical trial, researchers working on The Bionic Voice research project developed an electronic adaption of a PAL device called the Pneumatic Bionic Voice (PBV), which uses the patient's breath to create a humming sound that is then converted to speech with movement of the lips and tongue. The study found that a device exclusively driven by respiration could in fact aid in recreating the function of the larynx without any nerve input and produce a quality of voice better than the existing gold standard.
The device tested features a tube that goes from the stoma to the mouth and is cumbersome, as can be seen in the above image. However, the team has plans to develop a functional PBV prosthesis in the form of a "control unit" that can be applied over the stoma, and a "voice source" unit that sits on the roof of the mouth. Dr Ahmadi claims this device would be the first non-invasive, non-surgical, electronic voice prosthesis in the world and would be capable of producing more human-sounding speech than current devices.
A paper detailing the results of the pre-clinical trial appear in PLOS ONE, and Dr Ahmadi discusses the PBV in the video below.
Source: Western Sydney University