, results of a small, first-in-human study show.
A potential life changer for patients with amyotrophic lateral sclerosis (ALS), the minimally invasive device enables patients to carry out important activities of daily living.
“Our participants are able to use the device to perform tasks like sending email, texting loved ones and caregivers, browsing the web, and doing personal finances such as online banking,” study investigator Douglas J. Weber, PhD, professor of mechanical engineering and neuroscience, Carnegie Mellon University, Pittsburgh, told a press briefing.
The technology allowed one patient to write a book (due out later this year) and another patient to maintain communication despite losing his ability to speak, said the study’s lead investigator, Bruce Campbell, MBBS, PhD, professor of neurology, Royal Melbourne Hospital, University of Melbourne.
“In addition to providing patients with communicative capabilities not possible as a result of their disease, it is our goal to enable patients to be more independently involved in their care going forward, by enabling effective and faster communication directly with their caregiver and physician,” said Dr. Campbell.
The findings were presented at the 2022 annual meeting of the American Academy of Neurology.
Minimally invasive
ALS, also known as Lou Gehrig’s disease, is a progressive neurodegenerative disease that affects nerve cells in the brain and spinal cord. Patients with ALS eventually lose the ability to control muscle movement, often leading to total paralysis.
“Extending the period in which patients are able to communicate with loved ones and caregivers could provide a very meaningful benefit to patients with ALS,” said Dr. Weber.
Brain-computer interfaces measure and translate brain signals, with some functioning as motor neuro-prostheses. These devices provide direct communication between the brain and an external device by recording and decoding signals from the precentral gyrus as the result of movement intention.
“The technology has potential to empower the more than five million people in the U.S. who are severely paralyzed to once again perform important activities of daily living independently,” said Dr. Weber.
Until now, motor neuro-prostheses required surgery to remove a portion of the skull and place electrodes on to the brain. However, the new minimally invasive motor neuro-prostheses reach the brain by vascular access, dispensing with the need for a craniotomy.
“The brain-computer interface device used in our study is unique in that it does not require invasive open surgery to implant,” said Dr. Weber. “Instead this is an endovascular brain-computer interface.”
Using a catheter, surgeons feed the BCI through one of two jugular veins in the neck. They position an array of 16 sensors or electrodes on a stent-like scaffold that deploys against the walls of the superior sagittal sinus.
No adverse events
Describing the device, Dr. Weber said the electrodes or sensing elements are tiny and the body of the stent, which serves as a scaffold to support the electrodes, resembles a standard endovascular stent.
“It’s very small at the time of delivery because it’s held within the body of a catheter, but then when deployed it expands to contact the wall of the vein.”
The device transmits brain signals from the motor cortex to an electronics unit, located in a subcutaneous pocket that decodes movement signals. The machine-learning decoder is programmed as follows: When a trainer asked participants to attempt certain movements, like tapping their foot or extending their knee, the decoder analyzes nerve cell signals from those movement attempts. The decoder is able to translate movement signals into computer navigation.
The study included four patients with ALS who were paralyzed because of the disease and were trained to use the device.
A key safety endpoint was device-related serious adverse events resulting in death or increased disability during the post-implant evaluation period. Results showed all four participants successfully completed the 12-month follow-up with no serious adverse events.
Researchers also assessed target vessel patency and incidence of device migration at 3 and 12 months. Postoperative imaging showed that in all participants, the blood vessel that held the implanted device remained open and stayed in place.
Addressing the potential for blood clots, Dr. Weber said that so far there has been no sign of clotting or vascular occlusion.
“The device itself integrates well into the walls of the blood vessel over time,” he said. “Within the acute period after implantation, there’s time where the device is exposed to the blood stream, but once it becomes encapsulated and fully integrated into the blood vessel wall, the risks of thrombosis diminish.”