Brain Implant Helps Patients With ALS Paralysis Use Computers

A surgically implanted brain-computer interface (BCI) has made it possible for patients with severe paralysis to independently perform essential tasks, including online banking, shopping, and emailing.

The four patients in the safety and feasibility Stentrode with Thought-Controlled Digital Switch (SWITCH) study had severe bilateral upper limb paralysis caused by amyotrophic lateral sclerosis (ALS) and primary lateral sclerosis (PLS).

The stent-electrode device, called the Stentrode BCI, is made of a net-like material that holds 16 electrodes. It was inserted via a catheter into the jugular vein and navigated to the superior sagittal sinus (SSS), adjacent to the primary motor cortex. Once it was in place, investigators expanded the material so that it lay flush against the walls of the SSS.

A wire connects the electrodes to a small electronic device in the chest, which then decodes and wirelessly transmits conscious thoughts to the computer.

Dr Peter Mitchell

Co-principal investigator Peter Mitchell, MBBS, MMed, director of neurointervention at Royal Melbourne Hospital, Australia, told Medscape Medical News he was pleased with the results of this first-in-human clinical study of an endovascular BCI.

“The patients tolerated the procedure well and were typically discharged home within 48 hours,” said Mitchell, who performed the procedure along with his team at the Royal Melbourne Hospital.

The findings were published online January 9 in JAMA Neurology.

Over 90% Accuracy

All four study participants (mean age, 61 years) were men, of self-reported European ancestry, and had severe upper limb paralysis from ALS (n = 3) or PLS (n = 1)

After the insertion procedure, and with at-home training and aid from a home caregiver who was also trained in the study protocol, the patients used eye tracking to move the computer cursor to complete certain tasks, including composing a text message or an email.

Patients with severe paralysis using the Stentrode BCI can use their thoughts to control a digital device system.

Results showed the patients controlled the system with a mean accuracy of 94%.

They used the BCI and eye-tracking system not only to compose emails and text messages, according to the report, but to shop online and perform online banking tasks.

Mitchell and his team followed the patients for 12 months after the implant and noted that there were no serious adverse events (AEs) — and the device did not migrate from its original placement. Non-serious AEs included headache and bruising at the incision site, but these were resolved without further complaint.

Next steps must involve expanding the safety study into additional sites, such as the United States, and “extending into larger studies with efficacy as primary endpoints to prove functional utility,” Mitchell said.

Cautiously Optimistic

Commenting for Medscape Medical News, Sergey Stavisky, PhD, assistant professor, Department of Neurological Surgery, University of California Davis in Sacramento, said it is exciting “that after decades of brain-computer interface research being pioneered almost exclusively by academic labs, first in preclinical animal models and then in pilot clinical trials, the field has now matured to the point that multiple start-ups designing new electrodes and conducting early safety trials like this one.”

Dr Sergey Stavisky

Stavisky, who was not involved with the research, said he predicts that the mechanism used with the Stentrode BCI “has an excellent chance of working in other patient populations. The beauty of a brain-computer interface is that it records the movement intention at the source — here, that’s from the motor cortex — and thus upstream of the site of neurological damage across many different conditions.”

So, for example, this should work in patients who are paralyzed from subcortical stroke, Stavisky noted. “Indeed, other BCI studies have shown impressive results in that patient population.”

“There’s an urgent and unmet need for ways to restore lost communication and I’m cautiously optimistic that these recent industry investments will lead to medical devices that will start to meet this need,” Stavisky said.

The study was funded by Synchron, maker of the Stentrode BCI. Mitchell reports receiving institutional research support from Stryker Neurovascular and Medtronic outside the submitted work. Disclosures for the other investigators are fully listed in the original article. Stavisky reports no relevant financial relationships.

JAMA Neurology. Published online January 9, 2022. Abstract

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