Brain implant succeeds in amyotrophic lateral sclerosis

Implantation with a motor neuroprosthesis, an endovascular brain-computer interface, appears to be safe in amyotrophic lateral sclerosis (ALS) patients with paralysis and helps them operate a computer for daily tasks, according to a study presented at the American Academy of Neurology’s (AAN) Annual Meeting.

All four patients who underwent the implant procedure completed the 12-month follow-up with no serious adverse events that led to disability or death, said one of the study authors Dr Bruce Campbell of the University of Melbourne in Australia and a member of the AAN.

Results from postoperative imaging showed that the device stayed in position, with the blood vessel that held the device remaining open, Campbell added.

In terms of efficacy, all patients were able to use the motor neuroprosthesis with eye tracking—a technology that determined what the patient was looking at—for routine computer use. [Campbell B, et al, AAN 2022]

Campbell and his team noted that with the help of a decoder, one patient even managed to control a computer without an eye tracker. The machine-learning decoder was programmed to analyse nerve cell signals from certain movements, such as foot tapping or knee extending, and translate these signals into computer navigation.

“People with ALS eventually lose their ability to move their limbs, making them unable to operate devices like a phone or computer,” Campbell said in a statement.

“Our research is exciting because while other devices require surgery that involves opening the skull, this brain-computer interface device is much less invasive. It receives electrical signals from the brain, allowing people to control a computer by thought,” he added.

The endovascular motor neuroprosthesis used in the study facilitates direct communication between the brain and an external device by recording and decoding signals from the precentral gyrus or the primary motor cortex, a part of the brain that controls voluntary motor movements. Unlike previous neuroprostheses, the current device removes the need for a craniotomy. The device reaches the brain by vascular access, with a catheter guiding placement in the superior sagittal sinus.

The device has 16 sensors in total and is made with a net-like material that helps it expand along the wall of the blood vessel. This device is linked to an electronic unit in the chest, which in turn translates the brain signals from the motor cortex into commands for a laptop computer.

“Our research is still new, but it holds great promise for people with paralysis who want to maintain a level of independence,” said Campbell.

Acknowledging the small sample size of the current study, Campbell shared that he and his team are already conducting further studies in larger groups of patients from Australia as well as from the United States.