Synchron pauses brain-implant trial enrollment over a cable performance problem

Synchron has stopped enrolling participants in trials of its second-generation brain implant after finding a performance problem in its signal cable. The company told WIRED it would upgrade the hardware before recruitment resumes. The pause interrupts studies needed to move the experimental Stentrode system toward a larger trial and eventual US marketing approval.

The pause affects enrollment, rather than representing an FDA order to stop recruitment, according to Synchron. WIRED’s Emily Mullin reported the development on November 12. Two of the five US trial sites WIRED contacted confirmed recruitment was on hold at their locations. A coordinator at one site described the pause as a check on whether the device was producing the intended readouts, not a safety issue.

Wireless control still depends on an implanted cable

Stentrode is a brain-computer interface: a system that reads brain signals and translates them into commands for digital devices. Unlike an implant placed into brain tissue, its stent-like mesh tube is introduced through the jugular vein at the base of the neck. A catheter guides it to a position over the motor cortex, the brain region involved in movement. The device does not require brain surgery.

The newer version changes how that system connects. The first-generation Stentrode used an external wire resting on the user’s chest. The second generation has fewer electrodes and connects wirelessly using Bluetooth. Synchron began its multisite US trial this spring, with sister sites in Australia and Canada evaluating the newer device. Some participants have already received it.

The earlier system had demonstrated practical uses. Ten volunteers in the US and Australia received the first-generation device and used it to send emails and texts, browse the internet, shop online and conduct banking with their thoughts. Those results concern the earlier hardware; the current enrollment pause concerns the performance of the second-generation system now being evaluated.

Wireless communication does not eliminate every cable inside the system. Synchron identified the affected component as the lead, which carries signals from the Stentrode to the implanted electronics. Its explanation places the performance problem in that connection, rather than in the Stentrode itself. The company drew a separate distinction between performance and safety:

The issue does not involve the Stentrode itself and no safety issues related to the device have been identified. The pause was a company decision, not an FDA-directed action

Synchron, in a statement to WIRED

A wider upgrade before recruitment resumes

Synchron is choosing a broader response than replacing the problematic component alone. The company told WIRED it has brought lead design and manufacturing in-house. It plans to upgrade the whole Stentrode system rather than fix only the lead, and says enrollment will resume once those hardware upgrades are complete. That makes completion of the hardware work the condition for restarting recruitment.

The studies have a specific regulatory job: helping Synchron advance to a larger pivotal trial, which is needed for Food and Drug Administration marketing approval. The device remains experimental. CEO Tom Oxley nevertheless told WIRED that Synchron retains strong confidence in Stentrode’s potential to become a first-line therapy—a statement of confidence, not an approval or a demonstrated outcome from the paused studies.

For people already living with the implants, Synchron says its support commitment continues despite the enrollment pause. The company pledged to support participants with Stentrode devices throughout their lives and said its commitment to their care and well-being remains unchanged.