Synchron Stentrode

Learning Objectives

• Understand how the Stentrode works and why the endovascular approach is significant compared to other BCIs
• Identify the key clinical milestones and safety data from the COMMAND trial
• Evaluate the current state and realistic timeline for brain-computer interfaces reaching broad clinical availability

What Is the Synchron Stentrode?

The Stentrode is a brain-computer interface (BCI) developed by Synchron that takes a fundamentally different approach from competitors: it is implanted through blood vessels, not through open brain surgery. A physician threads the device through the jugular vein and positions it in a blood vessel adjacent to the motor cortex — the brain region responsible for movement planning. The procedure takes a median of 20 minutes and requires no craniotomy (skull opening).

Once implanted, the Stentrode detects neural signals associated with attempted movements. These signals are transmitted wirelessly to an external receiver and translated into digital commands, allowing patients with severe paralysis to control computers, smartphones, and smart home devices using their thoughts alone.

Synchron has implanted the Stentrode in approximately 10 patients globally through clinical trials. The COMMAND trial met its primary safety endpoint with zero device-related serious adverse events — a critical milestone for a device implanted near the brain. Notably, a Stentrode patient became the first BCI user to control an Apple Vision Pro and the first to use Amazon Alexa through a brain-computer interface.

Access

The Stentrode is currently available only through clinical trials. It is not approved for commercial sale in any country.

Patients interested in participating in clinical trials can visit synchron.com for eligibility information. Trials are limited to specific medical conditions (primarily ALS and severe paralysis).

Core Capabilities

Endovascular Implantation

The defining advantage of the Stentrode is the surgical approach. Traditional BCIs like Neuralink require a craniotomy — removing a section of skull and placing electrodes directly on or into brain tissue. The Stentrode avoids this entirely. A catheter is guided through the jugular vein to a blood vessel near the motor cortex, where the stent-mounted electrode array expands and integrates with the vessel wall. This is similar to the well-established stent procedure used in cardiology for decades.

The median implant time of 20 minutes and the avoidance of open brain surgery dramatically reduce surgical risk, recovery time, and the barrier to patient adoption. This approach is a key reason Synchron has been able to advance through clinical trials efficiently.

Digital Device Control

Patients with the Stentrode can control digital devices through detected neural signals. Current demonstrated capabilities include:

• Computer control: Cursor movement, clicking, typing, and web browsing
• Apple Vision Pro: First BCI patient to control Apple's spatial computing headset using thought
• Amazon Alexa: First BCI patient to operate voice-assistant devices through neural signals (without speaking)
• Smartphone operation: Texting, email, and app navigation on iOS and Android devices

Safety Profile

The COMMAND trial's primary endpoint was safety — specifically, the rate of device-related serious adverse events. The trial met this endpoint with zero such events. For a device implanted adjacent to the brain, this safety data is foundational. The endovascular approach avoids the infection risks and tissue damage associated with penetrating brain electrodes, which is a significant advantage for long-term implantation.

Strengths

• No open brain surgery: Endovascular approach eliminates craniotomy — dramatically lower surgical risk than penetrating BCIs
• Proven safety: COMMAND trial met primary safety endpoint with zero device-related serious adverse events
• Fast procedure: Median 20-minute implant time using established catheter techniques familiar to interventional neurologists
• First-mover milestones: First BCI patient to control Apple Vision Pro and first to use Amazon Alexa
• Lower adoption barrier: Patients and physicians are more likely to accept a procedure similar to cardiac stenting than open brain surgery
• Regulatory progress: Potentially the first BCI to reach FDA pivotal trial — the final stage before commercial approval

Limitations & Considerations

• Lower signal resolution: Endovascular placement reads signals through blood vessel walls — fewer electrodes and lower spatial resolution than devices placed directly on or in brain tissue
• Limited patient population: Currently only for patients with severe paralysis (primarily ALS) — not a consumer device
• Approximately 10 patients: The total implanted population is small — long-term reliability data is limited
• Not commercially available: Regulatory approval could take years depending on trial outcomes
• Motor cortex only: Current placement targets movement-related signals — broader cognitive or sensory applications are not yet addressed
• External hardware required: The implant communicates with an external receiver — the system is not fully internalized

Best Use Cases

When to consider alternatives:

• Higher signal resolution needed → Neuralink N1 or Precision Layer 7 (direct cortical placement, more electrodes)
• Non-invasive BCI → EEG-based systems (no surgery, but much lower accuracy and speed)
• Current commercial availability → No BCI is commercially available for consumers — all are investigational

Key Takeaways

• The Synchron Stentrode is implanted through blood vessels in approximately 20 minutes — no open brain surgery required — making it the least invasive BCI in clinical trials
• The COMMAND trial met its primary safety endpoint with zero device-related serious adverse events in approximately 10 patients
• Patients have demonstrated control of computers, Apple Vision Pro, and Amazon Alexa using neural signals alone
• The endovascular approach trades signal resolution for dramatically lower surgical risk, faster recovery, and greater patient acceptance — positioning Synchron as potentially the first BCI to reach FDA pivotal trial