NeuroPace · Grey Matter

NeuroPace is a medical device company in Mountain View, California, founded in 1997, that makes the RNS System, the one brain stimulator approved for epilepsy that waits to detect a seizure before it stimulates, and its history is the long work of building evidence for that single device.

NeuroPace. NeuroPace is a medical device company in Mountain View, California, founded in 1997, that makes the RNS System, the one brain stimulator approved for epilepsy that waits to detect a seizure before it stimulates, and its history is the long work of building evidence for that single device.

The company was incorporated in November 1997 to develop responsive stimulation: an implant that listens to the seizure focus through electrocorticography and delivers a burst of pulses only when its detectors recognise a seizure beginning. Its pivotal trial led to approval in the United States in November 2013 for adults with drug-resistant focal epilepsy, and it listed on Nasdaq in April 2021. Because patients upload the stored recordings from home, the company and its clinicians hold years of intracranial signals recorded during ordinary life, a kind of neural data that no hospital stay produces.

Its one device is responsive neurostimulation, a neurostimulator set into the skull with up to two leads of four contacts each at the focus.

It is trying to move from focal to generalized epilepsy. The NAUTILUS trial placed a depth lead in each centromedian nucleus of the thalamus in 87 people with drug-resistant idiopathic generalized epilepsy at 23 US centres. Its primary endpoint, the time to a second tonic-clonic seizure, did not differ from sham; at 18 months the median reduction in those seizures was 77 %, and 40 % of participants had none.

The regulator asked for more. NeuroPace filed for the new indication in December 2025, and in July 2026 the FDA answered that the application was not approvable in its current form and asked for additional clinical evidence, which the company said it would supply.

NeuroPace sells a treatment that is also a recording instrument.

Every new indication has to be won with trial data, and the recordings its implants gather between clinic visits are part of what the device gives clinicians and researchers.

Questions: Why did NeuroPace put its leads in the thalamus to treat generalized epilepsy? Generalized seizures involve both hemispheres from their first second, so there is no single focus where a lead could listen and stimulate as it does in focal epilepsy. The thalamus is the relay that the whole cortex shares, and its centromedian nucleus projects widely to both hemispheres and takes part in the rhythms that spread a generalized seizure. In the NAUTILUS trial each participant received one depth lead in the centromedian nucleus of each side, so a single small device could listen to, and act on, a circuit that reaches the entire cortex. Why did NeuroPace's trial in generalized epilepsy measure tonic-clonic seizures above all? Generalized tonic-clonic seizures are the ones that injure people, and their frequency is the strongest known risk factor for sudden unexpected death in epilepsy. The NAUTILUS trial therefore took as its primary endpoint the time until a second such seizure, and on that measure stimulation did not beat sham. Counted over 18 months instead, the same seizures fell by a median of 77 % and 40 % of participants had none, which is the evidence the company has put before the US regulator, who asked for more.