The technology behind Eclipse NeuroTech: a minimally invasive epidural brain-computer interface
The story of every penetrating electrode.
A silicon shank, finer than a hair, is positioned above the cortical surface.
Going in destroys neurons.
Neurons die on impact. The shank ruptures the pia, tears the capillaries in its path and crushes a column of brain cells on the way down.
The brain never stops fighting back.
Material left inside brain tissue keeps the immune response active. Microglia attack the material as long as it is there. This kills more brain cells.
The device begins to come apart.
Insulation cracks. Metals corrode in warm saline. Fragments break away and stay embedded in the tissue, where nothing can retrieve them.
Until the brain seals it off.
Scar tissue closes around the shank in a dense capsule. The signal disappears along with the cells that produced it.
This is the trade the field has accepted in exchange for signal amplitude.
We stay above the membrane.
The Eclipse array rests on the outer surface of the dura mater. It is placed through a simpler procedure.
Nothing is pierced. Nothing is torn.
No insertion trauma.
No cells crushed on the way in.
No foreign material inside brain tissue.
Nothing that corrodes or flakes inside the brain.
Five years in, the recording is unchanged.
Signal quality is stable.
A decade on, the signal is still there.
Since the implant does not touch brain tissue, scar tissue does not form within the brain. The recording does not have to fight a capsule that thickens every year.
Designed to stay in place beyond a decade.
Staying outside the dura reduces signal amplitude.
An electrode placed inside brain tissue records individual neuron activity.
Above the dura, electrodes record the activity of a small group of neurons.
The activity is fainter, but rich in data.
The structure that carries meaning is still in the recording. Recovering it is a question of algorithms, features, and models.
So we spent a decade closing the gap.
Our team has worked on decoding epidural activity for more than ten years, and was the first to turn an epidural recording into synthesised speech 7.
Why we chose the epidural approach.
Cortical lesions occur in 100% of patients after placement of an intracortical brain implant 3,4. Opening the dura increases the risks of several other severe complications. Below we compare the rates for penetrating and subdural electrodes, against rates associated with an epidural surgery.
A device meant to be placed, and forgotten.
Fewer complications and secondary effects.
Fewer days at the hospital.
Fewer revision surgeries.
A more durable device.
This is what patients, clinicians, and caregivers will choose.
References7 sources
- Arya R, Mangano FT, Horn PS, Holland KD, Rose DF, Glauser TA. Adverse events related to extraoperative invasive EEG monitoring with subdural grid electrodes: a systematic review and meta-analysis. Epilepsia 2013;54(5):828–839. doi:10.1111/epi.12073. PMID 23294329.
- Coucke B, Van Gerven L, De Vleeschouwer S, Van Calenbergh F, van Loon J, Theys T. The incidence of postoperative cerebrospinal fluid leakage after elective cranial surgery: a systematic review. Neurosurgical Review 2022;45(3):1827–1845. doi:10.1007/s10143-021-01641-y. PMID 34499261. Corrected version; erratum Neurosurg Rev 2022;45(3):2501, doi:10.1007/s10143-022-01797-1.
- Biran R, Martin DC, Tresco PA. Neuronal cell loss accompanies the brain tissue response to chronically implanted silicon microelectrode arrays. Experimental Neurology 2005;195(1):115–126. PMID 16045910.
- Szymanski LJ, Kellis S, Liu CY, et al. Neuropathological effects of chronically implanted, intracortical microelectrodes in a tetraplegic patient. J Neural Eng 2021;18(4):0460b9. doi:10.1088/1741-2552/ac127e
- Barrese JC, Rao N, Paroo K, et al. Failure mode analysis of silicon-based intracortical microelectrode arrays in non-human primates. J Neural Eng 2013;10(6):066014. doi:10.1088/1741-2560/10/6/066014
- Branco MP, Geukes SH, Aarnoutse EJ, Ramsey NF, Vansteensel MJ. Nine decades of electrocorticography: a comparison between epidural and subdural recordings. Eur J Neurosci 2023;57(8):1260–1288. doi:10.1111/ejn.15941
- Ticha MB, Ran X, Yvert B., et al., Neural Decoding of Overt Speech from ECoG Using Vision Transformers and Contrastive Representation Learning. preprint arXiv:2512.04618. arXiv 2025 Dec 4. https://arxiv.org/abs/2512.04618
Figures marked modelled are derived from extradural neurosurgeries, no published cohort of epidural brain computer interfaces reports these endpoints.
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