The Utah Intracortical Electrode Array (UIEA) — commonly called the Utah Array — is the gold-standard implanted BCI device for human neuroscience research and clinical trials. Invented by Richard Normann at the University of Utah in the late 1980s and early 1990s, it has been in continuous human use since 2004.

Physical Design

The Utah Array consists of:

  • 96 electrodes arranged in a 10x10 grid (minus 4 corners)
  • Silicon shanks 1.0–1.5 mm long, with individual tip coatings (platinum or iridium oxide) for recording and/or stimulation
  • Pitch: 400 µm between adjacent electrodes
  • Pneumatic insertion: The array is inserted into cortex using a pneumatic inserter (slapper) in a single rapid stroke (<200 ms) to minimize dimpling and mechanical tissue damage
  • CerePort connector: A titanium pedestal (percutaneous connector) that passes through the skull and scalp, providing a wired connection to external recording systems (Cerebus, NeuroPort)

Clinical Track Record

The Utah Array is the basis for most published human intracortical BCI demonstrations:

  • 2004: First human implant (Matthew Nagle, ALS, BrainGate study)
  • 2012: Cathy Hutchinson controls robotic arm for self-feeding (Nature)
  • 2016: Ian Burkhart restores voluntary hand movement via Utah Array + functional electrical stimulation
  • 2021: 62 WPM typing by imagined handwriting (Nature, BrainGate/Stanford)
  • 2021: Wireless Utah Array BCI demonstrated

Limitations

Despite its long track record, the Utah Array has known limitations:

  • Percutaneous connector: The wired skull pedestal creates infection risk and is not cosmetically acceptable for wide clinical deployment
  • Foreign body response: Rigid silicon shanks cause ongoing tissue damage; signal quality typically degrades over 12-24 months as glial scar encapsulates electrodes
  • Electrode count: 96 channels is relatively low compared to newer approaches (Neuralink's 1,024 or Precision's 1,024-channel ECoG)
  • Stiffness mismatch: Silicon (~200 GPa) vs. brain tissue (~1 kPa) — the mechanical mismatch drives neuroinflammation

Neuralink's N1 implant directly addresses these limitations with flexible polymer threads, a wireless charging/transmission system, and 10x higher electrode count.