Utah array
Also: Utah electrode array, UEA, Utah microelectrode array, Blackrock microelectrode array
By neuraspeak editorial · Updated 2026-10-07 · 1 min read
The Utah array is a small, square grid of silicon microneedle electrodes, about 4 mm across, that is implanted into the surface of the cortex to record the electrical activity of individual neurons or small groups of neurons.
What does a Utah array look like?
The classic version is a 10 by 10 grid of 100 needle-shaped electrodes spaced 400 micrometers apart, each about 1.5 mm long, with a recording site at the tip. That geometry gives a footprint of roughly 4 by 4 mm, smaller than a fingernail. Versions with different electrode counts exist: the 2006 BrainGate study used a 96-electrode array (Hochberg et al., Nature), while recent speech studies used arrays of 64 electrodes in an 8 by 8 grid (Willett et al., Nature 2023; Card et al., NEJM 2024). The array was developed at the University of Utah and is manufactured by Blackrock Neurotech. A wire bundle connects it to a connector mounted on the skull.
How long does a Utah array keep working?
Recording quality typically declines over time as tissue forms around the electrodes and materials degrade. A 2021 analysis of 55 Utah arrays in 17 monkeys and 2 people found an average recording lifespan of 622 days, with several arrays lasting more than 1,000 days and one about nine years; human implants tended to last longer than those in monkeys (Sponheim et al., Journal of Neural Engineering). Longevity varies widely between individuals and arrays.
Why it matters for speech BCI
The Utah array is the sensor behind several of the fastest published speech neuroprostheses. Willett et al. (Nature 2023) used four 64-electrode arrays in a participant with ALS and decoded speech at 62 words per minute; the two arrays in ventral premotor cortex (area 6v) carried the useful information, while the two in area 44, part of Broca's area, carried little. Card et al. (NEJM 2024) used four arrays totaling 256 electrodes in the precentral gyrus and reported 97.5% word accuracy over 8.4 months. Because it records from small groups of neurons, it captures fine detail about intended articulator movements.
Questions
Is the Utah array FDA approved?+
The Utah array has been used in humans in research under investigational device rules. It is not an approved commercial BCI product for restoring communication, and its human BCI use to date has been within clinical trials.
Why do speech BCIs use several Utah arrays?+
Each array covers only about 16 square millimeters. Speech involves coordinated control of the lips, tongue, jaw, and larynx, so researchers place multiple arrays to sample more of the relevant cortex.
Related: EEG vs intracortical recordingSpike sortingElectrocorticography (ECoG)Neural signal driftSpeech neuroprosthesis
Sources
- Hochberg et al., Neuronal ensemble control of prosthetic devices by a human with tetraplegia, Nature 442, 164-171 · 2006
- Willett et al., A high-performance speech neuroprosthesis, Nature 620, 1031-1036 · 2023
- Card et al., An Accurate and Rapidly Calibrating Speech Neuroprosthesis, New England Journal of Medicine 391, 609-618 · 2024
- Sponheim et al., Longevity and reliability of chronic unit recordings using the Utah, intracortical multi-electrode arrays, Journal of Neural Engineering · 2021
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