Wireless Intracortical Visual Prosthesis (ICVP) without intracranial cabling: Feasibility study results after 3 years

Electrical stimulation of cerebral cortex has shown promise in eliciting visual ^1-10 and somatosensory ^11-15 sensations in individuals with profound sensory deficits. So far, such devices implanted in humans have required intracranial cabling for electrodes, but tethering imposes forces on the electrodes that can damage tissue and the interface ^{16, 17} . Wireless intracortical microelectrode arrays have been proposed to both avoid these risks and simultaneously access large areas of cortex ^18-20 . The longevity of these wireless arrays and their effectiveness in human sensory stimulation, however, is unknown, particularly in dorsolateral occipital cortex. Here we show that 23/25 such devices (366/400 electrodes) implanted into a blind human function reliably over three years after implantation and improve functional vision when controlled by a camera (feasibility study, ClinicalTrials.gov: NCT04634383). Phosphenes from different arrays, concentrated near the center of vision, allowed the participant to distinguish horizontal/vertical gratings as fine as 2.4 cycles/degree. Counterintuitively, pausing camera-based stimulation during more than half of each second improved performance. Electrode properties have been largely stable throughout our first participant’s three years and our second participant’s one year with 32 arrays (512 electrodes). Our results demonstrate the feasibility of long-term wireless intracortical stimulation without intracranial cabling and approaches to improve human neuroprosthetic intracortical stimulation.