Objective. Intracortical microstimulation (ICMS) in somatosensory cortex can restore sensation to people with spinal cord injury. However, the recording quality from implanted microelectrodes can degrade over time and limitations in stimulation longevity have been considered a potential barrier to the clinical use of ICMS. Our objective was to evaluate recording stability of intracortical electrodes implanted in the motor and somatosensory cortex of one person. The electrodes in motor cortex had platinum tips and were not stimulated, while the electrodes in somatosensory cortex had sputtered iridium oxide film (SIROF) tips and were stimulated. Additionally, we measured how well ICMS was able to evoke sensations over time. Approach. We implanted microelectrode arrays with SIROF tips in the somatosensory cortex (SIROF-sensory) of a human participant with a cervical spinal cord injury. We regularly stimulated these electrodes to evoke tactile sensations on the hand. Here, we quantify the stability of these electrodes in comparison to non-stimulated platinum electrodes implanted in the motor cortex (platinum-motor) over 1500 days with recorded signal quality and electrode impedances. Additionally, we quantify the stability of ICMS-evoked sensations using detection thresholds. Main results. We found that recording quality, as assessed by the number of electrodes with high-amplitude waveforms (>100 V peak-to-peak), peak-to-peak voltage, noise, and signal-to-noise ratio, decreased over time on SIROF-sensory and platinum-motor electrodes. However, SIROF-sensory electrodes were more likely to continue to record high-amplitude signals than platinum-motor electrodes. Interestingly, the detection thresholds for stimulus-evoked sensations decreased over time from a median of 31.5 μA at day 100–10.4 μA at day 1500, with the largest changes occurring between day 100 and 500. Significance. These results demonstrate that ICMS in human somatosensory cortex can be provided over long periods of time without deleterious effects on recording or stimulation capabilities. In fact, the sensitivity to stimulation improved over time.

客观的。体感皮层的皮层内微刺激 (ICMS) 可以恢复脊髓损伤患者的感觉。然而，植入微电极的记录质量会随着时间的推移而下降，并且刺激寿命的限制被认为是 ICMS 临床使用的潜在障碍。我们的目标是评估植入一个人的运动和体感皮层的皮层内电极的记录稳定性。运动皮层中的电极具有铂尖端并且未受到刺激，而体感皮层中的电极具有溅射的氧化铱膜（SIROF）尖端并且受到刺激。此外，我们测量了 ICMS 随着时间的推移唤起感觉的能力。方法. 我们在患有颈脊髓损伤的人类参与者的体感皮层（SIROF 感觉）中植入了带有 SIROF 尖端的微电极阵列。我们定期刺激这些电极以唤起手部的触觉。在这里，我们量化了这些电极的稳定性，与植入运动皮层（铂马达）的非刺激铂电极相比，超过 1500 天，记录了信号质量和电极阻抗。此外，我们使用检测阈值量化 ICMS 诱发感觉的稳定性。主要结果。我们发现记录质量，由具有高振幅波形的电极数量（> 100V 峰峰值）、峰峰值电压、噪声和信噪比在 SIROF 感应电极和铂马达电极上随时间降低。然而，与铂马达电极相比，SIROF 感应电极更有可能继续记录高振幅信号。有趣的是，刺激诱发感觉的检测阈值随着时间的推移从第 100 天的 31.5 μA 的中位数下降到第1500天的 10.4 μA ，其中最大的变化发生在第 100 天和第 500 天之间。意义。这些结果表明，可以长时间提供人体感觉皮层中的 ICMS，而不会对记录或刺激能力产生有害影响。事实上，对刺激的敏感性随着时间的推移而提高。