Objective. The evaluation of the long-term stability of ElectroCorticoGram (ECoG) signals is an important scientific question as new implantable recording devices can be used for medical purposes such as Brain-Computer Interface (BCI) or brain monitoring. Approach. The long-term clinical validation of wireless implantable multi-channel acquisition system for generic interface with neurons (WIMAGINE), a wireless 64-channel epidural ECoG recorder was investigated. The WIMAGINE device was implanted in two quadriplegic patients within the context of a BCI protocol. This study focused on the ECoG signal stability in two patients bilaterally implanted in June 2017 (P1) and in November 2019 (P2). Methods. The ECoG signal was recorded at rest prior to each BCI session resulting in a 32 month and in a 14 month follow-up for P1 and P2 respectively. State-of-the-art signal evaluation metrics such as root mean square (RMS), the band power (BP), the signal to noise ratio (SNR), the effective bandwidth (EBW) and the spectral edge frequency (SEF) were used to evaluate stability of signal over the implantation time course. The time-frequency maps obtained from task-related motor activations were also studied to investigate the long-term selectivity of the electrodes. Main results. Based on temporal linear regressions, we report a limited decrease of the signal average level (RMS), spectral distribution (BP) and SNR, and a remarkable steadiness of the EBW and SEF. Time-frequency maps obtained during motor imagery, showed a high level of discrimination 1 month after surgery and also after 2 years. Conclusions. The WIMAGINE epidural device showed high stability over time. The signal evaluation metrics of two quadriplegic patients during 32 months and 14 months respectively provide strong evidence that this wireless implant is well-suited for long-term ECoG recording. Significance. These findings are relevant for the future of implantable BCIs, and could benefit other patients with spinal cord injury, amyotrophic lateral sclerosis, neuromuscular diseases or drug-resistant epilepsy.

客观的。评估皮层电图 (ECoG) 信号的长期稳定性是一个重要的科学问题，因为新的可植入记录设备可用于医疗目的，例如脑机接口 (BCI) 或大脑监测。方法。对用于神经元通用接口的无线植入式多通道采集系统 (WIMAGINE) 的长期临床验证进行了研究，该系统是一种无线 64 通道硬膜外 ECoG 记录器。在 BCI 协议的背景下，WIMAGINE 设备被植入到两名四肢瘫痪患者身上。本研究侧重于 2017 年 6 月（P1）和 2019 年 11 月（P2）双侧植入的两名患者的 ECoG 信号稳定性。方法. ECoG 信号在每次 BCI 会话之前在休息时记录，分别导致 P1 和 P2 的 32 个月和 14 个月的随访。最先进的信号评估指标，例如均方根 (RMS)、频带功率 (BP)、信噪比 (SNR)、有效带宽 (EBW) 和频谱边缘频率 (SEF)用于评估植入时间过程中信号的稳定性。还研究了从与任务相关的运动激活中获得的时间-频率图，以研究电极的长期选择性。主要 结果。基于时间线性回归，我们报告了信号平均电平 (RMS)、频谱分布 (BP) 和 SNR 的有限下降，以及 EBW 和 SEF 的显着稳定性。在运动想象中获得的时频图在手术后 1 个月和 2 年后显示出高度的辨别力。结论。随着时间的推移，WIMAGINE 硬膜外装置显示出高稳定性。分别在 32 个月和 14 个月内对两名四肢瘫痪患者的信号评估指标提供了强有力的证据，证明这种无线植入物非常适合长期 ECoG 记录。意义。 这些发现与植入式脑机接口的未来相关，并可能使其他脊髓损伤、肌萎缩侧索硬化、神经肌肉疾病或耐药性癫痫患者受益。