Data_Sheet_1_Long-Term Sheep Implantation of WIMAGINE®, a Wireless 64-Channel Electrocorticogram Recorder.docx

This article deals with the long-term preclinical validation of WIMAGINE® (Wireless Implantable Multi-channel Acquisition system for Generic Interface with Neurons), a 64-channel wireless implantable recorder that measures the electrical activity at the cortical surface (electrocorticography, ECoG). The WIMAGINE® implant was designed for chronic wireless neuronal signal acquisition, to be used e.g., as an intracranial Brain–Computer Interface (BCI) for severely motor-impaired patients. Due to the size and shape of WIMAGINE®, sheep appeared to be the best animal model on which to carry out long-term in vivo validation. The devices were implanted in two sheep for a follow-up period of 10 months, including idle state cortical recordings and Somato-Sensory Evoked Potential (SSEP) sessions. ECoG and SSEP demonstrated relatively stable behavior during the 10-month observation period. Information recorded from the SensoriMotor Cortex (SMC) showed an SSEP phase reversal, indicating the cortical site of the sensorimotor activity was retained after 10 months of contact. Based on weekly recordings of raw ECoG signals, the effective bandwidth was in the range of 230 Hz for both animals and remarkably stable over time, meaning preservation of the high frequency bands valuable for decoding of the brain activity using BCIs. The power spectral density (in dB/Hz), on a log scale, was of the order of 2.2, –4.5 and –18 for the frequency bands (10–40), (40–100), and (100–200) Hz, respectively. The outcome of this preclinical work is the first long-term in vivo validation of the WIMAGINE® implant, highlighting its ability to record the brain electrical activity through the dura mater and to send wireless digitized data to the external base station. Apart from local adhesion of the dura to the skull, the neurosurgeon did not face any difficulty in the implantation of the WIMAGINE® device and post-mortem analysis of the brain revealed no side effect related to the implantation. We also report on the reliability of the system; including the implantable device, the antennas module and the external base station.

本文探讨了WIMAGINE®（通用神经元接口的无源植入式多通道采集系统）的长期临床前验证，WIMAGINE®是一种64通道的无源植入式记录器，用于测量皮层表面的电生理活动（皮层电图，ECoG）。WIMAGINE®植入系统旨在进行长期的无线神经元信号采集，例如，作为严重运动障碍患者的颅内脑机接口（BCI）。鉴于WIMAGINE®的尺寸和形状，绵羊被认为是进行长期体内验证的最佳动物模型。设备在两只绵羊身上植入，进行了为期10个月的随访，包括静止状态下的皮层记录和躯体感觉诱发电位（SSEP）测试。在10个月的观察期间，ECoG和SSEP表现出相对稳定的行为。从感觉运动皮层（SMC）记录的信息显示了SSEP相位反转，表明在接触10个月后，感觉运动活动的皮层位置得以保留。基于对原始ECoG信号的每周记录，有效带宽对于两只动物都在230 Hz范围内，并且随时间表现出显著稳定性，意味着高频率带的保留对于使用BCI解码大脑活动至关重要。功率谱密度（dB/Hz）在对数尺度上，对于频率带（10–40）Hz、（40–100）Hz和（100–200）Hz分别为2.2、–4.5和–18。这项临床前研究的结果是WIMAGINE®植入系统的首次长期体内验证，突出了其通过硬脑膜记录大脑电活动以及将无线数字化数据发送到外部基站的能力。除了硬脑膜与颅骨的局部粘连外，神经外科医生在WIMAGINE®设备的植入以及脑部尸检分析中并未遇到任何困难，且未发现与植入相关的副作用。我们还报告了系统的可靠性，包括植入设备、天线模块和外部基站。