VLSI for Ambulatory EEG Epilepsy Monitoring

描述（由申请人提供）：本研究将创建一个小型且廉价的多通道生理数据采集系统。它将允许密集阵列（128或256通道）脑电图系统以与传统（19或32通道）系统相似的成本制造，并且它将使传统系统变得非常紧凑和廉价。最初的实现将是使用EGI的测地线传感器网（Geodesic Sensor Net）进行动态EEG记录，该电极系统以其舒适性和易于安装而著称，即使具有非常高的通道数（多达256个电极）。最近的高性能实验室脑电图放大器设计通过为每个通道使用单个24位δ - σ a /D转换器来提供全直流带宽能力。这种能力在癫痫研究中尤其重要，可以从人为噪声（如癫痫发作时的运动）中迅速恢复。此外，极低频（近直流电）现象可能具有临床意义。通过将多个低噪声输入仪表放大器通道和δ -sigma调制器组合在一个芯片上，然后将多个δ -sigma转换器的数字滤波和信号处理功能集成在一个FPGA（现场可编程门阵列）上，与现有系统相比，我们可以实现一个整体尺寸小得多、功耗低得多的全带宽数据采集单元。该系统将包括本地磁盘存储和无线数据链路，以便连续下载到基站。由于门诊记录成本较低，有更好的机会捕捉癫痫样事件，在各种环境下记录时间较长，因此门诊系统越来越多地接受脑电图用于癫痫评估。已发表的关于癫痫发作间期病灶源定位的研究表明，密集阵列脑电图在源估计方面有很大的改进。我们最近在华盛顿大学港景医院进行的研究表明，我们可以使用256通道系统进行数天的长期监测，在定位癫痫发作的准确性方面有可量化的提高。除了完全动态应用的好处之外，所提出的研究将使密集阵列测量变得具有成本效益，同时大大降低传统脑电图记录系统的成本和尺寸。如果计算能力的进步与数据采集技术的类似进步相匹配，则可以提高医疗设备的信息产量。提出的VLSI密集阵列脑电图系统将允许低成本，紧凑，无线动态采集人类大脑活动，用于长期监测癫痫发作特征等应用。

DESCRIPTION (provided by applicant): This research will create a small and inexpensive multichannel physiological data acquisition system. It will allow dense array (128 or 256 channel) EEG systems to be made at a similar cost as conventional (19 or 32 channels) systems, and it will allow conventional systems to become very compact and inexpensive. The initial implementation will be an ambulatory EEG recording using EGI's Geodesic Sensor Net, an electrode system noted for its comfort and ease of installation even with very high channel counts (to 256 electrodes). Recent high-performance laboratory EEG amplifier designs are providing full DC bandwidth capability, by using a single 24-bit delta-sigma A/D converter for each channel. This capability is especially important in epilepsy studies, for prompt recovery from artifactual noise (such as from movements during seizures). In addition, very low frequency (near DC) phenomena may be clinically significant. By combining multiple low-noise input instrumentation amplifier channels and delta-sigma modulators on a single chip, and then integrating the digital filtering and signal processing functions of multiple delta-sigma converters on a single FPGA (Field Programmable Gate Array), we can implement a full-bandwidth data acquisition unit with much smaller overall size and reduced power consumption, compared to existing systems. The system will incorporate local disk storage and a wireless data link for continuous downloading to a base station. Ambulatory systems are gaining increasing acceptance in EEG for epilepsy assessment, because of lower costs of outpatient recording and better opportunities to capture epileptiform events, with longer recording times in a variety of settings. Published research on source localization of interictal epileptic foci has shown that dense array EEG provides substantial improvements in source estimation. Our own recent research at the University of Washington Harborview Hospital shows we can conduct long-term monitoring for several days with the 256-channel system, with quantifiable improvements in accuracy of localizing seizure onset. In addition to the benefits for fully ambulatory applications, the proposed research will allow dense array measures to become cost- effective, while at the same time greatly reducing the cost and size of conventional EEG recording systems. Advances in computational capacity can improve the information yield from medical devices if matched by similar advances in data acquisition technology. The proposed VLSI dense array EEG system will allow low cost, compact, wireless ambulatory acquisition of human brain activity for applications such as long-term monitoring to characterize seizure onset in epilepsy.