VLSI for Ambulatory EEG Epilepsy Monitoring

描述（由申请人提供）：本研究的目标是创建定制的模拟VLSI半导体技术，使用EGFs测地线传感器网（EGFs Geodesic Sensor Net）为动态EEG记录提供轻量级，紧凑的数据采集系统，EGFs测地线传感器网是一种以其舒适性和易于安装而着称的电极系统，即使具有非常高的通道计数（到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，因为它可以从伪现象（例如在癫痫发作期间可能容易发生的情况）中迅速恢复，也因为非常低频的现象可能具有临床意义。通过将多个输入仪表放大器通道和δ -sigma调制器组合在一个芯片上，并将多个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，我们可以实现一个比现有系统更小的整体尺寸和更低功耗的全带宽系统设计。

DESCRIPTION (provided by applicant): The goal of this research is to create custom analog VLSI semiconductor technology to provide a lightweight, compact implementation of a data acquisition system for ambulatory EEG recording using EGFs 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 artifact situations (such as might easily occur during seizures), as well as because very low frequency phenomena may be clinically significant. By combining multiple input instrumentation amplifier channels and delta-sigma modulators on a single chip, and 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 system design with much smaller overall size and reduced power consumption, compared to existing systems. 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. One recent study of source localization of epileptic foci has shown that dense array EEG provides substantial improvements in source estimation, while a study in our own lab indicates that dense array also facilitates improved rates of interictal spike detection. Thus, any conventional (low density) research or clinical strategy (including efforts directed at seizure prediction and suppression) risks substantially sub-optimal result. In addition to the benefits for fully ambulatory applications, our proposed system will also lead to greater acceptability of inpatient high-density recordings, because of improved patient mobility and comfort of an un-tethered data acquisition mode. The system will incorporate local disk storage or a wireless data link for continuous downloading to a base station.