Department of Neurology, Leiden University Medical Centre, Leiden, The Netherlands.
Clin Neurophysiol. 2010 Dec;121(12):1992-7. doi: 10.1016/j.clinph.2010.05.006. Epub 2010 Jun 9.
Traditional electroencephalogram (EEG) recorders reject low frequencies and DC and therefore cannot handle fullband EEG. Dedicated fullband recorders use non-standard file formats, because the standard format (EDF) cannot handle large DC electrode offset voltages. Both facts limit the development and use of fullband EEG. We developed a modification that allows conventional equipment to record fullband EEG, and adapts both types of recorders to EDF.
The modification is a simple filter that attenuates the DC component and thus makes the EEG fit within traditional equipment limitations and EDF. The review software automatically 'de-attenuates' the DC component, without loss of information.
DC attenuation by a factor of 10 made both types of recorders store DC attenuated fullband EEG into EDF files. Recordings were made during 0.5-24h in 46 subjects. The DC de-attenuator automatically reconstructed the original fullband EEG within an amplitude range of ±100mV and with a resolution of 0.3μV. Using sintered Ag-AgCl electrodes attached with common procedures, reconstructed DC EEG in spontaneously moving subjects ranged between ±32mV.
The modification works. Fullband recordings can now be analyzed by independent software, archived and exchanged.
Any EEG system can be made to record fullband EEG into standard EDF.
传统的脑电图（EEG）记录器会拒绝低频和直流，因此无法处理全带宽 EEG。专用的全带宽记录器使用非标准文件格式，因为标准格式（EDF）无法处理大的直流电极偏移电压。这两个事实都限制了全带宽 EEG 的发展和使用。我们开发了一种改进方法，允许常规设备记录全带宽 EEG，并使这两种类型的记录器都适应 EDF。
该改进方法是一种简单的滤波器，可衰减直流分量，从而使 EEG 适应传统设备的限制和 EDF。审查软件会自动“去衰减”直流分量，而不会丢失信息。
通过将直流衰减 10 倍，使这两种类型的记录器都可以将 DC 衰减的全带宽 EEG 存储到 EDF 文件中。在 46 名受试者中进行了 0.5-24 小时的记录。DC 去衰减器自动在±100mV 的幅度范围内和 0.3μV 的分辨率内重建原始全带宽 EEG。使用烧结的 Ag-AgCl 电极，并采用常规的程序进行连接，在自主运动的受试者中重建的 DC EEG 范围在±32mV 之间。
该改进方法有效。现在可以使用独立的软件分析全带宽记录，进行存档和交换。
任何 EEG 系统都可以被改造为记录标准 EDF 的全带宽 EEG。
