Fig 1.
(a) Illustrations of stereo EEG with depth probes in the sagittal view. (b) Same as (a), except in the axial view. (c) Same as (a), except for electrocorticography with grid and strip electrodes. (d) Same as (c), except in the axial view. In practice, electrode quantity and spacing is solely determined by clinical need. (e) Neuroelectrophysiology sampled at 10 kHz using the Nihon Kohden JE-120A junction box. There are four intracranial electrode banks (separated by color, each with the capacity to record 64 iEEG electrodes).
Fig 2.
Methods of acquiring research EEG data from the clinical stream.
The five stages for clinical iEEG acquisition are shown with different branching points for collecting research data. The branching in black (research digital stream) is utilized in this work, while the rest in gray are shown for informational purposes. From left to right there is a decrease in clinical burden across the various methods of research EEG acquisition. Abbreviations: ADC (Analog-to-digital converter).
Table 1.
Overview of various methods to acquire EEG data.
Fig 3.
Network schematic for iEEG data acquisition.
Intracranial data recorded from implanted electrodes was acquired on both clinical and research ports of the clinical acquisition system (Nihon Kohden JE-120A). The research data was sampled at 10 kHz and transmitted to the hospital server room for storage via a Generic Routing Encapsulation (GRE) tunnel between routers. Labels 1, 2, and 3 on the router in the hospital server room represent Ether1, Ether2, and the GRE tunnel, respectively, of Table 2a. Abbreviations: VLAN (virtual local area network).
Fig 4.
Research hardware in patient room and hospital server room.
(a) A typical patient room used for iEEG neuromonitoring studies is photographed. The red box outlines where the research hardware is located. (b) The research router is placed on top of the amplifier on the clinical acquisition pole that is transported into the patient room during neuromonitoring studies. The dark green Ethernet cable is the only added connection needed from the clinical team to enable collection of the 10 kHz secondary research stream. (c) Our research computer and router is racked in the server stack in the hospital server room. (d) This is a close-up view of (c), showing only the research hardware that is part of our data infrastructure.
Table 2.
Network data rates and protocol overheads.
Fig 5.
Behavior of CPU load during research data collection.
The aggregate CPU load (%) of the router in the hospital server room during 5 minutes of research iEEG acquisition.