Acquisition material

There are different setup to acquire the iEEG with the epileptic patients, using 2 different amplfiers: a clinical one and a reserch one

Characteristics of the amplifiers

Clinical amplifiers

Nicolet (< 2010)

This amplifier has been used from xxxx to xxxx in order to record macroelectrodes

• maximum number of channels :
• samplig rate : 400 Hz
• input range :
• bandpass

Micromed: SD LTM 64 BS (2010 - July 2020)

This amplifier is used since xxxx in order to record macroelectrodes.

• maximum number of channels : 128 - 2 boxes of 64 inputs each
• samplig rate : 1024 Hz
• input range : +/- 3.2 mV
• bandpass : 0.18 - 220 Hz

Micromed: SD LTM 64 PLUS (September 2020 - )

This amplifier is used since September 2020 (pat_02968_1239) in order to record macroelectrodes.

• maximum number of channels : 128 - 2 boxes of 64 inputs each
• samplig rate : 1024 Hz
• input range : +/- 3.2 mV
• bandpass : 0.18 - 220 Hz

Research amplifiers

Neuralynx : Lynx (2010 - July 2012)

This amplifier has been used from 2010 to July 2010 in order to record only microelectrodes, with Cheetah software

Neuralynx : ATLAS (November 2012 - )

This amplifier is used since October 2012 in order to record microelectrodes and macroelectrodes.

• maximum number of channels : 160
• samplig rate : flexible but set to 4kHz for the macroelectrdoes and 32 kHz for the microelectrodes
• input range : flexible  but set to +/- 4mV
• bandpass : flexible  but set to 0.1 - 1000 Hz for the macroelectrodes and 0.1 - 8000 Hz for the microelectrodes
• acquisition software :
  • Cheetah : October 2012 - Mai 2022 (pat_02006_0436 - pat_03152_1614)
    • march 2022: direct RJ45 cable between Neuralynx and Micromed PCs (pat_03138_1601)
  • Pegasus : June 2022 - (pat_03167_1630 - )

Electrodes

Macroelectrodes

The macroelectrodes (AdTech®, Wisconsin) consist of 4-12 platinum contact electrodes with a diameter of 1.12 mm and length of 2.41 mm, with nickel-chromium wiring. The distance between the center of 2 contacts is 5 mm.

Microelectrodes

The macro-microelectrodes (AdTech®, Wisconsin) are of the Behnke-Fried type, consisting of 8 platinum contact electrodes with a diameter of 1.28 mm and length of 1.57 mm, embedded on the surface of a polyurethane tube with a hollow lumen. Eight 40 µm platinum-iridium microwires were inserted into the macroelectrode, protruding 3-6 mm into the cerebral tissue beyond the tip of the macroelectrode. The protruding microwires were cut to the desired length during the surgical procedure. The distance between contact 1 and 2 is 3 mm, between 2 and 3, 3 and 4, etc is 7 mm.

Connectors

Adtech CABRIO connectors

Those connectors are used for macroelectrodes

Neuralynx Headstages CHETs

Those connectors are used for microelectrodes, and can also be used for macroelectrodes

Acquisition setups (- macroelectrodes / -- microelectrodes)

Sleep electrodes

Since february 2017 (pat_02459_0912) scalp electrodes were added in order to record sleep activity. Some of the electrodes (emg and E1, E2) are removed during the week ends

• O1, Oz, O2
• E1, E2
• C3, M2 or C4, M1 for right and left implantation respectively

For the analysis they should be rereferenced as follow

Updates

September 2020

The epilepsy unit moved from Paul Castaigne to Marguerite Bottard.

The Micromed system has been renewed at the same time, but the Neuralynx system remains the same.

The first patient recorded in Margurite Bottard is pat_02968_1239, with the new Micromed system only

March 2022

Direct RJ45 cable installed between Neuralynx and Micromed PCs (first patient: pat_03138_1601)

June 2022

Upgrade of the Neuralynx software from Cheetah to Pegasus and update of Micromed's software.

First patient recorded with the new woftwares: pat_03167_1630

December 2023

The epilepsy moved back to the renew building now called : Institut de Neurologie

First patient recorded : pat_03364_1840