There are various ExG and EEG (sensor) cables available for the NeXus-10 MKII and NeXus-Q32. Our ExG sensor cable enables dual channel measurement of biopotentials like sEMG, ECG, EOG and EEG, where each channel has a separate Red (positive) and Black (negative) pole. That is called a bipolar measurement. For EEG often a linked-ear reference is used, where the black electrodes are shorted. Below you'll find a table with information about the various types of sensor cables. Note that the Q32 has a different system connector than the NeXus-10 series.
The image below shows the type of electrode connectors. Note that when you are measuring biopotentials (ExG) signals, you will always need to place a single ground (GND) electrode somewhere on the body, so that the instrumentation amplifiers have a ground reference. For this you need a (single) ground cable, the location of the ground electrode is not critical.
The difference between bi-polar and linked-ear cables
The standard dual channel ExG cable is the most universal cable for sEMG, ECG, EOG. It can also be used for 1 or 2 channels of EEG, where the black electrodes are placed on the earlobes (with an earclip) for an ear reference. In that case the black 1 and 2 are not linked. (shorted). Each dual channel ExG cable has 2 red and 2 black connectors. (the 1 and 2 are on the marked on the cable or on the snap-ons).
When a true linked ear reference is required, such as for the Z-Score libraries or certain forms of Neurofeedback, the best option is to get a linked ear cable for 2 or 4 channels. In those cables the black electrodes are all linked (shorted). The 4 channel linked-ear EEG cable has 4 red connectors (snap-on or TP) for each of the 4 electrode positions on the head and it has two black (or grey) connectors for the earlobes (or mastoids) on the left and right side. In that way a linked ear reference is created. Especially when using your NeXus system for 4 channel EEG, it is advisable to get a linked ear EEG cable. For 2 channels linked-ear you also have that option, but alternatively the standard dual channel ExG cable could be used, with the black electrodes on the earlobes, since the difference with linked-ear reference for 1 or 2 EEG channels is very small.
Snap-on or TP/DIN connectors
We provide NeXus users with two options for choosing the electrode type. For sEMG, ECG and EOG this will almost always be a snap-on electrode. For EEG the snap-on connectors can be used for the blue disc EEG electrodes, when applying Ten20 paste. The snap-ons are also necessary when using the small (black) EEG disc electrodes with Ten20 Paste or ECI electrode gel.
The TP/DIN connector is a standard for some EEG applications and TP is required when using the Minicap EEG TP Electrodes. These are sintered electrodes that are used with Ten20 EEG paste for individual placement, or for use with the Minicap (EEG Cap). You can find the electrodes and EEG Cap options in our webshop/store.