He electroencephalography test is done to record electrical activity of Brain like ECG of heart. It is 21 channel brain recording with ECG, EMG facility. It is equipped with LED photic stimulation unit.

Brain mapping facity is attraction to the recording along with spikes tracing. This is investigation done for detecting epilepsy/fit/Seizure.

this is a test done for detecting brain death also

This test is one of the componet of  lie detector test

In the pic, the electrodes (wires) are placed over scalp(head) and photic unit over face