User Tutorial:EEG Measurement Setup

This page is about the physical process required prior to EEG measurements. Although it appears simple and straightforward, a successful, good quality EEG recording requires attention to not-so obvious details, and practice.

Electrodes

• materials: Ag/AgCl, Sn, others
• inconsistent electrode materials obstruct measurement due to contact potentials
• ratio of electrode impedance to amplifier input impedance determines SNR; should be around 5-10kOhms
• measuring electrode impedance
• attaching electrodes to the head: skin preparation, gel

Electrode Caps

• useful to reproduce electrode positions, even if only a small number of electrodes are actually used
• simplifies cable connections
• standard electrode positions translate immediately into brain regions
• determining the Cz position on a subject's skull

Signal Quality

• power line noise
• muscular artifacts
• eye artifacts
• occipital alpha rhythm