Prepare the skin by shaving and scrubbing with an abrasive gel.
The main goal of skin preparation is to achieve stable electrode contact and low skin impedance. How thorough the preparation needs to be depends on the recording site (on the body) and the level of expected movement. Body parts with many hairs, sweat, and dirt require more attention. Moreover, for dynamic movements, a great quality of connection is important.
Preparation usually involves the following steps:
- Shaving to remove hair. Removing hair leads to improved adhesion of the electrodes.
- Scrubbing the skin with an abrasive gel. This step removes the dead skin cells, dirt, and sweat from the skin. TMSi recommends the use of NuPrep as scrub.
The participant should not experience discomfort while preparing the skin. However, the skin might turn red after preparation. This is usually an indication that the connection will be good.
Sometimes, the hygienic behavior of the participant can influence the electrode-skin connection. Using lotions or creams before the measurement can lead to higher impedances. Moreover, not showering for a long time can lead to an excess of oil on the body.