What instruction should a nurse provide to a client scheduled for a standard EEG?

For a client scheduled for a standard electroencephalogram (EEG), advising them to thoroughly shampoo their hair prior to the procedure is the most appropriate instruction. Clean hair is crucial because the electrodes that are placed on the scalp need a good contact to properly record the brain’s electrical activity. Oils, dirt, and hair products can interfere with the electrode's ability to gather accurate data, which may compromise the quality of the EEG readings. Therefore, ensuring that the scalp is clean and free from any products contributes to a successful test result.

While getting plenty of rest, avoiding medications, and eating beforehand may be relevant factors in a different context, they do not specifically address the immediate preparation needed for an EEG regarding scalp cleanliness. The focus on shampooing emphasizes the importance of optimal electrode placement and data acquisition during the test.