What should a nurse instruct a client to do before an EEG?

Shampooing the hair before an EEG is advised because it helps remove oils, hair products, and debris that could interfere with the electrodes' ability to pick up brain wave activity accurately. Clean hair ensures better contact between the scalp and the electrodes, enhancing the quality of the readings obtained during the electroencephalogram. This preparation is important to ensure that artifacts or unwanted signals do not obscure the brain activity that is being studied.

In contrast, the other options are not recommended practices before an EEG. Eating a heavy meal before the test could potentially affect brain wave patterns, leading to inaccurate results. Avoiding fluids may result in dehydration, which is not advisable since it could affect the patient's overall health and comfort. Lastly, stopping medications requires careful consideration, as some medications can alter brain activity or seizure thresholds. It is essential for individuals to consult with their healthcare provider regarding any medications before the procedure.