Eight-year-old daria was having some disturbances in her sleep, so her parents took her to a children's hospital to undergo various tests. she recalls sleeping in the hospital room with a bunch of wires stuck to her scalp. what technique was used in daria's sleep study?

The answer would be: EEG (Electroencephalogram)
EEG (Electroencephalogram) is a technique to monitor which brains is activated when a person is doing certain actions.
EEG (Electroencephalogram) machines will detect the electrical impulses sent by the Brain cells and will see which part of the brains produce the most heat during a certain activity.