Before the study begins, a sleep technologist will place sensors on your scalp, face, chest and legs. Keep in mind, hair braids and extensions may interfere with the placement of the electrodes. These will record your brainwaves to determine stages of sleep and other important data regarding your body’s activity during sleep. The sensors are not painful. Rarely, some people with sensitive skin develop minor skin irritation at the electrode sites. The sleep technologist will monitor you from a separate room throughout the night.