These studies are carried out in specially designed laboratories that monitor airflow, respiratory effort, leg movements and oxygen levels in the blood; by attaching electrodes to the face and scalp to measure brain (electroencephalogram or EEG) and muscle tone during a night's sleep. With newer technology, these assessments can be done in the comfort of your own home using a portable sleep monitor. Another is the Arousal Test, this test measures how long a person can stay awake in a quiet, dark, comfortable room. If the patient falls asleep within a few minutes of being in the room, this indicates that they may be suffering from a chronic sleep disorder. Another test is the Multiple Sleep Latency Test (MSLT). This test is based on the theory that if the patient is excessively sleepy, they will be able to fall asleep more quickly and is designed to measure daytime sleepiness. The patient is provided with a dark room to take a nap at two-hour intervals during the day. EEG and muscle tone are measured. The amount of time a person is awake until they try to fall asleep is measured to determine “sleep latency.” If the sleep latency results are 5 minutes or less, this indicates that the patient is most likely suffering from severe daytime sleepiness (medicine