brain, spinal cord, and nerve disorders
Narcolepsy
Diagnosis of Narcolepsy
Polysomnography Multiple sleep latency testing Doctors suspect narcolepsy when people with excessive daytime sleepiness have had episodes of muscle weakness. However, doctors cannot base the diagnosis on symptoms alone because other disorders can cause some of the same symptoms. Sleep paralysis and similar hallucinations occasionally occur in otherwise healthy adults, in people who have been sleep deprived, and in people with sleep apnea or depression. These symptoms may also occur when certain drugs are taken. Therefore, testing in a sleep laboratory is necessary. Sleep testingin a sleep laboratory consists of Polysomnography, done overnight Multiple sleep latency testing, done the next day is usually done in a sleep laboratory, which may be located in a hospital, clinic, hotel room, or other facility that is equipped with a bed, bathroom, and monitoring equipment. Electrodes are pasted to the scalp and face to record the brain's electrical activity ( Electroencephalography , or EEG) as well as eye movements. Applying these electrodes is painless. The recordings help provide doctors with information about sleep stages. Electrodes are also attached to other areas of the body to record heart rate ( Amultiple sleep latency testis done to distinguish between physical fatigue and excessive daytime sleepiness and to check for narcolepsy. People spend the day in a sleep laboratory. They are given the opportunity to take five naps at 2-hour intervals. They lie in a darkened room and are asked to take a nap. Polysomnography is used as part of this test to assess how quickly people fall asleep. It detects when people fall asleep and is used to monitor the stages of sleep during the naps and to determine whether REM (dreaming) sleep occurs. During multiple sleep latency testing, people with narcolepsy typically fall asleep quickly and have at least two REM naps. These tests involve monitoring and recording the activity of the brain, heart, breathing, muscles, and eyes. Various other body functions, including movement of the limbs, are also monitored and recorded. Usually, narcolepsy does not result from abnormalities that can be detected by brain imaging procedures, such as computed tomography (CT) or magnetic resonance imaging (MRI). However, doctors may use brain imaging and blood and urine tests to rule out other disorders that can cause excessive daytime sleepiness. 