Explanations of Other Sleep Disorders

Explanations of Narcolepsy

• Psychological Explanations
• Very early approach said that narcolepsy disguised sexual fantasies
• REM
• Classic symptons of narcolepsy is cataplexy. Similary to what happens in REM sleep.
• During daytime, narcolepsy often experience intrusions of REM type sleep.
• At night, narcoleptics have abnormal REM sleep.
• Malfunction in the system that regulates REM sleep.
• HLA
• In 1980s, narcolepsy was linked to a mutation of the immune system.
• Increased frequency of on type of HLA was found in narcoleptic patients.
• HLA molecules found on the surface of WBC and coordinate immune response.
• More than 90% of people suffering from narcolepsy with cataplexy found to have the HLA variety.
• Hypocretin
• Research has uncovered a link between hypocretin and narcolepsy.
• Hypocretin regulates sleep and wakefulness through interactions with systems that regulate emotion and homeostatis in the hypothalamus.
• There are about 10,000 to 20,000 hypocretin producing cells in the hypothalamus.
• In many narcoleptics a large number of these cells are missing, resulting in low levels of hypocretin.

Evaluation

• REM
• REM explanation supported by vogel who observed REM sleep at the onset of sleep in a narcoleptic patient.
• More commonly occurs later in the first cycle of sleep stages.
• Further supported by recordings of neuron activity in the brainstem of narcoleptic dogs.
• Cataplexy co-occured with brain cell activity which only occurs in REM sleep.
• HLA
• Specific HLA variant is not found in all narcoleptics; reasonably common in general population
• Hypocretin
• Evidence of Lower Levels
• First evidence for hypocretins came from narcoleptic dogs who were found to have a mutation in a gene on chromosone 12.
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