Analysis of Article Narcolepsy by Jerome M. Siegel
In his article “Narcolepsy,” Jerome M. Siegel discusses the disease and its possible causes. To begin with, Siegel defines the symptoms and problems associated with the disease. Moreover, he states what exactly the disease is, his research into its causes and effects on the nervous system, and the possibility that the narcolepsy may be an autoimmune disease.
The symptoms of narcolepsy include cataplexy, persistent daytime sleepiness, sleep paralysis, and hypnagogic hallucinations. Cataplexy is “a loss of skeletal muscle tone without loss of consciousness” (77). These cataplectic attacks often occur at emotional times. Such events could be laughter, sexual intercourse, physical exertion, and anger. Daytime sleepiness can make narcoleptics fall asleep at inappropriate times and although they may be refreshed after naps they are soon tired after. Sleep paralysis is the inability to move prior to falling asleep or waking. Finally, hypnagogic hallucinations are vivid dreams before sleep or when extremely tired.
Siegel then describes the two different types of sleep as non-REM and REM sleep. During non-REM sleep “the muscles are relaxed but maintain some tone, breathing is regular, the cerebral cortex generates high-voltage waves, and consumption of energy by the brain is minimal” (77). A person experiencing REM sleep, however, has irregular breathing and heart rate, the cerebral cortex generates waves almost like those seen in a waking state, rapid eye movements, high brain metabolism, lack of all muscle tone, and dreams occur. Normally people enter into non-REM sleep immediately upon falling asleep; however, narcoleptics enter into REM sleep first. This causes narcoleptics to lose muscle tone immediately upon falling asleep.
In order to study narcolepsy, research has focused around cataplexy because unlike sleepiness it never occurs in normal individuals. Research into narcoleptic dogs has shown that there is a genetic link in dogs, however, it has also shown that cataplexy occurred during vigorous play or when excited. Moreover, it was found that when the medial medulla is stimulated with an electrode muscle tone disappears. This effect appears to occur to prevent muscle movement during REM sleep and some muscle tone regulation while awake. Siegel found that during a cataplectic episode in the narcoleptic dogs this region of the brain became active. Additionally, it was found that in normal individuals this region of the brain is only highly active during REM sleep. A research in Siegel’s laboratory, Elizabeth Schenkel, demonstrated that normal animals with damaged medial medullas moved during REM sleep. Furthermore, other researchers showed that animals with damage higher on the brain stem, which connected to the medulla “raised their heads, walked and appeared to attack imaginary adversaries during REM sleep” (78).
Another area in the brain has been targeted in playing a role in...