- L Srimathi
Sleep is an integral part of all our lives, providing much needed rest to our body and helping it perform at its optimal best. Thus, it goes without saying that disorders stemming from inadequate sleep or excessive sleep can have a detrimental effect on an individual’s life. Narcolepsy is one of the most severe forms of neurological disorders related to excess, unregulated sleep. The regulation of the sleep-wake cycle takes place in the brain. The lateral hypothalamus in the brain secretes the neurotransmitters Orexin A (hypocretin 1) and Orexin B (hypocretin 2) which have a stimulatory effect on postsynaptic neurons with the respective orexin receptors, which further help in suppressing REM (Rapid Eye Movement) sleep. In narcoleptic patients, during early adolescence, an autoimmune response caused by the T cells kills off these neurons containing orexin receptors, leading to severe depletion in orexin levels.
This depletion leads to a spectrum of symptoms that involve sleep-cataplexy, sleep paralysis, hallucinations and persistent drowsiness. Based on the severity, narcolepsy has been classified into type 1 and type 2, the former being the more severe version, often accompanied by cataplexy (muscle weakness caused by strong emotions leading to temporary immobility).
Image credit - THE BRAIN FROM TOP TO BOTTOM (mcgill.ca)
Patients suffering from narcolepsy dream vividly even during seemingly small naps. As opposed to a normal person, they might experience prolonged periods of sleep paralysis in combination with eerie hallucinations- both hypnagogic (when falling asleep) and hypnopompic (before waking up). Sleep paralysis is also experienced by unaffected individuals but the intensity of the experience is multiplied manifold in narcoleptic patients as the hallucinations that often accompany them are terrifying.
Diagnosis is often done using polysomnography, a combination of electrocardiography, electroencephalography etc. and multiple sleep latency test- a technique using which time taken to enter REM sleep is measured over regular intervals. Narcolepsy is a chronic neurological disorder for which no cures exist currently. Stimulants are often prescribed as medication to manage narcolepsy. Since progression of the disorder often occurs in the formative years of an individual, it affects their social interactions and self-esteem. Medication helps to a certain extent but it is extremely important that these individuals receive support from their parents and peers to find some semblance of normal life.
For more, visit - https://www.nature.com/articles/s41583-018-0097-x
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