Narcolepsy is a neurological disorder characterized by the presence of excessive daytime sleepiness, cataplexy, hallucinations at the sleep-wake transition, and sleep paralysis.
Causes of narcolepsy
The exact cause of this disorder is not known, although currently the autoimmune origin, with associated genetic predisposition, tends to be considered.
Specialists in Clinical Neurophysiology have observed that patients with narcolepsy have a decrease in the neurotransmitter hypocretin (or orexin), secreted by the hypothalamus of the brain, which is necessary to maintain wakefulness. In the absence of hypocretin, the central nervous system allows the intrusion of REM (rapid eye movement) sleep phases during wakefulness. This alteration would give rise to daytime sleepiness and sleep disorders characteristic of narcolepsy.
Symptoms of narcolepsy
- Daytime sleepiness: this is the main symptom. It must be present for at least 3 months prior to the diagnosis of narcolepsy; it is usually intense, appearing in monotonous and inappropriate situations (talking, driving, eating), and in the form of uncontrolled sleep attacks.
- Cataplexy: they appear in the form of sudden crises of muscular hypotonia (head, knees, hands), sometimes severe, causing falls, without involvement of the ocular or respiratory musculature. The crises are usually triggered by intense emotions (laughter, anger, etc.).
- Sleep paralysis: patients report episodes in which they find themselves with a paralyzed body, awake and unable to move.
- Hallucinations in the sleep-wake transition: these are referred to as unreal perceptions (images, sounds) on entering or leaving sleep, of short duration. Other problems that often occur in patients with narcolepsy are: motor disturbances during sleep (agitated behavior, compulsive behaviors -such as smoking- or getting up to eat), episodes of intense dream perception during the day.
For the diagnosis of narcolepsy it is necessary to perform a nocturnal polysomnography followed by a multiple latency test, in order to study the structure of nocturnal sleep and, consecutively, to measure daytime sleepiness.
Treatment of narcolepsy
First of all, sleep hygiene measures should be established: maintain a regular sleep schedule (at least 7-8 hours of nighttime sleep) and, in some cases, it is necessary to take short scheduled naps (which the patient perceives as refreshing). Alcohol and sedative or hypnotic drugs should also be avoided without medical supervision.
As for pharmacological treatment, amphetamines and amphetamine derivatives (modafinil, methylphenidate) are used for daytime sleepiness, and in the presence of cataplexy, some antidepressants (fluoxetine, venlafaxine) or drugs such as sodium oxybate (available in hospitals) can be used.
What are the consequences for the affected person’s life?
It depends on the degree of evolution of the disease. At the beginning there is usually daytime sleepiness, which increases over the years, interfering with the patient’s daily life activities, and manifesting itself characteristically as a decrease in academic performance (children or adolescents with narcolepsy fall asleep in class), with memory and attention disturbances, and emotional problems.
If cataplexy is present, there are motor disorders such as involuntary movements in the perioral area, arms or legs, with occasional falls.
The quality of sleep is also often affected, with patients with narcolepsy frequently reporting that their sleep is insufficient and not restful.