Hypnagogic and hypnopompic hallucinations
Abnormal visual (most often) or auditory perceptions, or intense dreamlike states that occur while falling asleep (hypnagogic) or upon awakening (hypnopompic). Approximately 25% of patients with narcolepsy experience these hallucinations.
These hallucinations may often be pleasant, but are more often frightening or disturbing. They are almost always auditory or visual, but may involve other senses (e.g. tactile or vestibular).
o Visual hallucinations: May appear in color or as dark shadows; usually involves simple geometric shapes, animals or people.
o Auditory hallucinations: Simple sounds such as knocking on a door or a phone ring, but can also be threatening sounds or derogatory statements that can leave patients upset or terrified.
o Other senses: Smelling smoke (or other scent/odor) or having the sense of falling or feeling that someone or something is touching them
These hallucinations can be frightening enough that the patient becomes scared of falling asleep and resorts to reassuring behaviours such as having their pet sleep in the same room. Even if patients are well aware of the nature of these hallucinations, some patients report difficulty in differentiating dreams from reality and might occasionally be misdiagnosed as schizophrenic. These episodes are also difficult to distinguish from nightmares or unpleasant dreams, which also occur frequently in narcolepsy.
These hallucinations may often be pleasant, but are more often frightening or disturbing. They are almost always auditory or visual, but may involve other senses (e.g. tactile or vestibular).
o Visual hallucinations: May appear in color or as dark shadows; usually involves simple geometric shapes, animals or people.
o Auditory hallucinations: Simple sounds such as knocking on a door or a phone ring, but can also be threatening sounds or derogatory statements that can leave patients upset or terrified.
o Other senses: Smelling smoke (or other scent/odor) or having the sense of falling or feeling that someone or something is touching them
These hallucinations can be frightening enough that the patient becomes scared of falling asleep and resorts to reassuring behaviours such as having their pet sleep in the same room. Even if patients are well aware of the nature of these hallucinations, some patients report difficulty in differentiating dreams from reality and might occasionally be misdiagnosed as schizophrenic. These episodes are also difficult to distinguish from nightmares or unpleasant dreams, which also occur frequently in narcolepsy.
References
Ahmed I, Thorpy M. Clinical features, diagnosis and treatment of narcolepsy. Clin Chest Med 2010; 31: 371 – 381
Nishino S. Clinical and neurobiological aspects of narcolepsy. Sleep Medicine 2007; 2: 373 – 399
Dauvilliers Y., Arnulf I, Mignot E. Narcolepsy with Cataplexy. Lancet (Seminar) 2007; 369: 499 – 511
Images:
http://bouldersleeptherapy.com/disorders/narcolepsy.php/
autoimmunediseasesa2z.com
www3.unil.ch
Nishino S. Clinical and neurobiological aspects of narcolepsy. Sleep Medicine 2007; 2: 373 – 399
Dauvilliers Y., Arnulf I, Mignot E. Narcolepsy with Cataplexy. Lancet (Seminar) 2007; 369: 499 – 511
Images:
http://bouldersleeptherapy.com/disorders/narcolepsy.php/
autoimmunediseasesa2z.com
www3.unil.ch