hypnagogic hallucination

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Related to hypnagogic hallucination: narcolepsy, hypnopompic hallucination


a sensory impression (sight, touch, sound, smell, or taste) that has no basis in external stimulation. Hallucinations can have psychologic causes, as in mental illness, or they can result from drugs, alcohol, organic illnesses, such as brain tumor or senility, or exhaustion. When hallucinations have a psychologic origin, they usually represent a disguised form of a repressed conflict. adj. adj hallu´cinative, hallu´cinatory.
auditory hallucination a hallucination of hearing; the most common type.
gustatory hallucination a hallucination of taste.
haptic hallucination tactile hallucination.
hypnagogic hallucination a vivid, dreamlike hallucination occurring at sleep onset.
hypnopompic hallucination a vivid, dreamlike hallucination occurring on awakening.
kinesthetic hallucination a hallucination involving the sense of bodily movement.
olfactory hallucination a hallucination of smell.
somatic hallucination a hallucination involving the perception of a physical experience occurring within the body.
tactile hallucination a hallucination of touch.
visual hallucination a hallucination of sight.
Miller-Keane Encyclopedia and Dictionary of Medicine, Nursing, and Allied Health, Seventh Edition. © 2003 by Saunders, an imprint of Elsevier, Inc. All rights reserved.

hyp·na·gog·ic hal·lu·ci·na·tion

hallucination occurring when going to sleep in the period between wakefulness and sleep; one of the components of narcolepsy.
Synonym(s): hypnagogic image
Farlex Partner Medical Dictionary © Farlex 2012

hyp·na·gog·ic hal·lu·ci·na·tion

(hip'nă-goj'ik hă-lū'si-nā'shŭn)
A common symptom in narcolepsy characterized by vivid, dreamlike perceptions occurring with sleep onset. Often these perceptions involve fearful situations that are described as realistic and include visual, tactile, and auditory hallucinations.
Medical Dictionary for the Health Professions and Nursing © Farlex 2012
References in periodicals archive ?
A statistically significant association was found between respondents taking or not taking tricyclic antidepressant therapy and cataplexy symptom ratings ([chi square] = 10.253, df = 3, p = 0.0165), as well as the remaining REM-sleep symptom ratings (hypnagogic hallucinations: [chi square] = 8.814, df = 3, p = 0.0319; sleep onset paralysis: [chi square] = 13.301, df = 3, p = 0.0040; awakening paralysis: [chi square] = 9.214, df = 3, p = 0.0266).
Chi-square analyses showed a significant association between ADL interference and all of the individual classic narcoleptic symptoms (EDS: [chi square] = 178.74, df = 9, p [is less than] 0.0001; daytime sleep attacks: [chi square] = 151.326, df = 9, p [is less than] 0.0001; cataplexy: [chi square] = 145.269, df = 9, p [is less than] 0.0001; hypnagogic hallucinations: [chi square] = 61.564, df = 9, p [is less than] 0.0001; sleep onset paralysis: [chi square = 75.155, df = 9, p [is less than] 0.0001; awakening paralysis: [chi square] = 60.562, df = 9, p [is less than] 0.0001; restless night sleep: [chi square] = 39.099, df = 9, p [is less than] 0.0001).
EDS contributed 25% of the model variance, while cataplexy contributed 10%, sleep attack about 2%, sleep onset paralysis about 2% and hypnagogic hallucinations about 1%.
Multiple Linear Regression Analysis of Contributing Perceived Classic Narcoleptic Symptoms to Perceived ADL Interference Variable Regression Standard Beta coefficient error Entire model(*) 0.6912 EDS(**) 0.26862 0.04188 0.266 Cataplexy 0.28264 0.03904 0.265 Sleep attacks 0.16747 0.04050 0.170 Sleep onset paralysis 0.11617 0.03757 0.115 Hypnagogic hallucinations 0.07506 0.03126 0.089 Constant 0.45813 0.11900 Variable Multiple R [R.sup.2] Adjusted [R.sup.2] Entire model(*) 0.6335 0.4013 0.3960 EDS(**) 0.25 Cataplexy 0.10 Sleep attacks 0.02 Sleep onset paralysis 0.02 Hypnagogic hallucinations 0.01 Constant
Scientists have long suspected that hypnagogic hallucinations, sleep paralysis and cataplexy in people with narcolepsy are elements of REM sleep intruding into wake.
Sometimes this transition to REM sleep can occur immediately upon falling asleep (called SOREMPs) without ever entering NREM sleep, (17) leading to the occurrence of hypnagogic hallucinations and sleep paralysis.
Hypnagogic hallucinations in narcolepsy are similar to the hallucinations associated with REM sleep intrusions that occur during periods of wakefulness in some schizophrenia patients, possibly resulting in misdiagnosis.
(14,53) Drugs that treat cataplexy also reduce hypnagogic hallucinations and sleep paralysis.
Current treatments for narcolepsy consist primarily of stimulant drugs to maintain wakefulness and antidepressants and other drugs (e.g., sodium oxybate) to combat cataplexy, hypnagogic hallucinations, and sleep paralysis.
In contrast, a patient afflicted with more severe symptoms, including cataplexy, hypnagogic hallucinations and sleep fragmentation may require a more aggressive pharmaceutical paradigm.
In summary, narcolepsy is a complex disorder with multiple symptoms including excessive daytime sleepiness, cataplexy, hypnagogic hallucinations, sleep paralysis and sleep fragmentation.