Related Experiment Video
Updated: Dec 18, 2025
04:00
Author Spotlight: Assessing the Olfactory Effects of Airborne Pollutants — Buried Food and Social Odor Tests
Published on: September 13, 2024
1.3K
The influence of narcolepsy on olfactory function: a review.
Giselle de Martin Truzzi1, Maria Fernanda Naufel2, Sergio Tufik1
1Departamento de Psicobiologia, Universidade Federal de São Paulo, São Paulo, Brazil.
Sleep Medicine
|June 20, 2020
Summary
Narcolepsy, a sleep disorder, is linked to diminished olfactory function in patients. Hypocretin deficiency appears to be a key factor in this smell impairment.
Area of Science:
- Neurology
- Sleep Medicine
- Sensory Neuroscience
Background:
- Narcolepsy is a chronic neurological disorder characterized by the loss of hypocretin-producing neurons.
- It leads to excessive daytime sleepiness, cataplexy, and other sleep disturbances.
- Olfactory dysfunction is increasingly recognized as a comorbidity of narcolepsy.
Purpose of the Study:
- To review the existing literature on the impact of narcolepsy on human olfaction.
- To explore the relationship between hypocretin deficiency and olfactory impairment in narcolepsy.
Main Methods:
- A systematic literature search was conducted using PubMed, Embase, and Cochrane databases.
- Articles focused on olfactory function evaluation in narcolepsy patients were included.
- Keywords included 'narcolepsy' and 'olfaction disorder'.
Main Results:
- Seven studies met the inclusion criteria.
- Five studies reported diminished olfactory function in narcolepsy patients compared to controls.
- Narcolepsy diagnosis correlated with poorer olfactory test performance.
Conclusions:
- Narcolepsy is associated with significant olfactory deficits.
- Hypocretin deficiency is implicated as a primary cause of hyposmia in narcolepsy.
- Further research into the role of hypocretin in olfactory processing is warranted.
Related Concept Videos
01:24Sleep-Wake Cycles
2.6K
Sleep is an essential physiological process vital to maintaining overall well-being. The reticular activating system (RAS), a network of neurons in the brainstem, regulates wakefulness and sleep. While it may seem passive, sleep consists of distinct cycles, each with its unique characteristics and functions. Two key sleep phases are non-rapid eye movement (NREM) and rapid eye movement (REM).
NREM Sleep
NREM sleep comprises four progressive stages that seamlessly merge:
NREM Sleep
NREM sleep comprises four progressive stages that seamlessly merge:
2.6K
01:07Narcolepsy
371
Narcolepsy is a chronic sleep disorder characterized by pervasive, uncontrolled sleepiness and other sleep disturbances. One of its hallmark symptoms is an abrupt transition to REM sleep upon falling asleep, which causes symptoms typically associated with this phase to occur unexpectedly during wakefulness. These include the following symptoms, which typically last from a minute or two to half an hour.
371
01:03Olfactory Receptors: Location and Structure
11.0K
The process of olfaction, also known as the sense of smell, is a sophisticated chemical response system. The specialized sensory neurons that facilitate this process, known as olfactory receptor neurons, are situated in an upper segment of the nasal cavity, known as the olfactory epithelium. Olfactory sensory neurons are bipolar, with their dendrites extending from the epithelium's apex into the mucus that lines the nasal cavity. Airborne molecules, when inhaled, traverse the olfactory...
11.0K
01:20Physiology of Smell and Olfactory Pathway
11.7K
Humans detect odors with the help of specialized cells located in the upper part of the nasal cavity, called olfactory receptor neurons (ORNs). ORNs possess hair-like structures called cilia, which are receptive to sensations from the inhaled air. When an odorant molecule binds to a specific receptor on the cell of the cilia, it leads to a series of events that ultimately cause the ORN to send electrical signals to the olfactory bulb in the brain through the olfactory nerves.
The olfactory...
The olfactory...
11.7K
01:25Olfaction
47.8K
The sense of smell is achieved through the activities of the olfactory system. It starts when an airborne odorant enters the nasal cavity and reaches olfactory epithelium (OE). The OE is protected by a thin layer of mucus, which also serves the purpose of dissolving more complex compounds into simpler chemical odorants. The size of the OE and the density of sensory neurons varies among species; in humans, the OE is only about 9-10 cm2.
The olfactory receptors are embedded in the cilia of the...
The olfactory receptors are embedded in the cilia of the...
47.8K
01:24Substance Use Disorders Affecting Sleep
323
Substance use disorders involve a pattern of using drugs more extensively than intended and continuing use despite harmful consequences. This includes legal substances like alcohol and nicotine, as well as illegal drugs. These disorders often involve both physical and psychological dependence, reflecting compulsive use of substances that significantly alter thoughts, feelings, and behaviors, contributing to a major public health issue.
Understanding the concepts of physical dependence,...
Understanding the concepts of physical dependence,...
323