Sleepiness at the time of testing impairs olfactory performance

Area of Science:

• Neuroscience
• Sleep Medicine
• Ophthalmology

Background:

• Investigating the roles of hypocretin and dopamine dysfunction in hyposmia.
• Assessing excessive daytime sleepiness (EDS) as a factor in olfactory decline.
• Comparing olfaction in Parkinson disease (PD), restless leg syndrome (RLS), narcolepsy with cataplexy (NC), EDS, and healthy controls.

Purpose of the Study:

• To determine the differential roles of hypocretin, dopamine dysfunction, and EDS in hyposmia development.
• To compare olfactory function across various neurological and sleep disorder patient groups.

Main Methods:

• Studied 66 subjects: 14 PD, 13 NC, 12 RLS, 8 EDS, and 20 controls.
• Utilized the Sniffin'Sticks test for olfactory assessment.
• Employed Karolinska, Stanford, and Epworth sleepiness scales to measure sleepiness.

Main Results:

• Olfactory discrimination showed a negative correlation with subjective momentary sleepiness.
• PD patients exhibited significant olfactory deficits across all domains compared to other groups.
• No significant olfactory differences were observed between NC, RLS, EDS, and control groups.

Conclusions:

• Decreased olfaction was not confirmed in narcolepsy with cataplexy (NC) patients.
• Momentary sleepiness is a potential confounding factor in olfactory assessment, particularly in NC.
• Olfactory function is impaired in PD but normal in RLS.