Nostril Differences in the Olfactory Performance in Health and Disease

Area of Science:

• Neuroscience
• Ophthalmology
• Sensory system research

Background:

• Olfactory tests typically assess both nostrils together, potentially masking subtle olfactory deficits.
• Differences in olfactory sensitivity between nostrils may indicate early dysfunction.

Purpose of the Study:

• To investigate the diagnostic utility of monorhinal olfactory testing compared to birhinal testing.
• To establish normative data and cut-off values for monorhinal olfactory assessment.

Main Methods:

• Utilized the "Sniffin' Sticks" test on 458 participants (278 controls, 180 hyposmic patients).
• Assessed olfactory function monorhinally (one nostril at a time) across three tasks.
• Compared scores between nostrils to identify best and worst performing sides.

Main Results:

• Scores from the worst-performing nostril were most effective in identifying olfactory disorders.
• Monorhinal testing demonstrated higher efficiency in detecting olfactory dysfunction than birhinal testing.
• Established normative data and diagnostic cut-off values for monorhinal assessment.

Conclusions:

• Monorhinal olfactory testing enables earlier and more accurate diagnosis of olfactory dysfunction.
• This approach is particularly valuable for the early detection of neurodegenerative diseases.
• Highlights the importance of assessing each nostril independently for comprehensive olfactory evaluation.