Smell dysfunction in COVID-19 patients: More than a yes-no question

Area of Science:

• Neurology
• Infectious Diseases
• Otolaryngology

Background:

• Anosmia is a common early symptom of COVID-19, yet often assessed subjectively.
• Previous research has primarily categorized smell dysfunction as simply present or absent.

Purpose of the Study:

• To objectively evaluate olfactory dysfunction in COVID-19 patients using a standardized test.
• To compare smell function between COVID-19 patients with and without reported smell loss, and healthy controls.

Main Methods:

• A cohort of 57 COVID-19 patients and 34 healthy controls underwent the Quick Smell Identification Test (Q-SIT).
• Data collected included smell loss presence, onset, and other COVID-19 symptoms.
• Three groups were compared: healthy controls, COVID+ patients with smell loss (COVID w/ SL), and COVID+ patients without smell loss (COVID+ w/o SL).

Main Results:

• Smell loss was reported by 40.4% of COVID-19 patients.
• Objective testing showed significantly lower Q-SIT scores in COVID-19 patients compared to controls (p < 0.001).
• Anosmia/severe microsmia (Q-SIT≤1) was present in 87% of COVID+ w/ SL, 32.4% of COVID+ w/o SL, and 11.1% of controls.

Conclusions:

• Olfactory dysfunction in COVID-19 is more prevalent than subjective reports suggest.
• The Quick Smell Identification Test (Q-SIT) is a reliable tool for detecting smell dysfunction during pandemics.
• Objective olfactory assessment is crucial for understanding the full impact of COVID-19 on smell.