Quantitative evaluation and progress of olfactory dysfunction in COVID-19

Area of Science:

• Otorhinolaryngology
• Infectious Diseases
• Neurology

Background:

• Olfactory dysfunction is a common symptom of Coronavirus Disease 2019 (COVID-19).
• Previous studies often relied on patient self-reporting (anamnesis) for assessing smell loss.
• Quantitative data on the progression of COVID-19-related olfactory dysfunction is limited.

Purpose of the Study:

• To quantitatively analyze olfactory dysfunction in COVID-19 patients.
• To assess the recovery progress of olfactory dysfunction over a three-month period.
• To determine the frequency of olfactory dysfunction as an initial symptom of COVID-19.

Main Methods:

• Prospective investigation of patients with confirmed SARS-CoV-2 infection and new-onset olfactory dysfunction.
• Utilized the Brief Smell Identification Test (BSIT) to quantitatively measure olfactory function.
• Followed up with patients for three months, re-administering the BSIT to track symptom progression.

Main Results:

• 42 COVID-19 patients (mean age 41.2) presented with olfactory dysfunction (mean BSIT score 5.2).
• 85.7% of patients experienced full recovery of smell function within three months (mean BSIT score increased to 9.9).
• Olfactory dysfunction was the initial symptom in 40% of patients, preceding other symptoms by an average of two days.

Conclusions:

• Quantitative assessment using BSIT shows a high incidence of moderate-to-mild olfactory dysfunction in COVID-19 patients.
• A significant majority of patients achieve substantial recovery from smell loss within three months.
• The frequent presentation of olfactory dysfunction as an early symptom underscores its diagnostic value for COVID-19.