Olfactory testing in clinical settings - is there additional benefit from unilateral testing?

Area of Science:

• Otolaryngology
• Neuroscience
• Sensory Science

Background:

• Olfactory testing is typically performed bilaterally in clinical settings.
• Unilateral olfactory loss can be easily missed with standard testing procedures.
• Accurate diagnosis of olfactory dysfunction is essential for patient management.

Purpose of the Study:

• To determine if patients with self-reported olfactory disorders exhibit significant side differences in odor perception.
• To evaluate the effectiveness of the current olfactory testing procedure in detecting unilateral olfactory loss.
• To assess the prevalence of measured unilateral olfactory disorders in patients presenting with olfactory complaints.

Main Methods:

• Utilized the "Sniffin' Sticks" test battery, including threshold, discrimination, and odor identification tests.
• Administered olfactory testing to 518 patients with olfactory disorders, examining each nostril independently.
• Classified olfactory disorders based on patient history and clinical examination (e.g., trauma, sinonasal disease, URTI, tumor, idiopathic).

Main Results:

• A significant side difference in olfactory perception was detected in 23.4% of all patients presenting with olfactory disorders.
• A difference of ≥3 points in a subtest or ≥6 points in the composite score indicated a significant side difference.
• The study highlights the prevalence of lateralized olfactory dysfunction in patients seeking olfactory assessment.

Conclusions:

• Separate testing of each nostril is recommended to avoid missing lateralized olfactory disorders.
• Clinical olfactory testing procedures should incorporate unilateral assessment to improve diagnostic accuracy.
• Further evaluation may involve continued bilateral or separate nostril testing based on initial findings of asymmetry.