A New Method for Assessment of Retronasal Olfactory Function.

Objectives/hypothesis: The aim of the study was to develop a test for the assessment of retronasal olfaction in healthy participants and patients with olfactory disorders using "tasteless" powders.

Study Design: Prospective case-control series.

Methods: A total of 150 participants (110 women, 40 men, mean age = 40 ± 16 years) were recruited for this study; 100 were healthy controls and 50 were patients with olfactory loss due to infections of the upper respiratory tract (n = 25), idiopathic causes (n = 12), sinonasal disease (n = 7), and head trauma (n = 6).