RESUMEN
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). Orthonasal olfactory function was evaluated using the Sniffin' Sticks test battery, and retronasal olfaction was evaluated using powders lacking distinctive tastes administered to the oral cavity. To establish test-retest reliability, healthy participants had their orthonasal and retronasal function tested twice. RESULTS: The validity analyses revealed that the selected 16 stimuli differentiated between normosmic participants and patients with olfactory loss, and that retronasal and orthonasal olfaction were highly correlated. CONCLUSIONS: The results of the present study indicate that patients with olfactory loss and controls can be clearly separated using a reliable test of retronasal olfaction based on 16 retronasal stimuli. LEVEL OF EVIDENCE: 2b Laryngoscope, 131:E324-E330, 2021.