A New Method for Assessment of Retronasal Olfactory Function.

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. Prospective case-control series. 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. 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. 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. 2b Laryngoscope, 131:E324-E330, 2021.

Yoshino A ，Goektas G ，Mahmut MK ，Zhu Y ，Goektas O ，Komachi T ，Okubo K ，Hummel T ... -  《-》

Determination of Retronasal Olfactory Threshold Values.

The aim of this study was to generate normative data of retronasal olfactory threshold values for normosmic and hyposmic individuals and to test the validity of that data by determining the discriminative power for normosmic/hyposmic differentiation. Prospective, descriptive and methodological study. The orthonasal olfactory function of 20 normosmic and 20 hyposmic cases was evaluated using the Sniffin' Sticks Olfactory test. Sniffin' Sticks odor threshold, odor discrimination, and odor identification values and threshold discrimination identification (TDI) scores were recorded. A 13-item test battery previously prepared in our Rhinology Laboratory for retronasal olfactory threshold test that consisted of concentrated solutions prepared from 2:1 diluted 99% phenylethyl alcohol (PEA) and water was used. Each concentration was evaluated with water control, and if not answered correctly, the same process was continued by moving to a higher concentration series. Four consecutive correct answers were determined as the patient's retronasal olfactory threshold. A strong correlation was found between Sniffin' Sticks TDI scores and retronasal odor threshold values in the normosmic group (P < .001, r:0.67). A very strong correlation was found between Sniffin' Sticks TDI scores and retronasal olfactory threshold values in the hyposmic group (P < .001, r:0.81). Furthermore, receiver operating characteristic (ROC) analysis revealed that the sensitivity and the specificity of normosmic/hyposmic differentiation of retronasal olfactory threshold test was 95% and 100%, respectively. The diagnostic cutoff value was 8.5. This study shows that the retronasal olfactory test, a psychophysical odor test performed using an orally presented stimulus, can be used to differentiate normosmic and hyposmic cases. 3 Laryngoscope, 131:1608-1614, 2021.

Özay H ，Çetin AÇ ，Ecevit MC 《-》

Validation study of a novel approach for assessment of retronasal olfactory function with combination of odor thresholds and identification.

The present study aimed to establish a test battery for the clinical assessment of retronasal odor thresholds and retronasal odor identification. Prospective case-control series. Sixty participants (36 women, 24 men, mean age 37.6 ± 19.4 years) were enrolled in this study; 36 were healthy controls and 24 were patients with olfactory dysfunction. Orthonasal olfactory function was assessed with the "Sniffin' Sticks" test battery. Retronasal olfaction was assessed with oral odorant delivery using special containers for threshold function, and with oral tasteless powders for odor identification. Retronasal and orthonasal olfaction were significantly correlated for threshold scores, identification score, and the sum of threshold and identification score (TI score). Validity analyses showed that the retronasal TI score was able to discriminate between healthy controls and patients with olfactory dysfunction. Normosmic participants can be distinctly differentiated from patients with olfactory dysfunction using a valid test battery comprised of retronasal threshold and identification tests. Based on the current findings, we advocate a TI score of 16 as a cut-off between patients and controls. Therefore, TI scores of 17 and above would indicate retronasal normosmia.

Yoshino A ，Pellegrino R ，Luckett CR ，Hummel T ... -  《-》

Retronasal olfaction in chronic rhinosinusitis.

The goals of this study were to assess retronasal olfaction in patients with chronic rhinosinusitis (CRS) and describe clinical factors that influence retronasal olfaction. This study sought to investigate the influence of retronasal olfaction on patient-perceived outcomes and examine the relationship between retronasal and orthonasal olfaction. Retronasal olfactory function was tested using odorized powders in the oral cavity, whereas Sniffin' Sticks test (Burghart Instruments, Wedel, Germany) were used to assess orthonasal function prospectively in 69 adult CRS patients. Endoscopic evaluation of the olfactory cleft was scored using the Olfactory Cleft Endoscopy Scale (OCES). Several quality-of-life (QOL) instruments relating to sinonasal, olfactory, and chemosensory functions were used to assess the interactions between patient-reported outcome measures and retronasal olfaction. There was strong correlation between retronasal and total orthonasal olfaction scores (r = 0.77, P < 0.001) as well as retronasal scores with orthonasal subscores. Retronasal scores were worse in patients with nasal polyposis (P = 0.002), asthma (P = 0.04), and aspirin-exacerbated respiratory disease (AERD) (P = 0.02), whereas OCES was the only independent predictor of retronasal olfaction (r = -0.42, P < 0.001). Significant correlation existed between retronasal olfaction and olfactory-specific QOL and chemosensory smell scores. Few studies have examined retronasal olfaction in CRS patients. In this cohort, CRS patients demonstrated deficits in retronasal olfaction, with worse scores in patients with nasal polyposis, asthma, and AERD. Retronasal olfaction scores correlate with degree of inflammation of the olfactory cleft. Retronasal olfaction correlated strongly with orthonasal olfaction and patient-reported smell and taste metrics, although orthonasal olfaction may have a stronger correlation with these metrics. NA. Laryngoscope, 2437-2442, 2018.

Othieno F ，Schlosser RJ ，Storck KA ，Rowan NR ，Smith TL ，Soler ZM ... -  《-》

The use of freeze-dried retronasal stimuli to assess olfactory function.

To evaluate a test of olfactory perception that uses freeze-dried stimuli developed to rapidly release aromas capable of migrating to the olfactory mucosa retronasally. Validation study. Psychology and Chemistry Departments. First, 15 participants provided data for psychometric functions. Second, 70 participants made perceptual judgments of retronasal stimuli. Inclusion criterion included informed consent and a satisfactory Nasal Obstruction Symptom Evaluation result. First, psychometric functions were generated for two types of freeze-dried stimuli (coffee and orange) using the Single-Interval Adjustment Matrix method. Second, participants provided ratings of pleasantness, intensity, and familiarity and performed a standardised identification test using seven retronasally presented aromas alongside the previously validated Sniffin' Sticks orthonasal olfactory test. Psychometric functions indicated a dose-response relationship between aroma concentration and probability of detection. Test-retest reliability of the retronasal stimuli was acceptable (r70  = 0.72, P < 0.001), and identification scores were not dependent on testing method (ie, retronasal vs Sniffin' Sticks). Stimuli delivered using the Sniffin' Sticks test were rated more pleasant than their retronasal counterparts. Freeze-dried retronasal stimuli offer an easy-to-use and rapid means to test olfaction function and are arguably well suited for clinical practice, but require further development and trialing prior to the adoption in the clinical context.

Pal P ，Shepherd D ，Hamid N ，Hautus MJ ... -  《-》