Validation of the questionnaire of olfactory disorders (QOD) for the Brazilian population

BACKGROUND

The incidence of olfactory disorders has increased in recent years, mainly related to COVID-19 infection. In Brazil, over 37 million cases of COVID-19 have been reported, and approximately 10 % of those cases continue to experience olfactory disorders for more than one month. Despite the significant negative impact on well-being, there is currently no validated instrument to assess how olfactory disorders impact the quality of life in Brazil.

OBJECTIVES

This study aimed to validate the Questionnaire of Olfactory Disorders (QOD) for Brazilian Portuguese.

METHODS

The authors first performed translation, back-translation, expert review, pre-testing, psychometric evaluation and cultural adaptation of the English version of the questionnaire. To assure linguistic and conceptual equivalence of the translated questionnaire, 126 participants from two Brazilian states and varying degrees of olfactory loss answered the QOD and the World Health Organization Quality of Life bref (WHOQOL-bref) questionnaires. The University of Pennsylvania Smell Identification Test (UPSIT®) was used to quantify the olfactory loss. Furthermore, to evaluate the reliability of the Portuguese version a test-retest was performed on a subgroup of patients. The authors observed a high Cronbach's alpha (α = 0.86) for internal consistency of the quality of Life (QOD-QOL) statements.

FINDINGS

As expected, there was a negative correlation between QOD-QOL and UPSIT® (Spearman's ρ = -0.275, p = 0.002), since QOL score increases and UPSIT® score decreases with worsening of olfactory function. Correlations were moderate between QOD-QOL and WHOQOL-bref mean (Spearman's ρ = -0.374, p < 0.001) and weak to moderate between the QOD-QOL and Visual Analog Scale of the QOD regarding professional life, leisure, and private life (Spearman's ρ = -0.316, p = 0.000; Spearman's ρ = -0.293, p = 0.001; Spearman's ρ = -0.261, p = 0.004; respectively).

CONCLUSION

In conclusion, the authors have demonstrated a high internal consistency and validity of the Brazilian Portuguese version of the QOD for evaluating the quality of life in individuals with olfactory disorders.

Reliability and validity of the Arabic version of the brief version of the Questionnaire of Olfactory Disorders

Background

An accessible self-assessment questionnaire is needed to evaluate quality of life in olfactory dysfunction. The need to address this gap led to the development of the brief version of the Questionnaire of Olfactory Disorders (brief QOD), which holds particular value in the context of telemedicine.

Objectives

The aim of this study is to examine the reliability and validity of the Arabic brief QOD.

Methods

This study included 307 patients suffering from olfactory dysfunction as well as a control group filled a questionnaire including demographic information, the olfaction Visual Analog Scale (VAS), the Sino-nasal Outcome Test 22 (SNOT-22) questionnaire, and the Arabic version of the brief QOD. The Arabic brief QOD's reliability was assessed using Cronbach's α to measure internal consistency. To evaluate test-retest reliability, the intraclass correlation coefficient (ICC) was employed. The discriminative ability: score differences between the two groups were analyzed. The validity Arabic brief QOD was evaluated by comparing it to the olfaction VAS.

Results

The Cronbach's α coefficients were 0.757 for Questionnaire of Olfactory Disorders-Parosmia (QOD-P), 0.832 Questionnaire of Olfactory Disorders-quality of life (QOD-QoL), and 0.817 Questionnaire of Olfactory Disorders-visual analog scale (QOD-VAS). The reliability of the overall brief QOD was 0.93. The ICC exceeded the acceptable threshold of 0.7, indicating strong test-retest reliability. The highest correlation was observed between the SNOT-22 and QOD total scores (r = 0.552 and p < .001) as well as between SNOT-22 and QOD VAS (r = 0.512 and p < .001).

Conclusion

Excellent validity and reliability have been shown for the Arabic brief QOD as a self-assessment tool assessing quality of life among olfactory dysfunction patients.

Level of evidence

NA.

Validity and reliability of the Questionnaire of Olfactory Disorders for Italian-speaking patients with olfactory dysfunction

Objective

To translate and validate an Italian version of the Questionnaire of Olfactory Disorders (IT-QOD).

Materials and methods

This is a prospective, multicentre study that involved patients with olfactory dysfunction (OD). Both cases and controls underwent administration of the IT-QOD, Sino-Nasal Outcome Test-22 (SNOT-22) and psychophysical evaluation of orthonasal and retronasal olfactory function.

Results

The IT-QOD was administered to 96 patients and 38 controls. The Cronbach's alpha exceeded 0.90, indicating satisfactory internal consistency. The test-retest reliability was found to be high for both parosmia (rs = 0.944) and life quality (rs = 0.969). Patients with OD had significantly higher IT-QOD scores compared to healthy individuals (p < 0.001), indicating strong internal validity. The external validity was also satisfactory, as shown by the significant correlation with SNOT-22 (rs = -0.54) and the threshold, discrimination, and identification score (rs = -0.63).

Conclusions

The IT-QOD was demonstrated to be reliable and valid to assess the impact of OD on the quality of life of Italian-speaking patients.

Validity and Reliability of the Malay Questionnaire for Olfactory Disorders

Background

Olfactory disorders (OD) are an umbrella term for a diverse group of smell problems. Numerous tests and questionnaires have been formulated to identify and test the severity of smell impairment, which is not readily available or translated for the Malaysian population. This study aimed to translate the Questionnaire for Olfactory Disorders (QOD) and validate and test the reliability of the Malay Questionnaire for Olfactory Disorders (mQOD).

Methods

This cross-sectional study was conducted in two tertiary centres. A forward and backward translation was conducted for the QOD. The translated questionnaire was distributed to subjects with self-reported smell disorders on days 1 and 7. Internal consistency was analysed using Cronbach's alpha and test-retest reliability was tested with an intraclass correlation coefficient. Confirmatory factor analysis was performed to test construct validity.

Results

A total of 375 participants were recruited, 52 dropped out and 323 completed the questionnaire a second time. The Cronbach's alpha coefficient was 0.537 for parosmia (P), 0.892 for life quality (LQ), 0.637 for sincerity (S) and 0.865 for visual analogue score (VAS). The intraclass correlation coefficient (ICC) for domain scores was > 0.9, while the ICC for all items was good to excellent. A three-factor model for mQOD showed an acceptable fit with indices chi-square value (CMIN)/degree of freedom (DF) = 3.332, Tucker-Lewis fit index (TLI) = 0.923, comparative fit index (CFI) = 0.939, root mean square error of approximation (RMSEA) = 0.079 and standardised root mean square residual (SRMR) = 0.0574.

Conclusion

The mQOD is a valid and reliable tool for assessing OD in patients.

[Detection of disorders of the chemical senses-assessment of state of health by those affected]

Although hundreds of thousands of people seek medical help every year because of smell and taste disorders, the burden on patients is often underestimated by health care professionals. Numerous studies have demonstrated the impact of disorders of the chemical senses on quality of life. In clinical practice, the Questionnaire of Olfactory Disorders (QOD) has proven to be a good measure of the impact of olfactory loss on everyday life. Patient-reported outcome measures (PROMs) should therefore be used more frequently for better recording and assessing the needs of patients. In addition to education and treatment by specialized clinics, the provision and optimization of information platforms, support groups, and organizations should be promoted in Germany.

Reliability and validity of the Polish version of the Questionnaire of Olfactory Disorders

Background

The comprehensive counseling of patients with olfactory dysfunctions requires accurate diagnosis. The recommendations include subjective assessment. The Questionnaire of Olfactory Disorders (QOD) is a disease-specific questionnaire for the subjective evaluation of olfactory dysfunctions.

Material

The study included 54 patients with olfactory dysfunctions, who were recruited to the study group (SG). The other 47 patients without the history of olfactory dysfunction and nasal cavity pathology were voluntarily allocated to the control group (CG). The protocol of the study was introduced to each patient and included: olfactory testing with Sniffin' Stick test, fulfillment of the Polish version of World Health Organization Quality of Life brief questionnaire and completing of the Polish version of the QOD. All participants (101) were invited for refilling the QOD questionnaire after 2 weeks for the test-retest statistics.

Results

The Polish QOD statements were significantly correlated and met the requirement by having test-retest correlation larger than 0.7. We found that internal consistency of the test measured by Cronbach's alpha coefficient was very high. The mean scores of the QOD test in normosmic SG patients were compared with corresponding scores in normosmic CG patients using U Mann-Whitney test. The analysis revealed statistically significant differences on mean QOD scores for each domains except QOD-S between both groups.

Conclusions

The Polish version of the QOD demonstrated high rate of the validity and the reliability. This instrument may be widely used in research projects and clinical practice concerning olfactory disorders in Polish patients.

Level of Evidence

NA.

Italian version of the brief Questionnaire of Olfactory Disorders (brief-IT-QOD)

Objective

To evaluate the reliability and validity of the Italian brief-QOD (Brief-IT-QOD).

Methods

The study consisted of six phases: item generation, reliability analysis (112 dysosmic patients for internal consistency analysis and 61 for test-retest reliability analysis), normative data generation (303 normosmic subjects), validity analysis (comparison of Brief-IT-QOD scores of healthy and dysosmic subjects and scores correlation with psychophysical olfactory testing (TDI) and SNOT-22 scores), responsiveness analysis (10 dysosmic chronic rhinosinusitis with nasal polyps (CRSwNP) patients before and after biologic therapy), and cut-off value determination (ROC curve analysis of Brief-IT-QOD sensitivity and specificity).

Results

All subjects completed the Brief-IT-QOD. Internal consistency (α > 0.70) and test-retest reliability (ICC > 0.7) were acceptable and satisfactory for both questionnaire subscales. A significant difference between dysosmic and control subjects was found in both subscales (p < 0.05). Significant correlations between subscales scores and TDI and SNOT-22 scores were observed. Brief-IT-QOD scores before treatment were significantly higher than after biological therapy.

Conclusions

Brief-IT-QOD is reliable, valid, responsive to changes in QoL, and recommended for clinical practice and outcome research.

Olfactory Disorders Questionnaire: Scaling severity of quality-of-life impact

BACKGROUND

The Olfactory Disorders Questionnaire (ODQ) is widely used for patients suffering from olfactory disorders to depict the impact on quality of life. The aim of this study was to scale and produce reference values for patients ODQ score according to Becks Depression Inventory (BDI) severity.

METHODS

In this prospective study, a cross-sectional anonymous survey was created, which combined EQ-5D-5L, BDI and ODQ. Correlation was calculated between the three questionnaires. Receiver operator characteristic curves were created to produce cut-off values for ODQ scores based on three BDI categories (mild, borderline clinical and moderate-to-severe depression).

RESULTS

Of the 578 who responded to the survey, 445 completed all sections and were included in the study. Majority were female (n = 327,73.5%), median age group 55-70 years (n = 193,43.4%). There was a strong correlation between BDI score and total ODQ score. There was a clear gradient in total ODQ score for each BDI classification; those with mild depression had the lowest mean ODQ score (101.8, range 39-168), those with moderate-to-severe depression had the highest (138.24, range 74-177). Due to overlapping of confidence intervals we were unable to grade the ODQ score.

CONCLUSION

The study was unable to generate reference values for the ODQ due to lower numbers of patients with borderline clinical to extreme depression. However, we were able to appreciate the general trend, that the higher the ODQ score, the higher the risk of depression. These findings should guide clinical practice to ensure appropriate care and support is provided for those with olfactory dysfunction.

Adaptation and Validation of Portuguese Version of Olfactory Disorders Questionnaire (PT-ODQ)

Introduction

Olfactory dysfunction (OD) is often a devaluated sensorial affection. The objective evaluation of this dysfunction doesn’t evaluate its compromise in patients’ daily life. Therefore, the use of a Portuguese-validated tool is of uttermost importance to objectively scale the pathology presented by these patients.

Objective

We aim to validate and cross-culturally adapt the Olfactory Disorders Questionnaire (ODQ) in the Portuguese language.

Methods

A prospective study was carried out to evaluate and compare 56 consecutive patients who had olfactory disorders and 54 asymptomatic controls. A cross-cultural adaptation process was taken into account in order to transform the original English tool into a valid Portuguese version. We explored the psychometric properties of the European-Portuguese version of the Portuguese version of ODQ (PT-ODQ) concerning its internal consistency, reproducibility, feasibility, and discriminatory validity.

Results

Cronbach alpha for the tool was 0.924 showing strong internal consistency. We also found a statistically significant difference in PT-ODQ between patients with olfactory disorders and patients without olfactory disorders, according to the Mann-Whitney test.

Conclusions

The PT-ODQ seems to be a valid tool for assessing the individual effect of olfactory disorders on patients’ quality of life and, therefore, could be applied in olfactory disorders research and daily practice.

Validity and reliability of a french version of the olfactory disorders questionnaire

Objective

To validate a French version of the Olfactory Disorders Questionnaire (Fr-ODQ).

Methods

Patients with olfactory disorder (OD) and controls were enrolled from two medical centers. Individuals completed the Fr-ODQ and the French version of the sinonasal outcome tool-22 (SNOT-22). The extended Sniffin'Sticks procedure was used to test odor Threshold, Discrimination, and Identification (TDI). Cronbach’s alpha was used to measure the internal consistency of Fr-ODQ. The reliability and the external validity were evaluated through a test–retest approach and by correlating Fr-ODQ and SNOT-22 scores.

Results

Eighty-nine patients with OD and 65 healthy individuals completed the evaluations. The Cronbach’s alpha was 0.827, reporting adequate internal consistency. The test–retest reliability was high (r_s = 0.944, p = 0.001). The external validity was adequate regarding the significant correlation between Fr-ODQ and SNOT-22 (r_s = 0.498; p = 0.001). Patients with OD reported a significant higher score of Fr-ODQ than healthy individuals (p < 0.001), indicating a high internal validity. The baseline Fr-ODQ significantly improved after 3-month olfactory training, which corroborated the improvement of TDI scores.

Conclusion

The Fr-ODQ is the first patient-reported outcome questionnaire validated for French speaking patients. Fr-ODQ is reliable and valid for the evaluation of the olfactory dysfunction and the related impact on quality of life of French-speaking patients.

Supplementary Information

The online version contains supplementary material available at 10.1186/s40463-022-00598-2.

Predictive significance of the questionnaire of olfactory disorders-negative statements for olfactory loss in patients with chronic rhinosinusitis

Objectives

The questionnaire of olfactory disorder-negative statements (QOD-NS) is a valid and reliable instrument for assessing the olfactory-specific quality of life. This study aimed to explore the association between the QOD-NS and objective olfactory metrics (including objective olfactory cleft assessment) and then evaluate the predictive significance of the QOD-NS for olfactory loss in Chinese patients with chronic rhinosinusitis (CRS).

Methods

A total of 70 patients with CRS were enrolled in the study. Olfaction was assessed with Sniffin’ Sticks. The olfactory cleft was assessed by the sinus CT scan and nasal endoscopy (the Lund–Mackay olfactory cleft scale, LM-OC and olfactory cleft endoscopy scale, OCES). The QOD-NS and its short version were utilized to assess the patient-reported olfaction. The predictors associated with olfactory loss were analyzed by the logistic regression analysis. The optimal cutoff points of the predictors were determined by the receiver-operating characteristic curves and the Youden index.

Results

The TDI score in patients with CRS significantly correlated with the QOD-NS (r = − 0.755, P < 0.001), OCES (r = − 0.520, P < 0.001), LM-OC (r = − 0.615, P < 0.001). After adjusting for patient demographics and comorbidities, QOD-NS was significantly associated with olfactory dysfunction [odds ratio (OR) = 1.243; P = 0.001] and anosmia in patients with CRS (OR = 1.838; P = 0.006). Furthermore, the QOD-NS significantly correlated with the LM-OC (r = 0.610, P < 0.001), and the OCES (r = 0.464, P < 0.001) in patients with CRS. The QOD-NS had the highest predictive value for olfactory dysfunction (optimal cutoff = 10.5; Youden index = 0.635; area under the curve = 0.861) and anosmia (optimal cutoff = 20.5; Youden index = 0.790; area under the curve = 0.928) in patients with CRS.

Conclusion

The QOD-NS showed high validity and correlated well with objective olfactory metrics and olfactory cleft assessment in patients with CRS. The QOD-NS was a reliable predictor for olfactory dysfunction and anosmia in patients with CRS, which may aid in the fast screening of olfactory loss in the clinic.

Reliability and validity of a brief version of the Questionnaire of Olfactory Disorders (brief QOD) in patients with olfactory dysfunction

BACKGROUND

The aim of this study was to determine the reliability and validity of the brief version of Questionnaire of Olfactory Disorders (brief QOD).

METHODS

A total of 372 patients participated in this study. Olfactory function was examined using the Sniffin' Sticks test. The brief version of QOD, including 4 items concerning parosmia (QOD-P), 7 items concerning quality of life (QOD-QOL), and 3 visual analog scales to rate disease burden, awareness of the disorder and issues related to professional life (QOD-VAS), was used to assess subjective information on olfactory dysfunction. We evaluated the split-half reliability, internal consistency and validity of the brief QOD.

RESULTS

The split-half reliability was 0.60 (QOD-P), 0.87 (QOD-QOL), and 0.66 (QOD-VAS), respectively. The Cronbach's α coefficient was 0.63 (QOD-P), 0.87 (QOD-QOL), and 0.71 (QOD-VAS), respectively. Olfactory function was found to be associated with QOD-P, QOD-QOL and QOD-VAS.

CONCLUSIONS

The brief QOD is a suitable scale for the assessment of subjective severity of olfactory dysfunction for purposes such as treatment counseling, disability assessment, treatment control, and research in patients with olfactory disorder.

Cardiac Autonomic Dysfunction Is Associated with Severity of REM Sleep without Atonia in Isolated REM Sleep Behavior Disorder

123I-metaiodobenzylguanidine (MIBG) cardiac scintigraphy was performed to assess cardiac autonomic dysfunction and demonstrate its correlation with clinical and polysomnographic characteristics in patients with isolated rapid eye movement (REM) sleep behavior disorder. All subjects including 39 patients with isolated REM sleep behavior disorder and 17 healthy controls underwent MIBG cardiac scintigraphy for cardiac autonomic dysfunction assessment. The isolated REM sleep behavior disorder was confirmed by in-lab overnight polysomnography. A receiver operating curve was constructed to determine the cut-off value of the early and delayed heart-to-mediastinum ratio in patients with isolated REM sleep behavior disorder. Based on each cut-off value, a comparison analysis of REM sleep without atonia was performed by dividing isolated REM sleep behavior disorder patients into two groups. MIBG uptake below the cut-off value was associated with higher REM sleep without atonia. The lower heart-to-mediastinum ratio had significantly higher REM sleep without atonia (%), both with cut-off values of early (11.0 ± 5.6 vs. 29.3 ± 23.2%, p = 0.018) and delayed heart-to-mediastinum ratio (9.1 ± 4.3 vs. 30.0 ± 22.9%, p = 0.011). These findings indicate that reduced MIBG uptake is associated with higher REM sleep without atonia in isolated REM sleep behavior disorder.

Development of a Self-reported Olfactory Dysfunction Questionnaire (SODQ) to screen olfactory disorders in China

BACKGROUND

The diagnosis of olfactory dysfunction is challenging given the negligence during routine physical examination, inconvenience of diagnosis in clinical practice, and the inattention to cross-cultural adaptability. The study aimed to develop and validate a simple and effective self-reported olfactory dysfunction questionnaire (SODQ) for the initial screening of clinical olfactory disorders in China.

METHODS

A total of 121 subjects participated in the study; of these, 96 subjects completed the T&T olfactometer test and 12-item questionnaire, and 25 participants were retested using the SODQ after one week. The T&T olfactometer test examined the olfactory function and the questionnaire measured the ability to perceive common odors in daily life. We evaluated the factor structure, reliability, validity, and discriminative ability of the SODQ.

RESULTS

The final version of the SODQ consisted of 10 items with one factor. Test-retest and internal consistency were excellent. Convergent validity of the questionnaire with the T&T olfactory test was high. Furthermore, the discrimination ability was high for the questionnaire with an area under the curve of 0.95 and a cut-off point of 22.

CONCLUSIONS

The SODQ is a brief, valid, and repeatable tool that has the potential to effectively screen for clinical olfactory disorders from a subjective perspective.

Clinical Features of Olfactory Dysfunction in COVID-19 Patients

BACKGROUND

The aim of this study was to evaluate the subjective and objective olfactory function in coronavirus disease 2019 (COVID-19) patients and the effect of olfactory training.

METHODS

A prospective cohort study was performed in 53 patients who recovered from COVID-19 and visited our tertiary hospital. Subjective olfactory function was evaluated using the 11-point Likert scale (0-10) and the Korean version of the Questionnaire of Olfactory Disorders (QOD). Objective olfactory function was evaluated using Cross-Cultural Smell Identification Test (CC-SIT). Confirmed patients were followed up after 2 months of olfactory training.

RESULTS

The median, interquartile range (Q1-Q3) score of subjective olfactory function significantly deteriorated in patients with olfactory dysfunction (OD) than in those without OD, even after 3 months of onset (11-point Likert scale, 8, 6-9 vs. 10, 10-10; short version of QOD-negative statements, 19, 16-21 vs. 21, 21-21; QOD-visual analogue scale, 7, 1-13 vs. 0, 0-0; all P < 0.001). However, the objective olfactory function was not significantly different between the two groups (median, interquartile range; 11, 9-11 vs. 11, 9-11, P = 0.887). The percentage of patients with objective hyposmia (CC-SIT ≤ 10) was also not significantly different (47.4% vs. 40%, P = 0.762). OD in COVID-19 was normalized after 2 months of olfactory training in 70% of patients even after 3 months of olfactory impairment.

CONCLUSION

Although subjective olfactory function is significantly decreased in the OD group, the objective olfactory function was not significantly different. Moreover, olfactory training is effective in COVID-19 patients with OD.

Effect of olfactory bulb atrophy on the success of olfactory training

PURPOSE

To evaluate the success of olfactory training in patients with olfactory loss and olfactory bulb (OB) atrophy detected on magnetic resonance imaging (MRI) and other characteristics.

METHODS

This study included 48 patients with olfactory loss who underwent a nasal endoscopic examination and MRI before olfactory training. The Korean Version of the Sniffin' Sticks Test was performed before and after training. The olfactory training success was defined as an improvement of more than 6 points in the Threshold-Discrimination-Identification (TDI) score. Patient characteristics and OB atrophy pre-training were compared between successful and unsuccessful groups.

RESULTS

The etiology of olfactory loss included respiratory viral infection in 30 (62.5%), trauma in 10 (20.8%), and idiopathic loss in 8 (16.7%) patients. Twenty-three (47.9%) of 48 patients exhibited successful olfactory training. Etiology, age, gender, and symptom duration were not different between unsuccessful and successful groups. Pre-training discrimination, identification, and TDI scores were significantly different between unsuccessful and successful groups (P < 0.05). Success rate of patients with bilateral OB atrophy was significantly lower than that of patients with unilateral OB atrophy and normal morphology (P = 0.006). OB height was significantly lower in the unsuccessful group than in the successful group (P < 0.05). Bilateral OB atrophy was an independent risk factor for failure of olfactory training according to the multivariate analysis.

CONCLUSION

Olfactory loss patients with bilateral OB atrophy may not be able to improve olfactory function after olfactory training.

Trend of Olfactory and Gustatory Dysfunction in COVID-19 Patients in a Quarantine Facility

BACKGROUND

Olfactory and gustatory dysfunction has been reported as characteristic symptoms of coronavirus disease 2019 (COVID-19). This study evaluated olfactory and gustatory dysfunction in mild COVID-19 patients using validated assessment methods.

METHODS

A prospective surveillance study was conducted for mild COVID-19 patients who were isolated at the Gyeonggi International Living and Treatment Support Center (LTSC), Korea. Olfactory function was assessed using the Korean version of the Questionnaire of Olfactory Disorders (QOD) and Cross-Cultural Smell Identification Test (CC-SIT). Gustatory function was assessed using an 11-point Likert scale and 6-n-propylthiouracil, phenylthiocarbamide, and control strips. All patients underwent nasal and oral cavity endoscopic examination.

RESULTS

Of the 62 patients at the LTSC, 15 patients (24.2%) complained of olfactory or gustatory dysfunction on admission. Four of 10 patients who underwent functional evaluation did not have general symptoms and 2 were asymptomatic. The mean short version of QOD-negative statements and QOD-visual analogue scale scores were 13 ± 6 and 4.7 ± 3.6, respectively. The mean CC-SIT score was 8 ± 2. No patients showed anatomical abnormalities associated with olfactory dysfunction on endoscopic examination. The mean Likert scale score for function was 8 ± 2, and there were no abnormal lesions in the oral cavity of any patient.

CONCLUSIONS

The prevalence of olfactory and gustatory dysfunction was 24.2% in mild COVID-19 patients. All patients had hyposmia due to sensorineural olfactory dysfunction, which was confirmed using validated olfactory and gustatory evaluation methods and endoscopic examination. Olfactory and gustatory dysfunction may be characteristic indicators of mild COVID-19.

Validation of the olfactory disorders questionnaire for English-speaking patients with olfactory disorders

OBJECTIVES

To adapt the existing German language olfactory disorders questionnaire for use with English-speaking patients. To validate the adapted version for routine clinical use.

DESIGN

The translated version of the original German questionnaire was revised with a patient and a clinician to reflect British language and culture. Patients attending an olfactory dysfunction clinic were recruited to perform the adapted questionnaire on two occasions at least 1 month apart. Additional online participants completed the questionnaire via the charity Fifth Sense.

MAIN OUTCOME MEASURES

Retest reliability of the English olfactory disorders questionnaire (eODQ) in affected patients including potential for redundancy in any of the included questions. Correlation of eODQ scores with Sniffin' Sticks scores.

RESULTS

Eighty-seven patients reporting olfactory dysfunction were recruited and had a mean age of 48 with 35% of them being male; 50 datasets were available for analysis. A total of 957 members of the charity entered responses into the online questionnaire; 699 responses could be scored with participants' mean age of 55 years and with 69% reporting as female. The eODQ score and Sniffin' Sticks threshold, discrimination and identification score at timepoint 1 were correlated to assess for concurrent validity, (r = -0.15, P = 0.17) and showed no significant correlation. Female participants had a significantly higher mean total eODQ score than men, 55.75 compared to 52.28 (P = 0.001). The average score was 54.7 (SD 13.5) with a range from 26 to 87. The internal consistency of the questionnaire was good with a Cronbach's alpha of 0.90 (confidence intervals 0.89, 0.91).

CONCLUSIONS

The results of this study support the use of the eODQ in a native English-speaking population and highlight the different distinctions between "objective" testing of olfaction with the Sniffin' Sticks test, and the patient reported impact of olfactory dysfunction on daily life. These two types of assessment can be easily administered in an outpatient setting and used in the assessment and management of olfactory dysfunction.