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.