PURPOSE Although neglected by science for a long time, the sense of olfaction has received increasing attention from research areas including psychology, neuroscience, clinical medicine and nutrition. With the rise of psychophysical and neuroimaging re- search into olfaction, psychometric tools (e.g. questionnaires and scales) are the basis for the quantitative exploration of inter-in- dividual variability regarding olfactory related responses. The current systematic review is to summarize existing olfaction related questionnaires and/or scales. METHODS Peer-reviewed literature on scales and questionnaires related to perception of odors were searched from online databa- ses (PubMed, Web of Science and PsycINFO). Twenty-one articles that meet the following criteria were included in the review: "hu- man species", "no physical odor stimuli" and "describing the original development of the tool", and "with specific focus on olfaction or odor related responses or behaviors". The psychometric properties, advantages and possible disadvantages were discussed. RESULTS Existing psychometric measures focus on various aspects of olfactory related responses and behaviors, including af- fective experiences of odor perception, awareness and attitude towards olfaction, olfactory function and the quality of life change due to olfactory dysfunction, and the ability to create vivid mental odor images. While most of them have been tested to have good reliability and validity, some were relatively time-consuming due to the number of questionnaire items. Besides, although many measures have been used in clinical populations, few have provided information on the predictive validity regarding effecti- veness of clinical intervention on changes of certain responses or behaviors. SUMMARY The current review provides an overview of olfactory related questionnaires and scales, highlighting the emotional and affective impact of olfaction and the impact on quality of life due to olfactory dysfunction. With growing interest in olfaction as an important sense, the development and use of psychometrically sound measurements in conjunction with objective assess- ments will advance our understanding of human olfaction and olfactory dysfunction. The review provides a guide for researchers and clinicians alike to select olfactory scales suitable for olfactory research with different experimental purposes and specific samples.
A systematic review of olfactory related questionnaires and scales.