ABSTRACT
The sense of smell is one of the essential tools for all living things to survive. With recent increase in diseases associated with olfactory dysfunction, the evaluation of olfactory function aims to shed light on the understanding and assessment of the human olfactory system. The methods for assessing the olfactory function are largely divided into electrophysiological and psychophysical methods. The psychophysical inspections such as University of Pennsylvania Smell Identification Test (UPSIT), The Sniffin' Stick, and T & T Olfactometer are methods mostly based on questionnaires or simple apparatus. Those have been generally used in clinical and research field due to their relatively short examination time and low cost. The electrophysiological tests evaluate olfactory function based on objective measurements like biosignals and medical imaging. Compared to the psychophysical methods, they comparably have higher reliability and are possible to assess more specific diagnosis. However, the system configuration seems to be more complicated. In this paper, we review the overall evaluation methods of olfactory functions and suggest complementary points to improve conventional technologies.