Differences in Correlation between Subjective and Measured Olfactory and Gustatory Dysfunctions after Initial Ear, Nose and Throat Evaluation

Introduction Subjective chemosensory function can differ from measured function. Previous studies on olfactory assessment have found a positive correlation between subjective and measured scores. However, information on gustatory correlation between measured and subjective functions is sparse in patients who have undergone an initial ear, nose and throat (ENT) evaluation. Objectives To evaluate the correlation between subjective and measured olfactory and gustatory dysfunctions in a population complaining of taste and/or smell dysfunction after an initial ENT evaluation without chemosensory testing. Furthermore, we aimed to assess the need for chemosensory testing depending on the type of subjective chemosensory dysfunction. Methods A case series in which subjective chemosensory function was assessed through a questionnaire and measured chemosensory function was assessed by validated clinical tests. Results In total, 602 patients with complaints of olfactory and/or gustatory dysfunction were included. We found that 50% of the patients with normal gustatory function and an olfactory impairment classified their olfactory impairment as a subjective taste disorder. Furthermore, 98% of the patients who rated their olfactory function as absent did have a measurable olfactory impairment, but only 64% were anosmic. Conclusion Subjective gustatory dysfunction was poorly correlated with measured gustatory dysfunction, and was often found to reflect olfactory dysfunction. Contrarily, subjective olfactory dysfunction was positively correlated with measurable olfactory dysfunction. Although subjective anosmia was a strong indicator of measured anosmia or hyposmia, the existence of remaining olfactory function was frequently found in these patients. Validated chemosensory testing should be performed in patients with perceived olfactory or gustatory deficits, as this could help ensure increased diagnostic precision and a relevant treatment.