Smell and taste disorders in polyneuropathy: a prospective study of chemosensory disorders

Objective – The aim of the study was to assess the occurrence and the frequency of chemosensory dysfunction in patients with polyneuropathy (PNP). Methods – We performed a prospective observational study. Olfactory function was assessed using the standardized ‘Sniffin’ Sticks’ test to measure odor threshold for phenyl ethyl alcohol, odor discrimination, and odor identification. Gustatory function was assessed using the standardized ‘taste strips’ test. In addition, we assessed etiology, neurophysiology, and severity of the PNP, and the patients’ comorbidities and medication. Results – A total of 53 consecutive patients were enroled (15 women, 38 men; mean age 61 years); 27 of them (51%) exhibited olfactory dysfunction and 23 of them (43%) gustatory dysfunction. Patients with diabetic PNP had significantly lower taste scores than patients with inflammatory, genetic, or idiopathic PNP. In addition, odor identification was negatively correlated with PNP severity. Conclusion – The applied bedside tests are useful to detect chemosensory dysfunction in patients with PNP. Chemosensory dysfunction is quite frequent in these patients.