SENSORY THRESHOLDS IN THE STUDY OF ALTERATIONS IN SENSORY SENSITIVITY FOR PERCEPTION OF ODORS CAUSED BY COVID-19

COVID-19 disease has, among its symptoms, disturbances in smell and taste perception, which can lead to problems related to life quality. Sensitivity tests are important in measuring the ability to use the senses and the ability to detect, identify and/or differentiate stimuli. The objective of this work was to investigate the occurrence of alterations in sensory perception of individuals with total or partial loss of smell when infected by SARS-CoV-2, compared to individuals who were not diagnosed with the disease and did not present such symptoms. One hundred volunteers were recruited: 50 had a positive diagnosis for COVID-19 and olfactory dysfunction (COVID group) and 50 without a positive diagnosis and/or olfactory dysfunction (Control group). Four sessions of 3-AFC test were carried out for each odor solution studied (coffee, pineapple, lime and cinnamon) to determine the detection (DT) and recognition (RT) thresholds, in which each trio in each session was composed of two control samples (water) and a stimulus sample in increasing order of concentration between sessions (0.000001% to 1% v/v). In each session, the evaluator should say which sample was different and which odor was felt. The COVID group had higher DTs (p≤0.05) than the Control, for all odors. Individuals who had already been affected by the disease showed less sensitivity, as they were only able to detect olfactory stimuli at higher concentrations than those detected by the Control group. For RTs, there was a difference (p≤0.05) for all odors, and higher values were observed in the COVID group, demonstrating that these participants were only able to recognize odors at higher concentrations. The results demonstrate that individuals who tested positive for the disease and were affected by olfactory disorders have reduced sensitivity regarding the ability to detect and recognize odors, compared to individuals without a positive diagnosis and without symptoms.