SCENTinel 1.1 rapidly screens for COVID-19 related olfactory disorders

The COVID-19 pandemic has increased the prevalence of people suffering from olfactory disorders. In the absence of quick, population-wide olfactory tests, we developed SCENTinel, a rapid, inexpensive smell test to assess odor detection, intensity, and identification ability, which can discriminate anosmia (e.g., total smell loss) from normosmia (e.g., normal sense of smell) using a single odor. A new version, SCENTinel 1.1, extends the original test with one of four possible odors and a hedonic subtest (“how pleasant is the odor”). The purpose of this study was to determine if SCENTinel 1.1 can discriminate other types of olfactory disorders common to COVID-19, such as hyposmia (e.g., reduced sense of smell), parosmia (e.g., distorted odor perception), and phantosmia (e.g., odor sensation without an odor source). Participants (N=381) were divided into three groups based on their self-reported olfactory function: quantitative smell disorder (anosmia or hyposmia, N=135), qualitative smell disorder (parosmia and/or phantosmia; n=86), and normosmia (N=66). SCENTinel 1.1 classifies anosmia and normosmia groups with high sensitivity (AUC=0.94), similar to SCENTinel 1.0 (AUC=0.95). SCENTinel 1.1 also accurately discriminates quantitative from qualitative (AUC=0.76), and normosmia (AUC=0.84), and normosmia from qualitative (AUC=0.73) groups. We also considered a subset of participants who only reported one type of olfactory disorder. SCENTinel 1.1 discriminates hyposmia from parosmia (AUC=0.89), and anosmia (AUC=0.78); as well as parosmia from anosmia (AUC=0.82). Participants with parosmia had a significantly lower hedonic score than those without parosmia, indicating odor distortions are unpleasant. SCENTinel 1.1 is a rapid smell test that can discriminate quantitative (anosmia, hyposmia) and qualitative (parosmia, phantosmia) olfactory disorders, and it is among the only direct tests to rapidly screen for parosmia.