Proof-of-concept: SCENTinel 1.1 rapidly discriminates COVID-19 related olfactory disorders

Abstract

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.

Direct measures of liking and intensity of taste, smell, and chemesthetic stimuli are similar between young people reporting they did or did not have COVID-19

“…Even though this suggests that those subjects had some better smell and/or taste capabilities before COVID-19, lack of data on their pre-COVID-19 chemesthetic capabilities makes it impossible to precisely define to what degree their deficits were COVID-related, and what smell/taste qualities, and quantities were affected by COVID-19. This result also argues for the need for regular smell and taste screenings raised in other reports (Mainland et al, 2020;Hunter et al, 2023). Development and widespread use of relevant tests can benefit society, especially that it might help in early diagnosis of diseases in which smell loss is one of the symptoms, such as neurodegenerative diseases and accelerated cognitive decline (Albers et al, 2006;Dintica et al, 2019;Doty and Hawkes, 2019), or head trauma (Callahan and Hinkebein, 1999).…”

Using SCENTinel® to predict SARS-CoV-2 infection: insights from a community sample during dominance of Delta and Omicron variants

“…This was not explicitly discouraged or encouraged in the instructions. The SCENTinel ® odor detection and odor identification task (both its first and second attempt) were scored as dichotomies (i.e., correct/incorrect); the odor intensity rating was collected as a continuous variable and then scored as a dichotomy (i.e., ≤20 = smell loss; ≥21 = acceptable smell function) (8,34). The odor intensity cutoff of 20 was used based on a previous study that found that those who rated a moderate to strong odor <20 on a 1-100 scale was indicative of COVID-19 related smell loss (8,34).…”

“…The SCENTinel ® test is a rapid, accurate, inexpensive, and selfadministered screening test that combines assessments of three components of olfactory function: odor detection, odor intensity, and odor identification (29,34). The SCENTinel ® test card contains three boxes (A, B, or C) using Lift'nSmell technology (Scentisphere, Carmel, NY, United States).…”

“…Further odorant information can be found in Supplementary Table S2. SCENTinel ® 1.1 test cards were used from April 5 to August 20, 2021 (34), and SCENTinel ® 2.0 test cards were used from August 31, 2021 to July 5, 2022.…”

“…SCENTinel ® is a smell test developed to measure multiple dimensions of olfactory function (i.e., odor detection, intensity, and identification, summed into an overall score) within 2 min, making it a suitable point-of-care screening tool to assess smell loss (29,34). We have previously reported its ability to discriminate between those with a normal sense of smell (i.e., normosmia) and those with anosmia, hyposmia, and parosmia (i.e., odor distortions from a known source) (29,34).…”