Relationship between odor intensity estimates and COVID-19 prevalence prediction in a Swedish population

International audienceIn response to the coronavirus disease 2019 (COVID-19) pandemic, countries have implemented various strategies to reduce and slow the spread of the disease in the general population. For countries that have implemented restrictions on its population in a stepwise manner, monitoring of COVID-19 prevalence is of importance to guide the decision on when to impose new, or when to abolish old, restrictions. We are here determining whether measures of odor intensity in a large sample can serve as one such measure. Online measures of how intense common household odors are perceived and symptoms of COVID-19 were collected from 2440 Swedes. Average odor intensity ratings were then compared to predicted COVID-19 population prevalence over time i

Are Humans Constantly but Subconsciously Smelling Themselves?

All primates, including humans, engage in self-face-touching at very high frequency. The functional purpose or antecedents of this behaviour remain unclear. In this hybrid review we put forth the hypothesis that self-face-touching subserves self-smelling. We first review data implying that humans touch their own face at very high frequency. We then detail evidence from the one study that implicated an olfactory origin for this behaviour: This evidence consists of significantly increased nasal inhalation concurrent with self-face-touching, and predictable increases or decreases in self-face-touching as a function of subliminal odourant tainting. Although we speculate that self-smelling through self-face-touching is largely an unconscious act, we note that in addition, humans also consciously smell themselves at high frequency. To verify this added statement, we administered an online self-report questionnaire. Upon being asked, ~94% of ~400 respondents acknowledged engaging in smelling themselves. Paradoxically, we observe that although this very prevalent behaviour of self-smelling is of concern to individuals, especially to parents of children overtly exhibiting self-smelling, the behaviour has nearly no traction in the medical or psychological literature. We suggest psychological and cultural explanations for this paradox, and end in suggesting that human self-smelling become a formal topic of investigation in the study of human social olfaction

Olfactory sniffing signals consciousness in unresponsive patients with brain injuries.

After severe brain injury, it can be difficult to determine the state of consciousness of a patient, to determine whether the patient is unresponsive or perhaps minimally conscious1, and to predict whether they will recover. These diagnoses and prognoses are crucial, as they determine therapeutic strategies such as pain management, and can underlie end-of-life decisions2,3. Nevertheless, there is an error rate of up to 40% in determining the state of consciousness in patients with brain injuries4,5. Olfaction relies on brain structures that are involved in the basic mechanisms of arousal6, and we therefore hypothesized that it may serve as a biomarker for consciousness7. Here we use a non-verbal non-task-dependent measure known as the sniff response8-11 to determine consciousness in patients with brain injuries. By measuring odorant-dependent sniffing, we gain a sensitive measure of olfactory function10-15. We measured the sniff response repeatedly over time in patients with severe brain injuries and found that sniff responses significantly discriminated between unresponsive and minimally conscious states at the group level. Notably, at the single-patient level, if an unresponsive patient had a sniff response, this assured future regaining of consciousness. In addition, olfactory sniff responses were associated with long-term survival rates. These results highlight the importance of olfaction in human brain function, and provide an accessible tool that signals consciousness and recovery in patients with brain injuries

Erratum: Relationship between odor intensity estimates and COVID-19 prevalence prediction in a Swedish population (Chem. Senses (2020) DOI: 10.1093/chemse/bjaa034)

This is a correction notice for article bjz034 (DOI: https://doi. org/10.1093/chemse/bjaa034), published on 22 May 2020. Due to an error in the script used to create subsections of Figure 1, there was both a shift in the intensity data and an erroneous calculation of error bars in all panels. Figure 1 and the accompanying figure legend have been revised to show the correct levels and error bars. This script error only affected visualization of the data in Figure 1 and did not impact the reported data or conclusions.(Figure Presented)

Relationship Between Odor Intensity Estimates and COVID-19 Prevalence Prediction in a Swedish Population

International audienceIn response to the coronavirus disease 2019 (COVID-19) pandemic, countries have implemented various strategies to reduce and slow the spread of the disease in the general population. For countries that have implemented restrictions on its population in a stepwise manner, monitoring of COVID-19 prevalence is of importance to guide the decision on when to impose new, or when to abolish old, restrictions. We are here determining whether measures of odor intensity in a large sample can serve as one such measure. Online measures of how intense common household odors are perceived and symptoms of COVID-19 were collected from 2440 Swedes. Average odor intensity ratings were then compared to predicted COVID-19 population prevalence over time i

Relationship Between Odor Intensity Estimates and COVID-19 Prevalence Prediction in a Swedish Population (vol 45, bjaa034, 2020)

This is a correction notice for article bjz034 (DOI: https://doi. org/10.1093/chemse/bjaa034), published on 22 May 2020. Due to an error in the script used to create subsections of Figure 1, there was both a shift in the intensity data and an erroneous calculation of error bars in all panels. Figure 1 and the accompanying figure legend have been revised to show the correct levels and error bars. This script error only affected visualization of the data in Figure 1 and did not impact the reported data or conclusions.(Figure Presented)