Standardized Testing Demonstrates Altered Odor Detection Sensitivity and Hedonics in Asymptomatic College Students as SARS-CoV-2 Emerged Locally

Aerosol droplets have emerged as the primary mode of SARS-Cov-2 transmission and can be spread by infectious asymptomatic/pre-symptomatic persons rendering indicators of latent viral infection essential. Olfactory impairment is now a recognized symptom of COVID-19 and is rapidly becoming one of the most reliable indicators of the disease. We compared olfaction data from asymptomatic students, who were assessed as SARS-CoV-2 was unknowingly spreading locally, to students tested prior to the arrival of the virus. This study was naturalistic by design as testing occurred in the context of four research studies, all of which used the same inclusion/exclusion criteria and the same protocol to objectively assess odor detection, identification, and hedonics with physiological tests. Data from students (Cohort II; N=22) with probable SARS-CoV-2 exposure were compared to students tested just prior to local virus transmission (Cohort I; N=25), and a normative sample of students assessed over the previous four years (N=272). Students in Cohort II demonstrated significantly reduced odor detection sensitivity compared to students in Cohort I (t=2.60; P=.01; d=0.77; CI, 0.17, 1.36), with a distribution skewed towards reduced detection sensitivity (D=0.38; P=.005). Categorically, the exposed group was significantly more likely to have hyposmia (OR=7.74; CI, 3.1, 19.40), particularly the subgroup assessed in the final week before campus closure (OR=13.61; CI, 3.40, 35.66;). The exposed cohort also rated odors as less unpleasant (P<.001, CLES=0.77). A limitation of our study is that participants were not tested for COVID-19 as testing was unavailable in the area. Objective measures of olfaction may detect olfactory impairment in asymptomatic persons who are otherwise unaware of smell loss. The development of cost-effective, objective olfaction tests that could be self-administered regularly could aid in early detection of SARS-CoV-2 exposure, which is vital to combatting this pandemic.

Dreaming during the Covid-19 pandemic: Computational assessment of dream reports reveals mental suffering associated with negative feelings and contagion fear

Neuroscience and psychology agree that dreaming helps to cope with negative emotions and learn from experience. The current global threat related to the COVID-19 pandemic led to widespread social isolation. Does dreaming change and/or reflect mental suffering? To address these questions, we applied natural language processing tools to study 239 dream reports from 67 individuals either before the Covid-19 outbreak or during March-April, 2020, when quarantine was imposed in Brazil following the pandemic announcement by the WHO. Pandemic dreams showed a higher proportion of anger and sadness words, and higher average semantic similarities to the terms "contamination" and "cleanness". These features were associated with mental suffering related to social isolation, as they explained 39% of the variance in PANSS negative subscale (p=0.0092). These results corroborate the hypothesis that pandemic dreams reflect mental suffering, fear of contagion, and important changes in daily habits.