La rééducation des troubles olfactifs

En France, près d'une personne sur cinq souffre de troubles de l'odorat [1]. Cette prévalence a augmenté depuis l'apparition de la COVID-19 dont la dysosmie est un symptôme très fréquent, et persistant pour un certain nombre de patients [2]. Pourtant, la prise en soin des personnes dysosmiques reste insuffisante. Ici, nous proposons des pistes pour développer les rééducations olfactives basées sur l'exposition répétée aux odeurs, et nous présentons les résultats de plusieurs études ayant pour objectif d'améliorer l'efficacité de ces rééducations. Trois études sont présentées ici, impliquant des patients dysosmiques avec des étiologies diverses. La première (n = 22) compare une rééducation dans laquelle les odorants sont présentés avec ou sans contexte visuel et le suivi effectué est mensuel ;la seconde (n = 26) compare des modes de flairage différents et propose un accompagnement hebdomadaire (kiné) ;la troisième (n = 70) porte sur des dysosmies post-COVID, utilise une interface web et un suivi bimensuel et compare différents protocoles (produits du quotidien vs odorants fournis par l'expérimentateur à raison de 1 ou 3 en fonction du groupe). Les résultats de ces études montrent que les capacités olfactives peuvent être améliorées par la rééducation olfactive, et que cette amélioration est favorisée par l'utilisation d'un contexte visuel lors de l'apprentissage [3]. Par ailleurs, l'observance des patients est nettement favorisée par un accompagnement rapproché tel que celui pratiqué par un kinésithérapeute [4] , et par l'administration d'un kit de rééducation par le médecin prescripteur plutôt que par l'utilisation de produits du quotidien [5]. La rééducation olfactive par exposition répétée aux odeurs peut se montrer bénéfique dans la récupération de l'odorat. L'accompagnement des patients dysosmiques est un paramètre particulièrement important. En particulier, une stratégie de prise en charge pluriprofessionnelle est préconisée, alliant l'intervention de scientifiques, de médecins (généralistes, ORL) et de professions paramédicales telles que les kinésithérapeutes.

Systematic MRI in persistent post-Covid-19 olfactory dysfunction should be reassessed.

BACKGROUND: Magnetic resonance imaging (MRI) is the gold standard in the etiological assessment of a persistent olfactory dysfunction (OD). While the utility of imaging in COVID-19-related OD has yet to be established, MRI is recommended in all patients with persistent OD. The high prevalence of the latter after SARS-CoV-2 infection means evaluating this strategy is an important public health matter. METHODS: The main objective was to examine the impact of systematic MRI on the management of patients with OD. All adult patients consulting for persistent OD (>2 months) after primary SARS-COV-2 infection (PCR) between March 2020 and December 2021 were included (n = 67). The secondary objective was to evaluate the relationship between the severity of the OD as measured by psychophysical testing (ETOC) and the volume of the olfactory bulb (OB) measured by MRI. RESULTS: All patients underwent MRI, and none led to a change in diagnosis or treatment. Among them, 82% (55/67) were considered normal by the radiologist on initial interpretation. There were no significant differences (visual analysis or OB volume) between groups (mild, moderate, and severe hyposmia). CONCLUSION: Systematic MRI may be unnecessary in patients whose persistent OD began soon (a few days) after confirmed SARS-CoV-2 infection.

Phantom smells: a prevalent COVID-19 symptom that progressively sets in.

PURPOSE: One of the long-term symptoms of COVID-19 is phantosmia, a type of Olfactory Disorder (OD) that has deleterious impacts on patients' quality of life. The aim of this article was to study how this poorly understood qualitative OD manifests itself in the COVID-19. METHODS: 4691 patients with COVID-19 responded to our online questionnaire focusing on COVID-19-related OD. We first analyzed the prevalence of phantosmia in this population. Then, with the help of Natural Language Processing techniques, we investigated the qualitative descriptions of phantom smells by the 1723 respondents who reported phantosmia. RESULTS: The prevalence of phantosmia was of 37%. Women were more likely to report phantosmia than men, as well as respondents for whom OD was described as fluctuating rather than permanent, lasted longer, was partial rather than total and appeared progressively rather than suddenly. The relationship between OD duration and phantosmia followed a logarithmic function, with a prevalence of phantosmia increasing strongly during the first 2 months of the disease before reaching a plateau and no decrease over the 15 months considered in this study. Qualitative analyses of phantosmia descriptions with a sentiment analysis revealed that the descriptions were negatively valenced for 78% of the respondents. Reference to "tobacco" was more frequent in non-smokers. Source names and odor characteristics were used differently according to age and OD duration. CONCLUSION: The results of this descriptive study of phantosmia contribute to the current efforts of the medical community to better understand and treat this rapidly increasing COVID-19-related OD.

The autumnal lockdown was not the main initiator of the decrease in SARS-CoV-2 circulation in France.

Background: In response to the SARS-CoV-2 pandemic, governments have taken drastically restrictive public health measures with significant collateral effects. It is important to understand the impact of these measures on SARS-CoV-2 circulation. However, pandemic indicators lag behind the actual level of viral circulation and these delays are an obstacle to assessing the effectiveness of policy decisions. Here, we propose one way to solve this problem by synchronizing the indicators with viral circulation in a country (France) based on a landmark event. Methods: Based on a first lockdown, we measured the time lag between the peak of governmental and non-governmental surveillance indicators and the highest level of virus circulation. This allowed alignment of all surveillance indicators with viral circulation during the second period of the epidemic, overlaid with the type of public health measures implemented. Results: We show that the second peak in viral circulation in France happened ~21 October 2020, during the public health state of emergency but before the lockdown (31 October). Indicators also suggest that viral circulation decreased earlier in locations where curfews were implemented. Indicators did, however, begin to rise once the autumnal lockdown was lifted and the state of emergency resumed. Conclusions: Overall, these results suggest that in France, the 2020 autumnal lockdown was not the main initiator of the decrease in SARS-CoV-2 circulation and curfews were important in achieving control of the transmission. Less-restrictive measures may need to be balanced with more-stringent measures to achieve desirable public health outcomes over time.

An olfactory self-test effectively screens for COVID-19.

Background: Key to curtailing the COVID-19 pandemic are wide-scale screening strategies. An ideal screen is one that would not rely on transporting, distributing, and collecting physical specimens. Given the olfactory impairment associated with COVID-19, we developed a perceptual measure of olfaction that relies on smelling household odorants and rating them online. Methods: Each participant was instructed to select 5 household items, and rate their perceived odor pleasantness and intensity using an online visual analogue scale. We used this data to assign an olfactory perceptual fingerprint, a value that reflects the perceived difference between odorants. We tested the performance of this real-time tool in a total of 13,484 participants (462 COVID-19 positive) from 134 countries who provided 178,820 perceptual ratings of 60 different household odorants. Results: We observe that olfactory ratings are indicative of COVID-19 status in a country, significantly correlating with national infection rates over time. More importantly, we observe indicative power at the individual level (79% sensitivity and 87% specificity). Critically, this olfactory screen remains effective in participants with COVID-19 but without symptoms, and in participants with symptoms but without COVID-19. Conclusions: The current odorant-based olfactory screen adds a component to online symptom-checkers, to potentially provide an added first line of defense that can help fight disease progression at the population level. The data derived from this tool may allow better understanding of the link between COVID-19 and olfaction.

La rééducation olfactive: bénéfices d’une prise en soins pluri-professionnelle

Résumé Près d’un français sur cinq souffre de troubles de l’odorat (TO), ou dysosmie. Cette prévalence a augmenté depuis l’apparition de la COVID-19 dont la dysosmie est un symptôme très fréquent et possiblement persistant. Pourtant, la prise en soin des personnes dysosmiques reste insuffisante. Cet article ouvre des pistes pour développer les rééducations olfactives (RO) sur la base de protocoles déjà éprouvés, mais aussi pour améliorer l’accompagnement des patients dysosmiques. Pour cela, une stratégie de prise en charge pluri-professionnelle est préconisée, alliant l’intervention de scientifiques, de médecins (généralistes, ORL) et de professions paramédicales. Summary Nearly one in five French people suffer from olfactory disorders (TO), or dysosmia. This prevalence has increased since the onset of COVID-19, for which dysosmia is a very common and possibly persistent symptom. However, the care of people with dysosmia remains insufficient. This article opens up avenues for developing olfactory rehabilitation (OR) on the basis of existing protocols, but also for improving support for dysosmic patients. For this purpose, a multi-professional care strategy is recommended, combining the intervention of scientists, doctors (general practitioners, ENT) and paramedical professions.

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

In response to the 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 step-wise manner, monitoring of COVID-19 prevalence is of importance to guide 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 in the Swedish population and were found to closely track each other (r=-0.83). Moreover, we found that there was a large difference in rated intensity between individuals with and without COVID-19 symptoms and number of symptoms was related to odor intensity ratings. Finally, we found that individuals progressing from reporting no symptoms to subsequently reporting COVID-19 symptoms demonstrated a large drop in olfactory performance. These data suggest that measures of odor intensity, if obtained in a large and representative sample, can be used as an indicator of COVID-19 disease in the general population. Importantly, this simple measure could easily be implemented in countries without widespread access to COVID-19 testing or implemented as a fast early response before wide-spread testing can be facilitated.

Recovery From COVID-19-Related Olfactory Disorders and Quality of Life: Insights From an Observational Online Study.

Although olfactory disorders (OD) are among the most significant symptoms of COVID-19, recovery time from COVID-19-related OD and their consequences on the quality of life remain poorly documented. We investigated the characteristics and behavioral consequences of COVID-19-related OD using a large-scale study involving 3111 French respondents (78% women) to an online questionnaire over a period of 9 months covering different epidemic waves (from 8 April 2020 to 13 January 2021). In the patients who subjectively recovered from COVID-19-related OD (N = 609), recovery occurred on average after 16 days and most of the time within 1 month ("normal" recovery range); 49 subjectively recovered in 1-2.5 months, and several cases took up to 6.5 months. Among the patients with ongoing OD (N = 2502), 974 were outside the "normal" recovery range (persistent OD) and reported OD for 1-10 months. Developing a persistent OD was more likely with increasing age and in women and was more often associated with parosmia and phantosmia. The deleterious impact of COVID-19-related OD on the quality of life was significantly aggravated by OD duration and was more pronounced in women. Because persistent OD is not infrequent after COVID-19, has deleterious consequences on the quality of life, and receives few solutions from the health practitioners, it would be beneficial to implement screening and treatment programs to minimize the long-term behavioral consequences of COVID-19-related OD.

Smell and taste changes are early indicators of the COVID-19 pandemic and political decision effectiveness.

In response to the COVID-19 pandemic, many governments have taken drastic measures to avoid an overflow of intensive care units. Accurate metrics of disease spread are critical for the reopening strategies. Here, we show that self-reports of smell/taste changes are more closely associated with hospital overload and are earlier markers of the spread of infection of SARS-CoV-2 than current governmental indicators. We also report a decrease in self-reports of new onset smell/taste changes as early as 5 days after lockdown enforcement. Cross-country comparisons demonstrate that countries that adopted the most stringent lockdown measures had faster declines in new reports of smell/taste changes following lockdown than a country that adopted less stringent lockdown measures. We propose that an increase in the incidence of sudden smell and taste change in the general population may be used as an indicator of COVID-19 spread in the population.

More Than Smell-COVID-19 Is Associated With Severe Impairment of Smell, Taste, and Chemesthesis.

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments, such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, and generally lacked quantitative measurements. Here, we report the development, implementation, and initial results of a multilingual, international questionnaire to assess self-reported quantity and quality of perception in 3 distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, and 8 others, aged 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste, and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change ±100) revealed a mean reduction of smell (-79.7 ± 28.7, mean ± standard deviation), taste (-69.0 ± 32.6), and chemesthetic (-37.3 ± 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell but also affects taste and chemesthesis. The multimodal impact of COVID-19 and the lack of perceived nasal obstruction suggest that severe acute respiratory syndrome coronavirus strain 2 (SARS-CoV-2) infection may disrupt sensory-neural mechanisms.