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- Han, Pengfei, et al.
(författare)
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Neural processing of odor-associated words : an fMRI study in patients with acquired olfactory loss
- 2020
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Ingår i: Brain Imaging and Behavior. - : Springer Science and Business Media LLC. - 1931-7557 .- 1931-7565. ; 14, s. 1164-1174
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Tidskriftsartikel (refereegranskat)abstract
- Perception of olfactory information is mediated by both bottom-up (from molecules to perception) and top-down (e.g. cross-modal associative learning) processes. Acquired olfactory loss is a frequent disorder which is typically due to alterations in the bottom-up pathway. However, it is unclear how the top-down modulation of olfactory processing is affected by olfactory impairment. Our study aimed to investigate the top-down olfactory processing in patients with acquired olfactory loss and participants with normal olfaction. Using functional MRI, brain responses from 14 patients and 16 healthy controls were assessed during a task of expectation and reading of words with strong olfactory associations (OW) (e.g. “Rose”) and control words with little to no olfactory associations (CW) (e.g. “Door”). The expectation but not reading of the OW was associated with stronger neural activation in the angular gyrus and the inferior frontal gyrus extending to insula in the group of patients. During OW reading, the brain activation in the left OFC and right putamen was negatively correlated with odor identification score in patient and control groups, respectively. In addition, the duration of olfactory loss among patients was positively associated with activation in the left putamen during OW expectation. Taken together, these findings suggest an enhanced top-down olfactory modulation in patients with olfactory loss.
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2. |
- Iravani, Behzad, et al.
(författare)
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Relationship Between Odor Intensity Estimates and COVID-19 Prevalence Prediction in a Swedish Population
- 2020
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 45:6, s. 449-456
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Tidskriftsartikel (refereegranskat)abstract
- In 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 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 the 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 widespread testing can be facilitated.
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3. |
- Parma, Valentina, et al.
(författare)
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More Than Smell—COVID-19 Is Associated With Severe Impairment of Smell, Taste, and Chemesthesis
- 2020
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Ingår i: Chemical Senses. - : Oxford University Press (OUP). - 0379-864X .- 1464-3553. ; 45:7, s. 609-622
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Tidskriftsartikel (refereegranskat)abstract
- 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.
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