Keratan sulfate proteoglycan: putative template for neuroblast migratory and axonal fascicular pathways and fetal expression in globus pallidus, thalamus, and olfactory bulb.

Keratan sulfate (KS) is a proteoglycan secreted in the fetal brain astrocytes and radial glia into extracellular parenchyma as granulofilamentous deposits. KS surrounds neurons except dendritic spines, repelling glutamatergic and facilitating GABAergic axons. The same genes are expressed in both neuroblast migration and axonal growth. This study examines timing of KS during morphogenesis of some normally developing human fetal forebrain structures. Twenty normal human fetal brains from 9-41 weeks gestational age were studied at autopsy. KS was examined by immunoreactivity in formalin-fixed paraffin sections, plus other markers including synaptophysin, S-100ß protein, vimentin and nestin. Radial and tangential neuroblast migratory pathways from subventricular zone to cortical plate were marked by KS deposits as early as 9wk GA, shortly after neuroblast migration initiated. During later gestation this reactivity gradually diminished and disappeared by term. Long axonal fascicles of the internal capsule and short fascicles of intrinsic bundles of globus pallidus and corpus striatum also appeared as early as 9-12wk, as fascicular sleeves before axons even entered. Intense KS occurs in astrocytic cytoplasm and extracellular parenchyma at 9wk in globus pallidus, 15wk thalamus, 18wk corpus striatum, 22wk cortical plate, and hippocampus postnatally. Corpus callosum and anterior commissure do not exhibit KS at any age. Optic chiasm shows reactivity at the periphery but not around intrinsic subfasciculi. We postulate that KS forms a chemical template for many long and short axonal fascicles before axons enter and neuroblast migratory pathways at initiation of migration. Cross-immunoreactivity with aggrecan may render difficult molecular distinction.

[Features of olfactory impairment connected with trigeminal nerve system]. / Osobennosti narusheniya obonyaniya v aspekte sistemy troinichnogo nerva.

Data on the state of sense of smell in patients who had a new coronavirus infection caused by the SARS-CoV-2 virus are currently reduced because of the impairment of the olfactory nerve system. There are practically no results in studies of disorders in the trigeminal nerve system. OBJECTIVE: Qualitative assessment of olfactory disorders after COVID-19 according to the system of olfactory and trigeminal nerves with a targeted assessment of the functional component of olfactory disorders. MATERIAL AND METHODS: We examined 40 patients aged 19 to 66 who had a coronavirus infection. All patients underwent neurological, otorhinolaryngological examinations, olfactometry, filled out the hospital anxiety and depression scale. RESULTS: Anosmia was diagnosed in 5 (12.5%) patients, hyposmia in 21 (52.5%) patients, and normosmia in 14 (35%) patients. Formed: the 1st group - 14 patients (35%) with normogram according to olfactometry; the 2nd group - 26 patients (65%) with anosmia/hyposmia. In the 1st group, disorders of the anxiety-depressive spectrum were significantly more common. In the 2nd group, a low identification of odors was found, lying in the spectrum of fresh, sharp, unpleasant, irritating, compared with sweet and pleasant or neutral, which indicates a predominant lesion of the trigeminal system. CONCLUSION: In patients with complaints of impaired sense of smell after undergoing COVID-19, the possible functional nature of anosmia/hyposmia should be taken into account, which requires the referral of such patients to psychotherapeutic specialists, and the possible entry of olfactory disorders into the 'trigeminal' spectrum.

Olfactory bulb anomalies in KBG syndrome mouse model and patients.

ANKRD11 (ankyrin repeat domain 11) is a chromatin regulator and the only gene associated with KBG syndrome, a rare neurodevelopmental disorder. We have previously shown that Ankrd11 regulates murine embryonic cortical neurogenesis. Here, we show a novel olfactory bulb phenotype in a KBG syndrome mouse model and two diagnosed patients. Conditional knockout of Ankrd11 in murine embryonic neural stem cells leads to aberrant postnatal olfactory bulb development and reduced size due to reduction of the olfactory bulb granule cell layer. We further show that the rostral migratory stream has incomplete migration of neuroblasts, reduced cell proliferation as well as aberrant differentiation of neurons. This leads to reduced neuroblasts and neurons in the olfactory bulb granule cell layer. In vitro, Ankrd11-deficient neural stem cells from the postnatal subventricular zone display reduced migration, proliferation, and neurogenesis. Finally, we describe two clinically and molecularly confirmed KBG syndrome patients with anosmia and olfactory bulb and groove hypo-dysgenesis/agenesis. Our report provides evidence that Ankrd11 is a novel regulator of olfactory bulb development and neuroblast migration. Moreover, our study highlights a novel clinical sign of KBG syndrome linked to ANKRD11 perturbations in mice and humans.

Efficacy of Normalising Serum Zinc Level for Patients with Olfactory Dysfunction and Zinc Deficiency.

INTRODUCTION: Zinc deficiency may worsen the severity of olfactory dysfunction; however, the relationship between serum zinc levels and therapeutic effects on olfactory dysfunction remains uncertain. This study investigated the relationship between normalising serum zinc levels and the therapeutic effects on olfactory dysfunction. METHODS: Forty-two patients diagnosed with post-infectious, post-traumatic, and idiopathic olfactory dysfunction, with serum zinc levels <70 µg/dL, were included in the study. All patients were treated with mecobalamin, tokishakuyakusan, and polaprezinc. The patients were divided into 2 groups: the zinc-normalised (≥70 µg/dL) and zinc-deficient (<70 µg/dL) groups, based on their post-treatment serum zinc levels. Olfactory test results were compared in each of the 2 groups. RESULTS: The patients were treated for a median of 133 days. The zinc-normalised group had significantly better results in all olfactory tests (detection/recognition thresholds of the T&T olfactometer, odour identification test (Open Essence), Visual Analogue Scale for olfactory dysfunction, and self-administered odour questionnaire). In contrast, only the self-administered odour questionnaire showed a significant improvement in the zinc-deficient group, with no significant differences observed in the other olfactory tests. When comparing the changes in the olfactory test scores between the 2 groups, significant differences were observed in the detection/recognition thresholds of the T&T olfactometer test and Open Essence results. CONCLUSION: These findings suggest that patients with olfactory dysfunction may have difficulty improving their olfactory function if they also have zinc deficiency. Furthermore, normalisation of zinc deficiency may contribute to the improvement of olfactory dysfunction with general treatment.

Versatile Nanoparticulate Systems as a Prosperous Platform for Targeted Nose-Brain Drug Delivery.

The intranasal route has proven to be a reliable and promising route for delivering therapeutics to the central nervous system (CNS), averting the blood-brain barrier (BBB) and avoiding extensive first-pass metabolism of some drugs, with minimal systemic exposure. This is considered to be the main problem associated with other routes of drug delivery such as oral, parenteral, and transdermal, among other administration methods. The intranasal route maximizes drug bioavailability, particularly those susceptible to enzymatic degradation such as peptides and proteins. This review will stipulate an overview of the intranasal route as a channel for drug delivery, including its benefits and drawbacks, as well as different mechanisms of CNS drug targeting using nanoparticulate drug delivery systems devices; it also focuses on pharmaceutical dosage forms such as drops, sprays, or gels via the nasal route comprising different polymers, absorption promoters, CNS ligands, and permeation enhancers.

[Involvement of the trigeminal nerve system in the sense of smell]. / Uchastie sistemy troinichnogo nerva v obonyanii.

A systematic review of literature on the issue of involvement in the sense of smell, as well as the interaction between the trigeminal and olfactory nerves, was carried out. The article discusses the features of the chemical perception systems, as well as the treatment of olfactory disorders using transcranial electrical stimulation of the trigeminal nerve.

Olfactory Three-Needle Electroacupuncture Improved Synaptic Plasticity and Gut Microbiota of SAMP8 Mice by Stimulating Olfactory Nerve.

OBJECTIVE: To investigate the effects and mechanisms of olfactory three-needle (OTN) electroacupuncture (EA) stimulation of the olfactory system on cognitive dysfunction, synaptic plasticity, and the gut microbiota in senescence-accelerated mouse prone 8 (SAMP8) mice. METHODS: Thirty-six SAMP8 mice were randomly divided into the SAMP8 (P8), SAMP8+OTN (P8-OT), and SAMP8+nerve transection+OTN (P8-N-OT) groups according to a random number table (n=12 per group), and 12 accelerated senescence-resistant (SAMR1) mice were used as the control (R1) group. EA was performed at the Yintang (GV 29) and bilateral Yingxiang (LI 20) acupoints of SAMP8 mice for 4 weeks. The Morris water maze test, transmission electron microscopy, terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling (TUNEL) staining, Nissl staining, Golgi staining, Western blot, and 16S rRNA sequencing were performed, respectively. RESULTS: Compared with the P8 group, OTN improved the cognitive behavior of SAMP8 mice, inhibited neuronal apoptosis, increased neuronal activity, and attenuated hippocampal synaptic dysfunction (P<0.05 or P<0.01). Moreover, the expression levels of synaptic plasticity-related proteins N-methyl-D-aspartate receptor 1 (NMDAR1), NMDAR2B, synaptophysin (SYN), and postsynaptic density protein-95 (PSD95) in hippocampus were increased by OTN treatment (P<0.05 or P<0.01). Furthermore, OTN greatly enhanced the brain-derived neurotrophic factor (BDNF)/cAMP-response element binding (CREB) signaling and phosphatidylinositol 3-kinase/protein kinase B/mammalian target of rapamycin (PI3K/AKT/mTOR) signaling compared with the P8 group (P<0.05 or P<0.01). However, the neuroprotective effect of OTN was attenuated by olfactory nerve truncation. Compared with the P8 group, OTN had a very limited effect on the fecal microbial structure and composition of SAMP8 mice, while specifically increased the genera Oscillospira and Sutterella (P<0.05). Interestingly, the P8-N-OT group showed an abnormal fecal microbiota with higher microbial α-diversity, Firmicutes/Bacteroidetes ratio and pathogenic bacteria (P<0.05 or P<0.01). CONCLUSIONS: OTN improved cognitive deficits and hippocampal synaptic plasticity by stimulating the olfactory nerve and activating the BDNF/CREB and PI3K/AKT/mTOR signaling pathways. Although the gut microbiota was not the main therapeutic target of OTN for Alzheimer's disease, the olfactory nerve was essential to maintain the homeostasis of gut microbiota.

OLFATO: forma más antigua de comunicación y sentido preciso que el otorrinolaringólogo debe conocer a profundidad / SMELL: oldest form of communication and precise sense that the otolaryngologist must know in depth

Introducción: el papel clave del olfato, antiguo sistema sensorial, es proporcionar información sobre las sustancias químicas en el medio ambiente. El olfato desempeña un papel en la detección de compuestos peligrosos, el mantenimiento de la nutrición, el comportamiento interpersonal, la salud neurológica y la sensación de placer, entre otras funciones. En consecuencia, la disfunción olfativa puede conducir a un riesgo de lesiones, desnutrición, aislamiento social y una mala calidad de vida. Materiales y métodos: se realizó una exploración bibliográfica y se identificaron artículos de acuerdo con los criterios de inclusión y exclusión definidos y se tomaron aquellos con calidad en la evidencia. Discusión: el sistema olfativo humano tiene diferencias anatómicas, fisiológicas y genéticas considerables con respecto al de otros mamíferos. Conclusiones: las destrezas olfativas varían con factores como la edad, el sexo, la etapa de desarrollo, ciertas enfermedades otorrinolaringológicas y enfermedades generales.

Introduction: The key role of the ancient olfactory sensory system is to provide information about chemicals in the environment. Smell plays a role in the detection of dangerous compounds, the maintenance of nutrition, interpersonal behavior, neurological health, and the sensation of pleasure, among other functions. Consequently, olfactory dysfunction can lead to a risk of injury, malnutrition, social isolation, and a poor quality of life. Materials and methods: A bibliographical exploration was carried out and articles were identified according to the inclusion and exclusion criteria defined and those with quality evidence were taken. Discussion: The human olfactory system has considerable anatomical, physiological, and genetic differences from that of other mammals. Conclusions: Olfactory skills vary with factors such as age, sex, stage of development, certain ear, nose and throat diseases and general diseases.

Gastrointestinal, Respiratory, and Olfactory Neurotropism of Sars-Cov2 as a Possible Trigger of Parkinson's Disease: Is a Multi-Hit Multi-Step Process on the Cards.

Since the first emergence of COVID-19 on the global stage, there has been a wealth of evidence to suggest that SARS-Cov2 is not merely a pulmonary pathogen. This virus is unique in its ability to disrupt cellular pathways related to protein homeostasis, mitochondrial function, stress response, and aging. Such effects raise concerns about the long-term fate of survivors of COVID-19 infection, particularly regarding neurodegenerative diseases. The concept of interaction between environmental factors and alpha-synuclein formation in the olfactory bulb and vagal autonomic terminals with subsequent caudo-cranial migration has received much attention in the context of PD pathogenesis. Anosmia and gastrointestinal symptoms are two well-known symptoms of COVID-19, with evidence of an olfactory bulb and vagal infiltration by SARS-CoV2. This raises the possibility of the spread of the viral particles to the brain along multiple cranial nerve routes. Neurotropism, coupled with the ability of the SARS-Cov2 virion to induce abnormal protein folding and stress responses in the central nervous system, in presence of an inflammatory milieu, reinforced by hypoxia, coagulopathy, and endothelial dysfunction, reverberates the intriguing possibility of activation of a neurodegenerative cascade leading to the development of pathological alpha-synuclein aggregates and thus, triggering the development of PD in survivors of COVID19. This review attempts to summarize and critically appraise existing evidence from basic science research and clinical reports of links between COVID-19 and PD and explores the prospect of a multi-hit pathophysiological process, induced by SARS-Cov2 infection, ultimately converging on perturbed cellular protein homeostasis, which although is intriguing, presently lacks robust evidence for confirmation.

A new biomarker combining multimodal MRI radiomics and clinical indicators for differentiating inverted papilloma from nasal polyp invaded the olfactory nerve possibly.

Background and purpose: Inverted papilloma (IP) and nasal polyp (NP), as two benign lesions, are difficult to distinguish on MRI imaging and clinically, especially in predicting whether the olfactory nerve is damaged, which is an important aspect of treatment and prognosis. We plan to establish a new biomarker to distinguish IP and NP that may invade the olfactory nerve, and to analyze its diagnostic efficacy. Materials and methods: A total of 74 cases of IP and 55 cases of NP were collected. A total of 80% of 129 patients were used as the training set (59 IP and 44 NP); the remaining were used as the testing set. As a multimodal study (two MRI sequences and clinical indicators), preoperative MR images including T2-weighted magnetic resonance imaging (T2-WI) and contrast-enhanced T1-weighted magnetic resonance imaging (CE-T1WI) were collected. Radiomic features were extracted from MR images. Then, the least absolute shrinkage and selection operator (LASSO) regression method was used to decrease the high degree of redundancy and irrelevance. Subsequently, the radiomics model is constructed by the rad scoring formula. The area under the curve (AUC), accuracy, sensitivity, specificity, positive predictive value (PPV), and negative predictive value (NPV) of the model have been calculated. Finally, the decision curve analysis (DCA) is used to evaluate the clinical practicability of the model. Results: There were significant differences in age, nasal bleeding, and hyposmia between the two lesions (p < 0.05). In total, 1,906 radiomic features were extracted from T2-WI and CE-T1WI images. After feature selection, using 12 key features to bulid model. AUC, sensitivity, specificity, and accuracy on the testing cohort of the optimal model were, respectively, 0.9121, 0.828, 0.9091, and 0.899. AUC on the testing cohort of the optimal model was 0.9121; in addition, sensitivity, specificity, and accuracy were, respectively, 0.828, 0.9091, and 0.899. Conclusion: A new biomarker combining multimodal MRI radiomics and clinical indicators can effectively distinguish between IP and NP that may invade the olfactory nerve, which can provide a valuable decision basis for individualized treatment.

Nicotinic cholinergic regulation of olfactory bulb blood flow response in aged rats.

In our previous research, we had demonstrated the crucial role of neuronal nicotinic acetylcholine receptors (nAChRs) in potentiation of the olfactory bulb blood flow response to olfactory stimulation in adult rats. The present study examined the effects of nAChR activation on the olfactory bulb blood flow response in rats aged 24-27 months. We found that, under urethane anesthesia, unilateral olfactory nerve stimulation (300 µA, 20 Hz, 5 s) increased blood flow within the ipsilateral olfactory bulb, without changes in the systemic arterial pressure. The increase in blood flow was dependent upon the current and frequency of the stimulus. Intravenous administration of nicotine (30 µg/kg) had little effect on the olfactory bulb blood flow response to nerve stimulation at either 2 Hz or 20 Hz. These results suggest a reduction in nAChR-mediated potentiation of the olfactory bulb blood flow response in aged rats.

Impact of trigeminal and/or olfactory nerve stimulation on measures of inspiratory neural drive: Implications for breathlessness.

The perception of breathlessness is mechanistically linked to the awareness of increased inspiratory neural drive (IND). Stimulation of upper airway cold receptors on the trigeminal nerve (TGN) with TGN agonists such as menthol or cool air to the face/nose has been hypothesized to reduce breathlessness by decreasing IND. The aim of this systematic scoping review was to identify and summarize the results of studies in animals and humans reporting on the impact of TGN stimulation or blockade on measures of IND. Thirty-one studies were identified, including 19 in laboratory animals and 12 in human participants. Studies in laboratory animals consistently reported that as TGN activity increased, measures of IND decreased (e.g., phrenic nerve activity). In humans, stimulation of the TGN with a stream of cool air to the face/nose decreased the sensitivity of the ventilatory chemoreflex response to hypercapnia. Otherwise, TGN stimulation with menthol or cool air to the face/note had no effect on measures of IND in humans. This review provides new insight into a potential neural mechanism of breathlessness relief with selected TGN agonists.

Impact of trigeminal nerve and/or olfactory nerve stimulation on activity of human brain regions involved in the perception of breathlessness.

Breathlessness is a centrally processed symptom, as evidenced by activation of distinct brain regions such as the insular cortex and amygdala, during the anticipation and/or perception of breathlessness. Inhaled L-menthol or blowing cool air to the face/nose, both selective trigeminal nerve (TGN) stimulants, relieve breathlessness without concurrent improvements in physiological outcomes (e.g., breathing pattern), suggesting a possible but hitherto unexplored central mechanism of action. Four databases were searched to identify published reports supporting a link between TGN stimulation and activation of brain regions involved in the anticipation and/or perception of breathlessness. The collective results of the 29 studies demonstrated that TGN stimulation activated 12 brain regions widely implicated in the anticipation and/or perception of breathlessness, including the insular cortex and amygdala. Inhaled L-menthol or cool air to the face activated 75% and 33% of these 12 brain regions, respectively. Our findings support the hypothesis that TGN stimulation contributes to breathlessness relief by altering the activity of brain regions involved in its central neural processing.

Relationship between the severity of olfactory dysfunction and serum zinc levels.

PURPOSE: Although the association between zinc deficiency and olfactory dysfunction is inconclusive, zinc deficiency causes apoptosis of the olfactory ensheathing cells which is involved in olfactory nerve turnover and axon regeneration, thereby suggesting a possible relationship. We investigated the relationship between serum zinc levels and olfactory function in patients with olfactory dysfunction. METHODS: Ninety patients who had been diagnosed with post-infectious, posttraumatic, drug-induced, neurological and idiopathic olfactory dysfunction were included. Patients were divided into zinc normal group and zinc deficiency groups according to three reference values for serum zinc levels (60, 65, 70 µg/dL). The results of olfactory tests and patient backgrounds were used to compare the differences between the two groups. RESULTS: There were significantly worse detection and recognition thresholds in the T&T olfactometer and Open Essence (odor identification test) results in the zinc deficiency group (< 60 µg/dL). In addition, significant correlations between olfactory tests (detection/recognition thresholds in the T&T olfactometer and Open Essence results) and serum zinc levels < 65 µg/dL were observed. The zinc deficiency group < 70 µg/dL with idiopathic olfactory dysfunction had significantly worse olfactory tests (detection/recognition thresholds in the T&T olfactometer and Open Essence). In addition, there was a significant correlation between the detection/recognition thresholds in the T&T olfactometer and serum zinc levels in idiopathic olfactory dysfunction. CONCLUSIONS: Our findings suggest that zinc deficiency may exacerbate the severity of olfactory dysfunction. Furthermore, idiopathic olfactory dysfunction may be partly caused by zinc deficiency.

Wide-ranging migration and destination of early olfactory placode-derived neurons in chick embryos.

Cell migration from the olfactory placode (OP) is a well-known phenomenon wherein various cell types, such as gonadotropin-releasing hormone (GnRH)-producing neurons, migrate toward the telencephalon (TEL) during early embryonic development. However, the spatial relationship between early migratory cells and the forebrain is unclear. We examined the early development of whole-mount chick embryos to observe the three-dimensional spatial relationship among OP-derived migratory neurons, olfactory nerve (ON), and TEL. Migratory neurons that express highly polysialylated neural cell adhesion molecule (PSA-NCAM) emerge from the OP and spread over a relatively wide TEL area at the Hamburger and Hamilton (HH) stage 17. Most migratory neurons form a cellular cord between the olfactory pit and rostral TEL within HH18-20. The earliest axons from the olfactory epithelium (OE) were detected along this neuronal cord using DiI-labeling at HH21. Furthermore, a few PSA-NCAM-positive neurons were dispersed around the cellular cord and over the lateral TEL at HH18. A long cellular cord branch extending to the lateral TEL was transiently observed within HH18-24. These results suggest a novel migratory route of OP-derived neurons during the early developmental stages. Following GFP vector introduction into the OP of HH13-15 embryos, labeled neurons were detected around and within the lateral TEL at HH23 and HH27. At HH36, labeled cells were observed in the rostral-lateral TEL, including the olfactory bulb (OB) region. GFP-labeled and calretinin-positive neurons were detected in the OB, suggesting that early OP-derived neurons enter the forebrain and function as interneurons in the OB.

A Shift in SARS-CoV-2 Omicron Variant's Entry Pathway Might Explain Different Clinical Outcomes.

Globally, SARS CoV-2 omicron variant has led to a notable increase of COVID-19 diagnoses, although with less severe clinical manifestations and decreased hospitalizations. The omicron wave swelled faster than previous waves, completely displacing the delta variant within weeks, and creating worldwide concern about final, successful pandemic control. Some authors contend that symptoms associated to omicron differ from 'traditional' symptoms and more closely resemble those of the common cold. One major COVID-19 symptom frequent with other variants-loss of taste and smell-is rarely present with omicron. This may be of interest, since it has also been suggested that direct SARS-CoV-2 invasion into the brainstem through the olfactory nerves by transsynaptic pathways could provide one explanation for the acute respiratory distress syndrome refractory to treatment. Brainstem infection by SARS-CoV-2 can severely damage the respiratory center, triggering functional deviations that affect involuntary respiration, leading to acute respiratory distress syndrome refractory to treatment, the main cause of death in COVID-19 patients. A shift in the omicron SARS-CoV-2 entry pathway from cell-surface fusion, triggered by TMPRSS2, to cathepsin-dependent fusion within the endosome, may affect transmission, cellular tropism and pathogenesis. Therefore, we can hypothesize that this entrance modification may impact transmission from the olfactory nerve to the brainstem through transsynaptic pathways. A decrement of the virus's direct invasion into the brainstem could diminish respiratory center dysfunction, reducing acute respiratory distress syndrome and the need for mechanical ventilation.

Anatomical barriers against SARS-CoV-2 neuroinvasion at vulnerable interfaces visualized in deceased COVID-19 patients.

Can SARS-CoV-2 hitchhike on the olfactory projection and take a direct and short route from the nose into the brain? We reasoned that the neurotropic or neuroinvasive capacity of the virus, if it exists, should be most easily detectable in individuals who died in an acute phase of the infection. Here, we applied a postmortem bedside surgical procedure for the rapid procurement of tissue, blood, and cerebrospinal fluid samples from deceased COVID-19 patients infected with the Delta, Omicron BA.1, or Omicron BA.2 variants. Confocal imaging of sections stained with fluorescence RNAscope and immunohistochemistry afforded the light-microscopic visualization of extracellular SARS-CoV-2 virions in tissues. We failed to find evidence for viral invasion of the parenchyma of the olfactory bulb and the frontal lobe of the brain. Instead, we identified anatomical barriers at vulnerable interfaces, exemplified by perineurial olfactory nerve fibroblasts enwrapping olfactory axon fascicles in the lamina propria of the olfactory mucosa.

Anatomophysiological relationships and clinical considerations of taste and smell loss in patients with COVID-19.

BACKGROUND: There are numerous conflicting discussions about the outbreak of the new coronavirus 2019 (COVID-19). AIM: To present some anatomical and physiological considerations about two of the symptoms reported by patients: The loss or reduction of smell and taste. METHODS: The loss or reduction of smell and taste is presented in a peculiar way, with some cases of persistence even after COVID-19. For this, it was searched in three databases, PubMed/MEDLINE, Web of Science, and Scopus, using the following keywords: "Smell", "Taste", "Smell AND COVID-19", "Taste AND COVID-19", with no publication time restriction, only in English with full text available, excluding also brief communications, letters to the editor, editorials, reviews, comments, and conference abstracts. RESULTS: The search found 776 articles in the PubMed/MEDLINE database, 1018 in the Web of Science database, and 552 in the Scopus database, from which duplicates were removed (104 articles). Finally, 17 studies were selected for detailed analysis within the eligibility criteria, with titles and abstracts related to central nervous system lesions responsible for smell and taste. This review suggests that viral mechanisms of action may be related to lesions both at the local level and at the level of the central nervous system, lasting up to 3 to 4 wk. It is considered persistent if it exceeds this period, as reported in one case in this review. There are still few studies about the treatment, and among those addressed in this review, only two studies reported possible treatments and emphasized the scarcity of data, with the best option being treatments that do not cause harm, such as gustatory and olfactory physiotherapy. CONCLUSION: Given the scarcity of data, this review emphasizes the importance of prevention, through the correct use of personal protective equipment by health professionals and respect for local behavioral indications. It is also emphasized, through five studies, that there is a predominance of such symptoms in patients with COVID-19, which can be a tool to control dissemination, through the early isolation of patients until the results are ready.

Validation of the Connecticut olfactory test (CCCRC) adapted to Brazil / Validação do teste de olfato de Connecticut (CCCRC) adaptado para o Brasil

Abstract Introduction Olfactory changes are quite common in the population, causing a significant impact on the quality of life. Documentation of the olfactory function is essential for the diagnosis, treatment and follow-up of patients with inflammatory diseases of the upper airways, neurodegenerative diseases or viral infections. Among the different existing smell tests, the CCCRC is an inexpensive test, easy to apply, but it has not yet been evaluated on a large scale in the Brazilian population. Objective To validate the CCCRC smell test, after adaptation for the Brazilian population, evaluating the performance of healthy volunteers and the stability of the test in retests. Methods In this study, we carried out a cultural adaptation of the CCCRC test to Brazil. To validate and determine the normality scores, we applied the test to 334 healthy volunteers, aged >18 years of age. The retest was also carried out in up to four weeks on 34 additional volunteers to assess validity of the results. Results When evaluating the participants' performance, normosmia and mild hyposmia values were obtained in more than 95% of them. Women (58.4%) showed better accuracy than men (41.6%): p < 0.02, and individuals over 60 years of age showed worse performance (median: 6; 75th percentile: 6.5; 25th percentile). The test and retest of the 34 volunteers demonstrated that there was agreement (ICC, intraclass correlation coefficient) considered good in the left nostril (ICC = 0.65) and excellent in the right nostril (ICC = 0.77) in the combined score. Conclusion The CCCRC test adapted to Brazil showed normal values, similar to the originally-described test and validations in other countries, with a high reproducibility rate. Considering the highly favorable cost-benefit ratio, the adapted CCCRC is a very useful tool for measuring olfactory function in the Brazilian population.

Resumo Introdução Alterações olfativas são bastante comuns na população, causam significativo impacto na qualidade de vida. A documentação da função olfatória é fundamental para o diagnóstico, tratamento e seguimento de pacientes que cursam com doenças inflamatórias das vias aéreas superiores, neurodegenerativas ou infecções virais. Entre os diferentes testes de olfato existentes, o teste do Connecticut Chemosensory Clinical Research Center (CCCRC) é barato, de fácil aplicação, mas que ainda não foi avaliado em grande escala para a população brasileira. Objetivo Validar o teste de olfato CCCRC com adaptação para a população brasileira, avaliar o desempenho de voluntários saudáveis e a estabilidade do teste em retestes. Método Neste estudo fizemos adaptação cultural do teste CCCRC para o Brasil. Para validação e determinação dos escores de normalidade, aplicamos o teste em 334 voluntários saudáveis, com mais de 18 anos. O reteste foi ainda feito em até quatro semanas em 34 voluntários adicionais para avaliar concordância dos resultados. Resultados Avaliando o desempenho dos participantes, valores de normosmia e hiposmia leve foram obtidos em mais de 95% deles. Mulheres (58,4%) apresentaram melhor acurácia em relação aos homens (41,6%), p< 0,02; e indivíduos acima dos 60 anos apresentaram pior desempenho (mediana: 6; percentil 75: 6,5; percentil 25: 5). O teste e reteste dos 34 voluntários demonstrou que houve concordância (coeficiente de correlação intraclasse, CCI) considerada boa em narina esquerda (CCI = 0,65) e excelente em narina direita (CCI = 0,77) no escore combinado. Conclusão O teste CCCRC adaptado para o Brasil apresentou valores de normalidade semelhantes ao teste originalmente descrito e a validações em outros países, com alta taxa de reprodutibilidade. Considerando a relação custo-benefício altamente favorável, o CCCRC adaptado é uma ferramenta muito útil para mensuração da função olfatória na população brasileira.

The use of MRI in a tertiary smell and taste clinic: Lessons learned based on a retrospective analysis.

BACKGROUND: Olfactory dysfunction (OD) is a common but underreported problem that can significantly impact a patient's quality of life. OD is prevalent in over 5% of the adult population and can be broadly categorised into conductive and sensorineural causes. Magnetic Resonance Imaging (MRI) can form part of the diagnostic work up, although its exact role is often debated. OBJECTIVES: The aim of this study was to evaluate the value of MRI in managing patients with OD. DESIGN/METHOD: A retrospective analysis of the records of patients presenting to a national smell and taste clinic over a 5-year period was performed. Variables included demographics, endoscopic findings, final diagnosis, psychophysical smell test and imaging results. RESULTS: A total of 409 patients, with an age range of 10-93 years, underwent clinical assessment and smell testing, of which 172 patients (42%) had MRI scans. Imaging in younger age-groups was associated with a higher rate of positive findings, however identifiable causes for OD were recorded across the range. MRI provided both diagnostic and prognostic information in those with idiopathic, traumatic and congenital causes of OD. For example, MRI provided information on the extent or absence of gliosis in those with a head trauma history allowing further treatment and prognosis. CONCLUSION: We recommend the adjunct use of MRI in patients with a clear history and examination findings of head injury, congenital cases and in apparent idiopathic cases. MRI should be requested to compliment clinical findings with a view to aiding decision-making on treatment and prognosis independent of patient's age.