Olfactory disorders in coronavirus disease 2019 patients: a systematic literature review.

OBJECTIVE: Recent scientific literature has widely described a possible major role of smell dysfunction as a specific symptom of coronavirus disease 2019. This systematic review may provide a more holistic approach to current knowledge of the disease. METHODS: A systematic review was completed using Embase, PubMed and Web of Science databases that considered original articles focused on olfactory evaluation in coronavirus disease 2019 patients, published between March and May 2020, in English language. RESULTS: From the 483 research papers initially identified, 32 original studies were selected, comprising a total of 17 306 subjects with a laboratory confirmed diagnosis of coronavirus disease 2019. Individual study sample sizes ranged from 6 to 6452 patients. This comprehensive analysis confirmed that olfactory disorders represent an important clinical feature in coronavirus disease 2019, with a prevalence of 11-100 per cent in included patients, although there was heterogeneity in terms of assessment tools and population selection criteria. CONCLUSION: The results indicate that an accurate clinical evaluation should be carried out using structured questionnaires and tests with olfactory substances.

Hearing and cognitive impairment: a functional evaluation of associative brain areas in patients affected by Alzheimer's disease.

Auditory dysfunction observed in patients with cognitive diseases is probably due to the alteration of some brain areas involved in sound stimulus processing. The present study aimed to investigate differences in such processing and in connectivity of the primary auditory cortex in patients affected by Alzheimer's disease (AD) and in normal subjects. We examined 131 diagnosed AD patients and a control group (CG) of 36 normal subjects. After a complete clinical investigation, focused on hearing function, all subjects underwent a brain FDG PET/CT. AD subjects vs CG showed reduced glucose consumption in BA 6,7,8,39, whereas we did not find differences in the primary auditory cortex. In AD, connectivity analyses showed a positive correlation of the primary auditory cortex with BA 6,8,21,31,39,40,42 and a negative correlation with BA 19, cerebellum and basal ganglia. Our findings suggest that neurological evaluation of patients with hearing loss might allow earlier (preclinical) identification of those affected by cognitive impairment.

Nasal cytology in children: scraping or swabbing?

Nasal cytology has become a valuable tool in the assessment of a multitude of nasal pathologies in children. Collection methods differ significantly and even though the use of the nasal curette is regarded as the most reliable in adults, most practitioners use the nasal swab in children. However, no studies have validated the reliability and supposed better tolerability of the latter. We have compared these two sampling methods regarding their tolerability and analysed the diagnostic accuracy of the cotton nasal swab (NSW) to identify nasal cytotypes and rhinitis phenotypes, using nasal scraping (NSC) for comparison. In a multicentric prospective study we recruited 208 children and performed nasal cytology by means of NSW and NSC. Microscopic evaluating of the nasal cytotypes was performed and tolerability of NSW and NSC was tested. Our data revealed a significantly inferior diagnostic accuracy of NSW compared to NSC regarding reliability and cell counts. Our study is the first to shed light on the role of the sampling tools for pediatric nasal cytology. We documented a poor diagnostic accuracy of NSW, thus suggesting using only the nasal curette in clinical practice. Furthermore, tolerability did not differ between the two, refuting the common thesis that swabs are to be preferred when doing nasal cytology in children.