Olfaction and anosmia: From ancient times to COVID-19

Anosmia in COVID-19: Investigating the Role of Paranasal Sinus Mucosal Thickening

Background Anosmia has been identified as a distinctive symptom of COVID-19, leading to hypotheses about its pathophysiological underpinnings, including the potential role of paranasal sinus mucosal thickening. Objective To investigate the association between paranasal sinus mucosal thickening and anosmia in COVID-19 patients, providing insights into the complex clinical manifestations of the disease. Methods This retrospective cohort study analyzed CT paranasal sinus from 270 confirmed COVID-19 patients, divided into those with anosmia (n = 23, 8.52%) and those without anosmia (n = 247, 91.48%). Statistical analysis, including independent t-tests, was employed to compare mucosal thickening between the groups. Results The study found an average mucosal thickening of 0.03 in patients with anosmia and 0.02 in those without, with no statistically significant difference between the groups (p = 0.480, which is greater than 0.05). The findings suggest that mucosal thickening in the paranasal sinuses does not serve as a definitive correlate of anosmia among COVID-19 patients. Conclusion The absence of a significant correlation between paranasal sinus mucosal thickening and anosmia in COVID-19 patients indicates that the pathophysiology of anosmia may involve factors beyond anatomical changes, including direct viral effects and systemic inflammatory responses.

Clinical Neurology in Practice: The Tongue (part 2)

BACKGROUND

The tongue is an essential organ for the development of certain crucial functions such as swallowing and speech. The examination of the tongue can be very useful in neurology, as the various types of lingual alterations can lead to certain specific diagnoses, the tongue being a kind of 'mirror' of some neurological function.

REVIEW SUMMARY

To discuss the elements of clinical examination of the tongue in relation to neurological disorders. After reviewing the different superficial lesions of the tongue, we deal with various movement disorders of the tongue (fasciculations/myokimia, orolingual tremor, choreic movements of the tongue, dystonia of the tongue, lingual myoclonus, and psychogenic movements), disorders of taste and lingual sensitivity and lingual pain.

CONCLUSIONS

Examination of the tongue should not be limited to studying its motility and trophicity. It is equally important to check the sensory function and understand how to interpret abnormal movements involving the tongue. This study also aimed to demonstrate the importance of nonmotor tongue function in neurological practice.

Clinical Neurology in Practice: The Tongue (Part 1)

BACKGROUND

The tongue is an essential organ for the development of certain crucial functions, such as swallowing and language. The examination of the tongue can be very useful in neurology, as the various types of lingual alterations can lead to certain specific diagnoses, the tongue being a kind of "mirror" of some neurological function.

REVIEW SUMMARY

In this study, we reviewed the literature on anatomy, physiology, and the various aspects of the examination of the tongue.

CONCLUSIONS

Examination of the tongue should be an integral part of the clinical examination of the cranial nerves. This study aimed to demonstrate the importance of tongue motor and non-motor functions in neurological practice.

A novel task of canine olfaction for use in adult and senior pet dogs

While much work has been done in the field of canine olfaction, there has been little exploration of hyposmia or anosmia. This is partly due to difficulties in reducing confounds like training history and environmental distraction. The current study describes a novel olfaction test using spontaneous search behavior in dogs to find a hidden food treat in a three-choice task with both light-phase and dark-phase conditions. The study was performed in 18 adult control dogs, 18 senior/geriatric dogs enrolled in a longitudinal aging study, and a single dog with severe nasal pathology. In the senior/geriatric and control groups, dogs performed with higher accuracy (p < 0.0001) and were less likely to show biased selection strategy (p < 0.01) in the dark-phase than light-phase. While senior/geriatric dogs performed above chance, they had lower accuracy in the dark-phase compared to controls (p = 0.036). Dogs who scored higher on an owner questionnaire of cognitive decline showed a positive correlation with performance in the dark-phase; performance on additional cognitive tests did not correlate with performance in the dark-phase. This task can be used to quantify canine olfaction using clearly defined endpoints and spontaneous behaviors thus making it feasible to compare between and within groups of pet dogs.