Auswahl der wissenschaftlichen Literatur zum Thema „Olfactory disorders“

AbstractBackground:Olfactory disorders increase with age and often affect elderly people who have pre-dementia or dementia. Despite the frequent occurrence of olfactory changes at the early stages of neurodegenerative disorders such as Alzheimer's disease, olfactory disorders are rarely assessed in daily clinical practice, mainly due to a lack of standardised assessment tools. The aims of this review were to (1) summarise the existing literature on olfactory disorders in ageing populations and patients with neurodegenerative disorders; (2) present the strengths and weaknesses of current olfactory disorder assessment tools; and (3) discuss the benefits of developing specific olfactory tests for neurodegenerative diseases.Methods:A systematic review was performed of literature published between 2000 and 2015 addressing olfactory disorders in elderly people with or without Alzheimer's disease or other related disorders to identify the main tools currently used for olfactory disorder assessment.Results:Olfactory disorder assessment is a promising method for improving both the early and differential diagnosis of Alzheimer's disease. However, the current lack of consensus on which tests should be used does not permit the consistent integration of olfactory disorder assessment into clinical settings.Conclusion:Otolaryngologists are encouraged to use olfactory tests in older adults to help predict the development of neurodegenerative diseases. Olfactory tests should be specifically adapted to assess olfactory disorders in Alzheimer's disease patients.

The receptor cells in the olfactory neuroepithelium are regularly replaced and, when injured, regenerate from basal cells and reestablish their central connections. This process of reconstitution occurs throughout the life span after mechanical, chemical, and infectious injury. The history and physical findings in association with the quantification of the olfactory loss allow an etiologic diagnosis in many patients. Olfactory losses can be categorized as transport or sensorineural defects. Therapy for transport olfactory losses is frequently effective in restoring the sense of smell. Reasonable strategies for treatment of patients with sensorineural olfactory losses remain limited.

Since the outbreak of the SARS-CoV-2 pandemic, olfactory disorders have been reported as a frequent symptom of COVID-19; however, its pathogenesis is still debated. The aim of this review is to summarize the current understanding of the pathogenesis of smell impairment in the course of COVID-19 and to highlight potential avenues for future research on this issue. Several theories have been proposed to explain the pathogenesis of COVID-19-related anosmia, including nasal obstruction and rhinorrhea, oedema of the olfactory cleft mucosa, olfactory epithelial damage either within the olfactory receptor cells or the supporting non-neural cells (either direct or immune-mediated), damage to the olfactory bulb, and impairment of the central olfactory pathways. Although the pathogenesis of COVID-19-related anosmia is still not fully elucidated, it appears to be mainly due to sensorineural damage, with infection of the olfactory epithelium support cells via the ACE1 receptor and disruption of the OE caused by immense inflammatory reaction, and possibly with direct olfactory sensory neurons infection mediated by the NRP-1 receptor. Involvement of the higher olfactory pathways and a conductive component of olfactory disorders, as well as genetic factors, may also be considered.

Abstract Olfactory dysfunction (OD) is a common nonmotor symptom observed in several movement disorders. The severity and pattern of olfactory impairment vary among these conditions. Notably, olfactory impairment often precedes the clinical diagnosis of movement disorders by several years, yet it remains frequently unrecognized by patients and physicians until formal olfactory tests are undertaken. This review focuses on exploring OD across various movement disorders. A systemic search strategy incorporating key terms such as movement disorders, dystonic disorders, tic disorders, parkinsonian disorders, parkinsonism, ataxia, essential tremors, drug-induced akathisia, and olfaction disorders was employed to query databases including Embase, Scopus, and PubMed. After excluding irrelevant articles, 99 studies were selected for comprehensive review. OD is a persistent feature across all movement disorders, with the exception of pseudo supranuclear palsy. Among these conditions, olfactory impairment is much more frequent and severe in patients with Parkinson’s disease. Incorporating olfactory testing into the diagnostic evaluation of at-risk individuals or patients with established movement disorders is recommended. These olfactory tests offer a practical, cost-effective, and convenient diagnostic tool that may aid in the early identification and management of these conditions.

Background: the diagnosis of olfactory disorders remains a critical issue in clinical practice. Olfactory testing is the most commonly utilized diagnostic tool. Previously, we developed an olfactory test and validated it on healthy volunteers. Aim: to evaluate the diagnostic efficacy of a domestic olfactory test in detecting various olfactory disorders. Materials and Methods: this study included 100 patients presenting with typical olfactory disorders. Subjects were categorized into three groups: acute rhinosinusitis (AR) (n=50), polypous rhinosinusitis (PR) (n=25), and post-viral olfactory dysfunction (PVDO) (n=25). Olfactory function was assessed using the developed test and a visual analog scale (VAS) for comparative analysis. Olfactory threshold and odor discrimination ability were measured in all groups using the olfactory test. In the PR and PVDO groups, the assessment was conducted once on the examination day. In the AR group, assessments were performed twice: on the day of treatment and 14 days post-treatment. Results: olfactory dysfunction was detected in all groups. In the AR group, both the VAS and the domestic olfactory test indicated a decrease in olfactory threshold without changes in odor discrimination ability. Fourteen days post-treatment, improvements in olfactory threshold and odor discrimination were noted, although VAS scores demonstrated a decline. In the PR and PVDO groups, both VAS and the domestic olfactory test showed reductions in olfactory threshold and odor discrimination abilities. VAS results highly correlated with the olfactory threshold across all groups, and additionally with odor discrimination ability in the PVDO group. Conclusion: the study demonstrated the effectiveness of the domestic olfactory test in diagnosing typical olfactory disorders. KEYWORDS: olfaction, olfactory test, olfactory diagnostics, olfactory threshold, odor discrimination ability, acute rhinosinusitis, polypous rhinosinusitis, post-viral olfactory dysfunction, odor. FOR CITATION: Lebedeva G.V., Svistushkin M.V., Selezneva L.V., Kudryavtseva V.A., Pogosyan K.K., Zinchenko I.A., Svistushkin V.M. Possibilities of using the domestic olfactory test in the diagnosis of typical olfactory disorders. Russian Medical Inquiry. 2024;8(8):470–476 (in Russ.). DOI: 10.32364/2587-6821-2024-8-8-5.