xRead - Olfactory Disorders (September 2023)

20426984, 2022, 4, Downloaded from https://onlinelibrary.wiley.com/doi/10.1002/alr.22929, Wiley Online Library on [04/09/2023]. See the Terms and Conditions (https://onlinelibrary.wiley.com/terms-and-conditions) on Wiley Online Library for rules of use; OA articles are governed by the applicable Creative Commons License

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PATEL et al.

and would rather have an incorrect test result. It is also true that if these tests are to be truly utilized globally, many other countries do not have a high literacy rate. 1670 Development of simpler quantitative tests Electro-olfactography and adapted electroencephalogra phy have long been utilized in the research setting to try and provide more olfactory data points that are free from subjective and situational influence. 1272 However, once a provider finds themselves in the typical busy clinical set ting of their practice, it becomes impractical based on time, equipment, and space requirements to perform the type of tests that are currently established, regularly. This is a definite area of research that is ripe for development, and, simpler yet, universal quantitative testing is already being developed in some centers. 1671 and future therapeutic options It would be useful for the management of patients with OD if the efficacy of each treatment option offered to them could be predicted in advance. For example, the OD asso ciated with rhinosinusitis often responds to treatments directed at controlling underlying inflammation, such as ESS and steroid administration. These interventions are often effective, although, even in this population, patients must be counseled that there is no guarantee that they will regain their normal smelling ability, especially after a long duration of loss. In contrast, prior study has demon strated that systemic steroid treatment is more effective in patients with sinonasal inflammatory–related OD com pared with patients with IOD, especially when comparing with patients with sinonasal disease with nasal polyps. 1535 Other studies demonstrated that success of a trial of sys temic steroids may serve to verify that the loss is indeed inflammatory 137 and is a prognostic indicator for a signif icant benefit of topical steroid therapy. 1518 As for ESS, a duration of up to 4.5 years of self-reported smell loss has been suggested as the cutoff point for recovery of smell fol lowing ESS. 1672 A positive response to an intravenous olfac tory test (eg, prosultiamine), absence of OC lesions, female sex, and younger age were also identified as independent prognostic factors for better olfactory outcomes 3 months afterESS. 1673 In PVOD, multivariate analysis showed that younger age and residual OF were significantly associated with better olfactory recovery. 1540 A study in Japan showed that onset latency in the intravenous olfactory test may help predict when olfaction in patients with PVOD will improve. 1674 On C Management 1 Identify predictors of response to current

the other hand, PTOD or IOD were significantly associ ated with less possibility of improvements compared with PVOD in patients with OD receiving OT. 1326 Finally, there is a significant correlation between changes in OF and ini tial measurement of the total OBV, with larger volumes relating to higher improvement of OF, although this does not predict which therapeutic option is best for either group. 1675 A new methodology, radioisotope transport analysis, has demonstrated that high thallium migration from the nasal cavity to the OB is significantly correlated with better prog nosis in patients with OD, suggesting that patients with intact olfactory nerve fibers could be selected to use this imaging technique. 1067 2 A “cure” for all olfactory disorders In all probability, there will not be a single cure for all causes of OD. This is attributable to the fact that olfac tory disorders are not one monolithic entity, but instead can be dissected into different fractions, 1036 similar to what has been seen for many other disorders. For exam ple, during the past years we have learned that inflam mation of the nasal and sinus cavity is not uniform and that different forms of sinonasal disease respond differ ently to different treatments. 1676 Stimulating regeneration of OR neurons, 1662 transplantation of olfactory mucosa, and working to develop stem cell regeneration 189 or developing olfactory implants 1677 are excellent ideas but may have limited effects on CNS causes of olfactory dis orders residing at the level of the OB or the OFC. Detailed recognition and specification of these different entities is necessary. Future studies on these numerous ideas for an olfactory cure should therefore be more precise in terms of the selection of study participants. Increasing public awareness regarding the importance of OF and OD is significant in terms of empathy and sympa thy for patients experiencing these disorders, as well as an improvement of the understanding of the sense of smell, its disorders, and possible therapies for changes of the sense of smell. This has not happened to a significant extent in the past, although age-related olfactory loss is frequent and ≈ 5% of the general population have no functioning sense of smell. 14 This lack of awareness of OD is probably related to many factors, eg, the gradual decrease of OF with aging, or the lack of significance of the sense of smell for most work-related situations. However, the current global situation seems to be changing. One major driver appears 3 Increase public awareness of this disorder and its many implications