Can immersive olfactory training serve as an alternative treatment for patients with smell dysfunction?

Objectives: Olfactory training (OT) has emerged as a first-line therapeutic approach to the management of olfactory dysfunction. Conventional OT (COT) involves the systematic home-based exposure to four distinct odors. Previous research has demonstrated that immersive OT (IOT) involving full-body exposure to dozens of distinct odors could also improve overall olfactory function. This study compared IOT and COT in terms of efficacy. Methods: A total of 60 patients were enrolled and assigned to three groups. The IOT group (n = 25) underwent immersive exposure to 64 odors once daily in a specialized theater. COT participants (n = 17) sniffed four typical odors in a set of four jars twice daily at home. A control group (n = 18) underwent passive observation. Olfactory function was assessed before and after training. Results: Significant improvements in composite threshold-discrimination-identification (TDI) scores were observed after training in both the IOT (mean difference = 2.5 ± 1.1. p = .030) and COT (mean difference = 4.2 ± 1.3, p = .002) groups. No changes were observed in the control group. A significantly higher proportion of patients in the COT group (41%) presented improvements of clinical importance (TDI ≥5.5) compared to the controls (p = .018). The improvements attained in the IOT group (20%) were less pronounced (p = .38). Conclusion: While IOT did not exhibit the same efficacy as COT in restoring olfactory function, it still demonstrated promising outcomes. Future efforts to advance olfactory recovery should focus on cross-modal integration. Level of Evidence: Level 3.

Anterior Skull Base Abnormalities in Congenital Anosmia.

INTRODUCTION: The structures of the skull and the brain are related to each other. Prior work in individuals with isolated congenital anosmia (ICA) showed that these individuals were characterized by olfactory bulb (OB) defects. The aim of this study was to compare the morphological pattern of the anterior skull base surrounding the OB between individuals with ICA and normosmic controls. We meant to investigate whether these features can help distinguish abnormalities from normal variation. METHODS: We conducted a retrospective study to acquire T2-weighted magnetic resonance images from individuals diagnosed with ICA (n = 31) and healthy, normosmic controls matched for age and gender (n = 62). Between both groups, we compared the depth and width of the olfactory fossa, the angle of the ethmoidal fovea, as well as the angle of the lateral lamella of the cribriform plate. Within the ICA group, we further performed subgroup analyses based on the presence or absence of the OB, to investigate whether the morphology of the anterior skull base relates to the presence of OBs. The diagnostic performance of these parameters was evaluated using receiver operating characteristic analysis. RESULTS: Individuals with ICA exhibited a flattened ethmoid roof and shallower olfactory fossa when compared to controls. Further, the absence of the OB was found to be associated with a higher degree of flattening of the ethmoid roof and a shallow olfactory fossa. We reached the results in the following areas under the receiver operating characteristic curves: 0.80 - angle of fovea ethmoidalis, 0.76 - depth of olfactory fossa, 0.70 - angle of lateral lamella of the cribriform plate for significant differentiation between individuals with ICA and normosmic controls. CONCLUSION: Individuals with ICA exhibited an unusual anterior skull base surrounding the OB. This study supports the idea of an integrated development of OB and anterior skull base. Hence, the morphological pattern of the anterior skull base surrounding the OB helps distinguish individuals with ICA from normosmic controls and may therefore be useful for the diagnosis of ICA, although it is certainly not an invariable sign of congenital anosmia.

Trigeminal Sensory Neuropathy Predicts Chemosensory Dysfunction After Skull Base Surgery.

BACKGROUND: Trigeminal sensory neuropathy, characterized by diminished or exaggerated/painful sensation along the distribution of trigeminal branches, is one of the complications after skull base surgery. These procedures can also affect chemosensory functions and compromise the patients' quality of life. OBJECTIVE: To examine those postoperative complications in chemosensory and facial cutaneous sensory functions as well as their interaction. METHODS: A total of 61 patients being operated for various pathologies in the vicinity of trigeminal pathway (17 with trigeminal neuralgia, 20 with meningiomas, and 24 with vestibular schwannomas) and 50 healthy controls were enrolled in this case-control study. Postoperative trigeminal neuropathic symptoms were evaluated. The olfactory, gustatory, and intranasal trigeminal functions were assessed using the Sniffin' Stick olfactory test, lateralized taste strip test, and the lateralized intranasal trigeminal CO 2 detection thresholds, respectively. RESULTS: Patients with trigeminal neuralgia and meningioma had relatively decreased olfactory function, whereas those with vestibular schwannoma had a relative decrease in taste function. As for the relationship between the distribution of trigeminal neuropathy and chemosensory dysfunction, we found that V3 involvement predicted lower side-specific taste function. In addition, V2/V3 involvement predicted relatively lower side-specific intranasal trigeminal function. CONCLUSION: The present results suggest a differential involvement of the chemical senses in relation to the site and pathology of the lesions after surgery. The presence of trigeminal neuropathy is associated with taste and intranasal trigeminal dysfunction. The results serve as a basis for consultation regarding outcome prediction and patient education.

Variant brain-derived neurotrophic factor val66met polymorphism engages memory-associated systems to augment olfaction.

The neurogenetic basis of variability in human olfactory function remains elusive. This study examined olfactory performance and resting-state functional neuroimaging results from healthy volunteers within the context of the brain-derived neurotrophic factor (BDNF) val66met polymorphism with the aim of unraveling the genotype-associated intrinsic reorganization of the olfactory network. We found that the presence of the Met allele is associated with better olfactory identification and additional engagement of semantic memory system within the olfactory network, in an allele dosage-dependent manner. This suggests that the Met allele may promote adaptive neural reorganization to augment olfactory capacity.

Pretreatment age and serum lactate dehydrogenase as predictors of synchronous second primary cancer in patients with nasopharyngeal carcinoma.

OBJECTIVES: Nasopharyngeal carcinoma (NPC) is a common cancer and is treated primarily by chemotherapy and radiotherapy. However, NPC with synchronous second primary cancer (SSPC) is very rare and its risk factors, treatment and prognosis remain unclear. In this study, we aimed to analyze patients with NPC and SSPC, and attempt to find potential predictors for these patients. MATERIALS AND METHODS: We retrospectively collected 681 patients with NPC from 2006 to 2018. Patients in this study were divided into two groups: those patients with SSPC and those without SSPC. We then analyzed the demographic data and survival of these two groups. Independent predictors of SSPC were determined by multivariate regression analysis. A comprehensive review of the literature was also performed. RESULTS: We identified 17 NPC patients with SSPC in our case series and 13 cases in the literatures, and the most common SSPC is lung (16.1%). In univariate analysis, NPC patients with SSPC had older age (P < 0.001) and higher serum lactate dehydrogenase (LDH) (P = 0.008), compared with those without SSPC. In multivariate analysis, old age (P = 0.001) and high serum LDH (P = 0.023) remained independent predictors of SSPC, and a predictive equation model was established. NPC patients with SSPC had a significantly lower 5-year disease-specific survival rate compared with patients without SSPC (34.0% vs. 77.6%, P < 0.001) CONCLUSION: This study demonstrated that pretreatment age and serum LDH were independent predictors for SSPC in NPC patients. These independent factors can be used for early detection, and better facilitate the design of more appropriate treatment by medical professionals.

Minimal benefit of tonsillectomy in T1-T2 tonsillar squamous cell carcinoma treated with chemoradiotherapy.

BACKGROUND: Chemoradiotherapy (CRT) has become the mainstay of treatment for tonsillar squamous cell carcinoma (SCC). Pre-CRT tonsillectomy is frequently performed, mostly for small primary tumors (T1-T2). However, the benefits of pre-CRT tonsillectomy remain unclear. METHODS: A retrospective review was performed in 66 patients with T1-T2 tonsillar SCCs treated by CRT from 1997 to 2009. The efficacy of pre-CRT tonsillectomy was analyzed with regard to oncological and functional outcomes. RESULTS: Thirty patients (45.5%) received tonsillectomy (pre-CRT tonsillectomy group), and 36 patients (54.5%) did not (CRT group). Except for a trend toward more T1 cases (33.3% vs. 13.9%, p = 0.061) and significantly less chemotherapy use (60% vs. 86.1%, p = 0.016) in the pre-CRT tonsillectomy group, there were no differences between the two groups in terms of age, gender, N classification (nodal status), overall stage, radiation dose, duration, or technique. In the pre-CRT tonsillectomy group, eight cases (26.7%) achieved an adequate operative margin judged by the surgeon, and only one (12.5%) had a negative pathological margin. In long-term follow-up, there were no statistically significant differences between the two groups regarding local (93.3% vs. 91.7%, p = 0.82) or regional control (93.3% vs. 94.4%, p = 0.84). The pre-CRT tonsillectomy group did not have a better 5-year disease-specific survival rate (83.3% vs. 94.4%, p = 0.177) or 5-year overall survival rate (70% vs. 94.4%, p = 0.017). There were no differences in complications or functional results (feeding tube and tracheostomy dependence), and quality of life demonstrated no significant difference. CONCLUSION: Pre-CRT tonsillectomy contributes little to oncological and functional outcomes in patients with T1-T2 tonsillar SCC.

Twice-daily application of topical corticosteroids with a squirt system for patients with steroid-responsive olfactory impairment.

CONCLUSION: Twice-daily topical corticosteroid treatment using a squirt system was beneficial in maintaining improvements in olfactory dysfunction which had been achieved by oral steroid treatment. OBJECTIVES: Some patients suffering from olfactory dysfunction respond well to corticosteroids. However, maintaining these improvements is challenging. The aim of this study was to evaluate the maintenance effect of twice-daily topical steroid treatment using a squirt system. METHODS: Twenty-two anosmic patients with an increase in odor threshold, discrimination, and identification (TDI) scores in Sniffin' Sticks tests by more than six points after 1-week of oral steroid treatment were enrolled. All the patients used a squirt system to apply topical corticosteroids and were followed up at 1, 3, and 6 months. RESULTS: Nineteen, 16, and 10 patients were followed-up at 1, 3, and 6 months after treatment, respectively. All the patients had significant visual analog scale scores improvements compared to pre-treatment. The mean improvements in TDI scores were 9.80 (p < 0.001), 11.58 (p = 0.001), and 13.87 (p = 0.005) after 1, 3, and 6 months of treatment, respectively. The self-rated and objective olfactory function scores were maintained with steroid squirt therapy without significant decline, even in the patients who were followed up for 6 months.

Serotnin as a possible biomarker in obstructive sleep apnea.

Obstructive sleep apnea (OSA) is a highly prevalent disease which carries substantial public health burden. Polysomnography is the standard procedure used to diagnose OSA. However cost, accessibility, technical requirements, and skilled interpretation needs constrain its widespread use and have a role in the under-diagnosis of sleep disordered breathing. There is a clinical need to develop expedient and widely accessible tools to detect this disorder., Several biochemical markers have recently been proposed as diagnostic tools in OSA. Numerous neurochemicals directly influence the activity of upper airway dilator motor neurons, which subsequently influence respiration during sleep. Serotonin (5-HT) is one such neurochemical that has a key role in ventilatory stimulation. Herein, we review the current evidence demonstrating relationships between multiple biomarkers and sleep disordered breathing and focus on relationships between OSA and 5-HT. We discuss the possibility of biomarker-driven detection technology in the future as a means of diagnosing and monitoring OSA. Finally, we explore the specific role 5-HT may have in the future in both the diagnosis and treatment of OSA.