Olfactory capacity declines with aging, but increasing evidence shows that smell dysfunction is one of the early signs of prodromal neurodegenerative diseases such as Alzheimer’s and Parkinson’s disease. The study of olfactory ability and its role in neurodegenerative diseases arouses much interest in the scientific community. In neurology, olfactory impairment is a potential early marker for the onset of neurodegenerative diseases, but the underlying mechanism is poorly understood. The loss of smell is considered a clinical sign of early-stage disease and a marker of the disease’s progression and cognitive impairment. Highlighting the importance of biological bases of smell and molecular pathways could be fundamental to improve neuroprotective and therapeutic strategies. We focused on the review articles and meta-analyses on olfactory and cognitive impairment. We depicted the neurobiology of olfaction and the most common olfactory tests in neurodegenerative diseases. In addition, we underlined the close relationship between the olfactory and cognitive deficit due to nasal neuroepithelium, which is a direct extension of the CNS in communication with the external environment. Neurons, Nose, and Neurodegenerative diseases highlights the role of olfactory dysfunction as a clinical marker for early stages of neurodegenerative diseases when it is associated with molecular, clinical, and neuropathological correlations.

Background: Anosmia is defined as the complete absence of olfactory function, which can be caused by a variety of causes, with upper respiratory tract infections being among the most frequent causes. Anosmia due to SARS-CoV-2 infection has attracted attention given its main role in symptomatology and the social impact of the pandemic. Methods: We conducted systematic research in a clinicaltrials.gov database to evaluate all active clinical trials worldwide regarding drug therapies in adult patients for anosmia following SARS-CoV-2 infection with the intention of identifying the nearby prospects to treat Anosmia. We use the following search terms: “Anosmia” AND “COVID-19” OR “SARS-CoV-2” OR “2019 novel coronavirus”. Results: We found 18 active clinical trials that met our criteria: one phase 1, one phase 1–2, five phases 2, two phases 2–3, three phases 3, and six phases 4 studies were identified. The drug therapies that appear more effective and promising are PEA-LUT and Cerebrolysin. The other interesting drugs are 13-cis-retinoic acid plus aerosolized Vitamin D, dexamethasone, and corticosteroid nasal irrigation. Conclusions: COVID-19 has allowed us to highlight how much anosmia is an important and debilitating symptom for patients and, above all, to direct research to find a therapy aimed at curing the symptom, whether it derives from SARS-CoV-2 infection or other infections of the upper airways. Some of these therapies are very promising and are almost at the end of experimentation. They also provide hope in this field, which not addressed until recently.

Background: Management of high-grade carotid artery stenosis with concomitant ipsilateral parotid gland tumor presents a rare and challenging surgical condition. Due to the rarity of this dual pathology, standardized guidelines are lacking. Material and Methods: A retrospective study was conducted between January 2020 and May 2025. Six asymptomatic patients with significant carotid stenosis and coexisting ipsilateral Warthin’s tumor underwent simultaneous eversion CEA (carotid endarterectomy) and partial superficial parotidectomy/extracapsular enucleation via a single modified Blair’s incision. Results: Median follow-up was 43 months (range: 12–60 months). Postoperative and long-term survival at median follow-up was 100%, with a 5-year survival rate of 83.3% (one death at 50 months due to myocardial infarction). Disease-free survival at 5 years was 100% for Warthin’s tumor and 83.3% for carotid stenosis. No perioperative transient ischemic attacks (TIA), strokes, hematomas, salivary fistula or iatrogenic cranial nerve injuries occurred. Conclusions: In patients presenting with high-grade carotid stenosis and concomitant ipsilateral Warthin’s tumor, a simultaneous surgical approach is a feasible strategy. This approach eliminates the need for staged interventions, significantly reducing overall anesthetic risk, surgical burden, and healthcare resource utilization.