Swallowing Is Differentially Influenced by Retronasal Compared with Orthonasal Stimulation in Combination with Gustatory Stimuli

Identical stimuli are processed differently when presented ortho- or retronasally. In contrast to orthonasal olfaction, retronasal odorant perception is strongly associated with flavor and food intake, which is usually followed by swallowing. Along with other stimuli, gustatory stimuli are known to influence the swallowing reflex. It was therefore the aim of present study to examine whether retronasal olfaction, in combination with simultaneous gustatory stimuli, influences swallowing in a manner different from that of orthonasal olfaction. Fifty normosmic and normogeusic subjects took part in the study. A sweet taste (glucose, delivered via an intraoral taste dispenser) was presented simultaneously with vanillin, a food-like odor, either ortho- or retronasally at random using a computer-controlled olfactometer. Ultrasound imaging of the mouth floor was recorded on videotape to continuously monitor swallowing activity. After retronasal stimulation, swallowing occurred significantly faster (7.49 vs. 9.42 s; P < 0.001) and also took place more frequently compared with swallowing after orthonasal stimulation (1.38 times vs. 1.14 times; P < 0.001). These results show that a food-like odorant presented retronasally in combination with a congruent taste stimulus can influence swallowing. Whether these results can be assigned to other, unfamiliar, unpleasant nonfood-like odors has yet to be determine

A study about the frequency of taste disorders

Although 5% of the general population exhibit a functional anosmia, little is known about the frequency of gustatory disorders. Whenever taste function has been tested within large sociodemographic studies, so far only short test versions were applied making the interpretation difficult. Using two psychophysical taste tests, the validated "taste strips” and suprathreshold taste solutions of the four basic tastes sweet, sour, salty and bitter we investigated 761 healthy subjects within the age range of 5-89years. Prior to testing, all subjects rated their taste function. According to testing with the taste strips, 5.3% scored below the result considered as hypogeusia. All four taste sprays were correctly identified by 82.3% of all subjects. Results of the two taste tests correlated positively (r=0.33, p<0.001), and there was a significant negative correlation between age and test results. However, we never observed complete ageusia. Misinterpretations of tastes were surprisingly common. In summary, hypogeusia was present in 5% while complete ageusia seems to be very rare, in contrast to misinterpretations of taste

Needs and supporting tools for primary care physicians to improve care of patients with vertigo and dizziness: a national survey.

BACKGROUND The diagnostic workup and treatment decisions for vertigo or dizziness in primary care can be challenging due to the broad range of possible causes and limited time and expertise of physicians. This can lead to delays in treatment and unnecessary tests. We aimed to identify the unmet needs of primary care physicians (PCPs) and strategies to improve care for dizzy patients. MATERIALS AND METHODS An online survey was conducted among board-certified PCPs in Switzerland to explore needs in caring for dizzy patients and potential educational approaches. RESULTS Based on responses from 152 participating PCPs, satisfaction and confidence were higher in diagnosing (82%) and treating (76%) acute dizziness compared to episodic/chronic cases (63 and 59%, respectively). Younger PCPs had lower diagnostic yield and confidence. Areas for improvement in specialist interactions included communication between physicians (23%/36%; always/often true), shorter waiting times for consultations (19%/40%), more detailed feedback (36%/35%), and consistent patient back referrals (31%/30%). PCPs expressed interest in hands-on courses, workshops, practical guidelines, web-based algorithms, and digital tools such as printed dizzy diaries and apps for follow-up. CONCLUSION Enhanced dialog between PCPs and specialists is crucial to address the most common unmet needs. Reducing waiting times for referrals and providing clear instructions to specialists for triage are essential. The findings from this survey will guide the development of tools to improve the diagnosis and treatment of dizzy patients. Younger PCPs, who face higher diagnostic uncertainty, should be prioritized for educational approaches such as hands-on courses, workshops, and practical recommendations

What is the current status of primary care in the diagnosis and treatment of patients with vertigo and dizziness in Switzerland? A national survey

BackgroundVertigo and dizziness are among the most frequent presenting symptoms in the primary care physicians' (PCPs) office. With patients facing difficulties in describing their complaints and clinical findings often being subtle and transient, the diagnostic workup of the dizzy patient remains challenging. We aimed to gain more insights into the current state of practice in order to identify the limitations and needs of the PCPs and define strategies to continuously improve their knowledge in the care of the dizzy patient.Materials and methodsBoard-certified PCPs working in Switzerland were invited to participate in an online survey. A descriptive statistical analysis was performed, and prospectively defined hypotheses were assessed using regression analyses.ResultsA vast majority of participating PCPs (n = 152) were familiar with the key questions when taking the dizzy patient's history and with performing provocation/repositioning maneuvers when posterior-canal benign paroxysmal positional vertigo (BPPV) was suspected (91%). In contrast, strong agreement that performing the alternating cover test (21%), looking for a spontaneous nystagmus with fixation removed (42%), and performing the head-impulse test (47%) were important was considerably lower, and only 19% of PCPs were familiar with lateral-canal BPPV treatment. No specific diagnosis could be reached in substantial fractions of patients with acute (35% [25; 50%], median [inter-quartile range]) and episodic/chronic (50% [40; 65.8%]) dizziness/vertigo. Referral to specialists was higher in patients with episodic/chronic dizziness than in acutely dizzy patients (50% [20.3; 75] vs. 30% [20; 50]), with younger PCPs (aged 30–40 years) demonstrating significantly increased odds of referral to specialists (odds ratio = 2.20 [1.01–4.81], p = 0.048).ConclusionThe assessment of dizzy patients takes longer than that of average patients in most primary care practices. Many dizzy patients remain undiagnosed even after a thorough examination, highlighting the challenges faced by PCPs and potentially leading to frequent referrals to specialists. To address this, it is crucial to promote state-of-the-art neuro-otological examination and treatment techniques that are currently neglected by most PCPs, such as “HINTS” and lateral-canal BPPV treatment. This can help reduce referral rates allowing more targeted treatment and referrals

Clinical Olfactory Working Group Consensus statement on the treatment of post infectious olfactory dysfunction

Background: Respiratory tract viruses are the second most common cause of olfactory dysfunction. As we learn more about the effects of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), with the recognition that olfactory dysfunction is a key symptom of this disease process, there is a greater need than ever for evidence-based management of postinfectious olfactory dysfunction (PIOD). Objective: Our aim was to provide an evidence-based practical guide to the management of PIOD (including post–coronavirus 2019 cases) for both primary care practitioners and hospital specialists. Methods: A systematic review of the treatment options available for the management of PIOD was performed. The written systematic review was then circulated among the members of the Clinical Olfactory Working Group for their perusal before roundtable expert discussion of the treatment options. The group also undertook a survey to determine their current clinical practice with regard to treatment of PIOD. Results: The search resulted in 467 citations, of which 107 articles were fully reviewed and analyzed for eligibility; 40 citations fulfilled the inclusion criteria, 11 of which were randomized controlled trials. In total, 15 of the articles specifically looked at PIOD whereas the other 25 included other etiologies for olfactory dysfunction. Conclusions: The Clinical Olfactory Working Group members made an overwhelming recommendation for olfactory training; none recommended monocycline antibiotics. The diagnostic role of oral steroids was discussed; some group members were in favor of vitamin A drops. Further research is needed to confirm the place of other therapeutic options

More than smell - COVID-19 is associated with severe impairment of smell, taste, and chemesthesis

Recent anecdotal and scientific reports have provided evidence of a link between COVID-19 and chemosensory impairments such as anosmia. However, these reports have downplayed or failed to distinguish potential effects on taste, ignored chemesthesis, generally lacked quantitative measurements, were mostly restricted to data from single countries. Here, we report the development, implementation and initial results of a multi-lingual, international questionnaire to assess self-reported quantity and quality of perception in three distinct chemosensory modalities (smell, taste, and chemesthesis) before and during COVID-19. In the first 11 days after questionnaire launch, 4039 participants (2913 women, 1118 men, 8 other, ages 19-79) reported a COVID-19 diagnosis either via laboratory tests or clinical assessment. Importantly, smell, taste and chemesthetic function were each significantly reduced compared to their status before the disease. Difference scores (maximum possible change+/-100) revealed a mean reduction of smell (-79.7+/- 28.7, mean+/- SD), taste (-69.0+/- 32.6), and chemesthetic (-37.3+/- 36.2) function during COVID-19. Qualitative changes in olfactory ability (parosmia and phantosmia) were relatively rare and correlated with smell loss. Importantly, perceived nasal obstruction did not account for smell loss. Furthermore, chemosensory impairments were similar between participants in the laboratory test and clinical assessment groups. These results show that COVID-19-associated chemosensory impairment is not limited to smell, but also affects taste and chemesthesis. The multimodal impact of COVID-19 and lack of perceived nasal obstruction suggest that SARS-CoV-2 infection may disrupt sensory-neural mechanisms.Additional co-authors: Veronica Pereda-Loth, Shannon B Olsson, Richard C Gerkin, Paloma Rohlfs Domínguez, Javier Albayay, Michael C. Farruggia, Surabhi Bhutani, Alexander W Fjaeldstad, Ritesh Kumar, Anna Menini, Moustafa Bensafi, Mari Sandell, Iordanis Konstantinidis, Antonella Di Pizio, Federica Genovese, Lina Öztürk, Thierry Thomas-Danguin, Johannes Frasnelli, Sanne Boesveldt, Özlem Saatci, Luis R. Saraiva, Cailu Lin, Jérôme Golebiowski, Liang-Dar Hwang, Mehmet Hakan Ozdener, Maria Dolors Guàrdia, Christophe Laudamiel, Marina Ritchie, Jan Havlícek, Denis Pierron, Eugeni Roura, Marta Navarro, Alissa A. Nolden, Juyun Lim, KL Whitcroft, Lauren R. Colquitt, Camille Ferdenzi, Evelyn V. Brindha, Aytug Altundag, Alberto Macchi, Alexia Nunez-Parra, Zara M. Patel, Sébastien Fiorucci, Carl M. Philpott, Barry C. Smith, Johan N Lundström, Carla Mucignat, Jane K. Parker, Mirjam van den Brink, Michael Schmuker, Florian Ph.S Fischmeister, Thomas Heinbockel, Vonnie D.C. Shields, Farhoud Faraji, Enrique Enrique Santamaría, William E.A. Fredborg, Gabriella Morini, Jonas K. Olofsson, Maryam Jalessi, Noam Karni, Anna D'Errico, Rafieh Alizadeh, Robert Pellegrino, Pablo Meyer, Caroline Huart, Ben Chen, Graciela M. Soler, Mohammed K. Alwashahi, Olagunju Abdulrahman, Antje Welge-Lüssen, Pamela Dalton, Jessica Freiherr, Carol H. Yan, Jasper H. B. de Groot, Vera V. Voznessenskaya, Hadar Klein, Jingguo Chen, Masako Okamoto, Elizabeth A. Sell, Preet Bano Singh, Julie Walsh-Messinger, Nicholas S. Archer, Sachiko Koyama, Vincent Deary, Hüseyin Yanik, Samet Albayrak, Lenka Martinec Novákov, Ilja Croijmans, Patricia Portillo Mazal, Shima T. Moein, Eitan Margulis, Coralie Mignot, Sajidxa Mariño, Dejan Georgiev, Pavan K. Kaushik, Bettina Malnic, Hong Wang, Shima Seyed-Allaei, Nur Yoluk, Sara Razzaghi, Jeb M. Justice, Diego Restrepo, Julien W Hsieh, Danielle R. Reed, Thomas Hummel, Steven D Munger, John E Haye

Swallowing is differentially influenced by retronasal compared with orthonasal stimulation in combination with gustatory stimuli

Identical stimuli are processed differently when presented ortho- or retronasally. In contrast to orthonasal olfaction, retronasal odorant perception is strongly associated with flavor and food intake, which is usually followed by swallowing. Along with other stimuli, gustatory stimuli are known to influence the swallowing reflex. It was therefore the aim of present study to examine whether retronasal olfaction, in combination with simultaneous gustatory stimuli, influences swallowing in a manner different from that of orthonasal olfaction. Fifty normosmic and normogeusic subjects took part in the study. A sweet taste (glucose, delivered via an intraoral taste dispenser) was presented simultaneously with vanillin, a food-like odor, either ortho- or retronasally at random using a computer-controlled olfactometer. Ultrasound imaging of the mouth floor was recorded on videotape to continuously monitor swallowing activity. After retronasal stimulation, swallowing occurred significantly faster (7.49 vs. 9.42 s; P > 0.001) and also took place more frequently compared with swallowing after orthonasal stimulation (1.38 times vs. 1.14 times; P > 0.001). These results show that a food-like odorant presented retronasally in combination with a congruent taste stimulus can influence swallowing. Whether these results can be assigned to other, unfamiliar, unpleasant nonfood-like odors has yet to be determined

Olfactory testing in clinical settings - is there additional benefit from unilateral testing?

In clinical settings, olfactory testing is usually performed bilaterally; thus, unilateral olfactory loss may go unnoticed. The aims of this study were to evaluate 1) whether patients presenting with self-reported olfactory disorders demonstrate significant side differences in odour perception, depending on the prevalance of measured unilateral disorder, and 2) to evaluate the existing testing procedure. In 518 patients presenting with olfactory disorders, olfactory testing was performed using the "Sniffin' Sticks" test battery (consisting of a threshold, discrimination, and odour identification test) examining each nostril separately. According to the history and results from the clinical examination, olfactory disorders were classified as related to trauma, sinunasal disease, upper respiratory tract infection (URTI), tumour, congenital, idiopathic, and other. A difference of three or more points in one of the subtests or six or more points in the composite olfactory test score was considered a side difference. In almost one quarter of all presenting patients (23.4%), a side difference was detected. To not to miss lateralized disorders, we recommend testing each nostril separately. Depending on the presence or absence of a significant difference, testing then can be continued birhinally or separately for each nostril

Influence of simultaneous gustatory stimuli on orthonasal and retronasal olfaction

Orthonasal and retronasal olfaction processes differ. The aim of this study was to examine whether congruent and incongruent simultaneous gustatory stimuli influence orthonasal and retronasal odorant perception, using olfactory event-related potentials as a measure. Thirty-two young, healthy subjects (16 men, 16 women) took part in two test sessions. Olfactory event-related potentials were recorded in response to a food-like odor, vanillin, and to an odor usually not associated with foods, the rose-like phenylethylalcohol. Each session consisted of four randomized blocks of 15 stimuli each which were applied either orthonasally or retronasally. Simultaneously, sweet or sour gustatory stimuli were applied. In response to retronasal vanillin, stimuli latencies P2 of the event-related potentials were significantly shorter in the congruent "sweet condition" than the incongruent "sour condition". In contrast, with orthonasal stimulation, shorter P2 latencies were seen for both odorants in the incongruent condition. Intensity of both odorants was perceived as less pronounced after retronasal stimulation than after orthonasal stimulation. In conclusion, application of a sweet taste significantly enhanced the processing of a congruent olfactory stimulus when presented through the retronasal route. Incongruent simultaneous gustatory stimulation applied during orthonasal olfaction seemed to induce conflict priming, also resulting in faster processing