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Chow XH, Ting CM, Wan Hamizan AK, Zahedi FD, Tan HJ, Remli R, Khoo CS, Ombao H, Sahibulddin SZ, Husain S. Brain waves spectral analysis of human responses to odorous and non-odorous substances: a preliminary study. J Laryngol Otol 2024; 138:301-309. [PMID: 37259908 DOI: 10.1017/s0022215123000919] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 06/02/2023]
Abstract
OBJECTIVE The aim of this study was to identify the potential electrophysiological biomarkers of human responses by comparing the electroencephalogram brain wave changes towards lavender versus normal saline in a healthy human population. METHOD This study included a total of 44 participants without subjective olfactory disturbances. Lavender and normal saline were used as the olfactory stimulant and control. Electroencephalogram was recorded and power spectra were analysed by the spectral analysis for each alpha, beta, delta, theta and gamma bandwidth frequency upon exposure to lavender and normal saline independently. RESULTS The oscillatory brain activities in response to the olfactory stimulant indicated that the lavender smell decreased the beta activity in the left frontal (F7 electrode) and central region (C3 electrode) with a reduction in the gamma activity in the right parietal region (P4 electrode) (p < 0.05). CONCLUSION Olfactory stimulants result in changes of electrical brain activities in different brain regions, as evidenced by the topographical brain map and spectra analysis of each brain wave.
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Affiliation(s)
- Xiao Hong Chow
- Department of Otorhinolaryngology - Head and Neck Surgery, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia
| | - Chee Ming Ting
- Faculty of Engineering, School of Biomedical Engineering and Health Sciences, University of Technology Malaysia, Johor, Malaysia
- School of Information Technology, Monash University Malaysia, Bandar Sunway, Malaysia
| | - Aneeza Khairiyah Wan Hamizan
- Department of Otorhinolaryngology - Head and Neck Surgery, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia
| | - Farah Dayana Zahedi
- Department of Otorhinolaryngology - Head and Neck Surgery, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia
| | - Hui Jan Tan
- Department of Medicine, Neurology Unit, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia
| | - Rabani Remli
- Department of Medicine, Neurology Unit, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia
| | - Ching Soong Khoo
- Department of Medicine, Neurology Unit, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia
| | - Hernando Ombao
- Biostatistics Group, King Abdullah University of Science and Technology, Thuwal, Saudi Arabia
| | - Siti Zaleha Sahibulddin
- Department of Medicine, Neurology Unit, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia
| | - Salina Husain
- Department of Otorhinolaryngology - Head and Neck Surgery, Universiti Kebangsaan Malaysia Medical Center, Kuala Lumpur, Malaysia
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Kim K, Zhao K. A Nasal Aerodynamics Perspective of Retronasal Olfaction: Rodents vs. Humans. CHEMOSENS PERCEPT 2022; 15:124-134. [PMID: 37192933 PMCID: PMC10168102 DOI: 10.1007/s12078-022-09300-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/24/2022] [Accepted: 09/28/2022] [Indexed: 11/03/2022]
Abstract
Introduction Odor perception can be achieved through ortho or retronasal routes, with the latter being an important component of flavor perception. There are significant olfactory differences that exist between rats and humans and by understanding the role of structural differences, further insight can be gained into the mechanism of odorant perception via ortho or retronasal routes. Methods 3D human and rat (Sprague Dawley) computational models were used to investigate nasal anatomy impact on ortho vs. retronasal odorant transport to the olfactory epithelium. The nasal pharynx region was modified for human and rat models to probe nasal structure impact on ortho vs retro olfaction. 65 odorant absorption rates to the olfactory epithelium were extracted from each model. Results For human, the retronasal route provided higher peak odorant absorption compared to orthonasal route (left: 90% higher, right: 45% higher), but substantially lowered peak absorption for rat (medial: 97% lower, lateral: 75% lower). For both models, anatomical modification had minimal impact to orthonasal routes, but substantially modulated the retronasal route: decrease (left: -41.4%, right: -44.2%) for human, and increase to the medial (29.5%) but not to lateral (-14.3%) for rat. Conclusions There exist key differences between humans and rats regarding retro/orthonasal odorant transport routes, which matched well with experimental olfactory bulb activity data in literature. Implications While humans have equivalent odorant delivery between routes, the difference in retro and orthonasal routes in rodents is substantial and changes to the transverse lamina above the nasopharynx can substantially modulate the retronasal route, but not enough to bridge the gap between the two routes.
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Affiliation(s)
- Kanghyun Kim
- Department of Otolaryngology - Head & Neck Surgery, The Ohio State University, Columbus, OH
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH
| | - Kai Zhao
- Department of Otolaryngology - Head & Neck Surgery, The Ohio State University, Columbus, OH
- Department of Biomedical Engineering, The Ohio State University, Columbus, OH
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Fontana L, Albayay J, Fernandez-Prieto I, Zampini M. EXPRESS: Olfactory habituation for food and non-food odours. Q J Exp Psychol (Hove) 2022; 76:1209-1219. [PMID: 35866345 DOI: 10.1177/17470218221115046] [Citation(s) in RCA: 2] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022]
Abstract
Olfactory perception can be modulated by the repeated exposure to odours. Olfactory habituation is a reduced behavioural response to repetitive stimulation. Edibility is considered an important top-down feature that can affect olfactory perception, but whether it could modulate olfactory habituation when food or non-food odours are repeatedly smelled remains unclear. Indeed, due to their ecological salience, food odours attract attention automatically which might slow down habituation. This registered report aimed to determine whether olfactory habituation shows a different pattern when participants are presented with food or non-food odours. In a within-subject design, 50 participants were tested under satiated and fasted states in separated experimental sessions. In each session, participants were exposed to the same food and non-food odour in different blocks of 20 trials each. Participants rated the perceived odour intensity and pleasantness after each trial. We used an intermittent odour presentation to reduce olfactory fatigue while capitalising on the effect of cognitive states on habituation. Linear mixed-effects models showed that the perceived odour intensity decreased over time only for non-food odours. Conversely, the perceived odour pleasantness decreased significantly more across trials for food odours. These effects were retrieved regardless of the participant's hunger state. Our results are in line with the olfactory specific satiety theory which posits a specific decrease in the perceived pleasantness of food odours, without changes in the perceived odour intensity. In short, our findings indicate that perceived odour edibility modulates olfactory habituation, extending the previous literature on the impact of top-down factors on olfactory perception.
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Affiliation(s)
- Lara Fontana
- Center for Mind/Brain Sciences, University of Trento, Italy 19034
| | - Javier Albayay
- Center for Mind/Brain Sciences, University of Trento, Italy 19034
| | - Irune Fernandez-Prieto
- Center for Mind/Brain Sciences, University of Trento, Italy 19034.,Department of Neurosciences, Biomedicine and Movement Sciences, University of Verona, Italy
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Should Panelists Refrain from Wearing a Personal Fragrance Prior to Sensory Evaluation? The Effect of Using Perfume on Olfactory Performance. Foods 2022; 11:foods11030428. [PMID: 35159578 PMCID: PMC8834429 DOI: 10.3390/foods11030428] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/19/2021] [Revised: 01/20/2022] [Accepted: 01/26/2022] [Indexed: 02/01/2023] Open
Abstract
It is typically recommended that panelists should refrain from wearing personal fragrances, such as perfume or cologne, prior to sensory evaluation. Interestingly, no study has been reported as to whether panelists’ perceptions of test samples could be affected by personal fragrances worn by themselves. The objective of this study was, therefore, to determine the effect of such a personal fragrance on olfactory performance. Nineteen untrained participants were screened, recruited for, and underwent the Sniffin’ Sticks test designed for measuring olfactory performances that included the odor threshold, discrimination, and identification (TDI). The olfactory performance tasks were conducted under three fragrance level conditions: (1) control (no fragrance), (2) just-about-right (JAR), and (3) excessive, with a preliminary study used to identify both the JAR and excessive fragrance levels. The results showed that the odor discrimination, odor threshold, and combined TDI performances were significantly lowered in the two conditions with the perfume fragrance, while the odor identification performance exhibited no significant differences across all three conditions. These findings provide empirical evidence that even low to moderate levels of personal fragrance can significantly reduce individuals’ olfactory capabilities, possibly subsequently altering the perception of test samples during sensory evaluation.
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Xiao W, Sun Z, Yan X, Gao X, Lv Q, Wei Y. Differences in olfactory habituation between orthonasal and retronasal pathways. J Physiol Sci 2021; 71:36. [PMID: 34837939 PMCID: PMC10716942 DOI: 10.1186/s12576-021-00822-0] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/18/2021] [Accepted: 11/15/2021] [Indexed: 11/10/2022]
Abstract
The odorant arrives at nasal olfactory epithelium ortho- and retronasally. This experiment aimed to study the potential different olfactory habituation in orthonasal and retronasal pathways. 68 subjects were stimulated by constant airflow with an odor (50% phenethyl alcohol, PEA or 5% n-butyl acetate, BA) presented ortho- or retronasally. Participants rated the perceived odor intensity (0-10 points) per minute until the odor sensation disappeared. We also investigated the cross-habituation: when the subjects achieved full habituation, continue to rate odor intensity in a different pathway after instantly switching the odor stimulation pathway. The olfactory habituation curve was drawn. The differences of ratings between the orthonasal and retronasal olfaction at different time points and between male and female subjects were analyzed. The two odor intensity ratings decreased as the time extended, share the same "fast followed by slow" type. The ratings of orthonasal olfaction decreased faster than that of retronasal. The intensity rating of PEA of male retronasal approach was lower than that of female at the 5th min (p = 0.018). When orthonasal full habituation achieved, there was significant difference between the intensity ratings and the initial ratings of the retronasal stimulation pathway (p < 0.0001), and vice versa. We found obvious habituation as well as cross-habituation in both orthonasal and retronasal olfaction. The habituation of orthonasal olfaction was faster than that of retronasal olfaction. These different habituations were related to the gender.
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Affiliation(s)
- Wei Xiao
- Department of Otolaryngology Head & Neck Surgery, Zhongnan Hospital of Wuhan University, Wuhan, China
| | - Zhifu Sun
- Department of Otolaryngology Head & Neck Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Xiaoguang Yan
- Smell and Taste Clinic, TU Dresden, Dresden, Germany
| | - Xing Gao
- Department of Otolaryngology Head & Neck Surgery, Capital Institute of Pediatrics, Beijing, China
| | - Qianwen Lv
- Department of Otolaryngology Head & Neck Surgery, Beijing Anzhen Hospital, Capital Medical University, Beijing, China
| | - Yongxiang Wei
- Department of Otolaryngology Head & Neck Surgery, Capital Institute of Pediatrics, Beijing, China.
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Hannum ME, Fryer JA, Simons CT. Non-food odors and the duality of smell: Impact of odorant delivery pathway and labeling convention on olfactory perception. Physiol Behav 2021; 238:113480. [PMID: 34058218 DOI: 10.1016/j.physbeh.2021.113480] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/10/2021] [Revised: 05/15/2021] [Accepted: 05/25/2021] [Indexed: 01/19/2023]
Abstract
The olfactory system encompasses two perceptual pathways (orthonasal and retronasal) that activate the same receptors in the olfactory epithelium yet are thought to elicit different perceptions. Presently, a novel matching paradigm was employed using a non-food flavor set with low retronasal familiarity (honeysuckle, lavender, rose, and jasmine) to evaluate the effect of odor type on the Duality of Smell. Additionally, the influence of cognitive strategies used by subjects was assessed by manipulating the naming convention seen by the subjects: familiar (Honeysuckle, Lavender, Rose, Jasmine), unfamiliar (Inodora, Pedunculata, Beggeriana, Didymum), and generic (A, B, C, D). Subjects were presented with a reference, either in a vial (orthonasal delivery, ON) or a 2 oz. cup (retronasal delivery, RN) and instructed to match the same aroma from four unknowns, evaluated either by the same delivery route (congruent, e.g., ON-ON, RN-RN) or different route (incongruent, e.g., ON-RN, RN-ON) than the reference evaluation. All possible combinations of orthonasal and retronasal delivery for the reference and unknowns (e.g. ON-ON, RN-RN, ON-RN, RN-ON) were assessed by all subjects. Matching performance and signal detection measures indicated that, on average, subjects performed significantly better in the congruent conditions than in the incongruent conditions. These results suggest perceptual quality of aromas is route dependent and extend the Duality of Smell hypothesis to samples with low retronasal familiarity such as non-food odors. Labeling convention also had an impact on performance but, surprisingly, not in the direction anticipated. Indeed, as the information contained in the label decreased from familiar to generic reference names, performance increased. Moreover, depending on the labeling convention used, certain aromas were easier to match than others. The present research suggests odorant matching is a function of stimulus quality, cognitive strategy, and labeling convention.
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Affiliation(s)
- Mackenzie E Hannum
- Department of Food Science & Technology, The Ohio State University, 2015 Fyffe Rd., Columbus, OH 43210-1007
| | - Jenna A Fryer
- Department of Food Science & Technology, The Ohio State University, 2015 Fyffe Rd., Columbus, OH 43210-1007
| | - Christopher T Simons
- Department of Food Science & Technology, The Ohio State University, 2015 Fyffe Rd., Columbus, OH 43210-1007.
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Feldmeyer A, Johnson A, Ennis JM. Emotional profiles elicited from orthonasal and retronasal perceptions of food (fruit) and non‐food (floral) aromas. FLAVOUR FRAG J 2021. [DOI: 10.1002/ffj.3655] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
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Hannum M, Stegman MA, Fryer JA, Simons CT. Different Olfactory Percepts Evoked by Orthonasal and Retronasal Odorant Delivery. Chem Senses 2019; 43:515-521. [PMID: 29982522 DOI: 10.1093/chemse/bjy043] [Citation(s) in RCA: 20] [Impact Index Per Article: 4.0] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/04/2023] Open
Abstract
The Duality of Smell hypothesis suggests odorants delivered orthonasally elicit different sensations compared with those delivered retronasally despite activating the same receptors in the olfactory epithelium. Presently, we investigated this further using a matching paradigm free from odorant or semantic memory bias. Subjects were asked to evaluate an aroma delivered in one condition (orthonasal or retronasal delivery) and match the same aroma from 4 unknowns evaluated in the same or different delivery conditions. Panelists matched flavors in 4 delivery conditions: orthonasal-orthonasal, retronasal-retronasal, retronasal-orthonasal, and orthonasal-retronasal. For orthonasal presentation, panelists smelled samples using their nostrils, and for retronasal presentation, panelists swallowed aqueous flavors. In Experiment 1, panelists were instructed to match familiar flavors (banana, grape, orange, raspberry). In Experiments 2 and 3, panelists used the same experimental design with either 4 unfamiliar flavors (kinnow, longan, pawpaw, prunus) or 4 distinct subtypes of a strawberry flavor (woody, green, ripe, candy). In Experiment 1, the number of correct matches in each condition did not significantly differ suggesting stability in the perceptual construct across delivery routes. However, in Experiments 2 and 3, significantly more samples were correctly matched in the orthonasal-orthonasal and retronasal-retronasal conditions compared with the retronasal-orthonasal or orthonasal-retronasal conditions suggesting aroma perception is dependent on delivery route. Additionally, across the 4 delivery methods, the ability to correctly match flavors decreased as flavor familiarity decreased or similarity increased and may reflect the different cognitive strategies employed by subjects when matching these stimuli. Our results suggest odorant percepts are route-dependent and consistent with the Duality of Smell phenomenon.
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Affiliation(s)
- Mackenzie Hannum
- Department of Food Science & Technology, The Ohio State University, Columbus, OH, USA
| | - Margaret A Stegman
- Department of Food Science & Technology, The Ohio State University, Columbus, OH, USA
| | - Jenna A Fryer
- Department of Food Science & Technology, The Ohio State University, Columbus, OH, USA
| | - Christopher T Simons
- Department of Food Science & Technology, The Ohio State University, Columbus, OH, USA
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Retronasal Habituation: Characterization and Impact on Flavor Perception Using Time-Intensity. CHEMOSENS PERCEPT 2018. [DOI: 10.1007/s12078-018-9254-x] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
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