Evaluation of human electroencephalogram change for sensory effects of fragrance

Electroencephalography as an objective method for assessing subjective emotions during the application of cream

OBJECTIVE

To compare emotional responses elicited by four cosmetic products on different sensory modalities (smell, visual, and touch), and analyze the link between objective instrumental analysis results and subjective evaluation of participants occurring within dimensional valence-arousal model of emotions.

METHODS

In this study, four cream products exhibiting variations in olfactory perception, visual appearance and perception usability were selected. Electroencephalography (EEG) and a subjective emotion scale were used to assess participants' emotional responses during the sensory experience of utilizing the creams.

RESULTS

The study revealed that the objective emotional valence and arousal of different cream products exhibited certain variations at distinct stages of usage. The trend of valence differences induced by different products measured by EEG at the same stage was almost as same as measured by subjective evaluation. The correspondence between the valence measured by EEG closely approximated that obtained through subjective evaluation across various products at distinct stages of usage. These findings demonstrate a significant correlation between EEG-based valence and subjective valence, however, no such relationship was observed for arousal.

CONCLUSION

This study demonstrates the feasibility of using EEG as a method to assess emotions elicited by various stages of cosmetics application, including smelling, looking, rubbing, and afterfeel. This technique serves as a valuable supplement to traditional methods for examining emotional responses by providing more objective evidence.

The Effects of Essential Oils on the Nervous System: A Scoping Review

Essential oils are a mixture of natural aromatic volatile oils extracted from plants. The use of essential oils is ancient, and has prevailed in different cultures around the world, such as those of the Egyptians, Greeks, Persians, and Chinese. Today, essential oils are used in traditional and complimentary medicines, aromatherapy, massage therapies, cosmetics, perfumes and food industries. The screening effect of essential oils has been studied worldwide. They demonstrate a range of biological activities, such as antiparasitic, antifungal, antibacterial, antiviral, antioxidant, anti-inflammatory, anticancer, antiaging, and neuroprotective properties. In this scoping review, we provide a 10-year updated comprehensive assessment of volatile oils and their effects on the nervous system. MEDLINE, Scopus, and Google Scholar were systematically and strategically searched for original studies investigating these effects from 2012 to 2022. Approximately seventy studies were selected as included studies. Among these studies, several outcomes were reported, including antistress, antianxiety, analgesic, cognitive, and autonomic effects. Some essential oils showed developmental benefits, with the potential to induce neurite outgrowth. The neurotransmitter receptor level can also be modified by essential oil application. Physiological and pathophysiological outcome measures were reported. For physiological outcomes, arousal, cognitive performance, circadian eating behavior, emotional modulation, consumer acceptance, preferences, and willingness to buy were investigated. For pathophysiological conditions, pain, depression, anxiety, stress, sleep disorder, mental fatigue, agitated behavior, and quality of life were measured. In conclusion, essential oils showed promising effects on the nervous system, which can be further applied to their use in functional foods, drinks, and alternative therapy.

Aroma of the essential oil of peppermint reduces aggressive driving behaviour in healthy adults

Aggressive driving is of increasing concern in modern society. This study investigated the potential for the presence of an ambient aroma to reduce aggressive responses in a simulated driving situation. Previous literature has demonstrated the beneficial effect of peppermint (Mentha piperita) aroma on driver alertness and we aimed to identify any impact on aggressive driver behaviour. Fifty volunteers were randomly assigned to one of two conditions (peppermint essential oil aroma and no aroma). Aggressive driving behaviours were measured in a virtual reality driving simulator. The analysis indicated that the peppermint aroma significantly reduced aggressive driving behaviours. The presence of the aroma also produced medium sized effects on some aspects of mood from pre-test levels. These results provide support for the use of ambient aromas for the modification of driving behaviours. It is proposed that applying peppermint into daily driving may be a beneficial for reducing driver aggression.

Aromatherapy with inhalation effectively alleviates the test anxiety of college students: A meta-analysis

Objective

Test anxiety is one of the common psychological and behavioral problems of college students, which can result in poor academic performance and even academic failure. Aromatherapy has been proposed as a promising method to reduce test anxiety in college students, but its precise efficacy has not been fully confirmed. This meta-analysis evaluated the effects of aromatherapy on the symptoms of test anxiety in college students to serve as a reference for future research and provide more scientific and exact evidence.

Methods

PubMed, The Cochrane Library, Web of Science, Embase, CINAHL, Science Direct, Chinese National Knowledge Infrastructure (CNKI), Chinese Science and Technology Journal Full-Text Database (VIP), and Wanfang Data were electronically searched from inception to June 2022 to identify randomized controlled trials (RCTs) on aromatherapy for treating students' test anxiety. The Cochrane Risk of Bias Assessment Tool for RCTs was used by two reviewers to critically and independently assess the methodological quality of the included studies. Review Manager 5.4 was used for the meta-analysis. Stata 17.0 was used for sensitivity analysis and Egger's test.

Results

Seven RCTs included 425 patients, with a moderate risk of bias in the included studies. The meta-analysis found that aromatherapy effectively reduced test anxiety in college students (SMD = -0.67, p < 0.01), with high heterogeneity of results (I 2 = 72%). The different types of essential oil devices used in the study are the source of inter-study heterogeneity. Subgroup analysis suggested that most effective methods were aromatherapy with compound essential oils (SMD = -0.91, p < 0.01), and using cloths or pads as the essential oil devices (SMD = -1.03, p < 0.01). There was no difference between aromatherapy and placebo control groups (SMD = -0.65, p = 0.25).

Conclusion

Aromatherapy with inhalation can help relieve test anxiety in college students, but more and higher-quality studies are needed. This study provides a reference for future research designs in terms of the selection of essential oil types and devices and the design of research groups.

Systematic review registration

[https://www.crd.york.ac.uk/prospero/], identifier [CRD42022345767].

A Systematic Review on the Adult Alpha Brainwave Activity After Essential Oil Inhalation

Aroma extracts from plant species have been utilized since ancient times for a variety of discomforting circumstances. Aromatherapy is a recognized complementary therapeutic treatment performed in various ways such as massage or dermal application, with its main uses involving relaxation, pain relief, and stress management. Several studies have outlined that inhalation of fragrance may influence the brain function since their components can cross the blood-brain barrier and interact with central nervous system receptors. The aim of this review was to systematically present findings regarding alpha brain wave activity reported exclusively by electroencephalography. The study was conducted according to the Preferred Reporting Items for Systematic Reviews and Meta-Analyses guidelines. The PubMed and Scopus databases were screened for relevant papers, based on specific eligibility criteria. The final step of the process resulted in 13 studies published between 1998 and 2021, using different essential oils. Most of the studies revealed the increase of alpha brainwave activity post-essential oil inhalation. Given the proven positive outcomes of increased alpha wave activity on several domains such as cognitive performance and better mental state, further research on the impact of essential oil inhalation is warranted.

Remote photonic detection of human senses using secondary speckle patterns

Neural activity research has recently gained significant attention due to its association with sensory information and behavior control. However, the current methods of brain activity sensing require expensive equipment and physical contact with the tested subject. We propose a novel photonic-based method for remote detection of human senses. Physiological processes associated with hemodynamic activity due to activation of the cerebral cortex affected by different senses have been detected by remote monitoring of nano-vibrations generated by the transient blood flow to the specific regions of the human brain. We have found that a combination of defocused, self-interference random speckle patterns with a spatiotemporal analysis, using Deep Neural Network, allows associating between the activated sense and the seemingly random speckle patterns.

Lavender aromatherapy: A systematic review from essential oil quality and administration methods to cognitive enhancing effects

Modern society is reviving the practice of aromatherapy, and lavender is reported being the most worldwide purchased plant for essential oil (EO) extraction. Since recent studies reported cognitive enhancing effects of lavender besides the hypno-inducing effects, a literature review is needed. Considering EO quality and diffusion devices, we conducted a systematic review on the effects of lavender EO inhalation on arousal, attention and memory in healthy subjects. Starting from this new multidisciplinary perspective, cognitive effects were reviewed to link outcomes to effective and reproducible protocols. A systematic search on MEDLINE, ERIC, PsycInfo, Google Scholar, and Scopus databases using Cognitive Atlas and plant-related keywords was conducted. Among the 1,203 articles yielded, 11 met eligibility criteria. Subjects administered with lavender EO displayed arousal decrease and sustained attention increase. Controversial results emerged regarding memory. Lack of EO quality assessment and protocols heterogeneity did not allow assessing whether different EO composition differentially modulates cognition and whether placebo effect can be discerned from EO effect itself. However, GABAergic pathway modulation exerted by linalool, a major lavender EO constituent, might explain cognitive functions empowerment. We speculate aromatherapy could be a burgeoning cognition enhancing tool, although further investigation is required to reach robust conclusions.