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Wu W, Xu C, Liang Q, Zheng X, Xiao Q, Zhong H, Chen N, Lan Y, Huang X, Xie Q. Olfactory response is a potential sign of consciousness: electroencephalogram findings. Front Neurosci 2023; 17:1187471. [PMID: 37274218 PMCID: PMC10233028 DOI: 10.3389/fnins.2023.1187471] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 03/16/2023] [Accepted: 05/02/2023] [Indexed: 06/06/2023] Open
Abstract
Objective This study aimed to explore whether olfactory response can be a sign of consciousness and represent higher cognitive processing in patients with disorders of consciousness (DoC) using clinical and electroencephalogram data. Methods Twenty-eight patients with DoC [13 vegetative states (VS)/unresponsive wakefulness syndrome (UWS) and 15 minimally conscious states (MCS)] were divided into two groups: the presence of olfactory response (ORES) group and the absence of olfactory response (N-ORES) group according to behavioral signs from different odors, i.e., vanillin, decanoic acid, and blank stimuli. We recorded an olfactory task-related electroencephalogram (EEG) and analyzed the relative power and functional connectivity at the whole-brain level in patients with DoC and healthy controls (HCs). After three months, the outcomes of DoC patients were followed up using the coma recovery scale-revised (CRS-R). Results A significant relationship was found between olfactory responses and the level of consciousness (χ2(1) = 6.892, p = 0.020). For olfactory EEG, N-ORES patients showed higher theta functional connectivity than ORES patients after stimulation with vanillin (p = 0.029; p = 0.027). Patients with N-ORES showed lower alpha and beta relative powers than HCs at the group level (p = 0.019; p = 0.033). After three months, 62.5% (10/16) of the ORES patients recovered consciousness compared to 16.7% (2/12) in the N-ORES group. The presence of olfactory response was significantly associated with an improvement in consciousness (χ2(1) = 5.882, p = 0.023). Conclusion Olfactory responses should be considered signs of consciousness. The differences in olfactory processing between DoC patients with and without olfactory responses may be a way to explore the neural correlates of olfactory consciousness in these patients. The olfactory response may help in the assessment of consciousness and may contribute to therapeutic orientation.
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Affiliation(s)
- Wanchun Wu
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Chengwei Xu
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Qimei Liang
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Xiaochun Zheng
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Qiuyi Xiao
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Haili Zhong
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Na Chen
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Yue Lan
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Xiyan Huang
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
| | - Qiuyou Xie
- Joint Research Centre for Disorders of Consciousness, Department of Rehabilitation Medicine, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
- Department of Hyperbaric Oxygen, Zhujiang Hospital, Southern Medical University, Guangzhou, Guangdong, China
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Katmah R, Al-Shargie F, Tariq U, Babiloni F, Al-Mughairbi F, Al-Nashash H. A Review on Mental Stress Assessment Methods Using EEG Signals. SENSORS (BASEL, SWITZERLAND) 2021; 21:5043. [PMID: 34372280 PMCID: PMC8347831 DOI: 10.3390/s21155043] [Citation(s) in RCA: 35] [Impact Index Per Article: 11.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Download PDF] [Figures] [Subscribe] [Scholar Register] [Received: 05/31/2021] [Revised: 07/13/2021] [Accepted: 07/19/2021] [Indexed: 01/19/2023]
Abstract
Mental stress is one of the serious factors that lead to many health problems. Scientists and physicians have developed various tools to assess the level of mental stress in its early stages. Several neuroimaging tools have been proposed in the literature to assess mental stress in the workplace. Electroencephalogram (EEG) signal is one important candidate because it contains rich information about mental states and condition. In this paper, we review the existing EEG signal analysis methods on the assessment of mental stress. The review highlights the critical differences between the research findings and argues that variations of the data analysis methods contribute to several contradictory results. The variations in results could be due to various factors including lack of standardized protocol, the brain region of interest, stressor type, experiment duration, proper EEG processing, feature extraction mechanism, and type of classifier. Therefore, the significant part related to mental stress recognition is choosing the most appropriate features. In particular, a complex and diverse range of EEG features, including time-varying, functional, and dynamic brain connections, requires integration of various methods to understand their associations with mental stress. Accordingly, the review suggests fusing the cortical activations with the connectivity network measures and deep learning approaches to improve the accuracy of mental stress level assessment.
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Affiliation(s)
- Rateb Katmah
- Biomedical Engineering Graduate Program, American University of Sharjah, Sharjah 26666, United Arab Emirates;
| | - Fares Al-Shargie
- Department of Electrical Engineering, American University of Sharjah, Sharjah 26666, United Arab Emirates; (U.T.); (H.A.-N.)
| | - Usman Tariq
- Department of Electrical Engineering, American University of Sharjah, Sharjah 26666, United Arab Emirates; (U.T.); (H.A.-N.)
| | - Fabio Babiloni
- Department of Molecular Medicine, University of Sapienza Rome, 00185 Rome, Italy;
- College Computer Science and Technology, University Hangzhou Dianzi, Hangzhou 310018, China
| | - Fadwa Al-Mughairbi
- College of Medicines and Health Sciences, United Arab Emirates University, Al-Ain 15551, United Arab Emirates;
| | - Hasan Al-Nashash
- Department of Electrical Engineering, American University of Sharjah, Sharjah 26666, United Arab Emirates; (U.T.); (H.A.-N.)
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Harriss A, Johnson AM, Thompson JWG, Walton DM, Dickey JP. Cumulative soccer heading amplifies the effects of brain activity observed during concurrent moderate exercise and continuous performance task in female youth soccer players. JOURNAL OF CONCUSSION 2020. [DOI: 10.1177/2059700220912654] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/17/2022] Open
Affiliation(s)
- Alexandra Harriss
- Health and Rehabilitation Sciences, The University of Western Ontario, London, Ontario, Canada
| | - Andrew M Johnson
- School of Health Studies, The University of Western Ontario, London, Ontario, Canada
| | | | - David M Walton
- Health and Rehabilitation Sciences, The University of Western Ontario, London, Ontario, Canada
- School of Health Studies, The University of Western Ontario, London, Ontario, Canada
- School of Physical Therapy, The University of Western Ontario, London, Ontario, Canada
| | - James P Dickey
- School of Kinesiology, The University of Western Ontario, London, Ontario, Canada
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Bell IR, Lewis DA, Lewis SE, Schwartz GE, Brooks AJ, Scott A, Baldwin CM. EEG ALPHA SENSITIZATION IN INDIVIDUALIZED HOMEOPATHIC TREATMENT OF FIBROMYALGIA. Int J Neurosci 2009; 114:1195-220. [PMID: 15370183 DOI: 10.1080/00207450490475724] [Citation(s) in RCA: 14] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/26/2022]
Abstract
Fibromyalgia (FM) patients show evidence of sensitizability in pain pathways and electroencephalographic (EEG) alterations. One proposed mechanism for the claimed effects of homeopathy, a form of complementary medicine used for FM, is time-dependent sensitization (TDS, progressive amplification) of host responses. This study examined possible sensitization-related changes in EEG relative alpha magnitude during a clinical trial of homeopathy in FM. A 4-month randomized, placebo-controlled double-blind trial of daily orally administered individualized homeopathy in physician-confirmed FM, with an additional 2-month optional crossover phase, included three laboratory sessions, at baseline, 3 and 6 months (N = 48, age 49.2 +/- 9.8 years, 94% women). Nineteen leads of EEG relative alpha magnitude at rest and during olfactory administration of treatment and control solutions were evaluated in each session. After 3 months, the active treatment group significantly increased, while the placebo group decreased, in global alpha-1 and alpha-2 during bottle sniffs over sessions. At 6 months, the subset of active patients who stayed on active continued to increase, while the active-switch subgroup reversed direction in alpha magnitude. Groups did not differ in resting alpha. Consistent with the TDS hypothesis, sniff alpha-1 and alpha-2 increases at 6 months versus baseline correlated with total amount of time on active remedy over all subjects (r = 0.45, p = .003), not with dose changes or clinical outcomes in the active group. The findings suggest initiation of TDS in relative EEG alpha magnitude by daily oral administration of active homeopathic medicines versus placebo, with laboratory elicitation by temporolimbic olfactory stimulation or sniffing.
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Affiliation(s)
- Iris R Bell
- Program in Integrative Medicine, Department of Psychiatry, The Mel and Enid Zuckerman Arizona College of Public Health, University of Arizona, Tucson, Arizona, USA.
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Harada H, Rikimaru F, Mori T, Tanaka M, Shiraishi K, Kato T. Electroencephalographic changes during intravenous olfactory stimulation in humans. CLINICAL EEG (ELECTROENCEPHALOGRAPHY) 2002; 33:189-92. [PMID: 12449851 DOI: 10.1177/155005940203300410] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
The intravenous olfaction test with thiamin propyl disulfide (TPD) is a simple procedure widely used in Japan. An olfactory stimulus is provided by intravenous injection of TPD (2 ml) over the course of 20 sec. The subject smells n-propyl mercaptan (a decomposition product of TPD discharged from the blood into alveoli) in expired air after treatment. In this preliminary study we recorded electroencephalograms (EEGs) in normal subjects during three stages: 1) eyes-closed rest (prestimulus), 2) olfactory sensation after TPD injection, and 3) disappearance of sensation. In each of these stages, we calculated and compared EEG powers according to the band components of each electrode position. This study was designed a) to evaluate by frequency analysis EEG changes during olfactory sensation after TPD injection, and b) to identify the most significant changes in EEG power according to frequency band and electrode location. During the intravenous olfactory stimulation, alpha 2 and beta 2 waves were activated over the frontal and temporal regions. After disappearance of olfactory sensation, these waves decreased in the same regions. EEG powers returned to prestimulus levels.
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Affiliation(s)
- Hirofumi Harada
- Department of Otorhinolaryngology, School of Medicine, Fukuoka University, 7-45-1 Nanakuma, Jonan-ku, Fukuoka 814-0180, Japan
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Abstract
The effect of the lavender odorant on a Japanese version of Cox and Mackay's stress/arousal adjective checklist for three groups was studied. One group of 14 was placed into a (2 x 2- x 3 m) sound protected room for 20 min without the presentation of an odor, an analogous group of 15 received the odor oil, and one group of 13 received a nonstressful condition. Analysis suggested that lavender odorants were associated with reduced mental stress and increased arousal rate.
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Affiliation(s)
- N Motomura
- Department of Health Science, Osaka Kyoiku University, Kashiwara City, Japan.
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Gil-Carcedo LM, Gil-Carcedo E, Vallejo LA, Ortega P. Proposed classification scheme for quantitative olfactory function alterations. Otolaryngol Head Neck Surg 1999; 121:820-5. [PMID: 10580245 DOI: 10.1053/hn.1999.v121.a94215] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/11/2022]
Abstract
Given the need for a clinical classification for daily patient examinations to refer to each type of quantitative alteration in the sense of smell, we have created a topographic classification of such alterations, establishing groups to distinguish among patients with decreased or total loss of olfaction. Because the classification is based on the diagnosis of the different causes of anosmia, it implicitly includes etiologic and topographic considerations. We have established 3 main groups on the basis of the site of the causal lesion: conduction, sensorineural, and mixed anosmias. In addition, within the sensorineural anosmias, we distinguish between the epithelial, retroepithelial, and central anosmias.
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Affiliation(s)
- L M Gil-Carcedo
- Department of Otolaryngology-Head and Neck Surgery, Hospital Universitario "Del Rio Hortega", Valladolid, Spain
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