1
|
Wang B, Li M, Haihambo N, Qiu Z, Sun M, Guo M, Zhao X, Han C. Characterizing Major Depressive Disorder (MDD) using alpha-band activity in resting-state electroencephalogram (EEG) combined with MATRICS Consensus Cognitive Battery (MCCB). J Affect Disord 2024; 355:254-264. [PMID: 38561155 DOI: 10.1016/j.jad.2024.03.145] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/28/2023] [Revised: 03/24/2024] [Accepted: 03/25/2024] [Indexed: 04/04/2024]
Abstract
BACKGROUND The diagnosis of major depressive disorder (MDD) is commonly based on the subjective evaluation by experienced psychiatrists using clinical scales. Hence, it is particularly important to find more objective biomarkers to aid in diagnosis and further treatment. Alpha-band activity (7-13 Hz) is the most prominent component in resting electroencephalogram (EEG), which is also thought to be a potential biomarker. Recent studies have shown the existence of multiple sub-oscillations within the alpha band, with distinct neural underpinnings. However, the specific contribution of these alpha sub-oscillations to the diagnosis and treatment of MDD remains unclear. METHODS In this study, we recorded the resting-state EEG from MDD and HC populations in both open and closed-eye state conditions. We also assessed cognitive processing using the MATRICS Consensus Cognitive Battery (MCCB). RESULTS We found that the MDD group showed significantly higher power in the high alpha range (10.5-11.5 Hz) and lower power in the low alpha range (7-8.5 Hz) compared to the HC group. Notably, high alpha power in the MDD group is negatively correlated with working memory performance in MCCB, whereas no such correlation was found in the HC group. Furthermore, using five established classification algorithms, we discovered that combining alpha oscillations with MCCB scores as features yielded the highest classification accuracy compared to using EEG or MCCB scores alone. CONCLUSIONS Our results demonstrate the potential of sub-oscillations within the alpha frequency band as a potential distinct biomarker. When combined with psychological scales, they may provide guidance relevant for the diagnosis and treatment of MDD.
Collapse
Affiliation(s)
- Bin Wang
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing 100088, China; Advanced Innovation Center for Human Brain Protection, Capital Medical University, 100191 Beijing, China
| | - Meijia Li
- Faculty of Psychology and Center for Neuroscience, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Naem Haihambo
- Faculty of Psychology and Center for Neuroscience, Vrije Universiteit Brussel, 1050 Brussels, Belgium
| | - Zihan Qiu
- Avenues the World School Shenzhen Campus, Shenzhen 518000, China
| | - Meirong Sun
- School of Psychology, Beijing Sport University, Beijing 100084, China
| | - Mingrou Guo
- Department of Psychology, The Chinese University of Hong Kong, Hong Kong
| | - Xixi Zhao
- The National Clinical Research Center for Mental Disorders & Beijing Key Laboratory of Mental Disorders, Beijing Anding Hospital, Capital Medical University, Beijing 100088, China; Advanced Innovation Center for Human Brain Protection, Capital Medical University, 100191 Beijing, China.
| | - Chuanliang Han
- School of Biomedical Sciences and Gerald Choa Neuroscience Institute, The Chinese University of Hong Kong, Hong Kong.
| |
Collapse
|
2
|
DeVito EE, Sofuoglu M. Catechol-O-Methyltransferase Effects on Smoking: A Review and Proof of Concept of Sex-Sensitive Effects. Curr Behav Neurosci Rep 2022; 9:113-123. [PMID: 36644316 PMCID: PMC9838826 DOI: 10.1007/s40473-022-00251-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Accepted: 08/22/2022] [Indexed: 01/19/2023]
Abstract
Purpose of Review This article reviews recent research on how catechol-O-methyltransferase (COMT) may impact cigarette smoking behavior, and how effects may be sex-sensitive. Preliminary data are presented on sex-sensitive effects of COMT on response to short-term abstinence in individuals who smoke. Recent Findings Although research is mixed, functional variants in the COMT gene have been linked with smoking behavior, cessation outcomes and nicotine abstinence-related symptoms. Our proof-of-concept preliminary data from a human laboratory study of individuals who smoke cigarettes found that those with the high COMT enzyme activity genotype (Val/Val) reported more severe smoking urges and withdrawal symptoms following overnight abstinence than Met carriers. These effects were present in women, but not in men and were abstinent-dependent, in that they dissipated following nicotine administration. Summary The preliminary data showing sex-sensitive pharmacogenetic effects may shed light on mechanisms contributing to sex differences in barriers to smoking cessation or potential sex-specific treatment options.
Collapse
Affiliation(s)
- Elise E. DeVito
- Yale University School of Medicine, Department of Psychiatry, New Haven, CT, USA
| | - Mehmet Sofuoglu
- Yale University School of Medicine, Department of Psychiatry, New Haven, CT, USA
- VA Connecticut Healthcare System, West Haven, CT
| |
Collapse
|
3
|
Ahrens S, Laux J, Müller C, Thiel CM. Increased dopamine availability magnifies nicotine effects on cognitive control: A pilot study. J Psychopharmacol 2020; 34:548-556. [PMID: 32133910 PMCID: PMC7370651 DOI: 10.1177/0269881120907989] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
INTRODUCTION AND OBJECTIVES The ability to adapt to new task demands flexibly and to stabilise performance in the presence of distractors is termed cognitive control and is mediated by dopaminergic and cholinergic neurotransmission. We aimed to test the hypothesis that the effect of the cholinergic agonist nicotine on cognitive control depends on baseline dopamine levels. METHODS Thirty-eight healthy non-smokers (16 males; Mage=24.05 years) performed a cognitive control task including distractor and switch trials twice. Subjects were split into two parallel groups. One group received 2 g of L-tyrosine two hours prior to testing to manipulate dopamine availability experimentally, while the other group received placebo on both days. One hour later, both groups received in a within-subject design: on one day, a 7 mg nicotine patch; on the other day, a matched placebo. Response time costs for distractor and switch trials served as measures of cognitive stability and flexibility. RESULTS Nicotinic modulation reduced response time costs in switch trials and increased costs in distractor trials (nicotine×condition, p=0.027) with a trend-wise interaction between nicotine, L-tyrosine and trial type (nicotine×L-tyrosine×condition, p=0.068), which was due to stronger nicotine effects under L-tyrosine. CONCLUSIONS Our data provide preliminary evidence that nicotine has opponent effects on cognitive stability and flexibility. Subjects who received the dopamine precursor L-tyrosine were more prone to nicotine effects on behaviours, which are improvements in cognitive flexibility at the cost of decreased cognitive stability.
Collapse
Affiliation(s)
- Stefan Ahrens
- Biological Psychology, Department of Psychology, School of Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany,Stefan Ahrens, Biological Psychology, Department of Psychology, Carl von Ossietzky Universität Oldenburg, Ammerländer Heerstr. 114-118, Oldenburg, 26111, Germany. Emails: ;
| | - Joana Laux
- Biological Psychology, Department of Psychology, School of Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Christina Müller
- Biological Psychology, Department of Psychology, School of Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| | - Christiane M Thiel
- Biological Psychology, Department of Psychology, School of Medicine and Health Sciences, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany,Cluster of Excellence ‘Hearing4all’, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany,Research Centre Neurosensory Science, Carl von Ossietzky Universität Oldenburg, Oldenburg, Germany
| |
Collapse
|
4
|
Bossong MG, van Hell HH, Schubart CD, van Saane W, Iseger TA, Jager G, van Osch MJP, Jansma JM, Kahn RS, Boks MP, Ramsey NF. Acute effects of ∆9-tetrahydrocannabinol (THC) on resting state brain function and their modulation by COMT genotype. Eur Neuropsychopharmacol 2019; 29:766-776. [PMID: 30975584 DOI: 10.1016/j.euroneuro.2019.03.010] [Citation(s) in RCA: 14] [Impact Index Per Article: 2.8] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 10/10/2018] [Revised: 01/30/2019] [Accepted: 03/22/2019] [Indexed: 01/07/2023]
Abstract
Cannabis produces a broad range of acute, dose-dependent psychotropic effects. Only a limited number of neuroimaging studies have mapped these effects by examining the impact of cannabis on resting state brain neurophysiology. Moreover, how genetic variation influences the acute effects of cannabis on resting state brain function is unknown. Here we investigated the acute effects of ∆9-tetrahydrocannabinol (THC), the main psychoactive constituent of cannabis, on resting state brain neurophysiology, and their modulation by catechol-methyl-transferase (COMT) Val158Met genotype. Thirty-nine healthy volunteers participated in a pharmacological MRI study, where we applied Arterial Spin Labelling (ASL) to measure perfusion and functional MRI to assess resting state connectivity. THC increased perfusion in bilateral insula, medial superior frontal cortex, and left middle orbital frontal gyrus. This latter brain area showed significantly decreased connectivity with the precuneus after THC administration. THC effects on perfusion in the left insula were significantly related to subjective changes in perception and relaxation. These findings indicate that THC enhances metabolism and thus neural activity in the salience network. Furthermore, results suggest that recruitment of brain areas within this network is involved in the acute effects of THC. Resting state perfusion was modulated by COMT genotype, indicated by a significant interaction effect between drug and genotype on perfusion in the executive network, with increased perfusion after THC in Val/Met heterozygotes only. This finding suggests that prefrontal dopamine levels are involved in the susceptibility to acute effects of cannabis.
Collapse
Affiliation(s)
- Matthijs G Bossong
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, London SE5 8AF, United Kingdom.
| | - Hendrika H van Hell
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Chris D Schubart
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; Department of Psychiatry, Tergooi Hospital, Van Riebeeckweg 212, 1213 XZ Hilversum, The Netherlands
| | - Wesley van Saane
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, London SE5 8AF, United Kingdom
| | - Tabitha A Iseger
- Department of Psychosis Studies, Institute of Psychiatry, Psychology and Neuroscience, King's College London, 16 De Crespigny Park, London SE5 8AF, United Kingdom; Department of Experimental Psychology, Utrecht University, Heidelberglaan 1, 3584 CS Utrecht, The Netherlands; Research Institute Brainclinics, Bijleveldsingel 32, 6524 AD Nijmegen, The Netherlands
| | - Gerry Jager
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; Division of Human Nutrition, Wageningen University, Bomenweg 2, 6703 HD, Wageningen, The Netherlands
| | - Matthias J P van Osch
- Department of Radiology, Leiden University Medical Center, Albinusdreef 2, 2333 ZA Leiden, The Netherlands
| | - J Martijn Jansma
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; Department of Neurosurgery, Elisabeth-TweeSteden Hospital, Tilburg, The Netherlands
| | - René S Kahn
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands; Department of Psychiatry, Icahn School of Medicine at Mount Sinai, One Gustave L. Levy Place, Box 1230, New York, NY 10029-6574, United States
| | - Marco P Boks
- Department of Psychiatry, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| | - Nick F Ramsey
- Department of Neurology and Neurosurgery, Brain Center Rudolf Magnus, University Medical Center Utrecht, Heidelberglaan 100, 3584 CX Utrecht, The Netherlands
| |
Collapse
|
5
|
Steiner GZ, Fernandez FM, Coles M, Karamacoska D, Barkus E, Broyd SJ, Solowij N, Watson OT, Chiu CL, Lind JM, Barry RJ. Interrogating the Relationship Between Schizotypy, the Catechol-O-Methyltransferase (COMT) Val158Met Polymorphism, and Neuronal Oscillatory Activity. Cereb Cortex 2018; 29:3048-3058. [DOI: 10.1093/cercor/bhy171] [Citation(s) in RCA: 8] [Impact Index Per Article: 1.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/31/2018] [Revised: 06/24/2018] [Indexed: 02/07/2023] Open
Abstract
Abstract
The COMT Val158Met polymorphism affects the availability of synaptic dopamine in the prefrontal cortex and has been widely studied as a genetic risk factor for psychosis. Schizotypy is associated with an increased risk of psychosis, with some studies implicating similar neurobiological mechanisms to schizophrenia. The present study sought to interrogate the link between the COMT Val158Met polymorphism and schizotypy using electroencephalogram (EEG) to identify neurophysiological mechanisms underpinning psychosis risk. Neurotypical (N = 91) adults were genotyped for the COMT Val158Met polymorphism, completed the Schizotypal Personality Questionnaire (SPQ), and had eyes open resting-state EEG recorded for 4 min. SPQ suspiciousness subscale scores were higher for individuals homozygous for Val/Val and Met/Met versus Val/Met genotypes. Delta, theta, alpha-2, beta-1, and beta-2 amplitudes were lower for Val/Val than Met/Met individuals. Lower theta amplitudes were correlated with higher total SPQ scores (P = 0.050), and multiple regression revealed that higher delta, and lower theta and beta-2 amplitudes (but not COMT genotype) best predicted total SPQ scores (P = 0.014). This study demonstrates the importance of COMT genotype in determining trait suspiciousness and EEG oscillatory activity. It also highlights relationships between dopaminergic alterations, EEG and schizotypy that are dissimilar to those observed in schizophrenia.
Collapse
Affiliation(s)
- Genevieve Z Steiner
- NICM Health Research Institute and Translational Health Research Institute (THRI), Western Sydney University, Penrith NSW, Australia
- Brain & Behavior Research Institute and School of Psychology, University of Wollongong, Wollongong NSW, Australia
| | - Francesca M Fernandez
- Faculty of Science, Medicine and Health, University of Wollongong, Wollongong NSW, Australia
- School of Science, Australian Catholic University, Brisbane QLD, Australia
- School of Psychology and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong NSW, Australia
| | - Madilyn Coles
- NICM Health Research Institute and Translational Health Research Institute (THRI), Western Sydney University, Penrith NSW, Australia
| | - Diana Karamacoska
- NICM Health Research Institute and Translational Health Research Institute (THRI), Western Sydney University, Penrith NSW, Australia
- Brain & Behavior Research Institute and School of Psychology, University of Wollongong, Wollongong NSW, Australia
| | - Emma Barkus
- School of Psychology and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong NSW, Australia
| | - Samantha J Broyd
- School of Psychology and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong NSW, Australia
| | - Nadia Solowij
- School of Psychology and Illawarra Health and Medical Research Institute, University of Wollongong, Wollongong NSW, Australia
| | - Owen T Watson
- Faculty of Medicine and Health Sciences, Macquarie University, Macquarie Park NSW, Australia
| | - Christine L Chiu
- Faculty of Medicine and Health Sciences, Macquarie University, Macquarie Park NSW, Australia
| | - Joanne M Lind
- Faculty of Medicine and Health Sciences, Macquarie University, Macquarie Park NSW, Australia
- School of Medicine,Western Sydney University, Penrith NSW, Australia
| | - Robert J Barry
- Brain & Behavior Research Institute and School of Psychology, University of Wollongong, Wollongong NSW, Australia
| |
Collapse
|
6
|
Lozano-Soldevilla D. On the Physiological Modulation and Potential Mechanisms Underlying Parieto-Occipital Alpha Oscillations. Front Comput Neurosci 2018; 12:23. [PMID: 29670518 PMCID: PMC5893851 DOI: 10.3389/fncom.2018.00023] [Citation(s) in RCA: 37] [Impact Index Per Article: 6.2] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 12/15/2017] [Accepted: 03/20/2018] [Indexed: 12/25/2022] Open
Abstract
The parieto-occipital alpha (8–13 Hz) rhythm is by far the strongest spectral fingerprint in the human brain. Almost 90 years later, its physiological origin is still far from clear. In this Research Topic I review human pharmacological studies using electroencephalography (EEG) and magnetoencephalography (MEG) that investigated the physiological mechanisms behind posterior alpha. Based on results from classical and recent experimental studies, I find a wide spectrum of drugs that modulate parieto-occipital alpha power. Alpha frequency is rarely affected, but this might be due to the range of drug dosages employed. Animal and human pharmacological findings suggest that both GABA enhancers and NMDA blockers systematically decrease posterior alpha power. Surprisingly, most of the theoretical frameworks do not seem to embrace these empirical findings and the debate on the functional role of alpha oscillations has been polarized between the inhibition vs. active poles hypotheses. Here, I speculate that the functional role of alpha might depend on physiological excitation as much as on physiological inhibition. This is supported by animal and human pharmacological work showing that GABAergic, glutamatergic, cholinergic, and serotonergic receptors in the thalamus and the cortex play a key role in the regulation of alpha power and frequency. This myriad of physiological modulations fit with the view that the alpha rhythm is a complex rhythm with multiple sources supported by both thalamo-cortical and cortico-cortical loops. Finally, I briefly discuss how future research combining experimental measurements derived from theoretical predictions based of biophysically realistic computational models will be crucial to the reconciliation of these disparate findings.
Collapse
|
7
|
Ranzi P, Freund JA, Thiel CM, Herrmann CS. Encephalography Connectivity on Sources in Male Nonsmokers after Nicotine Administration during the Resting State. Neuropsychobiology 2017; 74:48-59. [PMID: 27802427 DOI: 10.1159/000450711] [Citation(s) in RCA: 1] [Impact Index Per Article: 0.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 04/21/2016] [Accepted: 09/09/2016] [Indexed: 11/19/2022]
Abstract
We present an encephalography (EEG) connectivity study where 30 healthy male nonsmokers were randomly allocated either to a nicotine group (14 subjects, 7 mg of transdermal nicotine) or to a placebo group. EEG activity was recorded in an eyes-open (EO) and eyes-closed (EC) condition before and after drug administration. This is a reanalysis of a previous dataset. Through a source reconstruction procedure, we extracted 13 time series representing 13 sources belonging to a resting-state network. Here, we conducted connectivity analysis (renormalized partial directed coherence; rPDC) on sources, focusing on the frequency range of 8.5-18.4 Hz, subdivided into 3 frequency bands (α1, α2, and β1) with the hypothesis that an increase in vigilance would modulate connectivity. Furthermore, a phase-amplitude coupling (mean resultant vector length; VL) analysis, was performed investigating whether an increase of vigilance would modulate phase-amplitude coupling. In the VL analysis we estimated the coupling of the phases of 3 low frequencies (α1, α2, and β1), respectively, with the amplitude of high-frequency oscillations (30-40 Hz, low γ). With rPDC we found that during the EC condition, nicotine decreased feedback connectivity (from the precentral gyrus to precuneus, angular gyrus, cuneus and superior occipital gyrus) at 10.5-12.4 Hz. The VL analysis showed nicotine-induced increases in coupling at 10.5-18.4 Hz in the precuneus, cuneus and superior occipital gyrus during the EC condition. During the EO condition, no significant results were found in connectivity or phase-amplitude coupling measures at any frequency range. In conclusion, the results suggest that nicotine potentially increases the level of vigilance in the EC condition.
Collapse
Affiliation(s)
- Paolo Ranzi
- Experimental Psychology Group, Department of Psychology, Cluster of Excellence 'Hearing4all', European Medical School, Carl von Ossietzky University, Oldenburg, Germany
| | | | | | | |
Collapse
|
8
|
Ranzi P, Thiel CM, Herrmann CS. EEG Source Reconstruction in Male Nonsmokers after Nicotine Administration during the Resting State. Neuropsychobiology 2017; 73:191-200. [PMID: 27225622 DOI: 10.1159/000445481] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 09/30/2015] [Accepted: 03/08/2016] [Indexed: 11/19/2022]
Abstract
Modern psychopharmacological research in humans focuses on how specific psychoactive molecules modulate oscillatory brain activity. We present state-of-the-art EEG methods applied in a resting-state drug study. Thirty healthy male nonsmokers were randomly allocated either to a nicotine group (14 subjects, 7 mg transdermal nicotine) or a placebo group (16 subjects). EEG activity was recorded in eyes-open (EO) and eyes-closed (EC) conditions before and after drug administration. A source reconstruction (minimum norm algorithm) analysis was conducted within a frequency range of 8.5-18.4 Hz subdivided into three different frequency bands. During EO, nicotine reduced the power of oscillatory activity in the 12.5- to 18.4-Hz frequency band in the left middle frontal gyrus. In contrast, in the EC condition, nicotine reduced the power in the 8.5- to 10.4-Hz frequency band in the superior frontal gyri and in the 10.5- to 12.4-Hz and 12.5- to 18.4-Hz frequency bands in the supplementary motor areas. In summary, nicotine reduced the power of the 12.5- to 18.4-Hz band in the left middle frontal gyrus during EO, and it reduced power from 8.5 to 18.4 Hz in a brain area spanning from the superior frontal gyri to the supplementary motor areas during EC. In conclusion, the results suggest that nicotine counteracts the phenomenon of anteriorization of α activity, hence potentially increasing the level of vigilance.
Collapse
Affiliation(s)
- Paolo Ranzi
- Experimental Psychology Group, Department of Psychology, Cluster of Excellence x2018;Hearing4all', European Medical School, Carl von Ossietzky University, Oldenburg, Germany
| | | | | |
Collapse
|