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Semantic processing features and schizotypal traits: A test-retest study. Int J Psychophysiol 2022; 178:1-8. [DOI: 10.1016/j.ijpsycho.2022.06.002] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/27/2021] [Revised: 05/30/2022] [Accepted: 06/02/2022] [Indexed: 11/18/2022]
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Almeida VN, Radanovic M. Semantic priming and neurobiology in schizophrenia: A theoretical review. Neuropsychologia 2021; 163:108058. [PMID: 34655651 DOI: 10.1016/j.neuropsychologia.2021.108058] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 06/23/2021] [Revised: 10/06/2021] [Accepted: 10/07/2021] [Indexed: 12/11/2022]
Abstract
In this theoretical review we bridge the cognitive and neurobiological sciences to shed light on the neurocognitive foundations of the semantic priming effect in schizophrenia. We review and theoretically evaluate the neurotransmitter systems (dopaminergic, GABAergic and glutamatergic) and neurobiological underpinnings of behavioural and electrophysiological (N400) semantic priming in the pathology, and the main hypotheses on their geneses: a disinhibition of the semantic spread of activation, a disorganised semantic storage or noisy lexical-semantic associations, a psychomotor artefact, an artefact of relatedness proportions, or an inability to mobilise contextual information. We further assess the literature on the endophenotype of Formal Thought Disorder from multiple standpoints, ranging from neurophysiology to cognition: considerations are weaved on neuronal (PV basket cell, SST, VIP) and receptor deficits (DRD1, NMDA), neurotransmitter imbalances (dopamine), cortical and dopaminergic lateralisation, inter alia. In conclusion, we put forth novel postulates on the underlying causes of controlled hypopriming, automatic hyperpriming, N400 reversals (larger amplitudes for close associations), indirect versus direct hyperpriming, and the endophenotype of lexical-semantic disturbances in schizophrenia.
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Affiliation(s)
- Victor N Almeida
- Faculdade de Letras, Universidade Federal de Minas Gerais (UFMG), Av. Pres. Antônio Carlos, 6627 - Pampulha, Belo Horizonte, MG, 31270-901, Brazil.
| | - Marcia Radanovic
- Laboratório de Neurociências (LIM-27), Faculdade de Medicina, Departamento e Instituto de Psiquiatria, Hospital das Clínicas HCFMUSP, Universidade de São Paulo, Brazil
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Siddiqui SV, Nizamie SH, Siddiqui MA, Jahan M, Garg S, Tikka SK, Shreekantiah U. Evaluation of N-400 Evoked Response Potential in schizophrenia: An endophenotype or a disease marker? Psychiatry Res 2021; 300:113907. [PMID: 33839423 DOI: 10.1016/j.psychres.2021.113907] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 05/16/2020] [Accepted: 03/27/2021] [Indexed: 01/07/2023]
Abstract
N400 evoked response potentials (ERP) reliably map key semantic deficits in schizophrenia. Assessing them as endophenotypes might help in better understanding of schizophrenia risk and their use as biomarkers. We aimed to study N400 as an endophenotype marker by comparing schizophrenia (SCZ), unaffected first-degree relatives (FDR) and healthy controls (HC) and, by assessing its ability to discriminate these groups. Drug naïve or free SCZ probands (n=30), their unaffected FDRs (n=30) and HC (n=30), underwent a 40-channel ERP recording while performing a custom-made, Hindi- sentence context paradigm task, containing congruent and incongruent conditions. Fifteen centro-parietal (CP) leads, further classified into three regions-midline (CPM), right (CPR) and left (CPL) were selected as electrodes-of-interest for assessing N400. During the incongruent condition, compared to both FDRs and HC, SCZ showed significantly longer N400 latency, at CPM, CPR and CPL, and significantly lesser (more negative) amplitude, at CPM; no significant difference was noted between FDR and HC groups. On discriminant functional analysis, significant N400 predictors could accurately classify 73.3% SCZ from HC and 75% of SCZ from FDR. We conclude that N400 deficits, elicited by the incongruent condition of the sentence task, could be potential biomarkers to define disease state in schizophrenia; they may not be endophenotype markers.
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Affiliation(s)
- Shazia Veqar Siddiqui
- Dr Shazia Veqar Siddiqui, Ph.D., M.Phil. Consultant Clinical Psychologist Healthy Minds, Lucknow, UP, India
| | - S Haque Nizamie
- Dr S-Haque Nizamie, M.D., D.P.M. Consultant Psychiatrist, Ex-Director Central Institute of Ranchi, Ranchi, India
| | - M Aleem Siddiqui
- Dr Mohd Aleem Siddiqui, M.D., D.P.M, Professor, Era's Lucknow Medical College and Hospital, UP, India
| | - Masroor Jahan
- Dr. Masroor Jahan, Ph.D., M.Phil. Additional Professor, Department of Psychology, RINPAS, Ranchi, India
| | - Shobit Garg
- Shobit Garg, M.D., D.P.M. Associate Professor, Department of Psychiatry, Shri Guru Ram Rai Institute of Medical and Health Sciences, 248001, Uttarakhand, India.
| | - Sai Krishna Tikka
- Sai Krishna Tikka, M.D., D.P.M. Associate Professor, Department of Psychiatry, All India Institute of Medical Sciences (AIIMS), Bibinagar, India
| | - Umesh Shreekantiah
- Umesh S., M.D., D.P.M. Assistant Professor, Central Institute of Psychiatry, Ranchi
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Hirano S, Spencer KM, Onitsuka T, Hirano Y. Language-Related Neurophysiological Deficits in Schizophrenia. Clin EEG Neurosci 2020; 51:222-233. [PMID: 31741393 DOI: 10.1177/1550059419886686] [Citation(s) in RCA: 13] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/16/2022]
Abstract
Schizophrenia is a severe psychiatric disorder that affects all aspects of one's life with several cognitive and social dysfunctions. However, there is still no objective and universal index for diagnosis and treatment of this disease. Many researchers have studied language processing in schizophrenia since most of the patients show symptoms related to language processing, such as thought disorder, auditory verbal hallucinations, or delusions. Electroencephalography (EEG) and magnetoencephalography (MEG) with millisecond order high temporal resolution, have been applied to reveal the abnormalities in language processing in schizophrenia. The aims of this review are (a) to provide an overview of recent findings in language processing in schizophrenia with EEG and MEG using neurophysiological indices, providing insights into underlying language related pathophysiological deficits in this disease and (b) to emphasize the advantage of EEG and MEG in research on language processing in schizophrenia.
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Affiliation(s)
- Shogo Hirano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Higashiku, Fukuoka, Japan.,Neural Dynamics Laboratory, Research Service, VA Boston Healthcare System, and Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Kevin M Spencer
- Neural Dynamics Laboratory, Research Service, VA Boston Healthcare System, and Department of Psychiatry, Harvard Medical School, Boston, MA, USA
| | - Toshiaki Onitsuka
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Higashiku, Fukuoka, Japan
| | - Yoji Hirano
- Department of Neuropsychiatry, Graduate School of Medical Sciences, Kyushu University, Higashiku, Fukuoka, Japan.,Neural Dynamics Laboratory, Research Service, VA Boston Healthcare System, and Department of Psychiatry, Harvard Medical School, Boston, MA, USA
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Wang K, Zhao YL, Tan SP, Zhang JG, Li D, Chen JX, Zhang LG, Yu XY, Zhao D, Cheung EFC, Turetsky BI, Gur RC, Chan RCK. Semantic processing event‐related potential features in patients with schizophrenia and bipolar disorder. Psych J 2019; 9:247-257. [PMID: 31788984 DOI: 10.1002/pchj.321] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/01/2019] [Revised: 10/15/2019] [Accepted: 10/16/2019] [Indexed: 11/07/2022]
Affiliation(s)
- Kui Wang
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Yan-Li Zhao
- Beijing Huilongguan Hospital, Beijing, China
| | | | | | - Dong Li
- Beijing Huilongguan Hospital, Beijing, China
| | | | | | - Xin-Yang Yu
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
| | - Dan Zhao
- School of Education, Changchun Normal University, Changchun, China
| | | | - Bruce I Turetsky
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Ruben C Gur
- Department of Psychiatry, Perelman School of Medicine, University of Pennsylvania, Philadelphia, Pennsylvania, USA
| | - Raymond C K Chan
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, CAS Key Laboratory of Mental Health, Institute of Psychology, Beijing, China
- Department of Psychology, University of Chinese Academy of Sciences, Beijing, China
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Van Assche L, Morrens M, Luyten P, Van de Ven L, Vandenbulcke M. The neuropsychology and neurobiology of late-onset schizophrenia and very-late-onset schizophrenia-like psychosis: A critical review. Neurosci Biobehav Rev 2017; 83:604-621. [DOI: 10.1016/j.neubiorev.2017.08.024] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 04/13/2017] [Revised: 07/25/2017] [Accepted: 08/30/2017] [Indexed: 01/20/2023]
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Électrophysiologie et vulnérabilité schizophrénique : la composante N400 comme endophénotype candidat ? Neurophysiol Clin 2013; 43:81-94. [DOI: 10.1016/j.neucli.2013.01.119] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/07/2012] [Revised: 01/22/2013] [Accepted: 01/28/2013] [Indexed: 11/20/2022] Open
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Abstract
PURPOSE OF REVIEW The purpose of this article is to review major findings in event related potential (ERP) research in schizophrenia patients, specifically focusing on the N400 component. RECENT FINDINGS Patients with chronic schizophrenia have difficulty using 'context' (understanding the meaning of the word relative to the sentence) in sentence processing studies and often show differences from control populations in language experiments using word priming. Both of these observations are associated with an abnormal N400 ERP component when compared with nonpsychotic individuals. Many studies of language function rely on priming paradigms that use pairs of words such that the first word in a pair is a 'prime' and a second word in a pair is a 'target', separated from the prime by a period of time known as the Stimulus Onset Asynchrony (SOA). If the SOA is short (i.e., below 400 ms) then it is believed that a priming study examines primarily processes of initial activation within semantic networks; if it is long (i.e., more than 400 ms) then it is believed that a priming study examines primarily processes of context use, generating predictions and matching these predictions against upcoming semantic information. Priming paradigms that use long SOAs are consistently associated with a more negative N400 (hence lack of priming) in schizophrenia, whereas priming paradigms using a short SOA produce either a normal N400 priming response or hyperpriming as shown by a reduced N400 and related to a hypothesized too rapid automatic spread of activation within the semantic memory pathway. Apparent differences among reported study results are likely due to paradigm differences that tap into different aspects of language processing. Although the presence of both hyperactivation within semantic networks and difficulties with the use of context is well known in schizophrenia, it is unclear whether these abnormalities are also present prior to illness onset in people who are at risk for development of schizophrenia or even present at the onset of illness. SUMMARY In order to clarify the findings reviewed here, future studies will be needed that focus on examining the N400 response in young people at high risk for developing the illness using multiple paradigms that probe different aspects of language function.
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Wang K, Cheung EFC, Gong QY, Chan RCK. Semantic processing disturbance in patients with schizophrenia: a meta-analysis of the N400 component. PLoS One 2011; 6:e25435. [PMID: 22022395 PMCID: PMC3192062 DOI: 10.1371/journal.pone.0025435] [Citation(s) in RCA: 40] [Impact Index Per Article: 3.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 05/04/2011] [Accepted: 09/05/2011] [Indexed: 11/18/2022] Open
Abstract
BACKGROUND Theoretically semantic processing can be separated into early automatic semantic activation and late contextualization. Semantic processing deficits have been suggested in patients with schizophrenia, however it is not clear which stage of semantic processing is impaired. We attempted to clarify this issue by conducting a meta-analysis of the N400 component. METHODS Twenty-one studies met the inclusion criteria for the meta-analysis procedure. The Comprehensive Meta-Analysis software package was used to compute pooled effect sizes and homogeneity. RESULTS Studies favoring early automatic activation produced a significant effect size of -0.41 for the N400 effect. Studies favoring late contextualization generated a significant effect size of -0.36 for the N400 effect, a significant effect size of -0.52 for N400 for congruent/related target words, and a significant effect size of 0.82 for the N400 peak latency. CONCLUSION These findings suggest the automatic spreading activation process in patients with schizophrenia is very similar for closely related concepts and weakly or remotely related concepts, while late contextualization may be associated with impairments in processing semantically congruent context accompanied by slow processing speed.
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Affiliation(s)
- Kui Wang
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
| | - Eric F. C. Cheung
- Castle Peak Hospital, Hong Kong Special Administrative Region, China
| | - Qi-yong Gong
- Huaxi MR Research Centre, Department of Radiology, West China Hospital/West China School of Medicine, Sichuan University, Chengdu, China
| | - Raymond C. K. Chan
- Neuropsychology and Applied Cognitive Neuroscience Laboratory, Key Laboratory of Mental Health, Institute of Psychology, Chinese Academy of Sciences, Beijing, China
- * E-mail:
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Van Petten C, Federmeier KD, Holcomb PJ. For distinguished contributions to psychophysiology: Marta Kutas. Psychophysiology 2010; 47:403-9. [DOI: 10.1111/j.1469-8986.2009.00930.x] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
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Froud K, Titone D, Marantz A, Levy DL. Brain/behavior Asymmetry in Schizophrenia: A MEG Study of Cross-modal Semantic Priming. JOURNAL OF NEUROLINGUISTICS 2010; 23:223-239. [PMID: 20396647 PMCID: PMC2852879 DOI: 10.1016/j.jneuroling.2009.03.001] [Citation(s) in RCA: 4] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 05/29/2023]
Abstract
Semantic priming has long been used to investigate how concepts and ideas are related at the level of language, and has become a convenient tool for assessing conceptual and semantic dysfunction in cognitive disorders, including schizophrenia. The study of semantic priming in schizophrenia has led to diverse results: enhanced priming, reduced priming, and priming equivalent to that found in nonpsychiatric comparison groups. A number of hypotheses have been proposed to explain some of the observed deficits in schizophrenia patients. For example, difficulties in word recognition may be due to hyperactivation of too many lexical representations or to a failure to inhibit lexical competitors. One way to distinguish between these possible explanations is to move beyond reliance on behavior alone and to examine the neural processes involved in lexical recognition. Here we present a magnetoencephalographic study of semantic priming in schizophrenia. Importantly, schizophrenia patients and healthy controls did not differ in performance on a priming task. We show that normal behavioral performance can occur in a context of aberrant neural responses. These findings suggest that normal behavioral responses in schizophrenia can be achieved through neural mechanisms that differ from those seen in the psychiatrically well brain.
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Affiliation(s)
- Karen Froud
- Department of Biobehavioral Sciences, Teachers College, Columbia University, New York NY 10027
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Sitnikova T, Perrone C, Goff D, Kuperberg GR. Neurocognitive mechanisms of conceptual processing in healthy adults and patients with schizophrenia. Int J Psychophysiol 2010; 75:86-99. [PMID: 20004221 PMCID: PMC2842912 DOI: 10.1016/j.ijpsycho.2009.12.002] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 09/09/2009] [Revised: 11/29/2009] [Accepted: 12/01/2009] [Indexed: 11/28/2022]
Abstract
This overview outlines findings of cognitive and neurocognitive studies on comprehension of verbal, pictorial, and video stimuli in healthy participants and patients with schizophrenia. We present evidence for a distinction between two complementary neurocognitive streams of conceptual analysis during comprehension. In familiar situations, adequate understanding of events may be achieved by mapping the perceived information on the associative and similarity-based connections between concepts in semantic memory - a process reflected by an N400 waveform of event-related electrophysiological potentials (ERPs). However, in less conventional contexts, a more flexible mechanism may be needed. We suggest that this alternative processing stream, reflected by a P600 ERP waveform, may use discrete, rule-like goal-related requirements of real-world actions to comprehend relationships between perceived people, objects, and actions. This neurocognitive model of comprehension is used as a basis in discussing studies in schizophrenia. These studies suggest an imbalanced engagement of the two conceptual streams in schizophrenia, whereby patients may rely on the associative and similarity-based networks in semantic memory even when it would be more adaptive to recruit mechanisms that draw upon goal-related requirements. Finally, we consider the roles that these conceptual mechanisms may play in real-life behavior, and the consequences that their dysfunction may have for disorganized behavior and inability to plan actions to achieve behavioral goals in schizophrenia.
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Emmerson LC, Ben-Zeev D, Granholm E, Tiffany M, Golshan S, Jeste DV. Prevalence and longitudinal stability of negative symptoms in healthy participants. Int J Geriatr Psychiatry 2009; 24:1438-44. [PMID: 19388007 DOI: 10.1002/gps.2284] [Citation(s) in RCA: 10] [Impact Index Per Article: 0.7] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/10/2022]
Abstract
OBJECTIVE Although negative symptoms are prominent in older patients with schizophrenia, it is unknown whether this pattern is prevalent in healthy participants. The objective of this study was to evaluate whether negative symptoms are present in healthy populations and to determine whether they are linked to illness-related processes or normal aging. METHODS A systemic review of 26 studies that have administered negative symptom assessments to healthy participants was conducted. In addition, 213 (age > 40 years old) healthy participants completed PANSS and SANS ratings at both baseline and 1-year follow-up. One-hundred participants also completed ratings after 3 years. RESULTS Across all reviewed studies, negative symptoms were absent in the majority of participants. Comparable results were found in the current study's large longitudinal evaluation with middle-aged to older adults. CONCLUSIONS Taken together, the data suggest that healthy volunteers do not suffer from prominent negative symptoms. This finding is consistent with the hypothesis that the greater prevalence and severity of negative symptoms in older patients is not related to normal aging but to illness-related processes.
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N400 deficits from semantic matching of pictures in probands and first-degree relatives from multiplex schizophrenia families. Brain Cogn 2009; 70:221-30. [PMID: 19307049 DOI: 10.1016/j.bandc.2009.02.004] [Citation(s) in RCA: 40] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [Journal Information] [Subscribe] [Scholar Register] [Received: 02/25/2008] [Revised: 02/01/2009] [Accepted: 02/03/2009] [Indexed: 11/23/2022]
Abstract
Endophenotypes is one emerging strategy in schizophrenia research that is being used to identify the functional importance of genetically transmitted, brain-based deficits present in this disease. Currently, event-related potentials (ERPs) are timely used in this search. Several ERPs, including N400, present deficits in relation to schizophrenia. In order to assess the genetic liability of N400 as a possible endophenotype, a picture semantic matching task (congruent and incongruent pairs of pictures) was performed by 21 unaffected first-degree relatives of patients with schizophrenia, 21 DSM-IV diagnosed schizophrenia probands, and 21 control subjects, matched by age, gender and educational level. Probands and relatives were selected form Multiplex schizophrenia families. Significantly reduced N400 amplitude for congruent categories in N400 was found in probands and relatives in relation to controls. The latency onset and the maximum peak latency of N400 were delayed in both, relatives and probands groups compared to control. The voltage maps of incongruous-minus-congruous difference indicate a more reduced right restricted negativity in probands and relatives, when compared to a widely extended bilateral negativity in controls. No general differences were found between patients and relatives. These results demonstrate an electrophysiological deficit in semantic match processing in clinically unaffected first-degree relatives of patients with schizophrenia, suggesting a possible use of this marker as endophenotype.
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Sitnikova T, Goff D, Kuperberg GR. Neurocognitive abnormalities during comprehension of real-world goal-directed behaviors in schizophrenia. JOURNAL OF ABNORMAL PSYCHOLOGY 2009; 118:256-77. [PMID: 19413402 PMCID: PMC2819083 DOI: 10.1037/a0015619] [Citation(s) in RCA: 25] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 01/20/2023]
Abstract
Origins of impaired adaptive functioning in schizophrenia remain poorly understood. Behavioral disorganization may arise from an abnormal reliance on common combinations between concepts stored in semantic memory. Avolition-apathy may be related to deficits in using goal-related requirements to flexibly plan behavior. The authors recorded event-related potentials (ERPs) in 16 patients with medicated schizophrenia and 16 healthy controls in a novel video paradigm presenting congruous or incongruous objects in real-world activities. All incongruous objects were contextually inappropriate, but the incongruous scenes varied in comprehensibility. Psychopathology was assessed with the Scales for the Assessment of Positive and Negative Symptoms (SAPS/SANS) and the Brief Psychiatric Rating Scale. In patients, an N400 ERP, thought to index activity in semantic memory, was abnormally enhanced to less comprehensible incongruous scenes, and larger N400 priming was associated with disorganization severity. A P600 ERP, which may index flexible object-action integration based on goal-related requirements, was abnormally attenuated in patients, and its smaller magnitude was associated with the SANS rating of impersistence at work or school (goal-directed behavior). Thus, distinct neurocognitive abnormalities may underlie disorganization and goal-directed behavior deficits in schizophrenia.
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Affiliation(s)
- Tatiana Sitnikova
- Athinoula A. Martinos Center for Biomedical Imaging, Department of Psychiatry, Massachusetts General Hospital, Charlestown, MA 02129, USA.
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Kiang M, Kutas M, Light GA, Braff DL. Electrophysiological insights into conceptual disorganization in schizophrenia. Schizophr Res 2007; 92:225-36. [PMID: 17383161 PMCID: PMC3974604 DOI: 10.1016/j.schres.2007.02.001] [Citation(s) in RCA: 45] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 08/24/2006] [Revised: 01/31/2007] [Accepted: 02/02/2007] [Indexed: 11/21/2022]
Abstract
Disorganized speech, or thought disorder, in schizophrenia may reflect abnormal processing of meaningful concepts. To examine whether schizophrenia involves abnormalities in how a meaningful context influences processing of concepts strongly, weakly, or not related to it, we used the N400, an event-related brain potential (ERP) index of semantic relatedness. ERPs were recorded from schizophrenia patients (n=18) and normal controls (n=18) while they viewed category definitions (e.g., a type of fruit), each followed by a target word that was either a high-typicality category exemplar (apple), low-typicality exemplar (cherry), or non-exemplar (clamp). Participants' task was to indicate via button-press whether or not the target belonged to the category. In both patients and controls, N400 amplitude was largest (most negative) for non-exemplars, intermediate for low-typicality exemplars, and smallest (least negative) for high-typicality exemplars. Compared to controls, patients showed a trend toward reduced N400 amplitude differences between non-exemplars and low-typicality exemplars. Most importantly, within patients, reduced N400 amplitude differences between high- and low-typicality exemplars were correlated with psychotic symptoms. This association of an N400 index of semantic processing with psychotic symptoms suggests that psychosis in schizophrenia may be associated with greater similarity in how concepts strongly and weakly meaningfully related to their context are processed.
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Affiliation(s)
- Michael Kiang
- Department of Cognitive Science, University of California-San Diego, 9500 Gilman Dr., Mail Code 0515, La Jolla, CA 92093-0515, USA.
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Debruille JB, Kumar N, Saheb D, Chintoh A, Gharghi D, Lionnet C, King S. Delusions and processing of discrepant information: an event-related brain potential study. Schizophr Res 2007; 89:261-77. [PMID: 16945505 DOI: 10.1016/j.schres.2006.07.014] [Citation(s) in RCA: 31] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/09/2006] [Revised: 07/15/2006] [Accepted: 07/19/2006] [Indexed: 10/24/2022]
Abstract
One possible explanation for why delusions persist despite the awareness of contradictory information is that the new information fails to be integrated. Interestingly, the amplitude of the N400 event-related brain potential (ERP) has been proposed as an index of the integration of information that is discrepant with expectancies whatever the task in which the potential is found. Thus, delusions may persist because of a deficit in integration as indexed by the N400. To test this hypothesis, ERPs were recorded in 35 schizophrenia patients (mean age=30.5+/-5.6 years) and 26 normal controls during a task in which they either had to decide whether or not each target word could be integrated into the category "animal", or had no decision to make, according to the prompt "animal?" or the prompt "inaction". In these conditions, the amplitudes of the N400s to target words that were discrepant with the category were found to be negatively correlated with delusion severity. The patient group was then dichotomized according to a median split of delusion severity, excluding the 5 patients with delusion scores at the median. Mean age, sex ratio, and severity of conceptual disorganization and hallucinations of the two subgroups differed. Controlling for these 4 covariates, the N400s for discrepant targets were found smaller in the 14 More-Delusional patients than in the 16 Less-Delusional patients. These results support the hypothesis that delusions are associated with smaller N400s in patients. Further studies should thus be done to test whether a deficit of N400 processes could have a causal role in the persistence of delusions.
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Affiliation(s)
- J Bruno Debruille
- Douglas Hospital Research Centre, Department of Psychiatry, McGill University, Montreal, Quebec, Canada.
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Kuperberg GR, Sitnikova T, Goff D, Holcomb PJ. Making sense of sentences in schizophrenia: Electrophysiological evidence for abnormal interactions between semantic and syntactic processing. JOURNAL OF ABNORMAL PSYCHOLOGY 2006; 115:251-65. [PMID: 16737390 DOI: 10.1037/0021-843x.115.2.251] [Citation(s) in RCA: 60] [Impact Index Per Article: 3.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/08/2022]
Abstract
Event-related potentials to critical verbs were measured as patients with schizophrenia and healthy controls read sentences word by word. Relative to their preceding context, critical verbs were (a) congruous, (b) incongruous and semantically unrelated to individual preceding words (pragmatic-semantic violations), (c) incongruous but semantically related to individual preceding words (animacy-semantic violations), or (d) syntactically anomalous. The N400 was modulated normally in patients, suggesting that semantic integration between individual words within sentences was normal in schizophrenia. The amplitude of the P600 to both syntactic and animacy-semantic violations was reduced in patients relative to controls. The authors suggest that, in schizophrenia, an abnormality in combining semantic and syntactic information online to build up propositional meaning leaves sentence processing to be primarily driven by semantic relationships between individual words.
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Kostova M, Passerieux C, Laurent JP, Hardy-Baylé MC. N400 anomalies in schizophrenia are correlated with the severity of formal thought disorder. Schizophr Res 2005; 78:285-91. [PMID: 15993568 DOI: 10.1016/j.schres.2005.05.015] [Citation(s) in RCA: 51] [Impact Index Per Article: 2.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Received: 03/07/2005] [Revised: 05/15/2005] [Accepted: 05/15/2005] [Indexed: 10/25/2022]
Abstract
We explored the link between N400 anomalies and clinical profile in schizophrenia patients. N400 was recorded in 50 schizophrenia patients and 40 healthy controls during a lexical decision task with semantic priming. Comparison between controls and schizophrenia patients showed the classical anomalies reported for N400 in schizophrenia patients: greater amplitude for related words and lack of N400 effect. Analyses of the correlations between N400 effect and various symptoms of schizophrenia (formal thought disorder, positive symptoms, negative symptoms, overall symptoms, mean neuroleptic dose) or socioeducational data (age, vocabulary level, number of years of study) revealed that only the correlation with formal thought disorder was significant: the higher the scores for formal thought disorder, the lower the N400 effect observed.
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Affiliation(s)
- Milena Kostova
- Equipe de Recherche en Psychologie clinique (EAD 2027), Université Paris 8, 2 rue de la Liberté, 93526 Saint-Denis, France.
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Ruchsow M, Trippel N, Groen G, Spitzer M, Kiefer M. Semantic and syntactic processes during sentence comprehension in patients with schizophrenia: evidence from event-related potentials. Schizophr Res 2003; 64:147-56. [PMID: 14613679 DOI: 10.1016/s0920-9964(02)00482-6] [Citation(s) in RCA: 37] [Impact Index Per Article: 1.8] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Language and thought disorders are core symptoms in schizophrenia. We therefore studied language comprehension processes in patients with schizophrenia and control subjects during a sentence processing paradigm using event-related potentials (ERPs). In the ERP, assignment of syntactic structure to a string of words is reflected by an early left anterior negativity (ELAN) at about 80 ms after stimulus onset. Integration of syntactic and semantic information into a coherent representation is indexed by a positive potential at 600 ms (P600). Amplitudes of the ELAN and the P600 components are higher for grammatically incorrect sentences. Semantic processes are associated with a negative deflection peaking at 400 ms (N400). N400 amplitude is higher in semantically incongruent sentences. Nineteen patients with DSM IV schizophrenia and 19 healthy controls were presented with correct, semantically incorrect (semantic mismatch) and grammatically incorrect sentences (syntactic mismatch). Syntactic mismatch elicited an ELAN component in both subject groups. However, only controls but not patients with schizophrenia exhibited a P600 syntactic mismatch effect. Semantic mismatch was associated with a larger N400 potential which did not differ between groups. These results suggest that patients with schizophrenia are not impaired in syntactic structure assignment as reflected by the ELAN, but show deficits in semantic-syntactic integration processes underlying the P600.
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Affiliation(s)
- Martin Ruchsow
- Department of Psychiatry, University of Ulm, Leimgrubenweg 12-14, D-89075 Ulm, Germany.
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Kostova M, Passerieux C, Laurent JP, Hardy-Baylé MC. An electrophysiologic study: can semantic context processes be mobilized in patients with thought-disordered schizophrenia? CANADIAN JOURNAL OF PSYCHIATRY. REVUE CANADIENNE DE PSYCHIATRIE 2003; 48:615-23. [PMID: 14631882 DOI: 10.1177/070674370304800908] [Citation(s) in RCA: 12] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 11/16/2022]
Abstract
OBJECTIVE The aim of this study was to test the hypothesis that reinforcing the structuring of verbal material may bring about an improvement in contextualization processes in patients with formal thought-disordered schizophrenia. METHOD A total of 38 schizophrenia patients with formal thought disorders and 24 matched healthy control subjects performed 2 lexical decision tasks, involving 2 levels of contextual structuring (with 16.7% and 33% of related words, respectively). The event-related potentials, N400 and late positive component (LPC), and behavioural variables (reaction times and error percentages) were analyzed. RESULTS A context-structuring effect was observed on LPC, but not on N400. In subjects with schizophrenia, the N400 anomalies (that is, increase in amplitude for the related words and reduction of the N400 effect) persisted in both context-structuring conditions. Similarly, a reduction in LPC amplitude for the unrelated word category, as well as a decrease in the LPC effect, was observed in these patients. CONCLUSIONS The schizophrenia patients with formal thought disorders did not benefit from the structuring of the context to implement context integration strategies. This deficit appears to be stable. The results are discussed within the framework of a previously published model of language comprehension.
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Affiliation(s)
- Milena Kostova
- Equipe de Recherche en Psychologie Clinique, Université Paris VIII, 2 rue de la Liberté, 93526 Saint-Denis, France.
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Hokama H, Hiramatsu KI, Wang J, O'Donnell BF, Ogura C. N400 abnormalities in unmedicated patients with schizophrenia during a lexical decision task. Int J Psychophysiol 2003; 48:1-10. [PMID: 12694896 DOI: 10.1016/s0167-8760(02)00156-3] [Citation(s) in RCA: 23] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
A lexical decision task was used to investigate semantic processing in schizophrenia. Eighteen unmedicated schizophrenics and 18 gender/age-matched controls were tested. Subjects were visually presented with pairs of words. The target word (S2) was either a non-word, semantically related, or unrelated to preceding word (S1). Subjects decided whether the S2 was a word or non-word. Event related potentials (ERPs) elicited by the S2, including N350, and the late positive component (LPC) were measured. The latency of the N350 was prolonged in schizophrenia. The N400 effect, measured by the mean amplitude (300-500 ms) from difference waves (unrelated word-related word, non-word-related word), was smaller in patients. Peak amplitude of the LPC was reduced and latency of the LPC was delayed in the schizophrenics. Behaviorally, control subjects responded much faster to related words compared to unrelated or non-words, while patients showed little difference in processing speed between word categories. A reduced N400 effect suggested inefficient utilization of the context, while prolonged latency of the ERP components suggested a general delay of semantic information processing in schizophrenia.
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Affiliation(s)
- Hiroto Hokama
- Department of Neuropsychiatry, Faculty of Medicine, University of the Ryukyus, 207 Uehara, Nishihara, Okinawa 903-0215, Japan.
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Kostova M, Passerieux C, Laurent JP, Saint-Georges C, Hardy-Baylé MC. Functional analysis of the deficit in semantic context processes in schizophrenic patients: an event-related potentials study. Neurophysiol Clin 2003; 33:11-22. [PMID: 12711128 DOI: 10.1016/s0987-7053(03)00006-6] [Citation(s) in RCA: 24] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022] Open
Abstract
AIM Schizophrenic patients exhibit a deficit in the semantic context processing strategies which might be responsible for the language and communication disorders that are characteristic of this condition. The aim of our study was to identify the nature of the contextualization processes which are lacking in schizophrenic patients, by distinguishing between processes for the generation of expectations and processes of semantic integration. PATIENTS AND METHOD Thirteen schizophrenic patients and 12 healthy controls performed two tasks: (a) a lexical decision task (LDT) with a highly structured sentence context and whose experimental characteristics made it possible to call strongly on predictive strategies, and (b) a LDT with classic semantic priming (the context being reduced to a single word). In this latter task, the small number of related words did not prompt the generation of expectations but instead called on the postlexical integration process. The event-related potentials (ERP) were recorded during the administration of the task. RESULTS AND CONCLUSION In the sentence task, we observed a modulation in the N400 amplitude due to the presence of expectations both in the schizophrenic and control participants: predictable words evoked a small N400 amplitude compared to the non-predictable words. In contrast, in the simple (priming) task, the semantic link evoked an N400 amplitude modulation in the control group exclusively. Our results indicate that schizophrenics could be able to use context to activate expectations for the most highly predictable item, and that their deficit appears when the processing strategy is based on the integration of the context stored in working memory.
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Affiliation(s)
- M Kostova
- Equipe de Recherche en Psychologie Clinique, Université Paris VIII, 2, rue de la Liberté, 93526 cedex 02, Saint-Denis, France.
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Takashima A, Ohta K, Matsushima E, Toru M. The event-related potentials elicited by content and function words during the reading of sentences by patients with schizophrenia. Psychiatry Clin Neurosci 2001; 55:611-8. [PMID: 11737794 DOI: 10.1046/j.1440-1819.2001.00913.x] [Citation(s) in RCA: 6] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/20/2022]
Abstract
Thought disorder is one of the main symptoms observed in schizophrenia and has been investigated in terms of language dysfunction. The purpose of the present study was to find whether there were any differences in identifying and processing between content (semantic) and function (syntax) words, and to elucidate whether semantic or syntax is more impaired for the schizophrenics. Event-related potentials were recorded in 13 patients with schizophrenia and 14 healthy controls, while they silently read three sets of passages. Event-related potentials were recorded for content words (noun, verb) and function words (auxiliary verb, particle) separately. For the healthy control group, the mean amplitude of P200 for the content word class was greater than for the function word class with fronto-central dominance. In contrast, no such difference was found for the schizophrenics mainly due to the reduction of P200 amplitude of the content words. Larger P200 for the content than the function word class suggests that greater resources were used to identify the content words. Lack of this difference found in patients with schizophrenia suggested that the disturbances in the semantics may be more attributable to the linguistic impairment than those in the syntax.
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Affiliation(s)
- A Takashima
- Department of Neuro-Psychiatry, Tokyo Metropolitan Hiroo General Hospital, Tokyo, Japan.
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Guillem F, Bicu M, Hooper R, Bloom D, Wolf MA, Messier J, Desautels R, Debruille JB. Memory impairment in schizophrenia: a study using event-related potentials in implicit and explicit tasks. Psychiatry Res 2001; 104:157-73. [PMID: 11711169 DOI: 10.1016/s0165-1781(01)00305-5] [Citation(s) in RCA: 50] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Although memory impairment is recognized as a major fact of schizophrenia, only a few studies have investigated memory impairments with specifically designed event-related potential (ERP) protocols. In this study, ERPs were recorded from 15 schizophrenia patients and 15 matched control subjects during implicit and explicit memory tasks for unfamiliar faces. The results showed that patients have a reduced modulation of an N400-like component in both the implicit and explicit tasks that suggests a deficient integration of incoming information with personal knowledge. Patients also displayed an enhanced frontally distributed activity in the explicit task that may represent an impairment in the integration of intrinsic contextual information, a disturbance in the ability to inhibit proactive interference or a combination of both processes. Finally, the modulation of the late positive component did not differ from that in control subjects in both implicit and explicit tasks, suggesting that the impairment in mnemonic binding processes suggested in schizophrenia is more qualitative, i.e. incomplete or inappropriate, due to the anomalies in antecedent processes. The correlations observed between impairments of ERP modulation and symptoms further support these interpretations.
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Affiliation(s)
- F Guillem
- Douglas Hospital Research Centre-Clinical Unit, Quebec, Verdun, Canada.
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Ohta K, Uchiyama M, Matsushima E, Toru M. An event-related potential study in schizophrenia using Japanese sentences. Schizophr Res 1999; 40:159-70. [PMID: 10593455 DOI: 10.1016/s0920-9964(99)00048-1] [Citation(s) in RCA: 42] [Impact Index Per Article: 1.7] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/18/2022]
Abstract
To examine the neurophysiological and cognitive characteristics of language disorder in schizophrenia, the N400 component and late positive component (LPC) of event-related potentials (ERPs) were investigated in medicated schizophrenic patients and health comparison subjects. The subjects were required to indicate whether Japanese sentence completions were semantically congruous or incongruous. The ERPs for the range of 300-500 ms to the incongruous completions contained a more negative component (N400), followed by LPC, which was inversely more positive for the incongruous than congruous condition. The N400 effect and the mean amplitude of the LPC were reduced in the patients. The attenuated N400 effect in schizophrenics mainly originated from an enhanced negativity for the congruous completions, suggesting that the use of context is poor in schizophrenia.
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Affiliation(s)
- K Ohta
- Department of Neuropsychiatry, Tokyo Medical and Dental University School of Medicine, Japan.
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Olichney JM, Iragui VJ, Kutas M, Nowacki R, Morris S, Jeste DV. Relationship between auditory P300 amplitude and age of onset of schizophrenia in older patients. Psychiatry Res 1998; 79:241-54. [PMID: 9704871 DOI: 10.1016/s0165-1781(98)00043-2] [Citation(s) in RCA: 27] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 11/29/2022]
Abstract
Auditory P300 amplitude reductions are well-established in young adults with schizophrenia. Little is known, however, regarding the P300 in older schizophrenia patients, especially those with late onset. We studied 28 middle-aged and elderly (mean age = 62.7 years) patients [14 with early onset schizophrenia (EOS) and 14 with late onset schizophrenia (LOS)] and 14 normal comparison (NC) participants using an auditory oddball paradigm. Event-related potentials were recorded from 15 scalp electrodes and six non-scalp sites. There were no significant differences between EOS and LOS groups in neuroleptic dosage, symptom severity, reaction times, target-detection accuracy, or N100 and N200 ERP measures. The EOS, but not the LOS, group had significantly smaller auditory oddball P300 amplitudes than the NC group. Twelve of the 14 LOS patients had P300 amplitudes in the normal range. Smaller P300 amplitudes were associated with earlier age of onset (r = 0.48), longer duration of illness (r = -0.49) and more severe alogia (r = -0.50). We conclude that P300 abnormalities in schizophrenia may be a marker for a disease subtype with early onset and more severe information-processing deficits.
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Affiliation(s)
- J M Olichney
- Department of Neurosciences, University of California, San Diego, La Jolla, USA
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Guérit JM. [International literature review concerning evoked potentials in 1997]. Neurophysiol Clin 1998; 28:73-9. [PMID: 9563000 DOI: 10.1016/s0987-7053(97)89579-2] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 02/07/2023] Open
Affiliation(s)
- J M Guérit
- Unité d'explorations électrophysiologiques du système nerveux, cliniques universitaires Saint-Luc, université catholique de Louvain, Bruxelles, Belgique
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