An MEG study of alpha modulation in patients with schizophrenia and in subjects at high risk of developing psychosis

Koh, Yul; Shin, Kyoo Ho; Kim, June Sic; Choi, Jung Seok; Kang, Do Hyung; Jang, Joon Hwan; Cho, Kwang Hyun; O’Donnell, Brian F.; Chung, Chun Kee; Kwon, Jun Soo

doi:10.1016/j.schres.2010.10.001

Cited by 65 publications

(54 citation statements)

References 32 publications

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“…A consistent finding in the schizophrenia literature is a significant decrease in patients’ alpha ERD [47], [50], [51]. One interpretation is that ERD reductions reflect impairments in sensory gating and/or task-related inhibitory mechanisms, which are driven by reductions in post-stimulus alpha activity relative to the pre-stimulus period.…”

Section: Discussionmentioning

confidence: 66%

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Impairments in Background and Event-Related Alpha-Band Oscillatory Activity in Patients with Schizophrenia

Abeles

Gomez‐Ramirez

2014

PLoS ONE

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Studies show that patients with schizophrenia exhibit impaired responses to sensory stimuli, especially at the early stages of neural processing. In particular, patients’ alpha-band (8–14 Hz) event-related desynchronization (ERD) and visual P1 event-related potential (ERP) component tend to be significantly reduced, with P1 ERP deficits greater for visual stimuli biased towards the magnocellular system. In healthy controls, studies show that pre-stimulus alpha (background alpha) plays a pivotal role in sensory processing and behavior, largely by shaping the neural responses to incoming stimuli. Here, we address whether patients’ ERD and P1 deficits stem from impairments in pre-stimulus alpha mechanisms. To address this question we recorded electrophysiological activity in patients with schizophrenia and healthy controls while they engaged in a visual discrimination task with low, medium, and high contrast stimuli. The results revealed a significant decrease in patients’ ERDs, which was largely driven by reductions in pre-stimulus alpha. These reductions were most prominent in right-hemispheric areas. We also observed a systematic relationship between pre-stimulus alpha and the P1 component across different contrast levels. However, this relationship was only observed in healthy controls. Taken together, these findings highlight a substantial anomaly in patients’ amplitude-based alpha background activity over visual areas. The results provide further support that pre-stimulus alpha activity plays an active role in perception by modulating the neural responses to incoming sensory inputs, a mechanism that seems to be compromised in schizophrenia.

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Section: Discussionmentioning

confidence: 66%

“…Anomalies in alpha-band activity of schizophrenia patients have also been found in stimulus-related responses, with the majority of studies reporting a significant decrease in patients’ alpha ERD [46], [47], [48], [49], [50], [51]. The etiology of this reduction is unknown.…”

Section: Introductionmentioning

confidence: 99%

Impairments in Background and Event-Related Alpha-Band Oscillatory Activity in Patients with Schizophrenia

Abeles

Gomez‐Ramirez

2014

PLoS ONE

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“…Although less impaired than schizophrenia, CHR patients have generalized neuropsychological deficits (Brewer et al, 2006; Hawkins et al 2004; Woodberry et al, 2010), and verbal memory deficits may be a predictor of psychosis (Brewer et al, 2005; Lencz et al, 2006; Woodberry et al, 2010). A promising line of research has recently implicated various electrophysiologic measures obtained during active and passive auditory paradigms as helpful tools in predicting transition to psychosis (Atkinson et al, 2012; Bodatsch et al, 2011; Frommann et al, 2008; Koh et al, 2011; Shaikh et al, 2012; van der Stelt et al, 2005; van Tricht et al, 2010). However, only smell identification deficits have been shown to discern whom among high-risk cases will specifically develop schizophrenia and its spectrum disorders (Brewer et al, 2003), which is agreement with evidence showing that impairments in odor identification are present before individuals develop psychotic symptoms (Woodberry et al, 2010).…”

Section: Introductionmentioning

confidence: 99%

Olfaction in the psychosis prodrome: Electrophysiological and behavioral measures of odor detection

Kayser

Tenke

Kroppmann

et al. 2013

International Journal of Psychophysiology

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Smell identification deficits (SIDs) are relatively specific to schizophrenia and its negative symptoms, and may predict transition to psychosis in clinical high-risk (CHR) individuals. Moreover, eventrelated potentials (ERPs) to odors are reduced in schizophrenia. This study examined whether CHR patients show SIDs and abnormal olfactory N1 and P2 potentials. ERPs (49 channels) were recorded from 21 CHR and 20 healthy participants (13 males/group; ages 13–27 years) during an odor detection task using three concentrations of hydrogen sulfide (H2S) or blank air presented unilaterally by a constant-flow olfactometer. Neuronal generator patterns underlying olfactory ERPs were identified and measured by principal components analysis (unrestricted Varimax) of reference-free current source densities (CSD). Replicating previous findings, CSD waveforms to H2S stimuli were characterized by an early N1 sink (345 ms, lateral-temporal) and a late P2 source (600 ms, mid-frontocentroparietal). N1 and P2 varied monotonically with odor intensity (strong > medium > weak) and did not differ across groups. Patients and controls also showed comparable odor detection and had normal odor identification and thresholds (Sniffin’ Sticks). However, olfactory ERPs strongly reflected differences in odor intensity and detection in controls, but these associations were substantially weaker in patients. Moreover, severity of negative symptoms in patients was associated with reduced olfactory ERPs and poorer odor detection, identification and thresholds. Three patients who developed psychosis had poorer odor detection and thresholds, and marked reductions of N1 and P2. Thus, despite the lack of overall group differences, olfactory measures may be of utility in predicting transition to psychosis among CHR patients.

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“…Georgopoulos et al showed that with a special data handling of MEG signal differentiation among subjects with schizophrenia, Alzheimer's disease, chronic alcoholism [63], and PTSD [64] and healthy controls with a significant degree of accuracy is possible. MEG abnormalities were also detectable in asymptomatic individuals who were at a high risk for developing psychosis [65].…”

Section: Magnetoencephalographymentioning

confidence: 96%

Advances in electrophysiology in the diagnosis of behavioral disorders

Boutros

Gjini

Arfken

2011

Expert Opinion on Medical Diagnostics

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Psychiatric electrophysiology currently plays a limited role in the diagnosis and management in psychiatry. This status is not supported by the existing literature. The underutilization of electrophysiological tests in psychiatry is propagated by the fact that the laboratories providing the service are not managed by psychiatrists. The authors propose that the first steps are to establish such laboratories and train psychiatrists to competently provide the service.

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An MEG study of alpha modulation in patients with schizophrenia and in subjects at high risk of developing psychosis

Cited by 65 publications

References 32 publications

Impairments in Background and Event-Related Alpha-Band Oscillatory Activity in Patients with Schizophrenia

Impairments in Background and Event-Related Alpha-Band Oscillatory Activity in Patients with Schizophrenia

Olfaction in the psychosis prodrome: Electrophysiological and behavioral measures of odor detection

Advances in electrophysiology in the diagnosis of behavioral disorders

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