Investigating neurophysiological markers of impaired cognition in schizophrenia

Hoy, Kate E.; Coyle, Hannah; Gainsford, Kirsten; Hill, Aron T.; Bailey, Neil W.; Fitzgerald, Paul B.

doi:10.1016/j.schres.2021.06.025

Cited by 13 publications

(13 citation statements)

References 57 publications

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“…Many studies have also investigated task-related theta activity. In particular, in SCZ theta power evoked during working memory or visual tasks was correlated with working memory performance [ 89 , 98 , 99 ], attention [ 84 ], speed of processing [ 84 , 88 , 89 ], visual learning [ 88 ] and social perception [ 87 ]. Using a machine learning approach, Johannesen et al [ 99 ], found that the machine learning model, combining the evoked activity of theta, alpha, beta and gamma bands, successfully predicted working memory performance.…”

Section: Resultsmentioning

confidence: 99%

Unveiling the Associations between EEG Indices and Cognitive Deficits in Schizophrenia-Spectrum Disorders: A Systematic Review

et al. 2022

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Cognitive dysfunctions represent a core feature of schizophrenia-spectrum disorders due to their presence throughout different illness stages and their impact on functioning. Abnormalities in electrophysiology (EEG) measures are highly related to these impairments, but the use of EEG indices in clinical practice is still limited. A systematic review of articles using Pubmed, Scopus and PsychINFO was undertaken in November 2021 to provide an overview of the relationships between EEG indices and cognitive impairment in schizophrenia-spectrum disorders. Out of 2433 screened records, 135 studies were included in a qualitative review. Although the results were heterogeneous, some significant correlations were identified. In particular, abnormalities in alpha, theta and gamma activity, as well as in MMN and P300, were associated with impairments in cognitive domains such as attention, working memory, visual and verbal learning and executive functioning during at-risk mental states, early and chronic stages of schizophrenia-spectrum disorders. The review suggests that machine learning approaches together with a careful selection of validated EEG and cognitive indices and characterization of clinical phenotypes might contribute to increase the use of EEG-based measures in clinical settings.

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Section: Resultsmentioning

confidence: 99%

Unveiling the Associations between EEG Indices and Cognitive Deficits in Schizophrenia-Spectrum Disorders: A Systematic Review

et al. 2022

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“…Statistical analyses were performed using SPSS version 24 (IBM Corp, Armonk, NY, USA), Prism version 7 (GraphPad, San Diago, CA, USA) and the FieldTrip MATLAB toolbox. To reduce the number of comparisons, we restricted analyses to the outcome measures indicated in our baseline analysis as being potential therapeutic targets, namely cortical reactivity as indexed via TEPs (specifically, the N40 and N100), TMS-related theta oscillations and task-related theta oscillations (Hoy et al, 2021). To control for both family wise error rate and false negatives, a significance value of p < 0.01 (two-tailed) was used for all analyses, with >0.01 and <0.05 considered a trend.…”

Section: Methodsmentioning

confidence: 99%

“…In order to identify the specific neurophysiological targets of intervention we conducted an analysis of the baseline data from the current trial, which included the 30 participants with schizophrenia described here as well as 27 healthy controls (Hoy et al, 2021). We identified reduced prefrontal cortical reactivity (a posited measure of cortical inhibition and excitation) and reduced theta oscillatory activity (both in response to TMS and task-related) as possible markers of impaired cognition in schizophrenia (Hoy et al, 2021). Cortical reactivity was assessed using combined TMS-EEG and indexed via TMS-Evoked Potentials (TEPs) (Hoy et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

“…We identified reduced prefrontal cortical reactivity (a posited measure of cortical inhibition and excitation) and reduced theta oscillatory activity (both in response to TMS and task-related) as possible markers of impaired cognition in schizophrenia (Hoy et al, 2021). Cortical reactivity was assessed using combined TMS-EEG and indexed via TMS-Evoked Potentials (TEPs) (Hoy et al, 2021). Therefore, for the current trial, we hypothesised that active stimulation, compared to sham, would lead to increased prefrontal cortical reactivity, enhanced theta oscillatory activity (both TMS-related and task-related) and improved cognitive performance.…”

Section: Introductionmentioning

confidence: 99%

“…In the current study we sought to directly investigate whether repeated sessions of anodal tDCS in participants with schizophrenia were able to engage proposed therapeutic targets and subsequently improve cognition. In order to identify the specific neurophysiological targets of intervention we conducted an analysis of the baseline data from the current trial, which included the 30 participants with schizophrenia described here as well as 27 healthy controls (Hoy et al, 2021). We identified reduced prefrontal cortical reactivity (a posited measure of cortical inhibition and excitation) and reduced theta oscillatory activity (both in response to TMS and task-related) as possible markers of impaired cognition in schizophrenia (Hoy et al, 2021).…”

Section: Introductionmentioning

confidence: 99%

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Investigating neurophysiological effects of a short course of tDCS for cognition in schizophrenia: a target engagement study

Hoy¹,

Coyle²,

Gainsford³

et al. 2022

Preprint

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BackgroundCognitive impairment is highly prevalent in schizophrenia and treatment options are severely limited. Development of effective treatments will rely on successful engagement of biological targets. There is growing evidence that the cognitive impairments in schizophrenia are related to impairments in prefrontal cortical inhibition and dysfunctional cortical oscillations.MethodsIn the current study we sought to investigate whether a short course of transcranial Direct Current Stimulation (tDCS) could modulate these pathophysiological targets. Thirty participants with schizophrenia were recruited and underwent neurobiological assessment (Transcranial Magnetic Stimulation combined with EEG [TMS-EEG] and task-related EEG) and assessment of cognitive functioning (n-back task and the MATRICS Consensus Cognitive Battery). Participants were then randomized to receive 5 sessions of either active or sham anodal tDCS to the left prefrontal cortex. Twenty-four hours after the last tDCS session participants repeated the neurobiological and cognitive assessments. Neurobiological outcome measures were TMS-evoked potentials (TEPs), TMS-related oscillations and oscillatory power during a 2-back task. Cognitive outcome measures were d prime and accurate reaction time on the 2-back and MATRICS scores.ResultsFollowing active tDCS there was a significant reduction in the N40 TEP amplitude in the left parietal occipital region. There were no other significant changes.ConclusionsFuture interrogation of evidence based therapeutic targets in large scale RCTs is required.

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Individualized time windows enhance TMS-EEG signal characterization and improve assessment of cortical function in schizophrenia

Mijancos-Martínez,

Bachiller,

Fernández-Linsenbarth

et al. 2024

Eur Arch Psychiatry Clin Neurosci

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Transcranial magnetic stimulation and electroencephalography (TMS-EEG) recordings are crucial to directly assess cortical excitability and inhibition in a non-invasive and task-free manner. TMS-EEG signals are characterized by TMS-evoked potentials (TEPs), which are employed to evaluate cortical function. Nonetheless, different time windows (TW) have been used to compute them over the years. Moreover, these TWs tend to be the same for all participants omitting the intersubject variability. Therefore, the objective of this study is to assess the effect of using different TWs to compute the TEPs, moving from a common fixed TW to more adaptive individualized TWs. Twenty-nine healthy (HC) controls and twenty schizophrenia patients (SCZ) underwent single-pulse (SP) TMS-EEG protocol. Firstly, only the HC were considered to evaluate the TEPs for three different TWs in terms of amplitude and topographical distribution. Secondly, the SCZ patients were included to determine which TW is better to characterize the brain alterations of SCZ. The results indicate that a more individualized TW provides a better characterization of the SP TMS-EEG signals, although all of them show the same tendency. Regarding the comparison between groups, the individualized TW is the one that provides a better differentiation between populations. They also provide further support to the possible imbalance of cortical excitability/inhibition in the SCZ population due to its reduced activity in the N45 TEP and greater amplitude values in the N100. Results also suggest that the SCZ brain has a baseline hyperactive state since the TEPs of the SCZ appear earlier than those of the HC.

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Investigating neurophysiological markers of impaired cognition in schizophrenia

Cited by 13 publications

References 57 publications

Unveiling the Associations between EEG Indices and Cognitive Deficits in Schizophrenia-Spectrum Disorders: A Systematic Review

Unveiling the Associations between EEG Indices and Cognitive Deficits in Schizophrenia-Spectrum Disorders: A Systematic Review

Investigating neurophysiological effects of a short course of tDCS for cognition in schizophrenia: a target engagement study

Individualized time windows enhance TMS-EEG signal characterization and improve assessment of cortical function in schizophrenia

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