Sources of Abnormal EEG Activity in Brain Infarctions

Fernández-Bouzas, Antonio; Harmony, Thalı́a; Fernández, Thalı́a; Silva‐Pereyra, Juan; Valdés, P.; Bosch, J.; Aubert, Eduardo Henrik; Casián, Gustavo; Ojeda, Gloria Otero; Ricardo, Josefina; Hernández-Ballesteros, Adriana; Santiago, E

doi:10.1177/155005940003100403

Cited by 44 publications

(21 citation statements)

References 17 publications

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“…Prior studies that showed deviant EEG activation patterns in stroke patients constantly reported abnormalities in the delta frequency range (Giaquinto et al 1994; Finnigan et al 2007, 2008; Finnigan and van Putten 2013; Fernandez-Bouzas et al 2000; Claassen et al 2004; Sheorajpanday et al 2011; Tecchio et al 2006). The majority of prior studies also demonstrated pathological alpha activity after stroke (Giaquinto et al 1994; Finnigan et al 2007; Finnigan and van Putten 2013; Sheorajpanday et al 2011; Claassen et al 2004; Tecchio et al 2006; Fernandez-Bouzas et al 2000). However, a few studies also reported on pathological theta or beta activity after stroke, which could not be observed in the present investigation (Giaquinto et al 1994; Tecchio et al 2006, 2007; Finnigan and van Putten 2013).…”

Section: Discussionmentioning

confidence: 99%

Upper Alpha Based Neurofeedback Training in Chronic Stroke: Brain Plasticity Processes and Cognitive Effects

Kober

Schweiger

Reichert

et al. 2017

Appl Psychophysiol Biofeedback

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In the present study, we investigated the effects of upper alpha based neurofeedback (NF) training on electrical brain activity and cognitive functions in stroke survivors. Therefore, two single chronic stroke patients with memory deficits (subject A with a bilateral subarachnoid hemorrhage; subject B with an ischemic stroke in the left arteria cerebri media) and a healthy elderly control group (N = 24) received up to ten NF training sessions. To evaluate NF training effects, all participants performed multichannel electroencephalogram (EEG) resting measurements and a neuropsychological test battery assessing different cognitive functions before and after NF training. Stroke patients showed improvements in memory functions after successful NF training compared to the pre-assessment. Subject B had a pathological delta (0.5–4 Hz) and upper alpha (10–12 Hz) power maximum over the unaffected hemisphere before NF training. After NF training, he showed a more bilateral and “normalized” topographical distribution of these EEG frequencies. Healthy participants as well as subject A did not show any abnormalities in EEG topography before the start of NF training. Consequently, no changes in the topographical distribution of EEG activity were observed in these participants when comparing the pre- and post-assessment. Hence, our results show that upper alpha based NF training had on the one hand positive effects on memory functions, and on the other hand led to cortical “normalization” in a stroke patient with pathological brain activation patterns, which underlines the potential usefulness of NF as neurological rehabilitation tool.

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Section: Discussionmentioning

confidence: 99%

Upper Alpha Based Neurofeedback Training in Chronic Stroke: Brain Plasticity Processes and Cognitive Effects

Kober

Schweiger

Reichert

et al. 2017

Appl Psychophysiol Biofeedback

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“…On the other hand, source EEG spectral analysis has a different objective: the estimation of S(x) the source cross-spectrum. This procedure, called frequency-domain VARETA, has been applied to the localization of brain tumors, infarcts and other type of cerebral lesions with great accuracy, including subcortical lesions , 2000Prichep et al, 2001). …”

Section: Eeg Source Spectral Analysismentioning

confidence: 99%

Specific EEG frequencies signal general common cognitive processes as well as specific task processes in man

Harmony

Fernández

Gersenowies³

et al. 2004

International Journal of Psychophysiology

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“…Many previous studies suggested that slow wave activity in the delta frequency range is highly typical in ischemic stroke [14, 16, 22, 24, 42–48] (Butz et al [16], 0.5–3 Hz; Sakamoto et al [22, 24], 0.3–4 Hz; Nuwer et al [43], 0.1–4 Hz; Nagata et al [44], 0.4–4 Hz; Nagata et al [45], 2.0–3.8 Hz; Finnigan et al [47], 1–4 Hz; Burghaus et al [48], <1 Hz). Furthermore, delta activity has the strongest correlation with regional cerebral blood flow in patients with supratentorial and unilateral cerebral infarction [44–46].…”

Section: Discussionmentioning

confidence: 99%

“…Electroencephalography (EEG), which is a method of electrophysiological examination, can also demonstrate the area of reversible cerebral ischemia (ischemic penumbra) as slow waves [12–14]. However, in the age of MRI, EEG has minimal clinical applications for evaluating cerebral ischemia because it has markedly low spatial resolution, which is due to the presence of the scalp, skull, and cerebrospinal fluid between the brain and the electrodes.…”

Section: Introductionmentioning

confidence: 99%

MEG Frequency Analysis Depicts the Impaired Neurophysiological Condition of Ischemic Brain

et al. 2016

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PurposeQuantitative imaging of neuromagnetic fields based on automated region of interest (ROI) setting was analyzed to determine the characteristics of cerebral neural activity in ischemic areas.MethodsMagnetoencephalography (MEG) was used to evaluate spontaneous neuromagnetic fields in the ischemic areas of 37 patients with unilateral internal carotid artery (ICA) occlusive disease. Voxel-based time-averaged intensity of slow waves was obtained in two frequency bands (0.3–4 Hz and 4–8 Hz) using standardized low-resolution brain electromagnetic tomography (sLORETA) modified for a quantifiable method (sLORETA-qm). ROIs were automatically applied to the anterior cerebral artery (ACA), anterior middle cerebral artery (MCAa), posterior middle cerebral artery (MCAp), and posterior cerebral artery (PCA) using statistical parametric mapping (SPM). Positron emission tomography with 15O-gas inhalation (15O-PET) was also performed to evaluate cerebral blood flow (CBF) and oxygen extraction fraction (OEF). Statistical analyses were performed using laterality index of MEG and 15O-PET in each ROI with respect to distribution and intensity.ResultsMEG revealed statistically significant laterality in affected MCA regions, including 4–8 Hz waves in MCAa, and 0.3–4 Hz and 4–8 Hz waves in MCAp (95% confidence interval: 0.020–0.190, 0.030–0.207, and 0.034–0.213), respectively. We found that 0.3–4 Hz waves in MCAp were highly correlated with CBF in MCAa and MCAp (r = 0.74, r = 0.68, respectively), whereas 4–8 Hz waves were moderately correlated with CBF in both the MCAa and MCAp (r = 0.60, r = 0.63, respectively). We also found that 4–8 Hz waves in MCAp were statistically significant for misery perfusion identified on 15O-PET (p<0.05).ConclusionsQuantitatively imaged spontaneous neuromagnetic fields using the automated ROI setting enabled clear depiction of cerebral ischemic areas. Frequency analysis may reveal unique neural activity that is distributed in the impaired vascular metabolic territory, in which the cerebral infarction has not yet been completed.

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Sources of Abnormal EEG Activity in Brain Infarctions

Cited by 44 publications

References 17 publications

Upper Alpha Based Neurofeedback Training in Chronic Stroke: Brain Plasticity Processes and Cognitive Effects

Upper Alpha Based Neurofeedback Training in Chronic Stroke: Brain Plasticity Processes and Cognitive Effects

Specific EEG frequencies signal general common cognitive processes as well as specific task processes in man

MEG Frequency Analysis Depicts the Impaired Neurophysiological Condition of Ischemic Brain

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