Effective assessments of electroencephalography during stroke recovery: contemporary approaches and considerations

Abstract

Stroke is one of the leading causes of permanent disability worldwide, relying conventionally on extended periods of physiotherapy to recover functional ability. While neuroimaging techniques and emerging neurorehabilitation paradigms have advanced our understanding of pathophysiological mechanisms underlying stroke, recent evidence has renewed focus on quantifying features of cortical activity present in electroencephalography recordings to greatly enhance our understanding of stroke treatment and recovery. This Neuro Forum article reviews these key advances and discusses the importance of quantifying electroencephalography in future assessments of stroke survivors.

Temporal Lobe Epilepsy, Stroke, and Traumatic Brain Injury: Mechanisms of Hyperpolarized, Depolarized, and Flow-Through Ion Channels Utilized as Tri-Coordinate Biomarkers of Electrophysiologic Dysfunction

“…However, despite the benefits of these tools, they fail to establish data that connects structural abnormality and electrophysiologic dysfunction in the brain that translates to improved clinical outcomes [14]. EEG provides cortical activity markers in real-time [15] which augment the time lag in neuroimaging. However, few facilities have compatible tools to perform these tests synchronisly and have led to decreased use of electrophysiologic tools in preference to BOLD MRI, perfusion CT, and specialized manipulations of scans as accessories to primary MRI and CT for many neurologic diseases.…”

“…Whether evaluation is in a mouse model or a hospital, the spatial discernment sacrificed by electroencephalography due to the bony scalp and other confounding obstacles between the electrodes and the signal cannot always be overcome by the timing integrity of the machine. Event related potentials, frequency spectrum analysis, and other mechanisms of analysis assist in overcoming these limitiations [15]. However, training and validation of the researcher’s technique can consume large amounts of research time.…”

Peer Review #1 of "Slower EEG alpha generation, synchronization and “flow”—possible biomarkers of cognitive impairment and neuropathology of minor stroke (v0.1)"

“…All the EEG recordings were visually inspected and discriminated using EEGLAB to eliminate any ocular, muscular, and other types of artefacts before further analysis. The final EEG signals, consisting of 10 minute artefact-free periods, were analyzed in MATLAB R2011a, using software originally developed in MATLAB 6.5 (Ciric et al, 2015(Ciric et al, , 2016Kalauzi et al, 2012;Lazic et al, 2015;2017;Petrovic et al, 2013aPetrovic et al, , 2013bPetrovic et al, , 2014Saponjic et al, 2013). We particularly analyzed the EEGs derived from the four lateral frontal (F3, F7, F4, F8), and corresponding lateral posterior (P3, P4, T5, T6) electrodes (Schleiger et al, 2014).…”

“…Since cortical activity varies during each stage of a stroke, the assessment of a stroke by EEG measurements has proven to be an essential monitoring standard for identifying spatiotemporal markers of cortical activity related to injury, the post-stroke re-organizational processes, and recovery (Iyer, 2017). The initial slowing of brain EEG activity in acute strokes could be characterized by analyzing the power of slower relative to faster EEG activities, such as the delta/alpha ratio (Finnigan et al, 2016;Schleiger et al, 2014).…”

“…The initial slowing of brain EEG activity in acute strokes could be characterized by analyzing the power of slower relative to faster EEG activities, such as the delta/alpha ratio (Finnigan et al, 2016;Schleiger et al, 2014). As the stroke progresses to the subacute and chronic stages, functional connectivity measures, such as phase synchrony within specific frequency band like alpha (Dubovik et al, 2012;Westlake et al, 2012), become more important for studying re-organizational processes, brain plasticity, and functional recovery (Iyer, 2017).…”