EEG spectral exponent as a synthetic index for the longitudinal assessment of stroke recovery

Lanzone, Jacopo; Colombo, Michele; Sarasso, Simone; Zappasodi, Filippo; Rosanova, Mario; Massimini, Marcello; Lazzaro, Vincenzo Di; Assenza, Giovanni

doi:10.1016/j.clinph.2022.02.022

Cited by 32 publications

(29 citation statements)

References 73 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Both parameters of the aperiodic component were estimated from 1-45 Hz using the 'Fitting oscillations and one over f' (FOOOF) algorithm (16) (see Methods). Oscillatory power in the delta (1-4 Hz), theta (4-8 Hz), alpha (8-13 Hz), beta (13)(14)(15)(16)(17)(18)(19)(20)(21)(22)(23)(24)(25)(26)(27)(28)(29)(30) and gamma (30)(31)(32)(33)(34)(35)(36)(37)(38)(39)(40)(41)(42)(43)(44)(45) bandwidth was calculated before and after the removal of the aperiodic component. The detection of oscillatory peak frequency was performed using the FOOOF algorithm.…”

Section: Resultsmentioning

confidence: 99%

“…Second, participants in this study were recruited after a variety of brain injuries, including stroke, traumatic and anoxic brain injury. Although the spectral slope is steeper in the hemisphere most affected by a stroke, (Lanzone et al, 2022), this study did not account for the location of the brain injury. Additionally, the trend towards low CRS-R score within this study's participants led to high imbalance between the classical diagnostic groups (i.e., coma, unresponsive wakefulness syndrome, minimally conscious state, emergence).…”

Section: Discussionmentioning

confidence: 99%

“…The strong evidence that the aperiodic EEG component distinguishes states of wakefulness from sleep (Lendner et al, 2020) and general anesthesia (Colombo et al, 2019;Lendner et al, 2020) motivated investigations of diagnostic value of this signal for unresponsive patients. In a clinical population, Lanzone et al (2022) proposed the aperiodic slope as an index for longitudinal recovery from stroke. To date, only a single study by Alnes et al (2021) assessed the spectral properties of pathologically unresponsive individuals and showed that the aperiodic component of the EEG is altered in patients in a coma, compared to healthy adults.…”

Section: Discussionmentioning

confidence: 99%

See 2 more Smart Citations

Aperiodic brain activity and response to anesthesia vary in disorders of consciousness

Maschke

Duclos²,

Owen

et al. 2022

Preprint

View full text Add to dashboard Cite

In the human electroencephalogram (EEG), oscillatory power peaks co-exist with non-oscillatory, aperiodic activity. Although EEG analysis has traditionally focused exclusively on oscillatory power, recent investigations have shown that the aperiodic EEG component can distinguish conscious wakefulness from sleep and anesthetic-induced unconsciousness (Lendner et al. 2020). This study investigates the aperiodic EEG component of individuals in a disorder of consciousness (DOC), and how it changes in response to exposure to anesthesia. High-density EEG was recorded from 43 individuals in a DOC. To measure the brain’s reaction to global perturbation, a subset of n = 16 were also exposed to a targeted infusion of propofol anesthesia. The aperiodic component was defined by the spectral slope and offset in the 1-45 Hz and 30-45 Hz range of the power spectral density. Brain network criticality and complexity were estimated using the pair correlation function (PCF) and Lempel-Ziv complexity, respectively. The level of responsiveness of all individuals in DOC was assessed using the Coma Recovery Scale-Revised (CRS-R). Recovery of consciousness was assessed three months post-EEG. At baseline, the EEG aperiodic component was more strongly correlated to the participants’ level of consciousness than the oscillatory component. Anesthesia caused a steepening of the spectral slope across participants. Importantly, the change in spectral slope positively correlated with the individual participant’s level of responsiveness. The spectral slope during exposure to anesthesia contained prognostic value for individuals with DOC. The anesthetic-induced change in aperiodic EEG was accompanied by loss of information-richness and a reduction in network criticality. The aperiodic EEG component in individuals with DOC has been historically neglected; this research highlights the importance of considering this measure for future research investigating brain mechanisms underlying consciousness.Significance StatementThe analysis of human EEG has traditionally focused on oscillatory power, which is characterized by peaks above a broadband, aperiodic component in the EEG power spectral density. This study is the first to demonstrate the value of the aperiodic EEG component and specifically, its reaction to propofol anesthesia for assessing individual’s level of, and capacity for, consciousness. Our results demonstrates that the pharmacological induced change in the aperiodic component accompanies the brain’s loss of network criticality and complexity. Most importantly, the magnitude of brain response to propofol anesthesia relies on an individual’s pre-anesthetic level of consciousness. Whereas the aperiodic EEG component has been historically neglected; this research highlights the necessity of considering this measure for future research that seeks to understand the neurophysiological underpinnings of consciousness.

show abstract

Section: Resultsmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

Aperiodic brain activity and response to anesthesia vary in disorders of consciousness

Maschke

Duclos²,

Owen

et al. 2022

Preprint

View full text Add to dashboard Cite

show abstract

“…39,40 Aperiodic EEG measures are under investigation in patients. 8 Further, E/I imbalance has been demonstrated in the subacute phase after stroke in humans and transcranial stimulation at gamma frequency was able to reduce the degree of inhibition and improve performance in a motor task. 41,42 Alternatively, pharmacological agents to modify E/I ratio are available.…”

Section: Discussionmentioning

confidence: 98%

Normalization of Aperiodic Electrocorticography Components Indicates Fine Motor Recovery After Sensory Cortical Stroke in Mice

Biskamp

Cainzos

Higgen

et al. 2022

Stroke

View full text Add to dashboard Cite

BACKGROUND: Electrophysiological signatures of ischemic stroke might help to develop a deeper understanding of the mechanisms of recovery. However, to identify critical windows for novel treatment approaches, suitable readout parameters in vivo with the potential to close the gap between functional modifications within the peri-infarct cortex and behavioral outcome on the systems-level are still lacking. METHODS: Wild-type mice were trained in a skilled reaching task and underwent permanent distal medial cerebral artery occlusion or sham intervention. Functional deficits and their recovery were monitored both behaviorally and electrophysiologically recording multichannel electrocorticography from both hemispheres. RESULTS: Ischemic strokes are located in sensory cortical areas. Affected mice presented fine motor deficits of their contralateral forepaw. Analyses of electrocorticography signals from awake animals demonstrated a modulation of the shape of power spectral density in the vicinity of the infarct. While power spectral density consists of both rhythmic oscillatory and nonrhythmic, aperiodic components, the alteration of spectrum shape was reflected in a transient increase of aperiodic exponents in the peri-infarct cortex. The relative power and frequency of slow oscillations remained unchanged. Exponents derived from motor areas significantly correlated with fine motor recovery, thus indicating functional modifications of neuronal activity. CONCLUSIONS: Aperiodic spectral exponents exhibited a unique spatiotemporal profile in the mouse cortex after stroke and might complement future translational studies providing a dynamic link from pathophysiology to behavior.

show abstract

“…Spectral Exponent (SE), a metric that reflects EEG slowing and quantifies the power-law decay of the EEG Power Spectral Density was shown to be sensitive to MCA stroke in patients and demonstrated renormalization after two months of physical rehabilitation. It is worth noting that SE renormalization significantly correlated with NIHSS improvement [ 31 ]. Another important measure is the slope of the power spectrum (also referred to as 1/f noise) may be potentially useful in clinical practice in patients with stroke.…”

Section: Discussionmentioning

confidence: 99%

Changes in Brain Electrical Activity after Transient Middle Cerebral Artery Occlusion in Rats

Sysoev

Prikhodko

Kan

et al. 2022

Neurology International

View full text Add to dashboard Cite

Objectives. Ischemic stroke is a leading cause of death and disability worldwide. To search for new therapeutic and pharmacotherapeutic strategies, numerous models of this disease have been proposed, the most popular being transient middle cerebral artery occlusion. Behavioral and sensorimotor testing, biochemical, and histological methods are traditionally used in conjunction with this model to assess the effectiveness of potential treatment options. Despite its wide overall popularity, electroencephalography/electrocorticography is quite rarely used in such studies. Materials and methods. In the present work, we explored the changes in brain electrical activity at days 3 and 7 after 30- and 45-min of transient middle cerebral artery occlusion in rats. Results. Cerebral ischemia altered the amplitude and spectral electrocorticogram characteristics, and led to a reorganization of inter- and intrahemispheric functional connections. Ischemia duration affected the severity as well as the nature of the observed changes. Conclusions. The dynamics of changes in brain electrical activity may indicate a spontaneous partial recovery of impaired cerebral functions at post-surgery day 7. Our results suggest that electrocorticography can be used successfully to assess the functional status of the brain following ischemic stroke in rats as well as to investigate the dynamics of functional recovery.

show abstract

EEG spectral exponent as a synthetic index for the longitudinal assessment of stroke recovery

Cited by 32 publications

References 73 publications

Aperiodic brain activity and response to anesthesia vary in disorders of consciousness

Aperiodic brain activity and response to anesthesia vary in disorders of consciousness

Normalization of Aperiodic Electrocorticography Components Indicates Fine Motor Recovery After Sensory Cortical Stroke in Mice

Changes in Brain Electrical Activity after Transient Middle Cerebral Artery Occlusion in Rats

Contact Info

Product

Resources

About