EEG Asymmetry Research Articles

One Phenomenon with Many Interpretations: Asymmetry of the Frontal EEG α Rhythm in Healthy People. Part I

One Phenomenon with Many Interpretations: Asymmetry of the Frontal EEG α Rhythm in Healthy People. Part I

EEG asymmetry and cognitive testing in MCI identification

BackgroundFinding the baseline resting-state EEG markers for early identification of cognitive decline can contribute to the identification of individuals at risk of further change. Potential applications include identifying participants for clinical trials, early treatment, and evaluation of treatment, accessible even from a community setting. MethodsAnalyses were completed on a sample of 99 (ages 60–90) consensus-diagnosed, community-dwelling African Americans (58 cognitively typical/HC, and 41 mildly cognitively impaired/MCI), who were recruited from the Michigan Alzheimer's Disease Research Center (MADRC) and the Wayne State University Institute of Gerontology. In addition to neuropsychological testing with CogState and Toolbox computerized batteries, resting-state EEGs (rsEEG, eyes closed) were acquired before and after participants were engaged in a visual motion direction discrimination task. rsEEG frontal alpha asymmetry (FAA) and frontal beta asymmetry (FBA) were calculated. ResultsFAA showed no difference across groups for the pre-task resting state. FBA was significantly different between groups, with more asymmetric frontal beta in MCI. Both physiological indices, however, along with computerized neuropsychological tests were significant predictors in logistic regression classification of MCI vs. control participants. ConclusionrsEEG asymmetries can contribute significantly to successful discrimination of older persons with MCI from those without, over and above cognitive testing, alone.

Frontal EEG asymmetry moderates the relation between borderline personality disorder features and feelings of social rejection in adolescents.

Although associations among borderline personality disorder (BPD), social rejection, and frontal EEG alpha asymmetry scores (FAA, a neural correlate of emotion regulation and approach-withdrawal motivations) have been explored in different studies, relatively little work has examined these relations during adolescence in the same study. We examined whether FAA moderated the relation between BPD features and rejection sensitivity following a validated social exclusion paradigm, Cyberball. A mixed, clinical-community sample of 64 adolescents (females = 62.5%; Mage = 14.45 years; SD = 1.6; range = 11-17 years) completed psychodiagnostic interviews and a self-report measure of BPD (Time 1). Approximately two weeks later (Time 2), participants completed a resting EEG recording followed by Cyberball. FAA moderated the relation between BPD features and overall feelings of rejection following Cyberball: individuals with greater relative left FAA had the highest and lowest feelings of social rejection depending on whether they had high and low BPD feature scores, respectively. Results remained after controlling for age, sex, gender, depression, and BPD diagnosis. These results suggest that FAA may moderate the relation between BPD features and social rejection, and that left frontal brain activity at rest may be differentially associated with those feelings in BPD. Findings are discussed in terms of the link between left frontal brain activity in the regulation and dysregulation of social approach behaviors, characteristic of BPD.

Long-term stability of frontal electroencephalogram alpha power and asymmetry at rest in adults born at extremely low or normal birth weight: A 10-year longitudinal study.

The idea that individual differences in resting frontal EEG alpha activity have "trait-like" features that are associated with stress vulnerabilities presumes that these physiological patterns should be stable across time. We know, however, relatively little regarding the very long-term (i.e., ≥10years) stability of resting frontal EEG alpha power and asymmetry in typically or atypically developing populations. Here, we examined the long-term stability of regional electroencephalogram (EEG) alpha (8-13Hz) power and asymmetry at rest across a decade in the oldest known prospectively followed cohort of extremely low birth weight (ELBW; <1000g) adult survivors and normal birth weight (NBW; >2500g) controls. Regional EEG was collected at rest from the left and right frontal (F3, F4) and parietal (P3, P4) scalp sites using a stretchable cap during baseline eyes-open and eyes-closed conditions in young adulthood (ages 21-25years) and again in adulthood (ages 30-35years). We found moderate stability in regional EEG absolute alpha spectral power measures across all scalp sites for each birth weight group between the young adulthood and adulthood assessments. As well, we found the frontal alpha asymmetry measure was stable, albeit weakly, between the two assessment periods only in the NBW group. However, parietal alpha asymmetry was weak-to-moderately stable for each birth weight group across the 10-year period. Findings are discussed in terms of their implications for understanding associations between individual differences in frontal and parietal brain activity at rest and long-term stress vulnerability in typical and atypical development.

Investigating the links between parent–child interactions and context-specific electroencephalography asymmetry: Neurophysiology behind a frustrating task

This study investigated the relations between parent–child interactions and infant brain activity in the context of a frustration eliciting task. Specifically, electroencephalography (EEG) data were recorded and processed to provide alpha frontal asymmetry indicators linked with approach/avoidance emotions and motivation. These data were collected from 53 mother–infant dyads during baseline and a toy retraction task, with play interactions coded for caregiving quality indicators. Hierarchical multiple linear regression analyses indicated that infants of more sensitive/responsive mothers and those engaging in more fast-paced/active play exchanges with caregivers demonstrated a relative left frontal activation response during toy retraction. Reciprocity/synchrony and directedness (parent vs. child directed) did not account for significant amounts of toy retraction EEG asymmetry response variance. It may be that infants experience greater frustration in the context of an attractive toy being removed when their typical play exchanges with caregivers are marked by sensitivity to their needs and are physically/verbally engaging. The findings are discussed in the context of the capability model of EEG asymmetry with regard to infant EEG.

Frontal EEG Asymmetry in Fathers who use Intimate Partner Violence

Frontal EEG Asymmetry in Fathers who use Intimate Partner Violence

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Background:Electroencephalography (EEG) studies in Autism Spectrum Disorder (ASD) have investigated spectral power, coherence of EEG rhythms and asymmetry of the bands across various brain regions. There is inadequate evidence for ascertaining hemispherical dominance/asymmetry of bands in sleep states. In this study, we aim to compute spatial delta asymmetries across cerebral hemispheres using EEG in preschool children with ASD in comparison to non-ASD age matched clinical controls in awake and sleep stages.Methods:Preschool children (2 to 6 years of age) underwent natural EEG recording up to 180 mins with 64 Channel EGI-GES400 system. ASD group had 28 children (24M, 4F). Controls who were diagnosed with ADHD, Specific Speech Delay, and Global Developmental Delay had 10 children (6M, 4F). None were on medication. Awake state, sleep stage 1 (N1), 2 (N2) and (N3) were included. An artefact-free continuous segment of 60s in all stages was selected manually. Power Spectral Density was computed for each epoch of 10s duration with 50% overlap using Welch’s periodogram. Delta [0.5-4Hz] power& asymmetry indices were computed for 36 scalp locations spanning 10 regions in both hemispheres (frontal, central, parietal, temporal and occipital regions).Results:N1 had right hemispherical dominance in only parietal & occipital. N2 was left central dominant for ASD. N3 had total right dominance across all areas with ASD > non-ASD throughout.Conclusions:We demonstrate EEG Delta band power differences in multiple cerebral regions indicating divergence in activities measure by spectral density which could be related to autistic trait differences and tendencies.

Electroencephalography Correlates of Well-Being Using a Low-Cost Wearable System.

Electroencephalography (EEG) alpha asymmetry is thought to reflect crucial brain processes underlying executive control, motivation, and affect. It has been widely used in psychopathology and, more recently, in novel neuromodulation studies. However, inconsistencies remain in the field due to the lack of consensus in methodological approaches employed and the recurrent use of small samples. Wearable technologies ease the collection of large and diversified EEG datasets that better reflect the general population, allow longitudinal monitoring of individuals, and facilitate real-world experience sampling. We tested the feasibility of using a low-cost wearable headset to collect a relatively large EEG database (N = 230, 22–80 years old, 64.3% female), and an open-source automatic method to preprocess it. We then examined associations between well-being levels and the alpha center of gravity (CoG) as well as trait EEG asymmetries, in the frontal and temporoparietal (TP) areas. Robust linear regression models did not reveal an association between well-being and alpha (8–13 Hz) asymmetry in the frontal regions, nor with the CoG. However, well-being was associated with alpha asymmetry in the TP areas (i.e., corresponding to relatively less left than right TP cortical activity as well-being levels increased). This effect was driven by oscillatory activity in lower alpha frequencies (8–10.5 Hz), reinforcing the importance of dissociating sub-components of the alpha band when investigating alpha asymmetries. Age was correlated with both well-being and alpha asymmetry scores, but gender was not. Finally, EEG asymmetries in the other frequency bands were not associated with well-being, supporting the specific role of alpha asymmetries with the brain mechanisms underlying well-being levels. Interpretations, limitations, and recommendations for future studies are discussed. This paper presents novel methodological, experimental, and theoretical findings that help advance human neurophysiological monitoring techniques using wearable neurotechnologies and increase the feasibility of their implementation into real-world applications.

EEG Frontal Asymmetry in Dysthymia, Major Depressive Disorder and Euthymic Bipolar Disorder

In the last few decades, the incidence of mood disorders skyrocketed worldwide and has brought an increasing human and economic burden. Depending on the main symptoms and their evolution across time, they can be classified in several clinical subgroups. A few psychobiological indices have been extensively investigated as promising markers of mood disorders. Among these, frontal asymmetry measured at rest with quantitative EEG has represented the main available marker in recent years. Only a few studies so far attempted to distinguish the features and differences among diagnostic types of mood disorders by using this index. The present study measured frontal EEG asymmetry during a 5-min resting state in three samples of patients with bipolar disorder in a Euthymic phase (EBD, n = 17), major depressive disorder (MDD, n = 25) and persistent depressive disorder (PDD, n = 21), once termed dysthymia. We aimed to test the hypothesis that MDD and PDD lack the typical leftward asymmetry exhibited by normal as well as EBD patients, and that PDD shows greater clinical and neurophysiological impairments than MDD. Clinical scales revealed no symptoms in EBD, and significant larger anxiety and depression scores in PDD than in MDD patients. Relative beta (i.e., beta/alpha ratio) EEG asymmetry was measured from lateral frontal sites and results revealed the typical greater left than right frontal beta activity in EBD, as well as a lack of asymmetry in both MDD and PDD. The last two groups also had lower bilateral frontal beta activity in comparison with the EBD group. Results concerning group differences were interpreted by taking into account both the clinical and the neurophysiological domains.

Fearful temperament in middle childhood predicts adolescent attention bias and anxiety symptoms: The moderating role of frontal EEG asymmetry.

The current study provided first analyses of the moderating effect of baseline-to-task frontal EEG asymmetry on the associations between 9-year fearful temperament and adolescent attention bias to threat as well as anxiety symptoms. Participants include a community sample of 122 children (60 boys, 62 girls; Mage = 14.66 years; Range = 11.82-18.13 years). Baseline-to-task frontal EEG asymmetry at age 9 moderated the relation between fearful temperament at age 9 and adolescent anxiety symptoms. Specifically, fearful temperament predicted adolescent anxiety symptoms when children showed greater right activation from baseline to an executive function task, but not greater left activation. Baseline-to-task frontal EEG asymmetry moderated the association between fearful temperament and sustained (i.e., stimulus onset asynchrony is 1250 ms) but not automatic attention bias (i.e., stimulus onset asynchrony is 500 ms). Children with greater left frontal activation from baseline to task more efficiently direct attention away from threat. Adolescent automatic attention bias to threat was related to concurrent anxiety symptoms. These findings illustrate the importance of considering frontal EEG asymmetry to shape how fearful children process threat and to influence their behavioral problems.

The Influence of Mental Imagery Expertise of Pen and Paper Players versus Computer Gamers upon Performance and Electrocortical Correlates in a Difficult Mental Rotation Task

We investigated the influence of mental imagery expertise in 15 pen and paper role-players as an expert group compared to the gender-matched control group of computer role-players in the difficult Vandenberg and Kuse mental rotation task. In this task, the participants have to decide which two of four rotated figures match the target figure. The dependent measures were performance speed and accuracy. In our exploratory investigation, we further examined midline frontal theta band activation, parietal alpha band activation, and parietal alpha band asymmetry in EEG as indicator for the chosen rotation strategy. Additionally, we explored the gender influence on performance and EEG activation, although a very small female sample section was given. The expected gender difference concerning performance accuracy was negated by expertise in pen and paper role-playing women, while the gender-specific difference in performance speed was preserved. Moreover, gender differences concerning electro-cortical measures revealed differences in rotation strategy, with women using top-down strategies compared to men, who were using top-down strategies and active inhibition of associative cortical areas. These strategy uses were further moderated by expertise, with higher expertise leading to more pronounced activation patters, especially during successful performance. However, due to the very limited sample size, the findings of this explorative study have to be interpreted cautiously.

Insomnia subtypes characterised by objective sleep duration and NREM spectral power and the effect of acute sleep restriction: an exploratory analysis

Insomnia disorder (ID) is a heterogeneous disorder with proposed subtypes based on objective sleep duration. We speculated that insomnia subtyping with additional power spectral analysis and measurement of response to acute sleep restriction may be informative in overall assessment of ID. To explore alternative classifications of ID subtypes, insomnia patients (n = 99) underwent two consecutive overnight sleep studies: (i) habitual sleep opportunity (polysomnography, PSG) and, (ii) two hours less sleep opportunity (electroencephalography, EEG), with the first night compared to healthy controls (n = 25). ID subtypes were derived from data-driven classification of PSG, EEG spectral power and interhemispheric EEG asymmetry index. Three insomnia subtypes with different sleep duration and NREM spectral power were identified. One subtype (n = 26) had shorter sleep duration and lower NREM delta power than healthy controls (short-sleep delta-deficient; SSDD), the second subtype (n = 51) had normal sleep duration but lower NREM delta power than healthy controls (normal-sleep delta-deficient; NSDD) and a third subtype showed (n = 22) no difference in sleep duration or delta power from healthy controls (normal neurophysiological sleep; NNS). Acute sleep restriction improved multiple objective sleep measures across all insomnia subtypes including increased delta power in SSDD and NSDD, and improvements in subjective sleep quality for SSDD (p = 0.03), with a trend observed for NSDD (p = 0.057). These exploratory results suggest evidence of novel neurophysiological insomnia subtypes that may inform sleep state misperception in ID and with further research, may provide pathways for personalised care.

Innovative Poincare's plot asymmetry descriptors for EEG emotion recognition.

Given the importance of emotion recognition in both medical and non-medical applications, designing an automatic system has captured the attention of several scholars. Currently, EEG-based emotion recognition has a special position, which has not fulfilled the desired accuracy rates yet. This experiment intended to provide novel EEG asymmetry measures to improve emotion recognition rates. Four emotional states have been classified using the k-nearest neighbor (kNN), support vector machine, and Naïve Bayes. Feature selection has been performed, and the role of employing a different number of top-ranked features on emotion recognition rates has been assessed. To validate the efficiency of the proposed scheme, two public databases, including the SJTU Emotion EEG Dataset-IV (SEED-IV) and a Database for Emotion Analysis using Physiological signals (DEAP) were evaluated. The experimental results indicated that kNN outperformed the other classifiers with a maximum accuracy of 95.49 and 98.63% using SEED-IV and DEAP datasets, respectively. In conclusion, the results of the proposed novel EEG-asymmetry measures make the framework a superior one compared to the state-of-art EEG emotion recognition approaches.

The relationship between habitual use and real-time emotion regulation strategies in adolescents: Evidence from frontal EEG asymmetry

Past research on emotion regulation has shown that cognitive reappraisal is a healthier and more effective emotion regulation strategy than expressive suppression. However, there are few studies in this field that combine real-time emotion regulation with the use of habitual emotion regulation strategies to observe the patterns of brain activity, and fewer studies focusing on adolescents. Frontal electroencephalography (EEG) asymmetry reflects the difference between brain activation in left and right frontal areas and is widely viewed as an effective biomarker of emotional reactivity and regulation. The present study investigated the asymmetry of the frontal EEG activity during adolescents' emotional regulation, and explored its relationship with adolescents’ habitual use of emotional regulation strategies. Habitual use of cognitive reappraisal and expressive suppression was measured with the emotion regulation questionnaire (ERQ). EEG was recorded from 54 adolescents (24 boys & 30 girls, Mage = 12.59), during the Reactivity and Regulation-Image Task. Results showed that adolescents who used cognitive reappraisal strategies more habitually exhibited greater left frontal asymmetry during real-time enhancement or reduction of negative emotions. In contrast, no significant correlation was found between habitual use of suppression and frontal alpha asymmetry. The results provide neurological evidence that, for adolescents, the use of habitual emotion regulation strategies may affect real-time emotion regulation, adolescents who use cognitive reappraisal more frequently are more capable or more prone to recruit appropriate brain regions in situations that need to regulate negative emotions. This reinforces the importance of the formation and use of correct emotion regulation habits for adolescents.

The Significance of LRDA With Bilateral Involvement Compared With GRDA on EEG in Critically Ill Patients.

Lateralized rhythmic delta activity (LRDA) is highly associated with seizures but generalized rhythmic delta activity (GRDA; symmetric by definition) has no known seizure association. A subset of LRDA includes patterns that are "bilateral asymmetric LRDA" (LRDA-ba), falling between purely unilateral LRDA and GRDA. The significance of this finding has not been previously addressed. Clinical, EEG, and imaging findings were reviewed in all patients with >6 hours of continuous EEG and LRDA-ba between 2014 and 2019. They were compared with a control group of patients with GRDA, matched 1:1 for prevalence, duration, and frequency of the predominant rhythmic pattern. Two hundred fifty-eight patients with LRDA-ba and 258 matched controls with GRDA were identified. Statistically significant findings included that patients with LRDA-ba were more likely to have presented with an ischemic stroke (LRDA-ba 12.4% vs. GRDA 3.9%) or subdural hemorrhage (8.9% vs. 4.3%); those with GRDA were more likely to have a metabolic encephalopathy (GRDA 10.5% vs. LRDA-ba 3.5%) or "altered mental state" without clear etiology (12.5% vs. 4.3%). Patients with LRDA-ba were significantly more likely to have a background EEG asymmetry (LRDA-ba 62.0% vs. GRDA 25.6%) or focal (arrhythmic) slowing (40.3% vs. 15.5%), and acute (65.5% vs. 46.1%) or focal (49.6% vs. 28.3%) abnormalities on computed tomography scan. Patients with LRDA-ba were more likely to have focal sporadic epileptiform discharges (95.4% vs. 37.9%), lateralized periodic discharges (32.2% vs. 5.0%), and focal electrographic seizures (33.3% vs. 11.2%); however, patients with LRDA-ba alone (i.e., without sporadic epileptiform discharges or PDs) showed only a trend toward increased seizures (17.3%) compared with a matched group of patients with GRDA alone (9.9%, P = 0.08). Patients with LRDA-ba had a higher proportion of acute focal abnormalities compared with a matched group of patients with GRDA. The LRDA-ba was associated with additional evidence of focal cortical excitability on EEG (sporadic epileptiform discharges and lateralized periodic discharges) and seizures but with only a trend toward increased seizures when other signs of focal excitability were absent.

Frontal EEG Asymmetry in Major Depression, Dysthymia and Bipolar Disorder

Depression is a mental disorder that continues to make life difficult or impossible for a depressed person and, if left untreated, can lead to dangerous activities such as self-harm and suicide. Nowadays, Electroencephalogram (EEG) has become an important diagnostic tool for many brain disorders. In this article, a new method for the detection of depression based on the reconstructed phase space (RPS) of EEG signals and geometrical features has been proposed. The RPS of the EEG signals of 22 normal and 22 depressed subjects are plotted in two-dimensional space and, based on their shape, 34 geometrical features are extracted. The p-values for the proposed features were significantly lower (p-value ≈ 0) indicating the capacity of the proposed geometric features for the normal and depression EEG signals classification tasks. For the purpose of reducing feature vector arrays, the performance of four optimization algorithms is checked, namely: ant colony optimization (ACO), grey wolf optimization (GWO), genetic algorithm (GA) and particle swarm optimization (PSO), in which GA with the ability of 58.8% was better than the other optimization algorithms for decreasing the feature vector arrays. Selected features are fed to the support vector machine (SVM) classifier with radial basis function (RBF) kernel and K-nearest neighbors (KNN) classifier with Euclidean and city block distances in 10-fold cross-validation (CV) strategy. The proposed framework achieved a fairly good average classification accuracy (ACC) of 99.30% and a Matthews correlation coefficient (MCC) of 0.98 using the selected features of the PSO algorithm and the SVM classifier. We found that the RPS of normal EEG signals has a more irregular, complex and unpredictable shape than the RPS of depression EEG signals which has more regular (simple) with less variation and more predictable shape; therefore, we can say that RPS of EEG signals can be used as a biomarker for psychiatrists which are simpler than the EEG signals in visual depression diagnostics. We also found that EEG signals from the right hemisphere are significant for depression detection than the left hemisphere. The proposed framework may be used in clinics and hospitals to detect depression disorder quickly and precisely.

Longitudinal investigation of shyness and physiological vulnerability: Moderating influences of attention biases to threat and safety.

Shyness has long been identified as a vulnerability factor to developing psychosocial problems, but there is heterogeneity in these observed outcomes. One potential factor underlying these relations is individual differences in threat sensitivity. Using a longitudinal design, we examined whether attentional biases toward social threat and safety measured during adulthood moderated the association between shyness measured in emerging adulthood (N = 83, nfemale = 48; Mage = 23.56 years, SDage = 1.09 years) and frontal electroencephalogram (EEG) asymmetry at rest, a physiological index of vulnerability to psychopathology, measured nearly a decade later in adulthood (Mage = 31.68 years, SDage = 2.27 years). We found that only biases to threat moderated the association between shyness and resting frontal EEG asymmetry longitudinally. In individuals who displayed relative vigilance to social threat, shyness was associated with greater relative right frontal EEG activity at rest (i.e., increased physiological vulnerability). These findings suggest that attentional biases to threat may play a role in understanding the relation between shyness and some known physiological vulnerabilities to psychopathology in adults.

Changes in Electric Brain Response to Affective Stimuli in the First Week of Antidepressant Treatment: An Exploratory Study

Introduction: Asymmetrical alpha and frontal theta activity have been discussed as neurobiological markers for antidepressant treatment response. While most studies focus on resting-state EEG, there is evidence that task-related activity assessed at multiple time points might be superior in detecting subtle early differences. Methods: This was a naturalistic study design assessing participants in a psychiatric in- and outpatient hospital setting. We investigated stimulus-related EEG asymmetry (frontal and occipital alpha-1 and alpha-2) and power (frontal midline theta) assessed at baseline and 1 week after initiation of pharmacological depression treatment while presenting affective stimuli. We then compared week 4 responders and nonresponders to antidepressant treatment. Results: Follow-up analyses of a significant group × emotion × time interaction (p < 0.04) for alpha-1 asymmetry showed that responders differed significantly at baseline in their asymmetry scores in response to sad compared to happy faces with a change in this pattern 1 week later. Nonresponders did not show this pattern. No significant results were found for alpha-2, occipital alpha-1, and occipital alpha-2 asymmetry or frontal midline theta power. Discussion: Our study addresses the gap in comparisons of task-related EEG activity changes measured at two time points and supports the potential value of this approach in detecting early differences in responders versus nonresponders to pharmacological treatment. Important limitations include the small sample size and the noncontrolled study design.

Elucidating Age and Sex-Dependent Association Between Frontal EEG Asymmetry and Depression: An Application of Multiple Imputation in Functional Regression

Frontal power asymmetry (FA), a measure of brain function derived from electroencephalography, is a potential biomarker for major depressive disorder (MDD). Though FA is functional in nature, it is typically reduced to a scalar value prior to analysis, possibly obscuring its relationship with MDD and leading to a number of studies that have provided contradictory results. To overcome this issue, we sought to fit a functional regression model to characterize the association between FA and MDD status, adjusting for age, sex, cognitive ability, and handedness using data from a large clinical study that included both MDD and healthy control (HC) subjects. Since nearly 40% of the observations are missing data on either FA or cognitive ability, we propose an extension of multiple imputation (MI) by chained equations that allows for the imputation of both scalar and functional data. We also propose an extension of Rubin’s Rules for conducting valid inference in this setting. The proposed methods are evaluated in a simulation and applied to our FA data. For our FA data, a pooled analysis from the imputed datasets yielded similar results to those of the complete case analysis. We found that, among young females, HCs tended to have higher FA over the θ, α, and β frequency bands, but that the difference between HC and MDD subjects diminishes and ultimately reverses with age. For males, HCs tended to have higher FA in the β frequency band, regardless of age. Young male HCs had higher FA in the θ and α bands, but this difference diminishes with increasing age in the α band and ultimately reverses with increasing age in the θ band. Supplementary materials for this article, including a standardized description of the materials available for reproducing the work, are available as an online supplement.

P-EG007. EEG power asymmetry as predictor of recovery in acute ischemic stroke patients

Introduction . After a stroke, optimal recovery of movement depends on the potential for neuroplasticity which allows surviving brain regions to reorganize into effective capable networks of supporting arm and hand function. There is evidence that reduced lateralized activation reflects the increased activity in the contralesional hemisphere, which reduces the extent of interhemispheric balance as demonstrated in many stroke studies. QEEG provides an objective measure of EEG asymmetry that correlates with clinical status and brain asymmetry seen on MRI. The objective of this study is to know whether EEG power asymmetry in the acute phase of stroke can predict stroke recovery after 90 days using the NIHSS score. Methods . All participants in this study underwent qEEG examination when they were in the acute phase of stroke. There are 4 power asymmetry (delta, theta, alpha, and beta) and ROC analysis are performed to determine the cut off of each band. On the 90th day after stroke onset, NIHSS examination was conducted. The statistical analysis was done by comparing the means of NIHSS score at 90 days in a group with and without asymmetry power of each band in qEEG. Results . Fifty-one subjects have accomplished this study. There are 16 participants with asymmetry and 35 participants without asymmetry result in alpha power. A significant result between alpha band power asymmetry 4+4,27 and symmetry 1,7+2,6 with 90th day of NIHSS (p=0,025) but there is no significant results in delta (p=0,066), theta (p=0,973), and beta asymmetry (p=0,323). Conclusion . Brain asymmetry quantitative EEG can describe the value of NIHSS day 90.