Effect of epilepsy, seizures and epileptiform EEG discharges on cognitive function

Patients with an established diagnosis of epilepsy were included in three groups on the basis of the absence (Group 2) or presence (Group 3) of epileptiform EEG discharges or subtle seizures (Group 4) during the cognitive assessment procedure. A separate age-matched non-epileptic control group (Group 1) was formed. Twenty-five patients were included in each of the four groups. Thus, a total of 100 patients were investigated. The patients were assessed with continuous 21-channel EEG and video-monitoring, combined with cognitive testing. The results show consistently lower performance on cognitive tests for Group 4, the group with subtle seizures. The difference with the control group was significant for the intelligence subtests and for the complex information processing test (p<0.05). No transient cognitive impairment was found. The results are discussed in the light of possible factors that may be responsible for the lower test-scores in the patients of Group 4: both the ictal effects of the seizures themselves, postictal effects and the effects of the epileptiform EEG discharges may have had an impact on cognitive performance. Finally the absence of evidence for transient cognitive impairment in a group with frequent epileptiform EEG discharges is discussed in detail.     

The cognitive effects of interictal epileptiform EEG discharges and short nonconvulsive epileptic seizures

Purpose: Educational difficulties or even severe cognitive deterioration is seen in many childhood epilepsy syndromes. Many of those cognitive deficits are related directly to the brain disorder underlying the epilepsy syndrome. However, in other types of epilepsy, the epileptic seizures and/or epileptiform activity can be the dominant factor. This is especially unknown for the more “subtle” short nonconvulsive seizure types. For this reason, we analyzed a new cohort of children. Methods: A cross‐sectional study of 188 children with epilepsy. Electroencephalography (EEG)–video recordings and cognitive testing were performed simultaneously. The results of children with short nonconvulsive seizures during a 2‐h testing session were compared with all children with epilepsy without seizures during the 2‐h cognitive testing session and with controls without epilepsy. In a second analysis the cognitive effects of frequency of epileptiform EEG discharges were analyzed. Key Findings: The cognitive effects of short nonconvulsive seizures were large, ranging from 0.5 to 1 standard deviation and concerned global cognitive function, speed of central information processing, and memory function. In children without seizures during cognitive testing, the occurrence of frequent epileptiform discharges showed more subtle effects. These effects were independent from the occurrence of short nonconvulsive seizures. Significance: We concluded that although the effect is less pronounced in number of areas involved and magnitude, the type of association between frequent epileptiform activity (>1% of the time) and cognitive function in children with epilepsy is comparable to the association between short nonconvulsive seizures and cognitive function.     

Nocturnal epileptiform EEG discharges, nocturnal epileptic seizures, and language impairments in children: review of the literature

This review addresses the effect on language function of nocturnal epileptiform EEG discharges and nocturnal epileptic seizures in children. In clinical practice, language impairment is frequently reported in association with nocturnal epileptiform activity. Vice versa, nocturnal epileptiform EEG abnormalities are a common finding in children with specific language impairment. We suggest a spectrum that is characterized by nocturnal epileptiform activity and language impairment ranging from specific language impairment to rolandic epilepsy, nocturnal frontal lobe epilepsy, electrical status epilepticus of sleep, and Landau-Kleffner syndrome. In this spectrum, children with specific language impairment have the best outcome, and children with electrical status epilepticus of sleep or Landau-Kleffner syndrome, the worst. The exact nature of this relationship and the factors causing this spectrum are unknown. We suggest that nocturnal epileptiform EEG discharges and nocturnal epileptic seizures during development will cause or contribute to diseased neuronal networks involving language. The diseased neuronal networks are less efficient compared with normal neuronal networks. This disorganization may cause language impairments.     

Risk for developing epilepsy and epileptiform discharges on EEG in patients with febrile seizures

Purpose: The aim of the present study was to investigate the correlation between epileptiform discharges on EEGs after febrile seizures and the prognosis of patients in terms of the development of epilepsy and recurrence of febrile seizures. This study also evaluated the characteristics of epileptiform discharges and EEG changes on follow-up examination. Methods: This study consisted of 36 children who presented to our hospital with febrile seizures and whose electroencephalograms (EEG) showed epileptiform discharges. The development of epilepsy and the recurrence of febrile seizures were compared between the study group (n = 36) and the control group (n = 87), which included children with febrile seizure but with normal EEG findings. Results: No significant correlation was detected between the recurrence rate of febrile seizures in patients with normal EEG (23 out of 87, 26.4%) findings and that of patients whose EEGs showed epileptiform discharges (12 out of 36, 33.3%) [adjusted OR 0.67 (0.26–1.68)]. However, 9 (25.0%) out of 36 patients with epileptiform discharges on EEG had epilepsy compared to 2 patients (2.3%) in the control group. The correlation was statistically significant [crude OR 10.88 (2.47–47.88) and adjusted OR 8.75 (1.49–51.6)]. Conclusion: Epileptiform discharges on the EEGs of patients with febrile seizures are important predictive risk factors of the development of epilepsy.     

临床下(癎)样放电对数学认知功能的影响

目的探讨临床下样放电对数学认知功能的影响。方法对11例经丙戊酸钠治疗后临床发作控制、但仍有频繁的临床下伴中央-颞区棘波的良性癫(BECTS)患儿(BECTS组)和11名正常儿童(正常对照组)进行以数学运算为刺激的事件相关电位(ERP)检测,并对检测结果进行比较分析。结果与正常对照组比较,BECTS组各导联P3潜伏期明显延长(均P<0.01),波幅明显降低(均P<0.05)。结论频繁的临床下癫样放电可能是造成BECTS儿童数学认知功能障碍的因素之一。     

1H-MR spectroscopy indicates severity markers in temporal lobe epilepsy: correlations between metabolic alterations, seizures, and epileptic discharges in EEG

PURPOSE: In this study, hippocampal metabolite alterations in (1)H-MR spectroscopy ((1)H-MRS) were correlated to the findings of intensive video-EEG monitoring and duration of seizure symptoms in patients with temporal lobe epilepsy (TLE). METHODS: The 14 patients with mesial TLE and no pathological findings in imaging were investigated by (1)H-MRS. Seizures were analyzed by: number of clinical seizures in 24 h, exact duration of clinical symptoms in 24 h, frequency of interictal epileptiform discharges (IEDs) and ictal activity, duration of ictal activity, and IEDs occurring within 24 h in intensive EEG monitoring. Pearson Correlation Coefficient (PCC) was calculated between spectral metabolite alterations and the parameters mentioned above. RESULTS: In the analysis, a negative correlation was found between total (t) NAA values and degree of IEDs in EEG (p = 0.04); a positive correlation was found between Cr levels and duration of seizure symptoms registered by video monitoring (p = 0.01). CONCLUSIONS: Our study shows that, in some patients, (1)H-MRS is able to refer the severity of TLE. The degree of tNAA reduction in (1)H-MRS, probably indicating neuronal dysfunction, is associated with interictal spiking in intensive EEG monitoring. Duration of seizure symptoms associated with increased Cr peaks probably reflects increased gliosis.     

Left-sided interictal epileptic activity induces shift of language lateralization in temporal lobe epilepsy: an fMRI study

PURPOSE: By using speech-activated functional MRI (fMRI), we investigated whether the frequency of left-sided interictal epileptic activity (IED: spikes or sharp waves on the EEG) is associated with atypical speech lateralization. METHODS: We investigated 28 patients (13 men, aged 17-59 years) with left-sided mesial temporal lobe epilepsy (MTLE) and 11 patients with right-sided MTLE as a control population. Only patients with unilateral hippocampal sclerosis with unilateral IED were included. For fMRI of individual patients, we contrasted images sampled during covert word generation with a low-level rest condition. With SPM99, an individual comparison for the contrast "word generation versus resting inactivity" was conducted. To characterize speech lateralization in individual patients, we calculated asymmetry indexes (AIs): the difference between activated left-sided and right-sided voxels was divided by all activated voxels. Analyzing long-term EEG, the first 2 min of each hour were evaluated for the frequency of IED. Univariate associations with AIs were assessed by Pearson's correlation and by t test. When testing the independent associations, multivariate linear regression was performed. RESULTS: The AIs in patients with left-sided MTLE were 0.40 +/- 0.53 on average (range, -0.83 to +1.0), whereas in right-sided MTLE, they were 0.78 +/- 0.15 (p = 0.029). For the further investigations, we included left-sided MTLE patients only. The median frequency of IED was six per hour (range, 0-240). Higher IED frequency was correlated with left-right shift of lateralization of speech fMRI activity (p = 0.002). CONCLUSIONS: Higher left-sided spike frequency in MTLE was associated with a left-right shift of speech representation, suggesting that chronic frequent interictal activity may induce a reorganization of speech lateralization.     

Significance of the EEG in the decision to initiate antiepileptic treatment in patients with epilepsy: A perspective on recent evidence

The significance of electroencephalography in the prediction of seizure recurrence after a first unprovoked seizure remains a topic of debate. Opinion on the initiation of antiepileptic treatment after a first seizure also remains divided. However, in view of recent evidence, this article is intended to highlight the significance of a properly performed EEG in the decision to initiate antiepileptic drug treatment as early as possible to prevent further morbidity and other consequences.     

The influence of the abundance and morphology of epileptiform discharges on diagnostic accuracy: How many spikes you need to spot in an EEG

ObjectiveThe operational definition of interictal epileptiform discharges (IEDs) of the International Federation of Clinical Neurophysiology (IFCN) described six morphological criteria. Our objective was to assess the impact of pattern-repetition in the EEG-recording, on the diagnostic accuracy of using the IFCN criteria. For clinical implementation, specificity over 95% was set as target.MethodsInterictal EEG-recordings of 20-minutes, containing sharp-transients, from 60 patients (30 with epilepsy and 30 with non-epileptic paroxysmal events) were evaluated by three experts, who first marked IEDs solely based on expert opinion, and then, independently from the first session evaluated the presence of the IFCN criteria for each sharp-transient. The gold standard was derived from long-term video-EEG recordings of the patientś habitual paroxysmal episodes.ResultsPresence of at least one discharge fulfilling five criteria provided a specificity of 100% (sensitivity: 70%). For discharges fulfilling fewer criteria, a higher number of discharges was needed to keep the specificity over 95% (5 discharges, when only 3 criteria were fulfilled). A sequential combination of these sets of criteria and thresholds provided a specificity of 97% and sensitivity of 80%.ConclusionsPattern-repetition and IED morphology influence diagnostic accuracy.SignificanceSystematic application of these criteria will improve quality of clinical EEG interpretation.     

Benign epileptiform discharges in Rolandic region with mesial temporal lobe epilepsy: MEG, scalp and intracranial EEG features

AIM OF THE STUDY: To report benign epileptiform discharges (BEDs) in the Rolandic region, coexisting in a pediatric patient with intractable localization-related epilepsy, secondary to hippocampal sclerosis. METHODS: We describe the clinical features, MRI, scalp video EEG, magnetoencephalography (MEG) and intracranial video EEG findings, and surgical outcome in a 9-year-old boy with BEDs and intractable complex partial seizures. RESULTS: MRI showed left hippocampal sclerosis. Scalp video EEG interictally demonstrated left temporal spike and sharply contoured slow waves, and right fronto-centro-temporal spike and waves. Ictal scalp video EEG showed left temporal rhythmic sharp waves after the clinical onset of epigastric aura, followed by staring. MEG showed interictal dipoles in the bilateral Rolandic regions with a uniform orientation and right hemispheric predominance. Intracranial video EEG, with bilateral mesial temporal depth and fronto-temporo-parietal strip electrodes, interictally showed polyspikes and slow waves with superimposed low-amplitude fast waves in the left mesial and posterior lateral temporal regions, and spike and waves in the bilateral fronto-parietal regions. Ictal onset was marked by low-amplitude fast waves in the left mesial and posterior lateral temporal regions. He underwent left anterior temporal lobectomy with hippocampectomy. Pathology was hippocampal sclerosis. Predominant right fronto-centro-temporal spike and waves and MEG right Rolandic dipoles persisted after surgery. He was seizure-free 14 months after surgery. CONCLUSION: This is the first report on MEG and intracranial video EEG features of BEDs in the Rolandic region, coexisting with hippocampal sclerosis. Persistence of contralateral benign MEG Rolandic dipoles after surgery indicates that BEDs are coincidental in mesial temporal lobe epilepsy. MEG identified Rolandic dipoles, although was unable to localize the deep and focal epileptogenic dipoles from the hippocampal sclerosis.     

Relative influence of epileptic seizures and of epilepsy syndrome on cognitive function

Cognitive impairment is frequently observed in children with epilepsy. We aimed at addressing to what extent cognitive function is affected by paroxysmal epileptiform activity with or without clinical seizures or by clinical features characteristic of the epilepsy syndrome. To this purpose, combined electroencephalographic (EEG) recording and cognitive testing (IQ and reaction times) were performed in 28 children. Frequent epileptiform EEG discharges significantly reduced reaction time, as did the occurrence of seizures during cognitive testing. Syndrome-related factors tended to affect cognitive functions as well: children with generalized epilepsy and high average seizure frequency obtained lower scores. Linear regression analysis showed that stable aspects of cognitive function, as reflected in intelligence level, are most closely related to the severity of the epilepsy syndrome (average seizure frequency), whereas transient aspects of cognitive function, such as reaction times, are related to the occurrence of epileptiform EEG discharges. This suggests that seizures have a direct effect on transient cognitive aspects, which can accumulate and result in effects on intelligence level.     

The cognitive impact of epileptiform EEG discharges and short epileptic seizures: Relationship to characteristics of the cognitive tasks

ObjectiveWe analyzed the effect of task dimensions (information processing demand; duration of the test; input modality) on the occurrence and cognitive impact of epileptiform EEG discharges (EEDs) or subtle epileptic seizures.MethodsOne hundred ninety-nine children, aged 6–17 years, were included consecutively in a prospective standardized study. All children were assessed with EEG, which was synchronized with a computerized cognitive FePsy test system.ResultsNo association was found between the occurrence of EEDs or subtle epileptic seizures and the three task dimensions introduced in our study. The Computerized Visual Searching Task (CVST) appeared to be particularly sensitive to direct cognitive effects of EEDs. The CVST and the three memory tests—Corsi’s Block Tapping and recognition of words/figures—were sensitive to the cognitive effects of subtle epileptic seizures.ConclusionOur results do not indicate a distinctive effect of information processing demand, duration of the test, or input modality on the occurrence of EEDs or subtle epileptic seizures. Effects on the impact on cognition are found when these three factors are combined.     

颞叶癫痫患者认知功能及其影响因素的研究

目的观察颞叶癫痫患者的认知功能状况,并进一步探讨社会人口学、临床发作、癫痫样放电等因素对患者认知功能的影响。方法对129例颞叶癫痫患者和90名健康对照者进行韦氏成人智力量表中国修订本(WAIS-RC)和临床记忆量表测定。结果颞叶癫痫患者总智商(full intelligence quotient,FIQ)、言语智商(verbal intelligence quotient,VIQ)、操作智商(performance intelligence quotient,PIQ)及记忆商(memory quotient,MQ)均明显低于健康对照者(P<0.001)。癫痫患者文化程度越高,其IQ及MQ越高(P<0.01);癫痫患者发作越频繁,其IQ及MQ越低(P<0.01);癫痫患者癫痫样放电越明显,其IQ及MQ越低(P<0.01)。多元逐步回归分析显示,影响患者FIQ和MQ的因素依次为发作频率和脑电图癫痫样放电。结论颞叶癫痫患者存在不同程度的认知功能障碍。关注颞叶癫痫患者的认知功能以及合理选择治疗方法、尽快控制癫痫发作是避免和减少患者认知功能损害的重要前提。     

睡眠中癎样放电对睡眠的影响

目的：观察不同睡眠时相中?样放电的情况,以及对不同发作类型患者生活品质（QOL ）的评价,探讨?样放电对癫?患者睡眠的影响以及睡眠对其Q O L的影响。方法：对132例癫?患者进行24 h录像脑电图（V‐EEG）及多项睡眠监测（PSG）检查,检测?样放电及分析睡眠结构。运用癫?患者生活质量量表‐31（QOLIE‐31）对不同发作类型患者进行QOL评估。结果：在全部132例患者中,非?性异常为32例（25．8％）,出现?样放电为52例（40．9％）,觉醒期及睡眠期?样放电检出率比较差异有显著意义（P＜0．05）。?样放电组和对照组相比NREM Ⅰ－Ⅱ期明显延长[分别为65．93（±9．1）％和58．67（±5．7）％],NREM Ⅲ期明显缩短[分别为17．78（±5．2）％和26．06（±8．2）％],差异均有统计学意义（P ＜0．05）;睡眠参数中?样放电组REM潜伏期明显延长,同时觉醒次数也增多。而非?性异常组REM 潜伏期、觉醒次数与正常对照组相比均有增加,但差异无统计学意义。不同发作类型睡眠结构差异无统计学意义。各种发作类型的患者各 QOL 指标均低于正常人群,差异有统计学意义（ P＜0．01）;全面性发作患者除药物影响外各指标均低于其他发作类型患者,差异有统计学意义;不同发作类型患者受到药物的影响无明显差异。结论：联合应用 V‐EEG及PSG可以更好地发现睡眠中?样放电,从而有助于确诊临床工作中难以发现的癫?。分析?样放电与睡眠时相之间的关系,以便指导临床癫?治疗,更好地控制癫?发作,改善患者QOL。     

EEG features of absence seizures in idiopathic generalized epilepsy: Impact of syndrome, age, and state

Purpose:   Factors influencing the electroencephalography (EEG) features of absence seizures in newly presenting children with idiopathic generalized epilepsy (IGE) have not been rigorously studied. We examined how specific factors such as state, provocation, age, and epilepsy syndrome affect the EEG features of absence seizures.
Methods:   Children with untreated absence seizures were studied using video-EEG recording. The influence of state of arousal, provocation (hyperventilation, photic stimulation), age, and epilepsy syndrome on specific EEG features was analyzed.
Results:   Five hundred nine seizures were evaluated in 70 children with the following syndromes: childhood absence epilepsy (CAE) 37, CAE+ photoparoxysmal response (PPR) 10, juvenile absence epilepsy (JAE) 8, juvenile myoclonic epilepsy (JME) 6, and unclassified 9. Polyspikes occurred in all syndromes but were more common in JME. They were brought out by drowsiness and sleep in fragments of generalized spike and wave (GSW). Polyspikes were more likely to occur during photic stimulation, but were not influenced by age independently. GSW was more likely to be disorganized in JME than JAE, and in JAE than CAE. Increasing age and levels of arousal were more likely to result in organized GSW. Factors specific to each child independently influenced EEG features; the nature of these factors has not been identified.
Discussion:   The EEG features of absence seizures are influenced by a complex interaction of age, epilepsy syndrome, level of arousal, provoking factors, and other intrinsic factors. Epilepsy syndrome alone cannot predict specific features of GSW; however, JME is more frequently associated with polyspikes and disorganization of the paroxysm.     

Effects of spontaneous recurrent seizures on cognitive function via modulation of SNAREs expression

Purpose: To explore whether soluble N-ethylmaleimide-sensitive factor attachment protein receptors (SNARE) complexes are involved in cognitive dysfunction induced by spontaneous recurrent seizures (SRS). Materials and methods: An animal model of epilepsy was established by intraperitoneal injection of kainic acid (KA). Following the onset of SRS, the rats were divided into control group, KA-SRS group, KA+SRS group and KA+SRS+VAP group. Morris water maze and open field test were conducted to evaluate the cognitive function. Protein and mRNA levels of SNAREs complex were measured by Western-blot and RT-PCR, respectively. Besides, the Ca²⁺ concentration in the hippocampus was also detected. Results: A delayed escape latency and a reduced number of platform crossings were found in the KA+SRS group. Meanwhile, a longer moving distance and time spent in central area were also observed during the open field test. Besides, the Ca²⁺ concentration in the hippocampus of the KA+SRS group was markedly increased. However, when compared with the KA+SRS group, all indices in the KA+SRS+VAP group were markedly improved. Moreover, the SNARE complexes in the hippocampus of the KA+SRS group were significantly increased when compared with both control group and KA+SRS+VAP group. Conclusions: Results of our study demonstrated that the cognitive dysfunction caused by SRS may be attributed to the modulation expression of SNARE complexes.     

托吡酯对癫痫大鼠认知功能及海马组织中NCAM的mRNA表达影响

目的研究托吡酯（TPM）对癫痫大鼠认知功能的影响以及使用TPM后大鼠海马组织中神经细胞粘附分子（NCAM）的mRNA表达变化。方法将大鼠随机分成生理盐水（NS）组、癫痫（EP）组、癫痫＋托吡酯治疗1周（TPM1周）组和癫痫＋托吡酯治疗4周（TPM4周）组,建立匹罗卡品诱导癫痫大鼠模型和TPM干预模型,观察大鼠的行为学改变,通过Morris水迷宫实验测试大鼠的学习记忆能力,并通过Real—TimePCR检测大鼠海马组织中NCAM的mRNA表达水平。结果EP组大鼠的逃避潜伏期大于NS组,原平台象限游泳时间百分比小于NS组,海马NCAM的mRNA表达水平高于NS组（P〈0．01）;TPM1周组和TPM4周组大鼠的逃避潜伏期大于EP组,原平台象限游泳时间百分比小于EP组,海马NCAM的mRNA表达水平低于EP组（P〈0.01）;TPM4周组大鼠的逃避潜伏期大于TPM1周组,原平台象限游泳时间百分比小于TPM1周组,海马NCAM的mRNA表达水平低于TPMI周组（P〈0.05）。结论大鼠产生癫痫持续状态后认知功能明显下降,海马NCAM的mRNA表达上调;使用大剂量TPM短期治疗后其认知功能进一步下降,海马NCAM的mRNA表达受抑,且下降与受抑程度与TPM的持续使用时间有关。     

The influence of sulthiame on EEG in children with benign childhood epilepsy with centrotemporal spikes (BECTS)

PURPOSE: To evaluate the effects of sulthiame (Ospolot; STM) monotherapy compared with placebo on the EEG in children with benign childhood epilepsy with centrotemporal spikes (BECTS). METHODS: Sixty-six patients (aged 3-11 years) entered a 6-month double-blind trial and were randomized to either STM (n = 31) or placebo (n = 35). Clinical data and general results have been reported elsewhere (1). One-hundred seventy-nine sleep EEGs were recorded at screening and after 4 weeks, 3 months, and 6 months. EEGs were analyzed by a blind reviewer using a standard protocol for each EEG. This standard protocol collected data on general changes, specific epileptiform, and nonspecific focal and generalized changes. A classification system was defined depending on rating of pathologic EEG changes. Because of the higher number of treatment-failure events (i.e., seizures) in the placebo group, there was an increasing imbalance between the two groups regarding the number of recorded sleep EEGs over time (STM, 104; placebo, 74). A Wilcoxon-Mann-Whitney U test was used to describe differences in the grade of pathology during individual follow-up between the two groups. RESULTS: The sleep-EEG was found to be normalized in 21 patients treated with STM (12/21 transient) and in five patients treated with placebo (4/5 transient). In the STM group, the EEG showed a marked improvement during intraindividual course when comparing the classification of follow-up EEGs at each time point with the screening EEG. Comparable improvements were not observed in the placebo group (exact two-tailed p value at 4 weeks, p < 0.0001; at 3 months, p = 0.0010; and at 6 months, p < 0.0001). CONCLUSIONS: STM had marked effects on the EEG in BECTS, which led to normalization in the majority of the patients. Most of those whose EEGs were not normalized showed improvement in the grade of EEG pathology. Normalization persisted in >50% of patients during the investigation. Spontaneous normalization in the placebo group reflects the wide spectrum of individual courses, which must be considered when analyzing drug effects on EEG in BECTS.     

The effect of Perampanel on EEG spectral power and connectivity in patients with focal epilepsy

ObjectiveQuantitative Encephalography (qEEG) depicts synthetically the features of EEG signal and represents a promising tool in the assessment of neurophysiological changes brought about by Anti-Seizure Medications (ASMs). In this study we characterized qEEG alterations related to add-on therapy with Perampanel (PER). PER is the only ASM presenting a direct glutamatergic antagonism, hence the characterization of PER induced EEG changes could help to better understand its large spectrum of efficacy.MethodsWe analysed standard-19 channel-EEG from 25 People with Epilepsy (PwE) both before (T0) and after (T1) the introduction of PER as add-on treatment. Normal values were obtained in 30 healthy controls (HC) matched for sex and age. EEGs were analysed using Matlab™ and the EEGlab and Brainstorm toolkits. We extracted spectral power and connectivity (Phase locking Value) of EEG signal and then compared these features between T0 and T1 and across groups (PwE, HC), we also evaluated the correlations with clinical features.ResultsPwE showed increased theta power (p = 0.036) after the introduction of PER but no significant change of EEG connectivity. We also found that PwE have reduced beta power (p = 0.012) and increased connectivity in delta (p = 0.013) and theta (p = 0.007) range as compared to HC, but no significant change was observed between T0 and T1 in PwE. Finally, we found that PwE classified as drug responders to PER have greater alpha power both at T0 and at T1 (p = 0.024) suggesting that this parameter may predict response to treatment.ConclusionsPER causes slight increase of theta activity and does not alter connectivity as assessed by standard EEG. Moreover, greater alpha power could be a good marker of response to PER therapy, and potentially ASM therapy in general.SignificanceOur results corroborate the hypothesis that pharmaco-EEG is a viable tool to study neurophysiological changes induced by ASM. Additionally, our work highlights the role of alpha power as a marker of ASM therapeutic response.