Clinical EEG and neuroscience最新文献

BackgroundAlzheimer's disease is a neurodegenerative condition characterized by the accumulation of misfolded proteins disrupting connectivity between brain regions. Electroencephalography provides optimal temporal resolution for assessing neuronal communication.ObjectiveTo detect and compare the localization of brain rhythms and the directional flow of oscillatory activity among default mode network nodes during the resting state in patients with amnestic mild cognitive impairment (aMCI) and healthy older adults (HOA).MethodsWe recruited 94 aMCI patients and 66 HOA. We conducted functional localization and connectivity analyses using scalp recordings of neuronal activity, estimated by eLORETA approach. We calculated the effective connectivity by applying the isolated effective coherence method, allowing the frequency decomposition of the directional flow of oscillatory activity between pairs of brain regions. Eight brain regions from the default mode network were selected.ResultsAlthough trends in spectral power were noted, no statistically significant differences were found between groups. Concerning iCOH analysis, both groups showed increased information flow from the posterior to the anterior nodes. Specifically, the precuneus was dominant in transmitting information to the anterior nodes of the DMN. Furthermore, aMCI patients had lower effective connectivity values than HOA.ConclusionsiCOH analysis effectively profiles default mode nodes during the resting state, adding information on both localization and directionality of information flow, as well as the involved EEG oscillations. Furthermore, it is well-suited to detect between-group connectivity differences, suggesting its usefulness as a biomarker in the prodromal clinical stage of AD.

IntroductionTranscranial direct current stimulation (tDCS) is investigated as an adjunct treatment in schizophrenia, but electroencephalographic (EEG) studies have produced inconsistent findings.ObjectiveTo review the literature and elucidate the effects of tDCS on EEG variables in schizophrenia. Method: This is a systematic scoping review according to PRISMA guidelines, consulting four databases: PubMed (MEDLINE), Cochrane Library, Web of Science and ScienceDirect. It was structured following PIO framework (Population, Intervention, Outcome): P: schizophrenia; I: tDCS; O: any EEG variable. For data synthesis, each time a variable was investigated, it was counted as an occurrence.ResultsA total of twenty-five papers were included, totaling forty-two occurrences: twenty-five were event-related potentials and seventeen were based on spectral/power, connectivity or coherence variables. Most papers applied 20 min of 2 mA stimulation (76%), in a bicephalic montage. The most investigated variable was the MMN, followed by N100, P300, EEG coherence, gamma activity, beta and alpha power. N100 was the variable that responded most to tDCS stimulation, with 80% response rate. Gamma activity had 67% response, MMN showed 60%, coherence, alpha and beta power 50%. All papers investigating P300 reported no significant results. Other EEG parameters were investigated only once.ConclusionEEG changes induced by tDCS in schizophrenia predominantly affected the sensory-auditory potential N100, had a lesser impact on pre-attentive potential MMN, and showed no observable effect on higher-order cognitive potentials, such as P300. The modulatory effects of tDCS on cognition are still unclear. This review was registered at the Open Science Framework (osf.io/7yzrj).

ObjectivesChildhood Occipital Visual Epilepsy (COVE) is a self-limited epileptic syndrome that typically begins in late childhood or adolescence characterized by brief visual seizures. The recent 2022 International League Against Epilepsy (ILAE) classification distinguishes COVE from photosensitive occipital lobe epilepsy (POLE), emphasizing the absence of photic-induced seizures in COVE. In this study, we aimed to describe the clinical and electrophysiological features of patients with COVE diagnosed according to the new ILAE criteria.MethodsThis retrospective cohort study analyzed 30 patients diagnosed with COVE at a tertiary epilepsy center between 1988 and 2023. Patients were selected based on ILAE 2022 criteria, and all cases with intermittent photic stimulation (IPS)-induced seizures were excluded.ResultsMost patients (93%) presented with elementary visual hallucinations, such as colorful lights. Orofacial seizures occurred in 7%, and 37% had nocturnal seizures. EEG abnormalities were primarily occipital and resolved in 85% of cases over time. Generalized spike-wave discharges (GSWDs) were rare (5%), and only one patient developed juvenile myoclonic epilepsy during follow-up. At final follow-up, 77% of patients achieved seizure freedom, and 47% discontinued medication.ConclusionCOVE is an epileptic syndrome associated with a favorable prognosis. By excluding photosensitivity in light of the newly proposed diagnostic criteria from the ILAE, future research should focus on a more homogenous group of COVE patients to enhance understanding of this syndrome. Accurate classification using updated ILAE criteria allows for clearer clinical delineation and more reliable outcome predictions.

IntroductionFacial emotion recognition is impaired in schizophrenia and contributes to profound social impairments. Healthy adults exhibit larger N170 amplitudes to emotional compared to neutral faces. Preliminary evidence suggests an inability to modulate N170 amplitude by emotional expression during chronic stages of the illness. The present investigation examined N170 modulation by emotion among patients with chronic (ChSz) and first hospitalized (FHSz) schizophrenia.MethodsEEG was recorded from 26 FHSz and 28 ChSz participants as well as 19 young (YC) and 21 older (OC) matched controls. Participants were asked to detect neutral faces among happy, angry, disgusted, fearful, and sad faces. N170 amplitudes were measured from P9/P10 electrodes. Symptoms were assessed using the Positive and Negative Syndrome Scale (PANSS).ResultsN170 amplitude modulation by facial emotion was observed across FHSz and YC (P < .001), though the typical right-hemisphere lateralization of this response observed in YC (P = .001) was absent in FHSz (P = .56). In contrast to OC (P = .009), ChSz did not exhibit N170 modulation by emotion (P = .32). Among ChSz, N170 modulation (mean N170 across emotional expressions minus N170 to neutral faces) at P9 were inversely correlated with PANSS negative scores (r = -.53).DiscussionResults suggests a progressive impairment of emotional facial expression processing as indexed by N170 modulation across illness stage. While losing the hemispheric specialization of face processing, FHSz exhibited preserved N170 amplitude modulation by facial emotion in contrast to ChSz. This deficit was also associated with negative symptoms, implicating progressive pathology of N170 generators in persistent and debilitating symptoms of the disorder.

P3a is an event-related potential that reflects the involuntary orienting of attention to salient stimuli. Abnormalities in P3a have been described in schizophrenia, but it is not known when they arise over the course of illness and whether they are progressive. Previous longitudinal studies of P3a have been inconclusive because of the heterogeneity in the diagnosis of psychotic patients, lack of follow-up data on controls, and relatively short follow-up periods. P3a, elicited by novel sounds, was assessed in 21 patients with first-episode schizophrenia and 36 healthy controls at baseline and reassessed in 14 patients and 23 controls after an average follow-up of six years. The longitudinal evaluation showed that the P3a amplitude was reduced in patients compared to controls at baseline but did not differ between groups at follow-up. Although P3a was reduced over the six-year interval in both groups, the reduction was greater in controls compared to patients. Longitudinal findings suggest that the P3a amplitude deficit is present at the onset of schizophrenia. Normalization of P3a amplitudes in patients at follow-up may reflect the premature aging effect on P3a at the onset of illness, a floor effect in P3a amplitudes of both groups at follow-up, or the reversal of the P3a deficit in patients over time. Interestingly, at baseline, the P3a amplitude in patients without follow-up data did not differ from controls and was greater than in patients with follow-up data. Baseline findings indicate a heterogeneity within the first-episode schizophrenia group.

ObjectiveThis cross-sectional study aimed to identify electrophysiological markers distinguishing stages of development, stability, and early aging in cortical auditory processing to elucidate neurophysiological changes in healthy auditory aging.MethodsWe evaluated 149 healthy participants (both sexes; aged 7-59 years) recruited from the general community via electronic media, posters, radio, and regional television, divided into six age groups (7-11, 12-17, 18-29, 30-39, 40-49, and 50-59 years). Eligibility criteria included normal hearing, no neurological disorders, and normal otoscopy. Cortical auditory evoked potentials (CAEPs) were recorded using the syllable /da/ (binaural stimulation, 70 dB HL) with eye-movement control.ResultsSignificant differences in P1 latency were observed between children (7-11 years) and older participants (12-59 years). N1 latency differed between children and adults (30-59 years), while N1 amplitude varied between adolescents (12-19 years) and adults aged 40-49 years. P1-N1 latency differed between adolescents and adults aged 40-59 years. Age correlated moderately negatively with P1/N1 latencies and weakly positively with N1 amplitude.ConclusionMaturational changes in P1/N1 latencies were evident, but no decline occurred during adulthood or pre-senescence, suggesting stable auditory processing until at least age 59.

IntroductionObsessive-compulsive disorder (OCD) affects 1.1-1.8% of the population, and adult females are more likely to suffer from it. Deep transcranial magnetic stimulation (dTMS) stimulates dorsomedial prefrontal cortex and anterior cingulate cortex - two frontal brain networks implicated in OCD. This study aims to identify a biological marker for beta rhythm that correlates with the treatment response works following dTMS.MethodsA total of 56 right-handed treatment-resistant OCD patients (35 female and 21 male) were retrospectively included in the study which were treated with FDA-approved dTMS protocol by using H7-coil for OCD. The Yale-Brown Obsessive Compulsive Scale (Y-BOCS) was used before and after dTMS to determine the severity of OCD symptoms and the responsiveness to therapy. Also, beta oscillations gathered from 19 electrodes quantitative electroencephalogram (QEEG) was assessed as treatment response prediction while controlling age and sex parameters.ResultsWhen controlling for sex and age, the Y-BOCS decline rate was linked to higher pretreatment beta activity in the parietal and occipital regions. In the second step of our analysis, we used a stepwise linear regression analysis to create a model predicting YBOCS decline rate. In this model, age (beta = -0.284, p = 0.030) and pretreatment beta parietal power band (beta = 0.312, p = 0.018) were the predictors.ConclusionAge and pretreatment parietal beta power bands may be used as a biomarker for predicting response to dTMS therapy if confirmed by further studies.

ObjectiveTo present a case of epileptic palinopsia successfully treated with lamotrigine and systematically review EEG findings, clinical features, and treatment outcomes of epileptic palinopsia.MethodsWe report a 58-year-old male with right occipital hemorrhage who developed seizures characterized by palinoptic phenomena four years post-injury. A systematic review of available cases was conducted using PRISMA guidelines and multiple databases (PubMed, Scopus, Embase, and Web of Science) through December 2024.ResultsThe patient's seizures included visual perseveration followed by bilateral tonic-clonic activity and achieved a >50% reduction in palinoptic phenomena with lamotrigine treatment over 20 months. Interictal EEG showed sharp and slow wave activity in the right temporal region, while MRI revealed right occipital encephalomalacia. The systematic review identified 40 cases from 34 articles (mean age 50.56 ± 16.10 years, 65.0% male). Interictal EEG abnormalities were present in 70.0% of cases, predominantly spikes/sharp waves (60.7%) localized to the right temporal and occipital regions. Ictal EEG recordings were available in 22.5% of cases. Both interictal (71.4%) and ictal (71.4%) findings demonstrated right-hemisphere predominance, particularly in the occipital region (30% of all cases, with 58.3% being right-sided). Structural abnormalities were identified in 26 cases, with tumors (42.3%) being the most common etiology. Anti-seizure drugs were prescribed in 57.5% of cases.ConclusionOur study highlights palinopsia as an overlooked seizure symptom with potential right hemispheric lateralization. Recognizing its EEG and neuroimaging patterns is essential for early diagnosis and treatment. Clinicians should maintain a high suspicion for epileptic palinopsia in patients with structural brain lesions involving temporo-occipital regions.

The term visual working memory (VWM) refers to the temporary storage of visual information. In electrophysiological recordings during the change detection task which relates to VWM, contralateral negative slow activity was detected. It was found to occur during the information is kept in memory and it was called contralateral delay activity. In this study, the characteristics of electroencephalogram frequencies of the contralateral and ipsilateral responses in the retention phase of VWM were evaluated by using time-frequency analysis (discrete wavelet transform [DWT]) in the change detection task. Twenty-six volunteers participated in the study. Event-related brain potentials (ERPs) were examined, and then a time-frequency analysis was performed. A statistically significant difference between contralateral and ipsilateral responses was found in the ERP. DWT showed a statistically significant difference between contralateral and ipsilateral responses in the delta and theta frequency bands range. When volunteers were grouped as either high or low VWM capacity the time-frequency analysis between these groups revealed that high memory capacity groups have a significantly higher negative coefficient in alpha and beta frequency bands. This study showed that during the retention phase delta and theta bands may relate to visual memory retention and alpha and beta bands may reflect individual memory capacity.