Clin EEG Neurosci [journal]
- Abnormal Somatosensory Synchronization in Patients With Paroxysmal Kinesigenic Dyskinesia: A Magnetoencephalographic Study. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Aug 11.
Paroxysmal kinesigenic dyskinesia (PKD) is a rare group of hyperkinetic movement disorders characterized by brief attacks of choreoathetosis or dystonia. To clarify the alterations of the functional connectivity within the somatosensory network in PKD patients, magnetoencephalographic (MEG) responses to paired median-nerve electrical stimulation were recorded in 10 PKD patients treated by carbamazepine or oxcarbamazepine and 22 age-matched controls. In patients, MEG recordings were obtained during drug-on and -off periods. Source-based functional connectivity analysis was performed between contralateral primary (cSI) and secondary (cSII), and ipsilateral secondary (iSII) somatosensory areas. During drug-off periods, patients with PKD demonstrated decreased cSI-iSII and increased cSII-iSII somatosensory connectivity at theta band. Drug-on periods lowered the functional connectivity in cSI-cSII at alpha and beta bands and in cSII-iSII at theta band compared with the drug-off periods. We suggest that altered theta functional connectivity in cSI-iSII and cSII-iSII could be the neurophysiological signatures in PKD.
- Cerebrospinal Fluid Biomarkers of Alzheimer's Disease Correlate With Electroencephalography Parameters Assessed by Exact Low-Resolution Electromagnetic Tomography (eLORETA). [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Aug 11.
Recently, cerebrospinal fluid (CSF) biomarkers related to Alzheimer's disease (AD) have garnered a lot of clinical attention. To explore neurophysiological traits of AD and parameters for its clinical diagnosis, we examined the association between CSF biomarkers and electroencephalography (EEG) parameters in 14 probable AD patients. Using exact low-resolution electromagnetic tomography (eLORETA), artifact-free 40-sesond EEG data were estimated with current source density (CSD) and lagged phase synchronization (LPS) as the EEG parameters. Correlations between CSF biomarkers and the EEG parameters were assessed. Patients with AD showed significant negative correlation between CSF beta-amyloid (Aβ)-42 concentration and the logarithms of CSD over the right temporal area in the theta band. Total tau concentration was negatively correlated with the LPS between the left frontal eye field and the right auditory area in the alpha-2 band in patients with AD. Our study results suggest that AD biomarkers, in particular CSF Aβ42 and total tau concentrations are associated with the EEG parameters CSD and LPS, respectively. Our results could yield more insights into the complicated pathology of AD.
- Contribution of Quantitative EEG to the Diagnosis of Early Cognitive Impairment in Patients With Idiopathic Parkinson's Disease. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Aug 3.
Cognitive dysfunction can emerge during the clinical course of Parkinson's disease (PD) even beginning in early stages, which requires extended neuropsychological tests for diagnosis. There is need for rapid, feasible, and practical tests in clinical practice to diagnose and monitor the patients without causing any discomfort. We investigated the utility of quantitative analysis of digital EEG (qEEG) for diagnosing subtle cognitive impairment in PD patients without evident cognitive deficits (ie, "normal cognition"). We enrolled 45 patients with PD and age- matched 39 healthy controls in the study. All participants had Mini-Mental State Examination (MMSE) score greater than 25. qEEG analysis and extensive neuropsychological assessment battery were applied to all participants. Test scores for frontal executive functions, verbal memory processes, attention span, and visuospatial functions were significantly lower than healthy controls (P < .01). qEEG analysis revealed a significant increase in delta, theta, and beta frequencies, and decrease in alpha frequency band in cerebral bioelectrical activity in patient group. In addition, power spectral ratios ([alpha + beta] / [delta + theta]) in frontal, central, temporal, parietal, and occipital regions were significantly decreased in patients compared with the controls. The slowing in EEG was moderately correlated with MMSE scores (r = 0.411-0.593; P < .01). However, qEEG analysis and extensive neuropsychological assessment battery were only in weak correlation (r = 0.230-0.486; P < .05). In conclusion, qEEG analysis could increase the diagnostic power in detecting subtle cognitive impairment in PD patients without evident cognitive deficit, perhaps years before the clinical onset of dementia.
- Electrophysiological Study on Cognitive Function in Systemic Lupus Erythematosus Patients With Previous Neuropsychiatric Involvement. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Jul 27.
This study aimed to evaluate P300 as an electrophysiological marker of cognitive function in patients with systemic lupus erythematosus (SLE) who had previous neuropsychiatric (NPSLE) involvement and were diagnosed to have cognitive impairment by standard neuropsychological tests. Event-related potentials (ERPs) were assessed by the auditory and visual oddball paradigms. Amplitude and latency of P300 at the frontal (Fz), central (Cz), and parietal (Pz) regions were determined and compared with controls. P300 detection was performed in NPSLE patients with pre-diagnosed cognitive impairment (n = 9), matched SLE patients without previous NPSLE (non-NPSLE) (n = 9), and healthy controls (n = 15). Auditory oddball task did not show any P300 abnormality between groups. Visual oddball task revealed reduced amplitude of P300 over Fz (P = .002) and Cz (P = .009) electrodes in NPSLE patients compared with healthy controls and among those who had predominant memory deficit (P = .01 at Fz). Abnormal P300 was also observed in non-NPSLE patients at Fz and Cz. Using visual oddball paradigm, abnormal P300 was found in NPSLE patients over frontal and parietal regions compared with normal controls but was not discriminative from possible subclinical disease in non-NPSLE patients. In conclusion, visual oddball paradigm was a more sensitive electrophysiological marker than auditory oddball paradigm for cognitive impairment in NPSLE patients.
- Quantitative EEG Neurometric Analysis-Guided Neurofeedback Treatment in Postconcussion Syndrome (PCS): Forty Cases. How Is Neurometric Analysis Important for the Treatment of PCS and as a Biomarker? [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Jun 27.
Postconcussion syndrome (PCS) has been used to describe a range of residual symptoms that persist 12 months or more after the injury, often despite a lack of evidence of brain abnormalities on magnetic resonance imaging and computed tomography scans. In this clinical case series, the efficacy of quantitative EEG-guided neurofeedback in 40 subjects diagnosed with PCS was investigated. Overall improvement was seen in all the primary (Symptom Assessment-45 Questionnaire, Clinical Global Impressions Scale, Hamilton Depression Scale) and secondary measures (Minnesota Multiphasic Personality Inventory, Test of Variables for Attention). The Neuroguide Traumatic Brain Index for the group also showed a decrease. Thirty-nine subjects were followed up long term with an average follow-up length of 3.1 years (CI = 2.7-3.3). All but 2 subjects were stable and were off medication. Overall neurofeedback treatment was shown to be effective in this group of subjects studied.
- Correlation Between Bispectral Index and Electrocorticographic Features During Epilepsy Surgery. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Jun 20.
Surgical resection guided by intraoperative electrocorticography (iECoG) has been in clinical use for many decades. The use of the bispectral index (BIS) for monitoring depth of anesthesia during different types of surgery, including epilepsy surgery, is increasing nowadays. The BIS is an EEG-derived variable indicating cortical electrical activity. However, the correlation between the BIS score and the iECoG score, with the purpose of optimizing the quality and time of the iECoG recordings in epilepsy surgery is unknown. The goal of this study was to evaluate the correlation between BIS values and iECoG parameters during the epilepsy surgery under anesthesia with propofol and fentanyl. This is a prospective study that included patients with epilepsy who underwent epilepsy surgery guided by BIS and iECoG (September 2008 to October 2013). Clinical, physiological, and sociodemographic characteristics are shown. We correlated the iECoG parameters (presence of burst suppressions [BS], suppression time [seconds], background frequency [Hz], and type of iECoG score by Mathern et al) with BIS values. We included 28 patients, 15/28 (53.5%) female, general mean age of 30.5 years (range 13-56 years). Patients underwent epilepsy surgery: 22/28 (79%) temporal and 6/28 (21%) extratemporal. We found a nonlinear polynomial cubic relationship between the mentioned variables noting that a BIS range of 40 to 60 gave the following results: iECoG BS periods <5 seconds, background frequency 10 to 17 Hz, and iECoG score 2 characterized by lack of >20-Hz background frequencies. No BS were observed with a BIS > 60. In conclusion BIS values and iECoG parameters during the epilepsy surgery under anesthesia with propofol and fentanyl have a nonlinear correlation. BS patterns were not found with a BIS > 60. These findings show that BIS is a nonlinear multidimensional measure, which possesses high variability with the iECoG parameters. BS patterns are not found with BIS > 60.
- Slow Activity in Focal Epilepsy During Sleep and Wakefulness. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Jun 10.
Introduction We aimed to test differences between healthy subjects and patients with respect to slow wave activity during wakefulness and sleep. Methods Fifteen patients affected by nonlesional focal epilepsy originating within temporal areas and fourteen matched controls underwent a 24-hour EEG recording. We studied the EEG power spectral density during wakefulness and sleep in delta (1-4 Hz), theta (5-7 Hz), alpha (8-11 Hz), sigma (12-15 Hz), and beta (16-20 Hz) bands. Results During sleep, patients with focal epilepsy showed higher power from delta to beta frequency bands compared with controls. The effect was widespread for alpha band and above, while localized over the affected hemisphere for delta (sleep cycle 1, P = .006; sleep cycle 2, P = .008; sleep cycle 3, P = .017). The analysis of interhemispheric differences showed that the only frequency band stronger over the affected regions was the delta band during the first 2 sleep cycles (sleep cycle 1, P = .014; sleep cycle 2, P = .002). During wakefulness, patients showed higher delta/theta activity over the affected regions compared with controls. Conclusions Patients with focal epilepsy showed a pattern of power increases characterized by a selective slow wave activity enhancement over the epileptic regions during daytime and sleep. This phenomenon was stronger and asymmetric during the first sleep cycles.
- How Different Are the Patients With Bilateral Hippocampal Sclerosis From the Unilateral Ones Clinically? [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Jun 10.
Purpose There is a lack of knowledge on consecutive patients with epilepsy associated with bilateral hippocampal sclerosis (BHS). We aimed to investigate the differentiating features of BHS in comparison with unilateral HS (UHS). Method We investigated our database for patients with epilepsy fulfilling the major magnetic resonance imaging criteria for BHS; namely, presence of bilateral atrophy and high signal changes on T2 and FLAIR series in the hippocampi. UHS patients seen in past 2 years were included as the control group. Clinical, EEG, and other laboratory findings, data on treatment response and epilepsy surgery were investigated from their files. Results A total of 124 patients (31 with BHS and 93 with UHS; 49 right-sided and 44 left-sided) were included. We found that 16.1% of the BHS and 18.3% of the UHS groups were not drug-refractory. A binary logistic regression analysis performed with significant clinical features disclosed that history of febrile status epilepticus, mental retardation, and status epilepticus were statistically more common in BHS group. Moreover, diagnosis of psychosis established by an experienced psychiatrist and slowing of the EEG background activity were both found significantly more frequent in BHS. 66.67% of the operated BHS patients showed benefit from epilepsy surgery. Conclusions BHS is a heterogeneous group, showing significant differences such as increased frequencies of mental retardation, status epilepticus, febrile status epilepticus and psychosis, in comparison to UHS. In all, 16.1% of the BHS cases showed a benign course similar to the UHS group and some patients with drug-resistant epilepsy may show benefit from epilepsy surgery.
- QEEG and LORETA in Teenagers With Conduct Disorder and Psychopathic Traits. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 Jun 7.
Background Few studies have investigated the impact of the psychopathic traits on the EEG of teenagers with conduct disorder (CD). To date, there is no other research studying low-resolution brain electromagnetic tomography (LORETA) technique using quantitative EEG (QEEG) analysis in adolescents with CD and psychopathic traits. Objective To find electrophysiological differences specifically related to the psychopathic traits. The current investigation compares the QEEG and the current source density measures between adolescents with CD and psychopathic traits and adolescents with CD without psychopathic traits. Methods The resting EEG activity and LORETA for the EEG fast spectral bands were evaluated in 42 teenagers with CD, 25 with and 17 without psychopathic traits according to the Antisocial Process Screening Device. All adolescents were assessed using the DSM-IV-TR criteria. The EEG visual inspection characteristics and the use of frequency domain quantitative analysis techniques (narrow band spectral parameters) are described. Results QEEG analysis showed a pattern of beta activity excess on the bilateral frontal-temporal regions and decreases of alpha band power on the left central-temporal and right frontal-central-temporal regions in the psychopathic traits group. Current source density calculated at 17.18 Hz showed an increase within fronto-temporo-striatal regions in the psychopathic relative to the nonpsychopathic traits group. Conclusions These findings indicate that QEEG analysis and techniques of source localization may reveal differences in brain electrical activity among teenagers with CD and psychopathic traits, which was not obvious to visual inspection. Taken together, these results suggest that abnormalities in a fronto-temporo-striatal network play a relevant role in the neurobiological basis of psychopathic behavior.
- Comparison of Amplitude-Integrated EEG and Conventional EEG in a Cohort of Premature Infants. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2016 May 25.
To compare amplitude-integrated EEG (aEEG) and conventional EEG (EEG) activity in premature neonates.Biweekly aEEG and EEG were simultaneously recorded in a cohort of infants born less than 34 weeks gestation. aEEG recordings were visually assessed for lower and upper border amplitude and bandwidth. EEG recordings were compressed for visual evaluation of continuity and assessed using a signal processing software for interburst intervals (IBI) and frequencies' amplitude. Ten-minute segments of aEEG and EEG indices were compared using regression analysis.A total of 189 recordings from 67 infants were made, from which 1697 aEEG/EEG pairs of 10-minute segments were assessed. Good concordance was found for visual assessment of continuity between the 2 methods. EEG IBI, alpha and theta frequencies' amplitudes were negatively correlated to the aEEG lower border while conceptional age (CA) was positively correlated to aEEG lower border (P < .001). IBI and all frequencies' amplitude were positively correlated to the upper aEEG border (P ≤ .001). CA was negatively correlated to aEEG span while IBI, alpha, beta, and theta frequencies' amplitude were positively correlated to the aEEG span.Important information is retained and integrated in the transformation of premature neonatal EEG to aEEG.aEEG recordings in high-risk premature neonates reflect reliably EEG background information related to continuity and amplitude.