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Clin EEG Neurosci [journal]
- Integrative Frequency Power of EEG Correlates with Progression of Mild Cognitive Impairment to Dementia in Parkinson's Disease. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2014 Dec 16.
Clinically, predicting the progression of mild cognitive impairment (MCI) and diagnosing dementia in Parkinson's disease (PD) are difficult. This study aims to explore an integrative electroencephalography (EEG) frequency power that could be used to predict the progression of MCI in PD patients. Twenty-six PD patients, in this study, were divided into the mild cognitive impairment group (PDMCI, 17 patients) and dementia group (PDD, 9 patients) according to cognitive performance. Beta peak frequency, alpha relative power, and alpha/theta power were recorded and analyzed for the prediction. Mini Mental State Examination (MMSE) scores at initiation, in the first year, and in the second year were examined. The sensitivity, specificity, positive predictive value, Matthew correlation coefficient, and positive likelihood ratio were calculated in both the integrative EEG biomarkers and single best biomarker. Of the 17 patients with MCI for 2 years, 6 progressed to dementia. Integrative EEG biomarkers, mainly associated with beta peak frequency, can predict conversion from MCI to dementia. These biomarkers had sensitivity of 82% and specificity of 78%, compared with sensitivity of 61% and specificity of 58% of the beta peak frequency. In conclusion, the integrative EEG frequency powers were more sensitive and specific to MCI progression in PD patients.
- Intractability in Epilepsy: Role of EEG Desynchronization in Early Identification. [LETTER]
- Clin EEG Neurosci 2014 Dec 15.
- Protocol Design Challenges in the Detection of Awareness in Aware Subjects Using EEG Signals. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2014 Dec 8.
Recent studies have evidenced serious difficulties in detecting covert awareness with electroencephalography-based techniques both in unresponsive patients and in healthy control subjects. This work reproduces the protocol design in two recent mental imagery studies with a larger group comprising 20 healthy volunteers. The main goal is assessing if modifications in the signal extraction techniques, training-testing/cross-validation routines, and hypotheses evoked in the statistical analysis, can provide solutions to the serious difficulties documented in the literature. The lack of robustness in the results advises for further search of alternative protocols more suitable for machine learning classification and of better performing signal treatment techniques. Specific recommendations are made using the findings in this work.
- Increased Beta Frequency (15-30 Hz) Oscillatory Responses in Euthymic Bipolar Patients Under Lithium Monotherapy. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2014 Dec 2.
The effect of lithium on neurocognition is not still fully explored. Brain oscillatory activity is altered in bipolar disorder. We aimed to assess the oscillatory responses of euthymic bipolar patients and how they are affected by lithium monotherapy. Event-related oscillations in response to visual target stimulus during an oddball paradigm in 16 euthymic drug-free and 13 euthymic lithium-treated bipolar patients were compared with 16 healthy controls. The maximum peak-to-peak amplitudes were measured for each subject's averaged beta (15-30 Hz) responses in the 0- to 300-ms time window over frontal (F3, Fz, F4), central (C3, Cz, C4), temporal (T7, T8), temporo-parietal (TP7, TP8), parietal (P3, Pz, P4), and occipital (O1, Oz, O2) areas. Patients under lithium monotherapy had significantly higher beta responses to visual target stimuli than healthy controls (P = .017) and drug-free patients (P = .015). The increase in beta response was observed at all electrode locations, however, the difference was statistically significant for the left (T7; P = .016) and right (T8; P = .031) temporal beta responses. Increased beta responses in drug-free patients and further significant increase in lithium-treated patients may be indicative of a core pathophysiological process of bipolar disorder and how it is affected by lithium. Whether the finding corresponds to lithium's corrective effect on the underlying pathology or to its neurocognitive side effect remains to be further explored. In either case, the finding is a sign that the oscillatory activity may be useful in tracking medication effect in bipolar disorder.
- Treatment of Psychogenic Nonepileptic Seizures: Updated Review and Findings From a Mindfulness-Based Intervention Case Series. [REVIEW]
- Clin EEG Neurosci 2014 Dec 2.
Psychogenic nonepileptic seizures (PNES) were first described in the medical literature in the 19th century, as seizure-like attacks not related to an identified central nervous system lesion, and are currently classified as a conversion disorder, according to the Diagnostic and Statistical Manual of Mental Disorders, fifth edition (DSM-5). While a universally accepted and unifying etiological model does not yet exist, several risk factors have been identified. Management of PNES should be based on interdisciplinary collaboration, targeting modifiable risk factors. The first treatment phase in PNES is patient engagement, which is challenging given the demonstrated low rates of treatment retention. Acute interventions constitute the next phase in treatment, and most research studies focus on short-term evidence-based interventions. Randomized controlled pilot trials support cognitive-behavioral therapy. Other psychotherapeutic and psychopharmacological interventions have been less well-studied using controlled and uncontrolled trials. Within the discussion of acute interventions, we present a preliminary evaluation for feasibility of a mindfulness-based psychotherapy protocol in a very small sample of PNES patients. We demonstrated in 6 subjects that this intervention is feasible in real-life clinical scenarios and warrants further investigation in larger scale studies. The final treatment phase is long-term follow-up. Long-term outcome studies in PNES show that a significant proportion of patients remains symptomatic and experiences continued impairments in quality of life and functionality. We believe that PNES should be understood as a disease that requires different types of intervention during the various phases of treatment.
- Altered Resting-State Cortical EEG Oscillations in Patients With Severe Asymptomatic Carotid Stenosis. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2014 Dec 2.
Asymptomatic carotid stenosis is characterized by altered cerebral hemodynamics and cognitive impairment, but the underlying neurophysiological mechanism remains unclear. To elucidate the alterations of cortical activities, resting-state electrophysiological activities were recorded from patients with mild (<30%; n = 10; age 57-85 years), moderate (30% to 50%; n = 11; age 66-88 years), and severe (>50%; n = 8; age 67-91 years) carotid stenosis. The current density and oscillatory power of the cortical sources were analyzed using the minimum norm estimates method combined with fast Fourier transform analysis. Our results indicate that the cortical current density among regions of the brain was similar, irrespective of the degree of carotid stenosis. With regard to the cortical oscillations, augmented theta activities in the bilateral parietal, left temporal, and left occipital regions and attenuated alpha activities in the bilateral frontal and right central regions were obtained in patients with severe asymptomatic carotid stenosis. We suggest that the source-based cortical oscillations at theta and alpha bands might reflect the alterations of the brain activities and characterize the altered neurophysiological mechanism of the brain with at least 50% occlusion of the carotid artery. Further longitudinal studies with larger populations are warranted to verify the present findings.
- An Integrative Neurocircuit Perspective on Psychogenic Nonepileptic Seizures and Functional Movement Disorders: Neural Functional Unawareness. [REVIEW]
- Clin EEG Neurosci 2014 Nov 27.
Functional neurological disorder (conversion disorder) is a neurobehavioral condition frequently encountered by neurologists. Psychogenic nonepileptic seizure (PNES) and functional movement disorder (FMD) patients are presented to epileptologists and movement disorder specialists respectively, yet neurologists lack a neurobiological perspective through which to understand these enigmatic groups. Observational research studies suggest that PNES and FMD may represent variants of similar (or the same) conditions given that both groups exhibit a female predominance, have increased prevalence of mood-anxiety disorders, frequently endorse prior abuse, and share phenotypic characteristics. In this perspective article, neuroimaging studies in PNES and FMD are reviewed, and discussed using studies of emotional dysregulation, dissociation and psychological trauma in the context of motor control. Convergent neuroimaging findings implicate alterations in brain circuits mediating emotional expression, regulation and awareness (anterior cingulate and ventromedial prefrontal cortices, insula, amygdala, vermis), cognitive control and motor inhibition (dorsal anterior cingulate, dorsolateral prefrontal, inferior frontal cortices), self-referential processing and perceptual awareness (posterior parietal cortex, temporoparietal junction), and motor planning and coordination (supplementary motor area, cerebellum). Striatal-thalamic components of prefrontal-parietal networks may also play a role in pathophysiology. Aberrant medial prefrontal and amygdalar neuroplastic changes mediated by chronic stress may facilitate the development of functional neurological symptoms in a subset of patients. Improved biological understanding of PNES and FMD will likely reduce stigma and aid the identification of neuroimaging biomarkers guiding treatment development, selection, and prognosis. Additional research should investigate neurocircuit abnormalities within and across functional neurological disorder subtypes, as well as compare PNES and FMD with mood-anxiety-dissociative disorders.
- Effectiveness of Rufinamide in the Treatment of Idiopathic Generalized Epilepsy With Atypical Evolution: Case Report and Review of the Literature. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2014 Nov 23.
Rufinamide (RFD) is a novel drug that was recently approved as an adjunctive treatment for Lennox-Gastaut syndrome. Despite its reported effectiveness in generalized seizures (tonic, atonic, or tonic-clonic) in this syndrome, few data on its use in idiopathic generalized epilepsy are available. Indeed, the scientific evidence to date is limited to anecdotal cases or isolated clinical experiences. We report an uncommon, though paradigmatic, case of a woman affected by juvenile absence epilepsy (JAE) who, following a prolonged seizure-freedom period and the consequent withdrawal of valproate, presented a seizure relapse accompanied by a worsening in her electroclinical pattern. In view of this atypical evolution of JAE, characterized by drug-resistant seizures (absence and generalized tonic-clonic) and the progressive increase in electroencephalographic (EEG) abnormalities, several antiepileptic drugs were used, though to no benefit. The use of RFD instead led to a gradual control of the seizures and normalization of the EEG findings. In addition to this clinical experience, we briefly review the literature on the use of RFD in refractory generalized epilepsy.
- Pharmaco-EEG: A Study of Individualized Medicine in Clinical Practice. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2014 Nov 23.
Pharmaco-electroencephalography (Pharmaco-EEG) studies using clinical EEG and quantitative EEG (qEEG) technologies have existed for more than 4 decades. This is a promising area that could improve psychotropic intervention using neurological data. One of the objectives in our clinical practice has been to collect EEG and quantitative EEG (qEEG) data. In the past 5 years, we have identified a subset of refractory cases (n = 386) found to contain commonalities of a small number of electrophysiological features in the following diagnostic categories: mood, anxiety, autistic spectrum, and attention deficit disorders, Four abnormalities were noted in the majority of medication failure cases and these abnormalities did not appear to significantly align with their diagnoses. Those were the following: encephalopathy, focal slowing, beta spindles, and transient discharges. To analyze the relationship noted, they were tested for association with the assigned diagnoses. Fisher's exact test and binary logistics regression found very little (6%) association between particular EEG/qEEG abnormalities and diagnoses. Findings from studies of this type suggest that EEG/qEEG provides individualized understanding of pharmacotherapy failures and has the potential to improve medication selection.
- Electroencephalographic Response to Different Odors in Healthy Individuals: A Promising Tool for Objective Assessment of Olfactory Disorders. [JOURNAL ARTICLE]
- Clin EEG Neurosci 2014 Nov 17.
The aim of the present study was to examine human central nervous system response to three different odors. Electrophysiological activity was recorded in the baseline state and for 3 odors, lemon, peppermint, and vanilla, in 16 healthy participants. Electrodes were separated into groups according to the spatial position on the head. Fast Fourier transformation was performed on every set, and mean value of activity in theta was exported. As theta showed statistically significant results, further analysis was based only on the theta frequency band. On electrodes FP1, F3, Fz, F4, F8, T7, C3, Cz, C4, T8, TP9, CP5, CP1, CP2, CP6, P7, P3, Pz, P4, P8, PO9, and PO10 there was statistically significant difference in the electrical activity of the brain between four conditions. For peppermint and lemon, there was statistically significant difference in activity between different regions-F(1.576, 23.637) = 16.030, P = .000 and F(1.362, 20.425) = 4.54, P = .035, respectively-where the activity in the central area was significantly reduced compared with the activity in the other 4 areas and in the left and right anterior and left posterior area, respectively. There was no statistically significant difference for vanilla between specific areas, F(1.217, 18.257) = 1.155, P = .309. The results indicate that olfactory stimuli can affect the frequency characteristics of the electrical activity of the brain.