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Objective: To assess whether different patterns of EEG rhythms during a Go/No-go motor task characterize patients with cortical myoclonus (EPM1) or with spinocerebellar ataxia (SCA)., Methods: We analyzed event-related desynchronization (ERD) and synchronization (ERS) in the alpha and beta-bands during visually cued Go/No-go task in 22 patients (11 with EPM1, 11 with SCA) and 11 controls., Results: In the Go condition, the only significant difference was a reduced contralateral beta-ERS in the EPM1 patients compared with controls; in the No-go condition, the EPM1 patients showed prolonged alpha-ERD in comparison with both controls and SCA patients, and reduced or delayed alpha- and beta-ERS in comparison with controls. In both conditions, the SCA patients, unlike EPM1 patients and controls, showed minimal or absent lateralization of alpha- and beta-ERD., Conclusions: EPM1 patients showed abnormal ERD/ERS dynamics, whereas SCA patients mainly showed defective ERD lateralization., Significance: A different behavior of ERS/ERD distinguished the two patient groups: the pattern observed in EPM1 suggests a prominent defect of inhibition occurring in motor cortex contralateral to activated segment, whereas the pattern observed in SCA suggested a defective lateralization attributable to the damage of cerebello-cortical network, which is instead marginal in patients with cortical myoclonus., (Copyright © 2019. Published by Elsevier B.V.)

Objective: The aim of this study was to verify the value of multiple neurophysiological tests in classifying disorders of consciousness (DOCs) in patients in a chronic vegetative or minimal consciousness state categorised on the basis of the Coma Recovery Scale (CRS)., Methods: The study included 142 patients, all of whom underwent long (18h) EEG-polygraphic recordings including one night. The EEG was scored using the Synek scale and sleep patterns using an arbitrary scale. Absolute total power and relative EEG power were evaluated in different frequency bands. Multimodal evoked potentials (EPs), including auditory event-related potentials, were also evaluated and scored., Results: The most information came from the combined multimodal EPs and sleep EEG scores. A two-step cluster analysis based on the collected information allowed a satisfactory evaluation of DOC severity. Spectral EEG properties seemed to be significantly related to DOC classes and CRS scores, but did not seem to make any significant additional contribution to DOC classification., Conclusions: Multiple electrophysiological evaluations based on EEG, sleep polygraphic recordings and multimodal EPs are helpful in assessing DOC severity and residual functioning in patients with chronic DOCs., Significance: Simple electrophysiological measures that can be easily applied at patients' bedsides can significantly contribute to the recognition of DOC severity in chronic patients surviving a severe brain injury., (Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.)

Electrophysiological studies indicate that Unverricht-Lundborg's disease (ULD), the most common form of progressive myoclonus epilepsy in Europe, is characterized by the involvement of multiple cortical regions in degenerative changes that lead to enhanced excitation and deficient inhibition. We searched for the haemodynamic correlates of these effects using functional MRI (fMRI) of self-paced index extensions, a well-accepted task highlighting significant differences. EEG and fMRI were simultaneously acquired in 11 ULD patients and 16 controls, performing the index extensions individually (event-related task) as well as repetitively (block task). ERD/ERS analysis was performed for the EEG data in the alpha and beta bands. fMRI time-series were analyzed using the traditional general linear model, as well as with an assumption-free approach, and by means of cross-region correlations representing functional connectivity. In line with the existing literature, ULD patients had enhanced desynchronization in the alpha band and reduced post-movement synchronization in the beta band. By contrast, fMRI did not reveal any difference between the two groups; there were no activation intensity, latency or extent effects, no significant engagement of additional regions, and no changes to functional connectivity. We conclude that, so long as the patients are executing a task which does not induce obvious action myoclonus, the hypothesized abnormalities in pyramidal neuron and interneuron dynamics are relatively subtle, embodied in processes which are not metabolically-demanding and take place at a time-scale invisible to fMRI.

Objective: To evaluate the EEG recorded in photosensitive idiopathic generalised epilepsy (IGE) patients at rest and during 14Hz IPS, frequency capable of inducing photoparoxysmal responses (PPRs)., Methods: Power spectrum density and coherence profiles were estimated using a block autoregressive parametric model (AR) in 28 patients and 22 controls., Results: At rest, the intra- and inter-hemispheric coherence spectra showed a significantly larger number of coherence peaks in the gamma band in patients with respect to controls. During intermittent photic stimulation (IPS), coherent gamma activity is mainly presented as IPS frequency harmonics; moreover, the patients' mean coherence values significantly increased. In six patients re-evaluated with IPS after putting on glasses with Z1 blue lens (which counteracts PPR) the spectral and coherence profiles tended to return to the resting ones., Conclusions: Patients are endowed with inherited EEG hyper-synchrony as shown by the large number of coherence peaks detectable under resting conditions, whereas IPS enhances intra- and inter-hemispheric mean coherence values in the gamma band. The persistence of alpha activity peaks during IPS in most controls but not in patients suggests that the alpha generating network plays a significant role in counteracting PPR., Significance: Both gamma and alpha EEG generators are involved in the PPR generation and in the widespread synchronisation characterising the IGE-associated photosensitivity.

We performed electroencephalography (EEG) and multimodal evoked potential (EP) studies in 16 patients with various forms of mitochondrial encephalomyopathy (ME). The electrophysiological investigations revealed signs of involvement of the peripheral and central nervous system (CNS) in 14 patients, with a high incidence of visual-EP (VEP) alterations, indicative of visual pathway vulnerability in mitochondrial diseases. No specific pattern of abnormalities emerged and, in particular, clinical and laboratory findings did not correlate with each other. EP (particularly VEP and electroretinogram) investigations should be part of the diagnostic work-up of patients with mitochondrial disorders in order to better characterize the clinical picture, disclose involvement of specific sensory systems of the CNS, and assess patients with atypical clinical presentations.