Abnormal Reactivity of the ∼20-Hz Motor Cortex Rhythm in Unverricht Lundborg Type Progressive Myoclonus Epilepsy

Silén, Teija; Forss, Nina; Jensen, Ole; Hari, Riitta

doi:10.1006/nimg.2000.0660

Cited by 48 publications

(25 citation statements)

References 17 publications

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“…The peak frequencies in the patients were below the slowed EEG peak frequency expected from normal aging (Nie- dermeyer and Lopes da Silva, 1987;McEvoy et al, 2001). A similar slowing of scalp EEG and MEG has been reported in patients with Parkinson's disease (Soikkeli et al, 1991), neurogenic pain (Gü cer et al, 1978), psychiatric disorders and during interictal phases of epilepsy (Clemens et al, 2000;Silen et al, 2000;Raghavachari et al, 2001). Note that increased lowfrequency oscillations also occur during sleep (Steriade, 2001) and cognitive tasks (Klimesch, 1999;Kahana et al, 2001), where they are considered as normal.…”

Section: Theta Dominance In Resting Eegmentioning

confidence: 66%

Thalamocortical theta coherence in neurological patients at rest and during a working memory task

Sarnthein¹,

Morel²,

Stein³

et al. 2005

International Journal of Psychophysiology

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We simultaneously recorded the local field potential (LFP) in the thalamus and the electroencephalogram (EEG) on the scalp of 5 patients suffering from neurogenic pain, epilepsy and movement disorders. In an earlier study [], we have investigated the slowing of EEG and the high thalamocortical coherence in the framework of thalamocortical dysrhythmia, the common underlying pathophysiology. The current study focuses on the effects of different cognitive conditions. When patients rested with eyes closed, a theta peak dominated the EEG spectra. The peak height was reduced upon opening the eyes, reminiscent of the classical alpha blocking. This peak reduction also appeared in the thalamic LFP recording. When patients activated their working memory by counting backwards, the theta peak increased in scalp EEG or in the LFP recorded in thalamic nuclei VA/VL. The coherence estimates between EEG and LFP ranged between 21% and 76% for different patients and cognitive conditions (mean: 50%). The involvement of both cortex and thalamus in working memory and the high thalamocortical coherence underline, in addition to cortico-cortical interactions, the importance of thalamocortical modules in the generation of higher cognitive functions.

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Section: Theta Dominance In Resting Eegmentioning

confidence: 66%

Thalamocortical theta coherence in neurological patients at rest and during a working memory task

Sarnthein¹,

Morel²,

Stein³

et al. 2005

International Journal of Psychophysiology

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“…The method provides a feasible way to facilitate clinical diagnosis of sensorimotor oscillatory activities (Mu rhythm) in few trials which can be useful for patients who are incapable of sustaining long experiments. The proposed method could be a powerful tool for probing neurophysiology in normal brain and pathophysiology in the diseased, 57 such as diagnosis of patients with Parkinson's disease, 46 Unverricht-Lundborg type myoclonic epilepsy, 54 and etc. It permits single-trial perspective and insightful view on subtle brain dynamics.…”

Section: Discussionmentioning

confidence: 99%

“…1,29,44 The power changes in event-related activities can be caused by the decrease or increase in synchrony of the underlying activated neuronal populations. Studies on EEG/MEG (electroencephalography/magnetoencephalography) event-related oscillatory activities have been used to probe neural information processing in many issues; for example, cognitive performance, 10,15,40 movement task, 43,[45][46][47]52 motor imagery task, 23,60 and clinical diagnostic index for neurophysiological disorders, such as Unverricht Lundborg Type Progressive Myoclonus Epilepsy, 54 Parkinson's disease, 4,46 and etc.…”

Section: Introductionmentioning

confidence: 99%

Single-Trial Analysis of Cortical Oscillatory Activities During Voluntary Movements Using Empirical Mode Decomposition (EMD)-Based Spatiotemporal Approach

Lee

Shang

et al. 2009

Ann Biomed Eng

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This study presents a method based on empirical mode decomposition (EMD) and a spatial template-based matching approach to extract sensorimotor oscillatory activities from multi-channel magnetoencephalographic (MEG) measurements during right index finger lifting. The longitudinal gradiometer of the sensor unit which presents most prominent SEF was selected on which each single-trial recording was decomposed into a set of intrinsic mode functions (IMFs). The correlation between each IMF of the selected channel and raw data on other channels were created and represented as a spatial map. The sensorimotor-related IMFs with corresponding correlational spatial map exhibiting large values on primary sensorimotor area (SMI) were selected via spatial-template matching process. Trial-specific alpha and beta bands were determined in sensorimotor-related oscillatory activities using a two-spectrum comparison between the spectra obtained from baseline period (-4 to -3 s) and movement-onset period (-0.5 to 0.5 s). Sensorimotor-related oscillatory activities were filtered within the trial-specific frequency bands to resolve task-related oscillatory activities. Results demonstrated that the optimal phase and amplitude information were preserved not only for alpha suppression (event-related desynchronization) and beta rebound (event-related synchronization) but also for profound analysis of subtle dynamics across trials. The retention of high SNR in the extracted oscillatory activities allow various methods of source estimation that can be applied to study the intricate brain dynamics of motor control mechanisms. The present study enables the possibility of investigating cortical pathophysiology of movement disorder on a trial-by-trial basis which also permits an effective alternative for participants or patients who can not endure lengthy procedures or are incapable of sustaining long experiments.

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“…Silén et al 2000 [34] reported a slower CMC peak frequency in beta band in patients with EPM1 studied with MEG and ascribed this slowing to degenerative changes in the brain or to drug treatment. In healthy subjects, MEG studies showed that the frequency of beta oscillations tends to decrease (whereas power increase) with the administration of benzodiazepine [35] or with aging [36].…”

Section: Discussionmentioning

confidence: 99%

The network sustaining action myoclonus: a MEG-EMG study in patients with EPM1

Franceschetti¹,

Canafoglia²,

Rotondi

et al. 2016

BMC Neurol

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BackgroundTo explore the cortical network sustaining action myoclonus and to found markers of the resulting functional impairment, we evaluated the distribution of the cortico-muscular coherence (CMC) and the frequency of coherent cortical oscillations with magnetoencephalography (MEG). All patients had EPM1 (Unverricht-Lundborg) disease known to present with prominent and disabling movement-activated myoclonus.MethodsUsing autoregressive models, we evaluated CMC on MEG sensors grouped in regions of interests (ROIs) above the main cortical areas. The movement was a repeated sustained isometric extension of the right hand and right foot. We compared the data obtained in 10 EPM1 patients with those obtained in 10 age-matched controls.ResultsAs expected, CMC in beta band was significantly higher in EPM1 patients compared to controls in the ROIs exploring the sensorimotor cortex, but, it was also significantly higher in adjacent ROIs ipsilateral and contralateral to the activated limb. Moreover, the beta-CMC peak occurred at frequencies significantly slower and more stable frequencies in EPM1 patients with respect to controls. The frequency of the beta-CMC peak inversely correlated with the severity of myoclonus.Conclusionsthe high and spatially extended beta-CMC peaking in a restricted range of low-beta frequencies in EPM1 patients, suggest that action myoclonus may result not only from an enhanced local synchronization but also from a specific oscillatory activity involving an expanded neuronal pool. The significant relationship between beta-CMC peak frequency and the severity of the motor impairment can represent a useful neurophysiological marker for the patients’ evaluation and follow-up.

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Abnormal Reactivity of the ∼20-Hz Motor Cortex Rhythm in Unverricht Lundborg Type Progressive Myoclonus Epilepsy

Cited by 48 publications

References 17 publications

Thalamocortical theta coherence in neurological patients at rest and during a working memory task

Thalamocortical theta coherence in neurological patients at rest and during a working memory task

Single-Trial Analysis of Cortical Oscillatory Activities During Voluntary Movements Using Empirical Mode Decomposition (EMD)-Based Spatiotemporal Approach

The network sustaining action myoclonus: a MEG-EMG study in patients with EPM1

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