Oscillatory cortical drive to isometrically contracting muscle in Unverricht-Lundborg type progressive myoclonus epilepsy (ULD)

Silén, Teija; Forss, Nina; Salenius, Stephan; Karjalainen, Tero; Hari, Riitta

doi:10.1016/s1388-2457(02)00196-7

Cited by 22 publications

(7 citation statements)

References 34 publications

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“…93 In patients suffering from progressive myoclonus epilepsy, the dexterity of hand action is impaired, and the decreased postmovement rebounds of the 20-Hz activity imply decreased cortical inhibition, as does a two-to fourfold increase in cortex-muscle coherence. 94,95 These results agree with the role of the motor cortex and its oscillatory activity in adapting skilled motor function.…”

Section: Spontaneous Oscillationssupporting

confidence: 82%

The brain in time: insights from neuromagnetic recordings

Hari

Parkkonen

Nangini

2010

Annals of the New York Academy of Sciences

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The millisecond time resolution of magnetoencephalography (MEG) is instrumental for investigating the brain basis of sensory processing, motor planning, cognition, and social interaction. We review the basic principles, recent progress, and future potential of MEG in noninvasive tracking of human brain activity. Cortical activation sequences from tens to hundreds of milliseconds can be followed during, e.g., perception, motor action, imitation, and language processing by recording both spontaneous and evoked brain signals. Moreover, tagging of sensory input can be used to reveal neuronal mechanisms of binaural interaction and perception of ambiguous images. The results support the emerging ideas of multiple, hierarchically organized temporal scales in human brain function. Instrumentation and data analysis methods are rapidly progressing, enabling attempts to decode the four-dimensional spatiotemporal signal patterns to reveal correlates of behavior and mental contents.

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Section: Spontaneous Oscillationssupporting

confidence: 82%

The brain in time: insights from neuromagnetic recordings

Hari

Parkkonen

Nangini

2010

Annals of the New York Academy of Sciences

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“…Our evidences agree with those obtained by [15] who found that the amplitude of the dominant coherent peaks were 2–4 fold compared with the healthy controls and reported an additional ipsilateral coherent activity in the majority of patients. Furthermore, our findings indicate that the cortical area involved in the coherent network is more extended with respect to sensorimotor cortex contralateral to activated limb and consistently includes ipsilateral sensorimotor cortex and sensors located in adjacent cortices.…”

Section: Discussionsupporting

confidence: 93%

“…Our results, indicating significantly higher beta-CMC values in EPM patients compared to controls agree with previous findings obtained in patients with progressive myoclonus epilepsies both on EEG and MEG data [1–3, 15], but they also reveal the presence of significant beta-CMC involving other regions besides parietal and frontal areas contralateral to the activated limb, and point out a significant shift of the beta CMC peak towards low beta frequencies in EPM1 patients.…”

Section: Discussionsupporting

confidence: 92%

“…We performed this study with the aim of evaluating the extent and the topographical distribution of the brain cortico-muscular network involved in the generation of myoclonus and the frequency characteristics of the peak at which CMC occurs. Several studies have already established the presence of high coherence values between EEG or MEG activity and myoclonic EMG bursts [3, 15], but only a few of them compared the extent of the cortico-muscular network activated in healthy and pathological conditions during the same motor task [16]. MEG signals are suitable to perform this investigation due to the lower interference of superficial tissues and because MEG signals, in contrast to EEG, do not need any reference potentially susceptible to distort CMC amplitude and phase relationships.…”

Section: Introductionmentioning

confidence: 99%

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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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“…Accordingly, there is evidence of cerebellar and brainstem involvement, and alterations in the basal ganglia have also been reported, which are supported by previous clinical evidence of the role of dopaminergic mechanisms . Furthermore, an abnormal thalamocortical loop has been suggested to produce the myoclonus by shortcutting the primary motor and sensory cortices . Enhanced thalamocortical oscillations have also been associated with alterations in postexcitatory inhibition and delayed recovery of excitability after a somatosensory‐evoked potential .…”

Section: Discussionmentioning

confidence: 53%

Alterations of motor cortical excitability and anatomy in Unverricht‐Lundborg disease

et al. 2013

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Unverricht-Lundborg disease is the most common form of progressive myoclonus epilepsies. In addition to generalized seizures, it is characterized by myoclonus, which usually is the most disabling feature of the disease. Classically, the myoclonus has been attributed to increased excitability of the primary motor cortex. However, inhibitory cortical phenomena have also been described along with anatomical alterations. We aimed to characterize the relationship between the excitability and anatomy of the motor cortex and their association with the severity of the clinical symptoms. Seventy genetically verified patients were compared with forty healthy controls. The symptoms were evaluated with the Unified Myoclonus Rating Scale. Navigated transcranial magnetic stimulation was applied to characterize the excitability of the primary motor cortex by determining the motor thresholds and cortical silent periods. In addition, the induced cortical electric fields were estimated using individual scalp-to-cortex distances measured from MRIs. A cortical thickness analysis was performed to elucidate possible disease-related anatomical alterations. The motor thresholds, cortical electric fields, and silent periods were significantly increased in the patients (P < 0.01). The silent periods correlated with the myoclonus scores (r = 0.48 to r = 0.49, P < 0.001). The scalp-to-cortex distance increased significantly with disease duration (r = 0.56, P < 0.001) and correlated inversely with cortical thickness. The results may reflect the refractory nature of the myoclonus and indicate a possible reactive cortical inhibitory mechanism to the underlying disease process. This is the largest clinical series on Unverricht-Lundborg disease and the first study describing parallel pathophysiological and structural alterations associated with the severity of the symptoms.

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Oscillatory cortical drive to isometrically contracting muscle in Unverricht-Lundborg type progressive myoclonus epilepsy (ULD)

Cited by 22 publications

References 34 publications

The brain in time: insights from neuromagnetic recordings

The brain in time: insights from neuromagnetic recordings

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

Alterations of motor cortical excitability and anatomy in Unverricht‐Lundborg disease

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