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Objective: To assess functional organization of the motor cortex in patients with Unverricht-Lundborg disease (EPM1A) using a combined neurophysiologic and imaging approach., Methods: EPM1A patients underwent transcranial magnetic stimulation (TMS)-based cortical mapping of the motor hand area. Moreover, they performed neuroimaging studies to assess functional magnetic resonance imaging (fMRI) activation maps related to motor hand task and cortical thickness (CTH) on T1-weighted 3D images., Results: The hand cortical representation was different in EPM1A patients from that of the control subjects both in TMS and in fMRI brain mapping, characterized by a posterior dislocation and a mild reduction in the activation of motor areas. CTH analysis revealed a thinning of both precentral and paracentral areas in the patients., Conclusions: We hypothesize that the altered cortical motor map reflects a functional reorganization of the residual cortical neuronal pool of the sensorimotor hand areas driven by plastic reorganization and/or pathophysiological mechanisms., Significance: Both pathophysiological process and plastic changes may represent two sides of the same phenomenon in the EPM1A patients; structural and functional brain mapping may help to identify functional reorganization of the cortical motor system., (Copyright © 2020 Elsevier B.V. All rights reserved.)

Perampanel (PER) is a novel anti-seizure medication useful in different types of epilepsy. We intended to assess the effectiveness of PER on cortical myoclonus and seizure frequency in patients with progressive myoclonus epilepsy (PME), using quantitative validated scales. Forty-nine patients aged 36.6 ± 15.6 years with PME of various aetiology (18 EPM1, 12 EPM2, five with sialidosis, one with Kufs disease, one with EPM7, and 12 undetermined) were enrolled between January 2017 and June 2018. PER at the dose of 2-12 mg (5.3 ± 2.5) was added to existing therapy. Myoclonus severity was assessed using a minimal myoclonus scale (MMS) in all the patients before and after 4-6 months of steady PER dose, and by means of the Unified Myoclonus Rating Scale (UMRS) in 20 patients. Logistic regression analysis was used to identify the factors potentially predicting treatment efficacy. Four patients dropped out in the first two months due to psychiatric side effects. In the remaining patients, PER reduced myoclonus severity as assessed using MMS (Wilcoxon test: p < 0.001) and UMRS (p < 0.001), with the 'Action myoclonus' section of the UMRS showing the greatest improvement. The patients with EPM1 or EPM1-like phenotype were more likely to improve with PER (p = 0.011). Convulsive seizures which have recurred at least monthly in 17 patients were reduced by >50%. Side effects occurred in 22/49 (44.8%) patients, the most common being irritability followed by drowsiness. PER is effective in treating myoclonus and seizures in PME patients. The frequency of psychiatric side effects suggests the need for careful patient monitoring., (Copyright © 2019 Elsevier B.V. All rights reserved.)

To asses the characteristics of severe action myoclonus in three patients with progressive myoclonus epilepsy (PME) due to sialidosis. We assessed EEG-EMG coherence, relative power (RP) and bandwidth (BW) of the EMG-peak associated with myoclonus; we also evaluated somatosensory evoked potentials and long-loop reflexes (LLRs). We compared the findings with those obtained in ten Unverricht-Lundborg (UL) patients. The presentation of sialidosis included macular cherry-red spot, skeletal malformation and polyneuropathy in the infantile form and optic atrophy in the juvenile form. From its onset in adolescence myoclonus rapidly worsened, quickly leading to severe disability. In sialidosis patients, the EMG-peak was characterised by higher RP (p<0.01) and narrower BW (p<0.02) than in UL. EEG-EMG coherence values were higher (p<0.05) than in UL patients. Taking into account both sialidosis and UL patients, the coherence values and the RP of the EMG-peak were directly correlated with the severity of the myoclonus; while BW values were inversely correlated. All these measures showed extreme values in sialidosis patients. In the sialidosis patients, the strongly rhythmic recurrence of the jerks reflected on LLR, which included multiple components. Subtle differences indicate an especially high level of cortical motor synchronization in the sialidosis patients, which may account for their particularly severe motor impairment. Neurophysiological indexes indicating high EEG-EMG synchronization parallels the severity of the myoclonus., (Copyright © 2011 Elsevier B.V. All rights reserved.)

Myoclonus has different clinical and neurophysiological features in patients with Unverricht-Lundborg (ULD) and Lafora body disease (LBD), probably because of a different cortical hyperexcitability profile. To investigate the role of intracortical inhibition in such different presentations, we used paired-pulse transcranial magnetic stimulation (TMS) in ten ULD and five LBD patients, all with a positive molecular diagnosis. All of the patients were treated with antiepileptic drugs (AEDs). In comparison with healthy subjects, both patient groups had significantly defective short intracortical inhibition (SICI), however LBD patients, but not ULD and healthy subjects, had a clear inhibition at ISI 6 ms and ISI 10 ms. Moreover, defective long interval cortical inhibition (LICI) was found in LBD but not ULD patients. The substantial reduction in SICI suggests that both ULD and LBD patients have impaired inhibitory interneuron pools which are involved in the generation of cortical reflex myoclonus, whereas the inhibition found in LBD patients at ISI 6 and 10 ms, as well the reduced inhibition found at long intervals, suggest a more complex circuitry dysfunction possibly involving both excitatory and inhibitory systems. These findings are probably related to the high epileptogenic propensity characterizing LBD with respect to ULD and to the more severely distorted neuronal network resulting from the pathogenesis of LBD., (Copyright 2010 Elsevier B.V. All rights reserved.)