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Cortical Myoclonus (cortical + myoclonu)

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Medical Sciences100%

Selected Abstracts

Cortical myoclonus masquerading as spinal myoclonus

MOVEMENT DISORDERS, Issue 15 2008
Ana Lucia Rosso MD
[source]

Adult-Onset Rasmussen's Encephalitis: Anatomical-Electrographic-Clinical Features of 7 Italian Cases

EPILEPSIA, Issue 2006
Flavio Villani
Summary:,Purpose: A limited number of cases of adult-onset Rasmussen's encephalitis (A-RE) have been reported, but the features of the syndrome are still unclear. The aim of this study was to verify the clinical features of A-RE, and outline a noninvasive approach that may allow its early diagnosis and treatment. Methods: Retrospective evaluation of extensive noninvasive work-up of seven patients with A-RE, including repeat clinical, neurophysiological, and neuroimaging investigations. Results: The study identified two distinct patterns of disease presentation, one characterized by focal motor epilepsy (the "epileptic" phenotype), and the other by focal cortical myoclonus (the "myoclonic" phenotype). Unilateral neurological deficits and brain atrophy were progressive in both phenotypes, but they were more prominent and were detected earlier in the "epileptic" phenotype. Conclusions: The anatomo-electroclinical features of these patients allowed a noninvasive diagnosis of A-RE and identification of two distinct disease phenotypes. Early noninvasive diagnosis can allow faster initiation of treatment. [source]

Autosomal Dominant Early-onset Cortical Myoclonus, Photic-induced Myoclonus, and Epilepsy in a Large Pedigree

EPILEPSIA, Issue 10 2006
Elena Gardella
Summary:,Purpose: Cortical tremor, a form of rhythmic cortical myoclonus (rhythmic CM), and epilepsy have been described in families with autosomal dominant inheritance. Linkage analyses revealed two putative loci on chromosome 2p and 8q. Clinical photosensitivity was not a prominent feature in such families. We describe a large Italian family with rhythmic CM, photosensitivity, and epilepsy. Methods: Twenty-three individuals of a five-generation family were studied. Linkage analyses for the loci on chromosome 2p11.1 and 8q23.3 were performed. Results: Of the 23 studied family members, 16 were affected. Rhythmic CM of childhood onset was present in all 16 individuals (onset ranging from 3 to 12 years), was associated with photic-induced myoclonic jerks in seven, and with epileptic seizures in six (onset ranging from 23 to 34 years). Five children of the V generation manifested also episodes of arousal with generalized tremor in early infancy ("tremulous arousals"). Jerk-locked back-averaging of rhythmic CM of six affected individuals, documented a premyoclonic EEG correlate. C-reflex at rest was present in two affected adults. Linkage analyses excluded mapping to the 2p11.1 and 8q23.3 loci. Conclusions: Clinical variability and severity of the phenotypes in this family are in line with those of previously described pedigrees with autosomal dominant cortical myoclonus and epilepsy. In this family, a progression of symptoms was found: rhythmic CM and tremulous arousals occurred in childhood, whereas visually induced manifestations and epileptic seizures occurred during adolescence,adulthood. Exclusion of linkage to the two known loci is consistent with genetic heterogeneity of such familial clustering of symptoms. [source]

Characterization of the Tetanus Toxin Model of Refractory Focal Neocortical Epilepsy in the Rat

EPILEPSIA, Issue 2 2005
Karen E. Nilsen
Summary:,Purpose: To characterize in detail a model of focal neocortical epilepsy. Methods: Chronic focal epilepsy was induced by injecting 25,50 ng of tetanus toxin or vehicle alone (controls) into the motor neocortex of rats. EEG activity was recorded from electrodes implanted at the injection site, along with facial muscle electromyographic (EMG) activity and behavioral monitoring intermittently for up to 5 months in some animals. Drug responsiveness was assessed by using the antiepileptic drugs (AEDs) diazepam (DZP) and phenytoin (PHT) delivered systemically, while 1,2,3,4-tetrahydro-6-nitro-2,3-dioxo-benzo[f]quinoxaline-7-sulfonamide (NBQX), a competitive antagonist at AMPA receptors, was administered directly to the brain to investigate the potential benefits of focal drug delivery. Results: Tetanus toxin induced mild behavioral seizures that persisted indefinitely in all animals. EEG spiking activity, occurring up to 80% of the time, correlated with clinical seizures consisting of interrupted behavioral activity, rhythmic bilateral facial twitching, and periods of abrupt motor arrest. Seizures were refractory to systemic administration of DZP and PHT. However, focal delivery of NBQX to the seizure site reversibly reduced EEG and behavioral seizure activity without detectable side effects. Conclusions: This study provides a long-term detailed characterisation of the tetanus toxin model. Spontaneous, almost continuous, well-tolerated seizures occur and persist, resembling those seen in neocortical epilepsy, including cortical myoclonus and epilepsia partialis continua. The seizures appear to be similarly resistant to conventional AEDs. The consistency, frequency, and clinical similarity of the seizures to refractory epilepsy in humans make this an ideal model for investigation of both mechanisms of seizure activity and new therapeutic approaches. [source]

Ictal Pattern of EEG and Muscular Activation in Symptomatic Infantile Spasms: A Videopolygraphic and Computer Analysis

EPILEPSIA, Issue 12 2002
Francesca Bisulli
Summary: ,Purpose: To investigate ictal muscular phenomena characterizing symptomatic infantile spasms (ISs) and their relation to ictal EEG. Methods: Four children with severe encephalopathy, neurologic impairment, and refractory ISs related to different dysplastic lesions, underwent videopolygraphic recordings collecting surface electromyogram (EMG) activity from several cranial and limb muscles to evaluate the pattern of muscular recruitment, duration, and side-to-side asymmetry of ISs. Acquired data were stored for off-line analysis by a computerized polygraphic system. Results: Spasms were characterized by a complex pattern of muscular activation. A constant or rostrocaudal propagation pattern was lacking in all patients. Intervals between the onset of EMG activity in different muscles in each spasm were very long: ,100,200 ms. Two patients, with hemispheric cortical dysplasia and agenesis of the corpus callosum, had asymmetric and asynchronous spasms in which the EMG onset of the muscles contralateral to the affected hemisphere constantly anticipated that of the ipsilateral ones. Backaveraging of EEG activity disclosed a high-amplitude EEG complex on the same side as the dysplastic lesion, preceding or succeeding the contralateral muscle activity onset. In the other two patients with diffuse cortical dysplasia, no EEG transient was related to EMG activity onset. Conclusions: Despite clinical similarity between spasms in the same patient, our data demonstrate the complexity and heterogeneity of these motor phenomena. Our findings cannot be explained simply in terms of cortical or reticular generators like other motor phenomena such as cortical myoclonus or startle reflex. [source]

Elemental mercury poisoning probably causes cortical myoclonus

MOVEMENT DISORDERS, Issue 13 2007
Mona Ragothaman MBBS
Abstract Mercury toxicity causes postural tremors, commonly referred to as "mercurial tremors," and cerebellar dysfunction. A 23-year woman, 2 years after injecting herself with elemental mercury developed disabling generalized myoclonus and ataxia. Electrophysiological studies confirmed the myoclonus was probably of cortical origin. Her deficits progressed over 2 years and improved after subcutaneous mercury deposits at the injection site were surgically cleared. Myoclonus of cortical origin has never been described in mercury poisoning. It is important to ask patients presenting with jerks about exposure to elemental mercury even if they have a progressive illness, as it is a potentially reversible condition as in our patient. © 2007 Movement Disorder Society [source]

Rhythmic cortical myoclonus in Niemann,Pick disease type C

MOVEMENT DISORDERS, Issue 9 2006
Laura Canafoglia MD
Abstract We here describe a patient with late-infantile Niemann,Pick disease type C (NPC) presenting with worsening myoclonus, seizures, cerebellar symptoms, mild mental impairment, and gaze palsy. Electroencephalographic (EEG) ,polymyographic examinations showed abnormally high and diffuse background alpha-activity, enhanced by intermittent photic stimulation. The electromyographic (EMG) showed quasirhythmic myoclonic jerks during motor activation. EEG,EMG frequency analysis (better than jerk-locked back-averaging) demonstrated the cortical origin of the myoclonus. Our observations indicate that cortical myoclonus may occur as the main symptom of NPC. © 2006 Movement Disorder Society [source]

Levetiracetam in patients with cortical myoclonus: A clinical and electrophysiological study,

MOVEMENT DISORDERS, Issue 12 2005
Pasquale Striano MD
Abstract Levetiracetam is a new antiepileptic agent that exerts antimyoclonic effects. We conducted an open-label trial to evaluate the effect of levetiracetam in chronic cortical myoclonus of diverse etiologies and to determine whether levetiracetam affects electrophysiological findings. Sixteen patients, aged between 19 and 72 years, with refractory, chronic, cortical myoclonus were recruited. We assessed myoclonus severity with the Unified Myoclonus Rating Scale (UMRS). The electrophysiological study comprised jerk-locked averaging, somatosensory evoked potentials (SEPs), and long loop reflex I. Levetiracetam was administered add-on at a starting dose of 500 mg twice per day up to the target dose of 50 mg/kg/day. Patients were reevaluated clinically and electrophysiologically 2 weeks after the titration phase. Fourteen patients completed the trial. Posttreatment UMRS scores showed an improvement of myoclonus in all cases. Pretreatment, 9 patients had "giant" SEPs. Posttreatment, the amplitude of these SEPs was reduced by more than 50% in 3 of 9 patients, and the mean N20-P25 amplitude was reduced significantly. Pre- and posttreatment SEP amplitude was not related to myoclonus severity or duration. Levetiracetam is a promising and a relatively easy-to-test antimyoclonic agent, which has the potential to improve significantly the patient's disability; however, its long-term efficacy should be verified in larger controlled studies. © 2005 Movement Disorder Society [source]