Peri-rolandic and fronto-parietal components of scalp-recorded giant SEPs in cortical myoclonus

Ikeda, Akio; Shibasaki, Hiroshi; Nakagawa, Takashi; Xu, Xiaoping; Terada, Kiyohito; Mima, Tatsuya; Kaji, Ryuji; Kawai, Itsuo; Tatsuoka, Yoshihisa; Kimura, Jun

doi:10.1016/0168-5597(95)00003-b

Cited by 51 publications

(40 citation statements)

References 29 publications

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“…SEP and C-reflex were recorded by the same methods as the ones previously reported from our laboratory (6). Briefly, electrical stimulus was delivered to the median nerve at a regular rate of 1.1 Hz.…”

Section: Methodsmentioning

confidence: 99%

Familial cortical myoclonic tremor as a unique form of cortical reflex myoclonus

Terada¹,

Ikeda²,

Mima³

et al. 1997

Movement Disorders

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Previously it was reported that some patients with tremor had the same electrophysiological findings as those seen in patients with cortical reflex myoclonus, and consequently the tremor was named "cortical tremor." In the present study, we examined six patients from three families with cortical tremor of relatively late onset. The inheritance pattern of cortical tremor was compatible with autosomal dominant trait. Those patients had relatively rhythmic involuntary movements (tremor) in the distal upper and lower limbs, especially during posture and/or fine movements. There was no cerebellar ataxia or dementia, and fits of loss of consciousness occurred only infrequently. Electrophysiologically, they had generalized spikes on electroencephalogram (EEG), giant cortical components of somatosensory evoked potential, an enhanced long-loop reflex (C-reflex), and cortical spikes preceding the rhythmic jerk demonstrable by the jerk-locked back averaging method, thus fulfilling the criteria of cortical reflex myoclonus. Furthermore, they had slow negative EEG shift starting 1-2 s prior to voluntary movements, suggesting that, as opposed to the conventional form of progressive myoclonus epilepsy (PME), the cerebellar efferent input to the motor cortices was normal. These clinical and electrophysiological pictures are distinct from those of familial essential tremor, familial essential myoclonus, or the conventional form of PME, and the term "familial cortical myoclonic tremor" will represent the clinical and electrophysiological features of this unique entity most appropriately.

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Section: Methodsmentioning

confidence: 99%

Familial cortical myoclonic tremor as a unique form of cortical reflex myoclonus

Terada¹,

Ikeda²,

Mima³

et al. 1997

Movement Disorders

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“…1A, 1B, 1C and 1D). Only 1 patient (Patient 4) had enlargements of P25 and N35 amplitudes according to our pervious study's criteria (7). However, the SEP waveforms were less likely to be "giant SEPs" because the N20 amplitude was also enlarged (Fig.…”

Section: Electrophysiological Studiesmentioning

confidence: 99%

“…Amplitudes of P25 and N35 were measured from a peak of the preceding component of the opposite polarity and that of N20 was from the prestimulus baseline level. The definition of giant SEPs was based on results reported in our previous study (7). We had also examined the 8 control subjects using the same settings.…”

Section: Electrophysiological Studiesmentioning

confidence: 99%

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Transient Myoclonic State with Asterixis: Primary Motor Cortex Hyperexcitability is Correlated with Myoclonus

et al. 2011

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Objective To clarify the clinical features and mechanism of the transience of myoclonus in patients with a transient myoclonic state with asterixis (TMA). Methods We investigated the clinical and eletrophysiological profiles of 6 patients with TMA (age: 84±3 years). During an asymptomatic period, somatosensory evoked potentials (SEPs) were recorded in all 6 patients and motor evoked potentials (MEPs) were examined in 1 patient. SEPs were recorded and jerk-locked back averaging (JLA) was performed in 2 patients while symptomatic. SEPs were also recorded from 8 aged control subjects (age: 68±5 years). Results All TMA patients had mild chronic systemic diseases. During an asymptomatic period, SEP amplitudes were not significantly enlarged in comparison with control subjects, and MEPs were normal. Examination of 2 patients during symptomatic period indicated no enlargement of SEP amplitudes and JLA disclosed a positive spike preceding myoclonic jerks. In one of these patients, the amplitude of the positive spike decreased once myoclonus improved. Conclusion TMA occurred in aged patients with mild chronic systemic diseases. JLA findings and the absence of giant SEPs further support that TMA is a cortical non-reflex myoclonus. In addition, transient hyperexcitability at the primary motor cortex disclosed by JLA correlated well with its transient symptoms.

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“…The physiological meaning of the frontal N30 somatosensory evoked potential (SEP) is still a matter of debate. [1][2][3]5,8,10,17,32,43,44,46,51 Indirect elements for solving this problem might be found by analyzing the modifications of the N30 component that occur in response to different physiological stimuli. Cortical SEPs can be elicited by stimulation of cutaneous as well as proprioceptive afferents.…”

mentioning

confidence: 99%

Different contribution of joint and cutaneous inputs to early scalp somatosensory evoked potentials

et al. 1999

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Peri-rolandic and fronto-parietal components of scalp-recorded giant SEPs in cortical myoclonus

Cited by 51 publications

References 29 publications

Familial cortical myoclonic tremor as a unique form of cortical reflex myoclonus

Familial cortical myoclonic tremor as a unique form of cortical reflex myoclonus

Transient Myoclonic State with Asterixis: Primary Motor Cortex Hyperexcitability is Correlated with Myoclonus

Different contribution of joint and cutaneous inputs to early scalp somatosensory evoked potentials

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