Milestones in myoclonus

Shibasaki, Hiroshi; Thompson, Philip D.

doi:10.1002/mds.23673

Cited by 42 publications

(30 citation statements)

References 96 publications

(107 reference statements)

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“…Alternatively (but non-exclusively), non-rhythmic rapid movements could be considered a form of action myoclonus. Similar movements have been identified in other neurodegenerative disorders of the cerebellum [32].…”

Section: Discussionsupporting

confidence: 79%

Disorders of Upper Limb Movements in Ataxia-Telangiectasia

et al. 2013

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Ataxia-telangiectasia is known for cerebellar degeneration, but clinical descriptions of abnormal tone, posture, and movements suggest involvement of the network between cerebellum and basal ganglia. We quantitatively assessed the nature of upper-limb movement disorders in ataxia-telangiectasia. We used a three-axis accelerometer to assess the natural history and severity of abnormal upper-limb movements in 80 ataxia-telangiectasia and 19 healthy subjects. Recordings were made during goal-directed movements of upper limb (kinetic task), while arms were outstretched (postural task), and at rest. Almost all ataxia-telangiectasia subjects (79/80) had abnormal involuntary movements, such as rhythmic oscillations (tremor), slow drifts (dystonia or athetosis), and isolated rapid movements (dystonic jerks or myoclonus). All patients with involuntary movements had both kinetic and postural tremor, while 48 (61%) also had resting tremor. The tremor was present in transient episodes lasting several seconds during two-minute recording sessions of all three conditions. Percent time during which episodic tremor was present was greater for postural and kinetic tasks compared to rest. Resting tremor had higher frequency but smaller amplitude than postural and kinetic tremor. Rapid non-rhythmic movements were minimal during rest, but were triggered during sustained arm postures and goal directed arm movements suggesting they are best considered a form of dystonic jerks or action myoclonus. Advancing age did not correlate with the severity of involuntary limb movements. Abnormal upper-limb movements in ataxia-telangiectasia feature classic cerebellar impairment, but also suggest involvement of the network between the cerebellum and basal ganglia.

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Section: Discussionsupporting

confidence: 79%

Disorders of Upper Limb Movements in Ataxia-Telangiectasia

et al. 2013

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“…Cortical or cortical reflex myoclonus (CM), previously termed “pyramidal myoclonus,” has received wide attention in the medical literature . It was first demonstrated in patients with familial myoclonic epilepsy by Ginker et al in 1938, who showed a close temporal relationship between cortical discharges on electroencephalography (EEG) and myoclonic jerks .…”

mentioning

confidence: 99%

The role of the cerebellum in the pathogenesis of cortical myoclonus

et al. 2014

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The putative involvement of the cerebellum in the pathogenesis of cortical myoclonic syndromes has been long hypothesized, as neuropathological changes in patients with cortical myoclonus have most commonly been found in the cerebellum rather than in the suspected culprit, the primary somatosensory cortex. A model of increased cortical excitability due to loss of cerebellar inhibitory control via cerebello-thalamo-cortical connections has been proposed, but evidence remains equivocal. Here, we explore this hypothesis by examining syndromes that present with cortical myoclonus and ataxia. We first describe common clinical characteristics and underlying neuropathology. We critically view information on cerebellar physiology with regard to motorcortical output and compare findings between hypothesized and reported neurophysiological changes in conditions with cortical myoclonus and ataxia. We synthesize knowledge and focus on neurochemical changes in these conditions. Finally, we propose that the combination of alterations in inhibitory neurotransmission and the presence of cerebellar pathology are important elements in the pathogenesis of cortical myoclonus.

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“…Additional somatosensory‐evoked potential (SSEP) analysis revealed no “giant SSEP” associated with cortical myoclonus . A successive, more exhaustive, polymyography revealed a myoclonus with brief burst duration between 50 and 80 ms with a consistent craniocaudal recruitment sequence . After averaging of 37 epochs (with the right trapezius muscle as a reference), a consistent recruitment sequence was noted in which subsequently the lower brainstem musculature (trapezius, N XI), other lower brainstem musculature (sternocleidomastoid, N XI), higher brainstem musculature (orbicularis oris, N VII), and muscles of the arm and leg (with a proximal‐distal gradient) were activated (Fig.…”

Section: Casementioning

confidence: 96%