Impairment of cortical inhibition in writer's cramp as revealed by changes in electromyographic silent period after transcranial magnetic stimulation

Filipović, Saša R.; Ljubisavljević, M.; Svetel, Marina; Milanović, Svetlana; Kačar, Aleksandra; Kostić, Vladimir

doi:10.1016/s0304-3940(97)13370-5

Cited by 110 publications

(64 citation statements)

References 21 publications

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“…Motor-evoked potential (MEP) recruitment was found to be enhanced and short-interval intracortical inhibition (SICI) reduced in patients with writer's cramp 84,85 and torticollis. 86 The silent period (SP), 87,88 similar to SICI, is reduced in dystonia. These data suggest that excitability is increased in the motor cortex in dystonia and, when taken together with rCBF studies of decreased activation in primary dystonia, suggest a reduction of intracortical inhibition in this disorder.…”

Section: Tmsmentioning

confidence: 99%

Pathophysiology of dystonia: A neuronal model

2002

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Dystonia has commonly been thought to represent a disorder of basal ganglia function. Although long considered a hyperkinetic movement disorder, the evidence to support such a classification was based on the presence of excessive involuntary movement, not on physiological data. Only recently, with the return of surgical procedures using microelectrode guidance for the treatment of dystonia, has electrophysiological data demonstrated an alteration in mean discharge rate, somatosensory responsiveness and the pattern of neuronal activity in the basal ganglia thalamocortical motor circuit. Previous models of dystonia suggested that reduced mean discharge rates in the globus pallidus internus (GPi) led to unopposed increases in activity in the thalamocortical circuit that precipitated the development of involuntary movement associated with dystonia. This model has subsequently been modified given the clear improvement in dystonic symptoms following lesions in the GPi, a procedure that is associated with a further reduction in pallidal output. The improvement in dystonia following pallidal lesions is difficult to reconcile with the "rate" hypothesis for hypokinetic and hyperkinetic movement disorders and has led to the development of alternative models that, in addition to rate, incorporate changes in pattern, somatosensory responsiveness and degree of synchronization of neuronal activity. Present models of dystonia, however, must not only take these changes into account but must reconcile these changes with the reported changes in cortical excitability reported with transcranial magnetic stimulation, the changes in metabolic activity in cortical and subcortical structures documented by positron emission tomography (PET), and the alterations in spinal and brainstem reflexes. A model incorporating these changes together with the reported changes in neuronal activity in the basal ganglia and thalamus is presented.

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Section: Tmsmentioning

confidence: 99%

Pathophysiology of dystonia: A neuronal model

2002

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“…2 Several studies on patients with writer's cramp have demonstrated reduced inhibition at various motor system levels, 2,3 particularly in the hand primary motor area. 4,5 Reduced inhibition at cortical level may be responsible for reduced specificity of the muscle activation during movement. Patients with focal hand dystonia also show abnormalities in movement preparation.…”

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confidence: 99%

Corticospinal excitability during motor imagery of a simple tonic finger movement in patients with writer's cramp

et al. 2005

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Motor imagery (MI) is the mental rehearsal of a motor act without overt movement. Using transcranial magnetic stimulation (TMS), we tested the effect of MI on corticospinal excitability in patients with writer's cramp. In 10 patients with writer's cramp and 10 healthy controls, we applied focal TMS over each primary motor area and recorded motor evoked potentials (MEPs) from contralateral hand and arm muscles while participants imagined a tonic abduction of the index finger contralateral to the stimulated hemisphere. In healthy controls and patients, the MEP amplitude in the relaxed first dorsal interosseus muscle (FDI) showed a muscle-specific increase during MI; however, the increase was less pronounced in patients than in healthy controls. In addition, in patients but not in controls, the MEP amplitude also increased in hand and forearm muscles not involved in the imagined movement. This abnormal spread of facilitation was observed in the affected and unaffected upper limb. MI of simple hand movements is less efficient and less focussed in patients with writer's cramp than it is in normal subjects.

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“…For example, Filipović et al (1997) showed that cortical inhibition in writer's cramp is impaired during writing tasks, but not necessarily during simple aimless contractions of the same muscle with the similar force, while Beck et al (2008) showed that motor cortex inhibition in hand dystonia is selectively impaired at the initiation phase of a movement.…”

mentioning

confidence: 99%

Dystonia – a disorder of dynamics of brain plasticity modulation?

Filipović

2012

Acta Physiologica

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Impairment of cortical inhibition in writer's cramp as revealed by changes in electromyographic silent period after transcranial magnetic stimulation

Cited by 110 publications

References 21 publications

Pathophysiology of dystonia: A neuronal model

Pathophysiology of dystonia: A neuronal model

Corticospinal excitability during motor imagery of a simple tonic finger movement in patients with writer's cramp

Dystonia – a disorder of dynamics of brain plasticity modulation?

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