Enhanced dorsal premotor–motor inhibition in cervical dystonia

Richardson, Sarah Pirio

doi:10.1016/j.clinph.2014.10.140

Cited by 21 publications

(17 citation statements)

References 28 publications

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“…The CSP evaluation in dystonia has not produced consistent results. Most studies report a decrease (Chen et al, 1997; Filipović et al, 1997; Rona et al, 1998; Pirio Richardson, 2015), or a trend toward a reduction of CSP (Schwenkreis et al, 1999), interpreted as a correlate to the cortical hyperexcitability, more rarely unchanged (Stinear and Byblow, 2004). Furthermore, to assess the neurons membrane excitability in dystonia, the MT, and the RC (Ziemann et al, 1996a; Chen et al, 1997; Werhahn et al, 1999; Ziemann et al, 2004; Murase et al, 2005) were assessed and were consistently normal in both primary and non-primary dystonia (Quartarone et al, 2009; Kojovic et al, 2013).…”

Section: Dystonia and Tms: A Window Into Pathophysiological Insightsmentioning

confidence: 99%

“…A conditioning TMS was applied to the dorsal PMC and then a test pulse to the ipsilateral motor cortex, at an interval of 6 ms, in nine patients with cervical dystonia, compared to nine healthy subjects. It resulted in enhanced dorsal premotor–motor cortical inhibition, independent of the severity of the disease (Pirio Richardson, 2015). This enhanced inhibition is more consistent with an endophenotypic marker widespread in the brain, as it has been evidenced in the setting of task-specific dystonia, such as writer’s cramp (Pirio Richardson et al, 2014), and is hypothesized by the authors as compensatory to reduce abnormal motor output and sustained muscle contraction.…”

Section: Dystonia and Tms: A Window Into Pathophysiological Insightsmentioning

confidence: 99%

“…The clinical evaluation, based on the Toronto Western Spasmodic Torticollis rating Scale (TWSTRS), was performed before and after each session. Lower TWSTRS scores, indicating improvement, were observed after rTMS over the premotor and motor cortical areas (Pirio Richardson, 2015). These results in cervical dystonia are in line with the efficacy of targeting the premotor and the motor cortices in focal hand dystonia (Siebner et al, 2003; Murase et al, 2005; Borich et al, 2009; Kimberley et al, 2013).…”

Section: Therapeutic Procedures In Dystoniamentioning

confidence: 99%

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Contribution of TMS and rTMS in the Understanding of the Pathophysiology and in the Treatment of Dystonia

Lozeron

Poujois

Richard

et al. 2016

Front. Neural Circuits

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Dystonias represent a heterogeneous group of movement disorders responsible for sustained muscle contraction, abnormal postures, and muscle twists. It can affect focal or segmental body parts or be generalized. Primary dystonia is the most common form of dystonia but it can also be secondary to metabolic or structural dysfunction, the consequence of a drug’s side-effect or of genetic origin. The pathophysiology is still not elucidated. Based on lesion studies, dystonia has been regarded as a pure motor dysfunction of the basal ganglia loop. However, basal ganglia lesions do not consistently produce dystonia and lesions outside basal ganglia can lead to dystonia; mild sensory abnormalities have been reported in the dystonic limb and imaging studies have shown involvement of multiple other brain regions including the cerebellum and the cerebral motor, premotor and sensorimotor cortices. Transcranial magnetic stimulation (TMS) is a non-invasive technique of brain stimulation with a magnetic field applied over the cortex allowing investigation of cortical excitability. Hyperexcitability of contralateral motor cortex has been suggested to be the trigger of focal dystonia. High or low frequency repetitive TMS (rTMS) can induce excitatory or inhibitory lasting effects beyond the time of stimulation and protocols have been developed having either a positive or a negative effect on cortical excitability and associated with prevention of cell death, γ-aminobutyric acid (GABA) interneurons mediated inhibition and brain-derived neurotrophic factor modulation. rTMS studies as a therapeutic strategy of dystonia have been conducted to modulate the cerebral areas involved in the disease. Especially, when applied on the contralateral (pre)-motor cortex or supplementary motor area of brains of small cohorts of dystonic patients, rTMS has shown a beneficial transient clinical effect in association with restrained motor cortex excitability. TMS is currently a valuable tool to improve our understanding of the pathophysiology of dystonia but large controlled studies using sham stimulation are still necessary to delineate the place of rTMS in the therapeutic strategy of dystonia. In this review, we will focus successively on the use of TMS as a tool to better understand pathophysiology, and the use of rTMS as a therapeutic strategy.

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Section: Dystonia and Tms: A Window Into Pathophysiological Insightsmentioning

confidence: 99%

Section: Dystonia and Tms: A Window Into Pathophysiological Insightsmentioning

confidence: 99%

Section: Therapeutic Procedures In Dystoniamentioning

confidence: 99%

See 1 more Smart Citation

Contribution of TMS and rTMS in the Understanding of the Pathophysiology and in the Treatment of Dystonia

Lozeron

Poujois

Richard

et al. 2016

Front. Neural Circuits

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show abstract

“…Cervical dystonia is a chronic neurological disorder characterized by sustained and involuntary contractions of the neck muscles, and is the most common form of focal dystonia (Xiao et al, 2012). Cervical dystonia has traditionally been ascribed to dysfunction of the basal ganglia (Galardi et al, 1996;Naumann et al, 1998), but abnormalities have been observed in many other brain regions including the cerebellum (Batla et al, 2015), prefrontal cortex , midbrain (Holmes et al, 2012), motor cortex (Richardson, 2015), and somatosensory cortex (Prudente et al, 2016). This has led to the suggestion that cervical dystonia is a 'network disorder' resulting from dysfunction in multiple different brain regions (Jinnah et al, 2006).…”

Section: Introductionmentioning

confidence: 99%

Network localization of cervical dystonia based on causal brain lesions

Corp

Joutsa

Darby

et al. 2019

Brain

171

177

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These authors contributed equally to this work.Cervical dystonia is a neurological disorder characterized by sustained, involuntary movements of the head and neck. Most cases of cervical dystonia are idiopathic, with no obvious cause, yet some cases are acquired, secondary to focal brain lesions. These latter cases are valuable as they establish a causal link between neuroanatomy and resultant symptoms, lending insight into the brain regions causing cervical dystonia and possible treatment targets. However, lesions causing cervical dystonia can occur in multiple different brain locations, leaving localization unclear. Here, we use a technique termed 'lesion network mapping', which uses connectome data from a large cohort of healthy subjects (resting state functional MRI, n = 1000) to test whether lesion locations causing cervical dystonia map to a common brain network. We then test whether this network, derived from brain lesions, is abnormal in patients with idiopathic cervical dystonia (n = 39) versus matched controls (n = 37). A systematic literature search identified 25 cases of lesion-induced cervical dystonia. Lesion locations were heterogeneous, with lesions scattered throughout the cerebellum, brainstem, and basal ganglia. However, these heterogeneous lesion locations were all part of a single functionally connected brain network. Positive connectivity to the cerebellum and negative connectivity to the somatosensory cortex were specific markers for cervical dystonia compared to lesions causing other neurological symptoms. Connectivity with these two regions defined a single brain network that encompassed the heterogeneous lesion locations causing cervical dystonia. These cerebellar and somatosensory regions also showed abnormal connectivity in patients with idiopathic cervical dystonia. Finally, the most effective deep brain stimulation sites for treating dystonia were connected to these same cerebellar and somatosensory regions identified using lesion network mapping. These results lend insight into the causal neuroanatomical substrate of cervical dystonia, demonstrate convergence across idiopathic and acquired dystonia, and identify a network target for dystonia treatment. Abbreviations: DBS = deep brain stimulation; rs-fcMRI = resting state functional connectivity MRI Brain network of cervical dystonia

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“…How these findings may relate to CD in humans remain to be established. Pathological studies and physiological investigations of individuals with CD have pointed to abnormalities of the cerebral cortex, cerebellum, or vestibular pathways (8–13). Routine clinical imaging studies only rarely reveal overt anatomical defects in the brain in individuals with CD, and these are scattered across many regions such as the cerebral cortex, basal ganglia, cerebellum, midbrain, brainstem, and spinal cord (14).…”

Section: Introductionmentioning

confidence: 99%

A Functional Magnetic Resonance Imaging Study of Head Movements in Cervical Dystonia

et al. 2016

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Cervical dystonia (CD) is a neurological disorder characterized by abnormal movements and postures of the head. The brain regions responsible for these abnormal movements are not well understood, because most imaging techniques for assessing regional brain activity cannot be used when the head is moving. Recently, we mapped brain activation in healthy individuals using functional magnetic resonance imaging during isometric head rotation, when muscle contractions occur without actual head movements. In the current study, we used the same methods to explore the neural substrates for head movements in subjects with CD who had predominantly rotational abnormalities (torticollis). Isometric wrist extension was examined for comparison. Electromyography of neck and hand muscles ensured compliance with tasks during scanning, and any head motion was measured and corrected. Data were analyzed in three steps. First, we conducted within-group analyses to examine task-related activation patterns separately in subjects with CD and in healthy controls. Next, we directly compared task-related activation patterns between participants with CD and controls. Finally, considering that the abnormal head movements in CD occur in a consistently patterned direction for each individual, we conducted exploratory analyses that involved normalizing data according to the direction of rotational CD. The between-group comparisons failed to reveal any significant differences, but the normalization procedure in subjects with CD revealed that isometric head rotation in the direction of dystonic head rotation was associated with more activation in the ipsilateral anterior cerebellum, whereas isometric head rotation in the opposite direction was associated with more activity in sensorimotor cortex. These findings suggest that the cerebellum contributes to abnormal head rotation in CD, whereas regions in the cerebral cortex are involved in opposing the involuntary movements.

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Enhanced dorsal premotor–motor inhibition in cervical dystonia

Cited by 21 publications

References 28 publications

Contribution of TMS and rTMS in the Understanding of the Pathophysiology and in the Treatment of Dystonia

Contribution of TMS and rTMS in the Understanding of the Pathophysiology and in the Treatment of Dystonia

Network localization of cervical dystonia based on causal brain lesions

A Functional Magnetic Resonance Imaging Study of Head Movements in Cervical Dystonia

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