In dystonic and spastic movement disorders, abnormalities of motor control and somatosensory processing as well as cortical modulations associated with clinical improvement after botulinum toxin A (BoNT-A) treatment have been reported, but electrophysiological evidence remains controversial. In the present observational study, we aimed to uncover central correlates of post-stroke spasticity (PSS) and BoNT-A-related changes in the sensorimotor cortex by investigating the cortical components of somatosensory evoked potentials (SEPs). Thirty-one chronic stroke patients with PSS of the upper limb were treated with BoNT-A application into the affected muscles and physiotherapy. Clinical and electrophysiological evaluations were performed just before BoNT-A application (W0), then 4 weeks (W4) and 11 weeks (W11) later. PSS was evaluated with the modified Ashworth scale (MAS). Median nerve SEPs were examined in both upper limbs with subsequent statistical analysis of the peak-to-peak amplitudes of precentral P22/N30 and postcentral N20/P23 components. At baseline (W0), postcentral SEPs were significantly lower over the affected cortex. At follow up, cortical SEPs did not show any significant changes attributable to BoNT-A and/or physiotherapy, despite clear clinical improvement. Our results imply that conventional SEPs are of limited value in evaluating cortical changes after BoNT-A treatment and further studies are needed to elucidate its central actions.

• MeSH
• Botulinum Toxins, Type A administration & dosage   MeSH
• Stroke complications   physiopathology   MeSH
• Adult MeSH
• Upper Extremity innervation   MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Follow-Up Studies MeSH
• Neuromuscular Agents administration & dosage   MeSH
• Median Nerve drug effects   physiopathology   MeSH
• Stroke Rehabilitation methods   MeSH
• Aged MeSH
• Evoked Potentials, Somatosensory drug effects   MeSH
• Somatosensory Cortex drug effects   physiopathology   MeSH
• Muscle Spasticity diagnosis   drug therapy   etiology   physiopathology   MeSH
• Exercise Therapy methods   MeSH
• Treatment Outcome MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Young Adult MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Observational Study MeSH
• Names of Substances
• Botulinum Toxins, Type A MeSH
• Neuromuscular Agents MeSH

The complex phenomenological understanding of dystonia has transcended from the clinics to genetics, imaging and neurophysiology. One way in which electrophysiology will impact into the clinics are cases wherein a dystonic clinical presentation may not be typical or a "forme fruste" of the disorder. Indeed, the physiological imprints of dystonia are present regardless of its clinical manifestation. Underpinnings in the understanding of dystonia span from the peripheral, segmental and suprasegmental levels to the cortex, and various electrophysiological tests have been applied in the course of time to elucidate the origin of dystonia pathophysiology. While loss of inhibition remains to be the key finding in this regard, intricacies and variabilities exist, thus leading to a notion that perhaps dystonia should best be gleaned as network disorder. Interestingly, the complex process has now spanned towards the understanding in terms of networks related to the cerebellar circuitry and the neuroplasticity. What is evolving towards a better and cohesive view will be neurophysiology attributes combined with structural dynamic imaging. Such a sound approach will significantly lead to better therapeutic modalities in the future.

• Keywords
• Brain plasticity, Dystonia, Network disorder, Neurophysiology,
• MeSH
• Dystonic Disorders * MeSH
• Dystonia * MeSH
• Humans MeSH
• Cerebellum MeSH
• Cerebral Cortex MeSH
• Neurophysiology MeSH
• Check Tag
• Humans MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH

In dystonic and spastic movement disorders, however different in their pathophysiological mechanisms, a similar impairment of sensorimotor control with special emphasis on afferentation is assumed. Peripheral intervention on afferent inputs evokes plastic changes within the central sensorimotor system. Intramuscular application of botulinum toxin type A (BoNT-A) is a standard evidence-based treatment for both conditions. Apart from its peripheral action on muscle spindles, a growing body of evidence suggests that BoNT-A effects could also be mediated by changes at the central level including cerebral cortex. We review recent studies employing electrophysiology and neuroimaging to investigate how intramuscular application of BoNT-A influences cortical reorganization. Based on such data, BoNT-A becomes gradually accepted as a promising tool to correct the maladaptive plastic changes within the sensorimotor cortex. In summary, electrophysiology and especially neuroimaging studies with BoNT-A further our understanding of pathophysiology underlying dystonic and spastic movement disorders and may consequently help develop novel treatment strategies based on neural plasticity.

• Keywords
• botulinum toxin, dystonia, electrophysiology, functional magnetic resonance imaging, neural plasticity, spasticity,
• MeSH
• Botulinum Toxins, Type A adverse effects   therapeutic use   MeSH
• Dystonia diagnosis   drug therapy   physiopathology   MeSH
• Muscle, Skeletal innervation   MeSH
• Humans MeSH
• Magnetic Resonance Imaging MeSH
• Brain Mapping MeSH
• Cerebral Cortex diagnostic imaging   drug effects   physiopathology   MeSH
• Neuromuscular Agents adverse effects   therapeutic use   MeSH
• Neuronal Plasticity drug effects   MeSH
• Recovery of Function MeSH
• Motor Activity drug effects   MeSH
• Treatment Outcome MeSH
• Animals MeSH
• Check Tag
• Humans MeSH
• Animals MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Review MeSH
• Names of Substances
• Botulinum Toxins, Type A MeSH
• Neuromuscular Agents MeSH

Botulinum toxin type A (BoNT) is considered an effective therapeutic option in cervical dystonia (CD). The pathophysiology of CD and other focal dystonias has not yet been fully explained. Results from neurophysiological and imaging studies suggest a significant involvement of the basal ganglia and thalamus, and functional abnormalities in premotor and primary sensorimotor cortical areas are considered a crucial factor in the development of focal dystonias. Twelve BoNT-naïve patients with CD were examined with functional MRI during a skilled hand motor task; the examination was repeated 4 weeks after the first BoNT injection to the dystonic neck muscles. Twelve age- and gender-matched healthy controls were examined using the same functional MRI paradigm without BoNT injection. In BoNT-naïve patients with CD, BoNT treatment was associated with a significant increase of activation in finger movement-induced fMRI activation of several brain areas, especially in the bilateral primary and secondary somatosensory cortex, bilateral superior and inferior parietal lobule, bilateral SMA and premotor cortex, predominantly contralateral primary motor cortex, bilateral anterior cingulate cortex, ipsilateral thalamus, insula, putamen, and in the central part of cerebellum, close to the vermis. The results of the study support observations that the BoNT effect may have a correlate in the central nervous system level, and this effect may not be limited to cortical and subcortical representations of the treated muscles. The results show that abnormalities in sensorimotor activation extend beyond circuits controlling the affected body parts in CD even the first BoNT injection is associated with changes in sensorimotor activation. The differences in activation between patients with CD after treatment and healthy controls at baseline were no longer present.

• Keywords
• Botulinum toxin, Brain plasticity, Cervical dystonia, Functional MRI,
• MeSH
• Afferent Pathways diagnostic imaging   drug effects   MeSH
• Botulinum Toxins, Type A therapeutic use   MeSH
• Adult MeSH
• Oxygen blood   MeSH
• Middle Aged MeSH
• Humans MeSH
• Magnetic Resonance Imaging methods   MeSH
• Statistics, Nonparametric MeSH
• Neuromuscular Agents therapeutic use   MeSH
• Image Processing, Computer-Assisted MeSH
• Psychomotor Performance drug effects   MeSH
• Aged MeSH
• Sensorimotor Cortex diagnostic imaging   drug effects   MeSH
• Torticollis * diagnostic imaging   drug therapy   physiopathology   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Names of Substances
• Botulinum Toxins, Type A MeSH
• Oxygen MeSH
• Neuromuscular Agents MeSH

Sensory trick is an unusual clinical feature in cervical dystonia that attenuates disease symptoms by slight touch to a specific area of the face or head. Using a semi-quantitative questionnaire-based study of 197 patients with idiopathic cervical dystonia, we sought to determine probable pathophysiologic correlates, with the wider aim of examining its eventual clinical significance. The typical sensory trick, i.e., light touch, not necessitating the use of force leading to simple overpowering of dystonic activity, was present in 83 (42.1 %) patients. The vast majority of the patients required a specific sequence of sensorimotor inputs, including touch sensation on the face or different areas of the head, and also sensory and motor input of the hand itself. Deviations often led to a significant decrease in effectiveness and lack of expected benefit. Moreover, patients able to perform the maneuver reported compellingly higher subjective effect of botulinum toxin treatment (median 7 vs. 5 on a scale of 0-10; p < 0.0001) and lower depression score (median 10 vs. 14 on the Montgomery Åsberg Depression Rating scale; p < 0.001). Overall, the results point to marked disruption of sensorimotor networks in cervical dystonia. The mechanism of the sensory trick action may be associated with balancing the abnormal activation patterns by specific sensorimotor inputs. Its presence may be considered a positive predictive factor for responsiveness to botulinum toxin treatment.

• Keywords
• Botulinum toxin, Cervical dystonia, Sensory trick, Treatment effectiveness,
• MeSH
• Adult MeSH
• Physical Stimulation * MeSH
• Touch * MeSH
• Middle Aged MeSH
• Humans MeSH
• Surveys and Questionnaires MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Torticollis * MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged, 80 and over MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

Traditionally, the pathophysiology of cervical dystonia has been regarded mainly in relation to neurochemical abnormities in the basal ganglia. Recently, however, substantial evidence has emerged for cerebellar involvement. While the absence of neurological "cerebellar signs" in most dystonia patients may be considered at least provoking, there are more subtle indications of cerebellar dysfunction in complex, demanding tasks. Specifically, given the role of the cerebellum in the neural representation of time, in the millisecond range, dysfunction to this structure is considered to be of greater importance than dysfunction of the basal ganglia. In the current study, we investigated the performance of cervical dystonia patients on a computer task known to engage the cerebellum, namely, the interception of a moving target with changing parameters (speed, acceleration, and angle) with a simple response (pushing a button). The cervical dystonia patients achieved significantly worse results than a sample of healthy controls. Our results suggest that the cervical dystonia patients are impaired at integrating incoming visual information with motor responses during the prediction of upcoming actions, an impairment we interpret as evidence of cerebellar dysfunction.

• MeSH
• Basal Ganglia physiopathology   MeSH
• Adult MeSH
• Dystonia congenital   MeSH
• Middle Aged MeSH
• Humans MeSH
• Motor Cortex physiopathology   MeSH
• Cerebellum physiopathology   MeSH
• Movement physiology   MeSH
• Psychomotor Performance physiology   MeSH
• Reaction Time physiology   MeSH
• Aged MeSH
• Torticollis congenital   physiopathology   MeSH
• Time Perception physiology   MeSH
• Check Tag
• Adult MeSH
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH

The aim of this study was to find whether 1-Hz cerebellar repetitive transcranial magnetic stimulation (rTMS) could affect upper limb movement in early-stage Parkinson's disease (PD). Twenty patients with PD underwent one session with real and one with sham rTMS. rTMS (1 Hz, 600 pulses) was targeted at the right lateral cerebellum. Before and after rTMS, patients performed two motor tests with their fingers and hands (ball test, nine-hole peg test). The duration of these tests was measured. There were statistically significant differences (p < 0.05) in the results of the tests after real stimulation and sham stimulation. We excluded the impact of learning. After real rTMS, we observed a significantly faster response in the ball test and a slower response in the nine-hole peg test, both on the right upper limb. This study indicates the influence of 1-Hz cerebellar rTMS in modifying the voluntary movements of the upper limb in PD. This influence is differentiated: the improvement of gross motor skills and the worsening of fine motor skills.

• MeSH
• Single-Blind Method MeSH
• Middle Aged MeSH
• Humans MeSH
• Motor Skills physiology   MeSH
• Cerebellum physiology   MeSH
• Parkinson Disease physiopathology   therapy   MeSH
• Arm physiology   MeSH
• Psychomotor Performance physiology   MeSH
• Reaction Time physiology   MeSH
• Aged MeSH
• Transcranial Magnetic Stimulation methods   MeSH
• Check Tag
• Middle Aged MeSH
• Humans MeSH
• Male MeSH
• Aged MeSH
• Female MeSH
• Publication type
• Journal Article MeSH
• Research Support, Non-U.S. Gov't MeSH
• Randomized Controlled Trial MeSH