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Dystonic Patients (dystonic + patient)

Distribution by Scientific Domains

Medical Sciences	100%

Selected Abstracts

Evolution of Brain Impedance in Dystonic Patients Treated by GPi Electrical Stimulation

NEUROMODULATION, Issue 2 2004
Simone Hemm BME.
Abstract Deep Brain Stimulation is an effective treatment of generalized dystonia. Optimal stimulation parameters vary between patients. This article investigates the influence of electrical brain impedance and delivered current on the brain response to stimulation. Twenty-four patients were bilaterally stimulated in the globus pallidus internus through two implanted four-contact electrodes. The variation of brain impedance and current measurements was correlated with stimulation parameters, time course, and clinical outcome. When a contact was activated, a statistically significant and reversible decrease of brain impedance was found. Impedance and current values and their variations with time significantly differed between patients. The absolute impedance did not significantly correlate with the final outcome. We conclude that the reversible decrease of impedance reflects an adaptive long-term mechanism, which could be due to a plasticity phenomenon, but has no prognostic value. Impedance and current measurements give new complementary information for parameter adjustment and trouble shooting and should therefore be included in all patients' follow-up. [source]

Early cinematographic studies of generalized dystonia

MOVEMENT DISORDERS, Issue 10 2006
Christopher G. Goetz MD
Abstract Among movement disorders, dystonia is a particularly complex phenomenon and difficult to describe. For this reason, cinematographic documents were particularly important to the establishment of this disorder within the neurological nosology. The seminal 1944 article on dystonia by E. Herz anchored its arguments in moving film documentation, published with frame-by-frame demonstrations of dystonic patients. Although the original films that comprised the basis of this article have not been located, two related contemporaneous films, one by Herz in association with T.J. Putnam, and one by S.P. Goodhart and B.H. Balser, have been located. Incorporating standard and several innovative filming techniques, these films and their accompanying text material capture the particular movements of dystonia, revealing the anatomical patterns of the twisting spasms, and emphasize their action exacerbation. The films demonstrate the variety of dystonic movements appreciated during this period, consider psychogenic, postencephalitic, and hereditary forms, and refer to the treatment of dystonia by surgery and plaster casts. © 2006 Movement Disorder Society [source]

Impaired heteronymous somatosensory motor cortical inhibition in dystonia

MOVEMENT DISORDERS, Issue 11 2003
Laura Bertolasi MD
Abstract A typical pathophysiological abnormality in dystonia is cocontraction of antagonist muscles, with impaired reciprocal inhibitory mechanisms in the spinal cord. Recent experimental data have shown that inhibitory interactions between antagonist muscles have also a parallel control at the level of the sensorimotor cortex. The aim of this work was to study heteronymous effects of a median nerve stimulus on the corticospinal projections to forearm muscles in dystonia. We used the technique of antagonist cortical inhibition, which assesses the conditioning effect of median nerve afferent input on motor evoked potentials (MEPs) elicited by transcranial magnetic stimulation (TMS) in ipsilateral forearm extensor muscles at rest. Nine healthy subjects and 10 patients with torsion dystonia participated in the study. MEPs and somatosensory evoked potentials were normal in patients. In healthy subjects, median nerve stimulation at 15- to 18-msec intervals inhibited the test MEPs in forearm extensors. In dystonic patients, median nerve stimulation delivered at the same conditioning,test intervals elicited significantly less inhibition of the test MEP. On the whole, these data suggest an impaired sensory,motor integration in dystonia and, more specifically, the decreased antagonistic cortical inhibition could suggest that functional interactions between antagonist muscles are primarily impaired at the cortical level. © 2003 Movement Disorder Society [source]

Deficits of temporal discrimination in dystonia are independent from the spatial distance between the loci of tactile stimulation

MOVEMENT DISORDERS, Issue 2 2002
Michele Tinazzi MD
Abstract To assess whether spatial variables influence deficits of temporal somesthetic discrimination in dystonic patients, 10 patients with idiopathic dystonia and 12 healthy controls were tested with pairs of non-noxious electrical stimuli separated by different time intervals. Stimuli were delivered: (1) to the pad of the index finger (same-point condition), (2) to the pad and to the base of the index finger (same-finger condition), and (3) to the pad of the index and ring fingers (different-finger condition). Subjects were asked to report whether they perceived single or double stimuli in the first condition and synchronous or asynchronous stimuli in the second and third conditions. Somesthetic temporal discrimination thresholds (STDTs) were obtained by computing the shortest time interval at which stimuli, applied to the left or the right hand, were perceived as separate in the first condition or asynchronous in the second and third conditions. STDTs were significantly higher in dystonic patients than controls in all three conditions. In both dystonia patients and controls, STDTs resulted highest in conditions whereby stimuli were maximally separated in space. Results extend current knowledge of deficits of somesthetic temporal discrimination in dystonia by showing that temporal deficits are not influenced by spatial variables. © 2002 Movement Disorder Society. [source]

Somatosensory disinhibition in dystonia

MOVEMENT DISORDERS, Issue 4 2001
Emma Frasson MD
Abstract Despite the fact that somatosensory processing is inherently dependent on inhibitory functions, only excitatory aspects of the somatosensory feedback have so far been assessed in dystonic patients. We studied the recovery functions of spinal N13, brainstem P14, parietal N20, P27, and frontal N30 somatosensory evoked potentials (SEPs) after paired median nerve stimulation in 10 patients with dystonia and in 10 normal subjects. The recovery functions were assessed (conditioning stimulus: S1; test stimulus: S2) at interstimuls intervals (ISIs) of 5, 20, and 40 ms. SEPs evoked by S2 were calculated by subtracting the SEPs of the S1 only response from the SEPs of the response to the paired stimuli (S1 + S2), and their amplitudes were compared with those of the control response (S1) at each ISI considered. This ratio, (S2/S1)*100, investigates changes in the excitability of the somatosensory system. No significant difference was found in SEP amplitudes for single stimulus (S1) between dystonic patients and normal subjects. The (S2/S1)*100 ratio at the ISI of 5 ms did not significantly differ between dystonic patients and normal subjects, but at ISIs of 20 and 40 ms, this ratio was significantly higher in patients than in normals for spinal N13 and cortical N20, P27, N30 SEPs. These findings suggest that in dystonia there is an impaired inhibition at spinal and cortical levels of the somatosensory system which would lead to an abnormal sensory assistance to the ongoing motor programs, ultimately resulting in the motor abnormalities present in this disease. © 2001 Movement Disorder Society. [source]