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Query: UMLS:C0038454 (stroke)
 147,016 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Writer's cramp is a highly specific movement disorder in which handwriting is impaired while most other manual skills are often unaffected. On the basis of abnormal findings in experiments measuring the control of grip forces, it has been suggested that writer's cramp is caused by a deficit of sensorimotor integration. The aim of our study was to determine whether there is a functional link between sensory deficits, abnormalities in the control of grip force, and handwriting disorders. We compared the grip force and handwriting performance of writer's cramp patients with that of control subjects and with that of a stroke patient suffering a purely somatosensory deficit of his dominant hand (patient S1). We found that: (1) writer's cramp patients and patient S1 had elevated grip-force levels; (2) training reduced the grip force to near-normal levels in all writer's cramp patients but not in S1; (3) effortful writing performance also induced increased grip-force levels in healthy subjects; and (4) patient S1 had normal handwriting movements. These findings suggest that the elevated pretraining gripforce levels of writer's cramp patients might be a consequence of their effortful writing style and do not reflect a deficit of sensorimotor integration. Moreover, the good handwriting performance of patient S1 shows that a severe somatosensory deficit is not a sufficient condition for a handwriting disorder. These findings disagree with the sensorimotor explanation of writer's cramp.
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PMID:Is writer's cramp caused by a deficit of sensorimotor integration? 1124 74

Writer's cramp is a task-specific hand dystonia affecting handwriting. Clinical scores such as the Arm Dystonia Disability Scale (ADDS) or Writer's Cramp Rating Scale (WCRS) as well as kinematic analysis of handwriting movements have been used to assess functional impairment in affected patients. In 21 patients with writer's cramp and healthy controls, we analyzed the kinematics of writing and cyclic drawing movements. We rated the severity of dystonia using the ADDS and WCRS and correlated the clinical scores with movement kinematics. Mean stroke frequency was significantly reduced in dystonic patients. Drawing movements showed more frequently a decrease in stroke frequency than handwriting movements. During circle drawing, mean vertical peak velocity was more variable in patients relative to controls, indicating an impaired ability to reproduce the same kinematic pattern over time. An increase in vertical writing pressure was only observed during handwriting but not during circle drawing and may reflect a compensatory effort to stabilize the pencil. Kinematic measures and individual ADDS and WCRS scores did not correlate with each other. The lack of correlation is not surprising as ADDS, WCRS, and kinematic analysis probe different aspects of motor impairment. The ADDS characterizes how dystonia affects a set of fine manual tasks, whereas the WCRS scores the manifestation of dystonia during handwriting. Therefore, the clinical scores and kinematic analysis of handwriting provide complementary insights into motor impairment. Future studies need to address which combination of clinical scores and kinematic measures are most appropriate to quantify impairment in writer's cramp.
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PMID:How to assess motor impairment in writer's cramp. 1723 Apr 62

There is increasing evidence that the cerebellum has a role in the pathophysiology of primary focal hand dystonia and might provide an intervention target for non-invasive brain stimulation to improve function of the affected hand. The primary objective of this study was to determine if cerebellar transcranial direct current stimulation (tDCS) improves handwriting and cyclic drawing kinematics in people with hand dystonia, by reducing cerebellar-brain inhibition (CBI) evoked by transcranial magnetic stimulation (TMS). Eight people with dystonia (5 writer's dystonia, 3 musician's dystonia) and eight age-matched controls completed the study and underwent cerebellar anodal, cathodal and sham tDCS in separate sessions. Dystonia severity was assessed using the Writer's Cramp Rating Scale (WRCS) and the Arm Dystonia Disability Scale (ADDS). The kinematic measures that differentiated the groups were; mean stroke frequency during handwriting and fast cyclic drawing and average pen pressure during light cyclic drawing. TMS measures of cortical excitability were no different between people with FHD and controls. There was a moderate, negative relationship between TMS-evoked CBI at baseline and the WRCS in dystonia. Anodal cerebellar tDCS reduced handwriting mean stroke frequency and average pen pressure, and increased speed and reduced pen pressure during fast cyclic drawing. Kinematic measures were not associated with a decrease in CBI within an individual. In conclusion, cerebellar anodal tDCS appeared to improve kinematics of handwriting and circle drawing tasks; but the underlying neurophysiological mechanism remains uncertain. A study in a larger homogeneous population is needed to further investigate the possible therapeutic benefit of cerebellar tDCS in dystonia.
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PMID:Anodal transcranial direct current stimulation to the cerebellum improves handwriting and cyclic drawing kinematics in focal hand dystonia. 2604 19