الفهرس 
Introduction and Aim of the WorkOnly 14 pages are availabe for public view
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Abstract
Summery and Conclusion
Background: Cortical excitability of the primary motor cortex is abnormally increased in patients with focal dystonia. Therefore, decreasing cortical excitability by low frequency rTMS of the motor cortex might results in beneficial effects on motor functions in focal dystonia.
Objective: To study the effect of repetitive transcranial magnetic stimulation (rTMS) of the motor cortex on the cortical excitability and any clinical improvement in focal dystonia.
Subjects and Methods: Fifteen focal dystonia patients and 15 normal subjects as a control group were included in this study. Complete history taking and clinical examination by Fahn-Marsden dystonia rating scale (FMD scale) were applied for all the patients. Assessment of cortical excitability by measuring resting motor threshold (RMT), active motor threshold (AMT), motor evoked potential amplitude at 130% of the RMT, cortical silent period (CSP) at 125% of RMT and input-output curve were performed for all the patients and normal control group. Then, low frequency repetitive transcranial magnetic stimulation (rTMS) session, 1 Hz and intensity of RMT, was performed then all the parameters for assessment of cortical excitability were done again, after that both the patients group and the control group received daily session for consecutive 5 days then the parameters were assessed again after 5 days. Also FMD scale was evaluated for the patients group after 5 days.
Results: The mean age of the patients was 26.3 ± 10.05; the mean duration of illness was 7.07 ± 10.5, 60% of the patients diagnosed as hemidystonia, 20% as idiopathic torsion torticollus, 13% as dystonic writer’s cramp and 7% as lower limb dystonia.
At the base line assessment, there was significant difference between the patients group and normal control group regarding the RMT and CSP, but no significant difference regarding AMT, MEP amplitude and input-output curve.
After rTMS sessions, there were significant changes in RMT, AMT and CSP in patients but no changes could be detected in the normal control group but MEP amplitude and input-output curve showed no changes in patients or normal control group.
Regarding Clinical changes in dystonic patients as measured by FMD scale no significant clinical improvement could be detected.
So, we concluded that dystonia patients have definite cortical hyperexcitability and can be decreased by low frequency rTMS but no clinical improvement can be detected.
Recommendations
For the future research in this field we suggest to increase the sample of patients to allow better analysis of their data and to have more reliable results.
Also we suggest study homogeneous group of focal dystonia patients i.e. one group only to give more accurate results and study separate pathophysiology.
Further researches are needed to study other areas like premotor area and supplementary motor area to study the effect of their stimulation on focal dystonia.
Study cortical excitability in focal dystonia using paired-pulse stimulation is recommended to estimate of trans-synaptic excitability of inhibitory and excitatory interneuron circuits in the motor cortex.
Further studies are needed to test whether more reliable and specific effects can be obtained with different stimulation protocols, or by giving repeated days of stimulation, or by giving patients rTMS sessions when patients are performing tasks that activate certain neural circuits. However, a prerequisite for optimizing therapeutic efficacy of rTMS is a detailed knowledge of how rTMS interacts with the dysfunctional motor system in dystonia. The combination of rTMS with functional brain mapping provides a powerful approach to tackle these issues and will help to transfer rTMS from merely the scientific domain into a therapeutic application.
Finally, we recommend studying the effect of paired associative stimulation (PAS) in focal dystonia patients as the changes in cortical plasticity may be more beneficial than just decreasing the cortical hyperexcitability