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Academia Mexicana de Neurología, A.C.

2008, Number 1

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Rev Mex Neuroci 2008; 9 (1)

Physiopathological studies in dystonias

Gómez FL, Maragoto RC, López FG, Padilla PE

Language: Spanish
References: 26
Page: 8-13
PDF size: 144.86 Kb.


ABSTRACT

Introduction: Dystonia is a syndrome characterised by sustained muscle contractions which frequently cause twisting and repetitive movements or abnormal postures; it could be the result of an imbalance of excitation and inhibition. Objectives: To present the results of 2 studied groups of patients with focal and generalized dystonias, in whom we explored different aspects related to cortical excitability and somatotopic organization in primary motor area. Patients and methods: We selected 30 focal dystonic patients(FD) and 10 with generalized idiopathic dystonia (GID). In all of them, motor threshold with transcranial magnetic stimulation(TMS) was calculated and in patients with FD a motor mapping with TMS procedure was carried out. Patients with GID were explored to evaluate the total duration of the electromyographic silent period (EMGSP) with TMS; and the effects of bilateral pallidotomy performed by stereotactic surgery before and 1, 3, 6, 12, 24 and 36 months after of surgery. Ten healthy control subjects were included in the investigation in order to complete the statistical analysis. Results: It was demonstrated the presence of statistically significant differences in motor area with responses to TMS in patients with FD (p ‹ 0.05) in the contralateral hemisphere to the symptomatic limb; the behaviour of the active motor threshold also was different in patients compared to control subjects. GID patients had shorter EMGSP than control subjects (p ‹ 0.05); surgery induced favourable clinical changes, and an increment in the duration of the EMGSP. Conclusion: Dystonia is a maladaptive form of neuroplasticity which is expressed via a dysfunction in the excitatory/inhibitory balance in cortical and subcortical motor circuits.


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