Abstract

Objective: In the treatment of tremor and rigidity in patients with Parkinson’s disease the nucleus ventralis intermedius of thalamus has been an exquisite target that can be localized easily on ventriculograms. This experimental study is aimed to evaluate the effects of electrical stimulation of vim nucleus on symptoms and signs of Parkinson’s disease.

Methods: Eleven deep drain stimulators were stereotactically implanted in the nucleus ventralis intermedius of 10 patients who had medically intractable Parkinson’s disease. Postoperative evaluations were performed using conventional Unified Parkinson’s Disease Rating Scale (UPDRS). We also assessed the effects of underlying variables on the surgical outcome.

Results: Our patients were followed up for a mean period of 18 months. Considering UPDRS, all patients showed significant improvements in their tremor scores, (mean=75.75%). Thalamic stimulation decreased rigidity scores at a mean of 75.09%. The mean improvement of motor function scores was 53.02% whereas daily life activities ameliorated at a mean of 38.07%.

Conclusion: Deep brain stimulation of the nucleus ventralis intermedius has become a promising treatment option for patients with tremor dominant Parkinson’s disease that do not respond to medical therapy. Cases with bilateral medically intractable symptoms can be safely treated using bilateral deep brain stimulation. In patients with previous thalamotomy, electrical stimulation can improve ipsilateral and contralateral tremor, avoiding major side effects of bilateral thalamotomy. Neurostimulation may be superior to ablative surgery, given its reversibility and modifiability of stimulation parameters, including no lesion at the stimulated site and the same and comparable outcome with minimal or reversible complications.

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