Article
Apparative measurement of tremor and ataxia in multiple sclerosis patients: stimulation of the thalamic ventralis intermedius nucleus (VIM) improves both tremor and ataxia
Apparative Messung von Tremor und Ataxie bei Patienten mit Multipler Sklerose: die Stimulation des Nukleus ventralis intermedius thalami (VIM) bessert den Tremor und die Ataxie
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Authors
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J. Spiegel
- Neurologische Universitätsklinik, Universität des Saarlandes
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G. Fuß
- Neurologische Universitätsklinik, Universität des Saarlandes
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J. Moringlane
- Neurochirurgische Universitätsklinik, Universität des Saarlandes
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U. Dillmann
- Neurologische Universitätsklinik, Universität des Saarlandes
| Published: | May 4, 2005 |
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Outline
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Objective
Ataxia and tremor are common symptoms in multiple sclerosis (MS), which are hardly influenced by pharmacological treatment. We now studied the effect of contralateral VIM stimulation on ataxia and tremor using potentiometry and tremor analysis.
Methods
We investigated 6 patients with a primary (n=1) or secondary (n=5) chronic progressive MS (range 36-66 years, median 41.5 years). The patients sat in a chair with one arm abducted rectangularely. This arm was strapped into a splint with one fixed section for the upper arm and one further section for the forearm. The latter allowed horizontal movements in the elbow joint. The patients had to perform rhythmic alternating flexion and extension movements in the elbow joint. The rhythm was provided auditorily by a click tone stimulator. The spatial extent of movement was marked. 6 manoeuvres (spatial extents of 48°, 83° at frequencies of 0.9 Hz, 1.5 Hz, 2.5 Hz each) had to be absolved. By means of the potentiometer, horizontal movements of the forearm were converted into a variable voltage. These measures were done without and during contralateral VIM stimulation each. Postural tremor was measured using surface EMG from the biceps and triceps brachii muscle. Tremor amplitude was estimated by the amplitude of tremor bursts. 3 patients had been further investigated before the VIM electrode was implanted.
Results
In 5 patients the spatial and temporal accuracy of the alternating forearm movements improved significantly after the stimulation had been switched on. 1 of these 5 patients was unable to perform the most simple manoeuvre without stimulation. In 1 patient there was no clear difference of movement accuracy between the „on“ and the „off“ condition. We found no significant difference between the presurgical state and the postsurgical „off“ condition. Tremor decreased respectively disappeared during contralateral VIM stimulation.
Conclusions
The VIM stimulation may be a therapeutical alternative in the treatment of ataxia and tremor in multiple sclerosis. Potentiometry and tremor analysis represent available methods for studying therapy effects of deep brain stimulation.
