Article
Development of hyperkinesias after long-term pallidal stimulation for dystonia
Search Medline for
Authors
Published: | June 8, 2016 |
---|
Outline
Text
Objective: The globus pallidus internus (GPi) is regarded as an established and safe target for deep brain stimulation (DBS) in dystonia. Recent reports on the occurrence of bradykinetic symptoms like freezing, postural instability and micrographia after chronic DBS of the GPi in patients with dystonia however stimulated a discussion on alternative targets. Here, we report on the unusual occurrence of dyskinesias upon chronic pallidal stimulation.
Method: A 74-year-old man with segmental dystonia including blepharospasm, orofacial dystonia and aerophagia underwent bilateral stereotactic implantation of DBS electrodes in the GPi. Eleven years later during effective chronic DBS for dystonia he experienced gradual onset of hyperkinetic involuntary movements mainly concerning his arms but also his trunk.
Results: Detailed assessment in various conditions showed that off DBS resulted in an increase of both choreatic hyperkinesias and dystonia. High frequency and low amplitude DBS improved both dystonia and hyperkinesias, while high voltage DBS resulted in further improvement of dystonia but also in increased hyperkinesias. As a compromise between optimal stimulation for dystonia and hyperkinesias we finally choose a bipolar intermediate amplitude stimulation mode.
Conclusions: Chronic pallidal DBS might be accompanied not only by bradykinetic symptoms but also in the rare case by hyperkinesias. Such an occurrence requires complex reassessment of stimulation programming.