title: Dyskinesias and grip control in Parkinson's disease are normalized by chronic stimulation of the subthalamic nucleus.
abstract: Deep-brain stimulation of the subthalamic nucleus appears to reduce levodopa-induced dyskinesias, but whether this effect is caused by the reduction of the total levodopa ingestion or represents a direct effect on the motor system is unknown. Precision grip force of grasping movements and levodopa-induced dyskinesias was analyzed in 10 parkinsonian patients before and after 3 months of deep-brain stimulation of the subthalamic nucleus. Peak grip force was abnormally increased before surgery in the off-drug state and, particularly, in the on-drug state (sensitization). This grip force upregulation normalized with chronic deep-brain stimulation in both conditions (desensitization). Peak-dose dyskinesias also improved, and off-dystonia was completely abolished. Mean dosage of dopaminergic drugs was reduced, but force overflow and dyskinesias were equally improved in 2 patients without a reduction. Despite the same single levodopa test dose, force excess and levodopa-induced dyskinesias were drastically reduced after 3 months of deep-brain stimulation of the subthalamic nucleus. This indicates that direct effects of deep-brain stimulation of the subthalamic nucleus on levodopa-induced dyskinesias are likely to occur. Grip force overflow is a promising parameter to study the desensitizing effect of chronic deep-brain stimulation on levodopa-induced dyskinesias.
authors.affiliation: Department of Neurology, Christian Albrechts University, Kiel, Germany.
authors.forename: Roland
authors.initials: R
authors.lastname: Wenzelburger
authors.forename: Bao-Rong
authors.initials: BR
authors.lastname: Zhang
authors.forename: Meike
authors.initials: M
authors.lastname: Poepping
authors.forename: Bettina
authors.initials: B
authors.lastname: Schrader
authors.forename: Dieter
authors.initials: D
authors.lastname: Müller
authors.forename: Florian
authors.initials: F
authors.lastname: Kopper
authors.forename: Urban
authors.initials: U
authors.lastname: Fietzek
authors.forename: Hubertus M
authors.initials: HM
authors.lastname: Mehdorn
authors.forename: Günther
authors.initials: G
authors.lastname: Deuschl
authors.forename: Paul
authors.initials: P
authors.lastname: Krack
mesh_terms: D004305:Dose-Response Relationship, Drug; D020820:Dyskinesias / Q000209:etiology / Q000503:physiopathology* / Q000628:therapy*; D004599:Electric Stimulation Therapy; D018737:Hand Strength; D006801:Humans; D007980:Levodopa / Q000008:administration & dosage / Q000627:therapeutic use; D010300:Parkinson Disease / Q000150:complications*; D012016:Reference Values; D012720:Severity of Illness Index; D020531:Subthalamic Nucleus / Q000503:physiopathology*; D013997:Time Factors
chemical_list: D007980:Levodopa