Objective: To control subthalamic nucleus deep brain stimulation (STN DBS) induced dyskinesias in Parkinson’s disease (PD) using directionality.

Background: Levodopa-induced dyskinesias (LID) frequently occur in PD patients, particularly in those with motor fluctuations. STN DBS diminishes motor fluctuations and also dyskinesias, allowing anti-PD medication reduction. However, persistent dyskinesias may be induced by STN DBS and difficult to control. We describe four PD patients, who pre-operatively exhibited bothersome LID of the head. The head dyskinesias re-occured post-operatively when using particular DBS settings and were resolved using directionality.

Method: 4 patients  (1 woman, age 54 and 3men, ages 61, 61 and 68, mean duration of disease at time of surgery: 12 years), with LID of the head before surgery were implanted with directional leads (Vercise Cartesia™, Boston Scientific). Lead localization was determined based on postoperative images (CT scan and rotational fluoroscopy). The DBS settings were analyzed using Brainlab elements and Guide^TM XT. The programmed parameters were selected through detailed contact mapping, searching for optimal respons, while avoiding side effects.

Results: After DBS, the mean levodopa dose was reduced from 1200 mg to 625 mg. Certain DBS contacts induced head dyskinesias, which were reproducible even when the anti-PD medication was stopped for 12 hours, and similar to the LID of the head before surgery.  Using directional stimulation the head dyskinesias subsided, allowing levodopa and dopamine agonists (DA) re-intake for optimal control of the PD symptoms. According to the lead localisation images we hypothesise that the head dyskinesias were provoked by stimulating the dorso–posterior STN.

Conclusion: Post-operative STN DBS head dyskinesias are similar to levodopa-induced dyskinesias, and probably induced by stimulating the dorso-posterior region of the STN.  Current steering may resolve the head dyskinesias, while providing satisfactory therapeutic respons. Patients with pre-operative dyskinesias may best be treated with directional stimulation to avoid so-called brittle dyskinesias (1), although a larger group of patients are needed to confirm our findings.

References: 1. Sriram A, Foote KD, Oyama G, Kwak J, Zeilman PR, Okun MS. Brittle Dyskinesia Following STN but not GPi Deep Brain Stimulation. Other Hyperkinet Mov (N Y). 2014 Jun 5;4:242. doi: 10.7916/D8KS6PPR. eCollection 2014. PMID: 24932426

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MDS Abstracts - https://www.mdsabstracts.org/abstract/persistent-head-dyskinesias-following-stn-dbs-in-parkinsons-disease-resolve-using-directionality/