Objective: To evaluate preliminary efficacy and safety of bilateral ventralis oralis posterior (VOP) deep brain stimulation (DBS) for the treatment of acquired dystonia in children and young adults

Background: Pallidal deep brain stimulation (DBS) is efficacious for severe, medication refractory isolated dystonia, providing 50-60% long-term improvement. Unfortunately, pallidal stimulation response rates in acquired dystonia are modest and unpredictable with frequent non-responders. Acquired dystonia is more common in pediatric populations than isolated dystonia and more recalcitrant to standard treatments. Given the limitations of pallidal DBS in acquired dystonia, alternative brain targets should be explored

Method: Four participants, three with perinatal brain injuries, one with postencephalitic symptomatic dystonia, underwent bilateral VOP and bimonthly evaluations for 12 months. The primary efficacy outcome was the change in Burke-Fahn-Marsden (BFMDS) and Barry-Albright (BADS) Dystonia Rating Scales from baseline to 12 months. Video documentation was used for blinded ratings. Secondary outcomes included evaluation of spasticity, quality of life (PedsQL, modified Unified Parkinson Disease Rating Scale Part II, UPDRS-II) and neuropsychological assessments. Adverse events were monitored for safety

Results: All participants tolerated the procedure well and there were no safety concerns or serious adverse events. There was an average improvement of 21.5% in BFMDRS motor subscale but only 1.6% in BADS. However, a blinded video review of dystonia severity showed considerably more modest results. The BFMDRS Disability subscale improved by 15.7%, the PedsQL total score by 27%, and the modified UPDRS part II by 19.3%. Spasticity worsened on average by 18.4% in upper and 30.7% in lower extremities. However, neither the participants, caregivers nor clinicians considered the increase clinically relevant. Neuropsychological assessments were unchanged one year after surgery

Conclusion: Bilateral thalamic neuromodulation by DBS for severe, refractory acquired dystonia was well tolerated. Primary and secondary outcomes showed highly variable treatment effect sizes comparable to pallidal stimulation in this population. As previously described, improvements in quality of life and disability were not reflected in dystonia severity scales, suggesting a need for the development of scales specifically for acquired dystonia

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MDS Abstracts - https://www.mdsabstracts.org/abstract/thalamic-deep-brain-stimulation-for-acquired-dystonia-in-children-and-young-adults-a-phase-i-clinical-trial/