Objective: To evaluate clinical motor outcomes, the patient´s subjectively perceived benefit and the frequency of the use of directional lead stimulation in subjects with Essential tremor (ET) and Parkinson's disease (PD) after implantation of segmented-lead electrodes in the ventrolateral thalamus (VIM), subthalamic nucleus (STN) or globus pallidum (GPI).
Background: Directional Deep Brain Stimulation (DBS) provides the capability to customize the stimulation field in order to maximize the therapeutic efficacy while minimizing side-effects. To date, there is a lack of evidence on the clinical outcomes resulting from use of directional DBS.
Methods: PD and ET patients were bilaterally implanted in the STN or the GPI and the VIM, respectively. After initial monopolar review, patients initially received conventional, ring-mode, omnidirectional stimulation. During subsequent patient evaluations, unidirectional or bidirectional stimulation was utilized to compensate for stimulation-related side effects. Clinical Global Impression (CGI-Csub; 7 point-scale: 1=very much improved, 7=very much worsened) scale was used to quantify and track patient progress and treatment response over time. Additionally, motor symptom relief was also assessed through use of appropriate standardized clinical scales. All evaluations were performed 3-6 months post-permanent implant.
Results: A total of 11 patients [5 PD patients (age= 67.0 ± 4.3 years, 2 males); 6 ET patients (age= 71.7 ± 4.3 years, 5 males)] were included in this analysis. At 3-6 months post-stimulation, PD patients with STN-DBS reported that their treatment response was “much improved” (CGI-Csub =2 ± 1). One PD patient receiving GPI-DBS claimed no subjective change (CGI-Csub =4). In ET patients with VIM-DBS, the outcome “improved” (CGI-Csub =2.6 ± 2.1); there was excellent response in 3 patients, but postoperative stimulation-induced worsening of ataxia in 1 patient.
Conclusions: Preliminary clinical data resulting from use of directional DBS in movement disorders patients suggests an improvement in some patients in the motor outcomes while minimizing stimulation-induced side effects. Our clinical experience with directional DBS indicates that it is safe and effective in providing optimal therapeutic benefit in patients with movement disorders.