Patient-Specific Model-Based Investigation of Speech Intelligibility and Movement during Deep Brain Stimulation

Abstract

Background/Aims: Deep brain stimulation (DBS) is widely used to treat motor symptoms in patients with advanced Parkinson’s disease. The aim of this study was to investigate the anatomical aspects of the electric field in relation to effects on speech and movement during DBS in the subthalamic nucleus. Methods: Patient-specific finite element models of DBS were developed for simulation of the electric field in 10 patients. In each patient, speech intelligibility and movement were assessed during 2 electrical settings, i.e. 4 V (high) and 2 V (low). The electric field was simulated for each electrical setting. Results: Movement was improved in all patients for both high and low electrical settings. In general, high-amplitude stimulation was more consistent in improving the motor scores than low-amplitude stimulation. In 6 cases, speech intelligibility was impaired during high-amplitude electrical settings. Stimulation of part of the fasciculus cerebellothalamicus from electrodes positioned medial and/or posterior to the center of the subthalamic nucleus was recognized as a possible cause of the stimulation-induced dysarthria. Conclusion: Special attention to stimulation-induced speech impairments should be taken in cases when active electrodes are positioned medial and/or posterior to the center of the subthalamic nucleus.

Influence of heterogeneous and anisotropic tissue conductivity on electric field distribution in deep brain stimulation

“…This model was regarded as a baseline model for comparison with the two other models. In Model II the methods previously developed by our group was followed [6,8]. The tissue was modelled as heterogeneous and isotropic based on preoperative T2 weighted stereotactic MRI.…”

“…An example is patient-specific computer simulations of the electric field generated during DBS [6,7]. Åström et al, have previously used pre-and postoperative MRI acquired during the planning and the postoperative follow-up of the surgical DBS procedure for creating patient-specific models and simulations of DBS [6,8]. Brain tissue is classified in the MRI and material properties from the literature are allotted to each classified MRI-voxel.…”

Stereotactic implantation of deep brain stimulation electrodes: a review of technical systems, methods and emerging tools

“…3). The latter technique has been used for evaluation of speech intelligibility and movement in ten patients with Parkinson's disease where DBS electrodes were implanted in the STN [5]. …”

“…These can also be used to advance and optimise the treatment of an individual patient and act as a tool for training and for simulation of electrical field in target areas before the actual surgical procedure is done. Such simulations can allow for 3D visualizations of the electric field influenced by the stimulation and match it to the patient's clinical outcome [5,80]. As DBS has become more commonly used, there have been increasing reports of postoperative neuropsychiatric complications, including depression, mania, aggression, and language disturbances [19,47,120].…”

Guiding Deep Brain Stimulation interventions by fusing multimodal uncertainty regions

“…In the case of PD the most effective target areas for electrode placement are the subthalamic nuclei (STN) with sizes of a few millimeters [27] and are located in both hemispheres. As misplaced stimulation electrodes can have severe side effects, including speech difficulties, increased tremor, or long term memory problems [1], accurate electrode placement is crucial [31]. Nowadays the access path to the target region is planned using magnetic resonance imaging (MRI).…”