scholarly journals The Active Electrode in the Living Brain: The Response of the Brain Parenchyma to Chronically Implanted Deep Brain Stimulation Electrodes

2020 ◽  
Author(s):  
Judith Evers ◽  
Madeleine Lowery
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Foreign Body Response ◽  
Surrounding Tissue ◽  
Active Electrode ◽  
Fibrous Sheath ◽  
Tissue Impedance ◽  
Implanted Electrodes ◽  
Postmortem Studies ◽  
Deep Brain

Abstract BACKGROUND Deep brain stimulation is an established symptomatic surgical therapy for Parkinson disease, essential tremor, and a number of other movement and neuropsychiatric disorders. The well-established foreign body response around implanted electrodes is marked by gliosis, neuroinflammation, and neurodegeneration. However, how this response changes with the application of chronic stimulation is less well-understood. OBJECTIVE To integrate the most recent evidence from basic science, patient, and postmortem studies on the effect of such an “active” electrode on the parenchyma of the living brain. METHODS A thorough and in-part systematic literature review identified 49 papers. RESULTS Increased electrode-tissue impedance is consistently observed in the weeks following electrode implantation, stabilizing at approximately 3 to 6 mo. Lower impedance values are observed around stimulated implanted electrodes when compared with unstimulated electrodes. A temporary reduction in impedance has also been observed in response to stimulation in nonhuman primates. Postmortem studies from patients confirm the presence of a fibrous sheath, astrocytosis, neuronal loss, and neuroinflammation in the immediate vicinity of the electrode. When comparing stimulated and unstimulated electrodes directly, there is some evidence across animal and patient studies of altered neurodegeneration and neuroinflammation around stimulated electrodes. CONCLUSION Establishing how stimulation influences the electrical and histological properties of the surrounding tissue is critical in understanding how these factors contribute to DBS efficacy, and in controlling symptoms and side effects. Understanding these complex issues will aid in the development of future neuromodulation systems that are optimized for the tissue environment and required stimulation protocols.

Brain shift: an error factor during implantation of deep brain stimulation electrodes

2007 ◽  
Vol 107 (5) ◽  
pp. 989-997 ◽  
Author(s):  
Yasushi Miyagi ◽  
Fumio Shima ◽  
Tomio Sasaki
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Brain Shift ◽  
Mr Images ◽  
Implanted Electrodes ◽  
Error Factor ◽  
Bilateral Surgery ◽  
Second Procedure ◽  
The Brain ◽  
Deep Brain

Object The goal of this study was to focus on the tendency of brain shift during stereotactic neurosurgery and the shift's impact on the unilateral and bilateral implantation of electrodes for deep brain stimulation (DBS). Methods Eight unilateral and 10 bilateral DBS electrodes at 10 nuclei ventrales intermedii and 18 subthalamic nuclei were implanted in patients at Kaizuka Hospital with the aid of magnetic resonance (MR) imaging–guided and microelectrode-guided methods. Brain shift was assessed as changes in the 3D coordinates of the anterior and posterior commissures (AC and PC) with MR images before and immediately after the implantation surgery. The positions of the implanted electrodes, based on the midcommissural point and AC–PC line, were measured both on x-ray films (virtual position) during surgery and the postoperative MR images (actual position) obtained on the 7th day postoperatively. Results Contralateral and posterior shift of the AC and PC were the characteristics of unilateral and bilateral procedures, respectively. The authors suggest the following. 1) The first unilateral procedure elicits a unilateral air invasion, resulting in a contralateral brain shift. 2) During the second procedure in the bilateral surgery, the contralateral shift is reset to the midline and, at the same time, the anteroposterior support by the contralateral hemisphere against gravity is lost due to a bilateral air invasion, resulting in a significant posterior (caudal) shift. Conclusions To note the tendency of the brain to shift is very important for accurate implantation of a DBS electrode or high frequency thermocoagulation, as well as for the prediction of therapeutic and adverse effects of stereotactic surgery.

Speech changes induced by deep brain stimulation of the subthalamic nucleus in Parkinson disease: involvement of the dentatorubrothalamic tract

2016 ◽  
Vol 126 (6) ◽  
pp. 2017-2027 ◽  
Author(s):  
Albert J. Fenoy ◽  
Monica A. McHenry ◽  
Mya C. Schiess
Keyword(s):  
Deep Brain Stimulation ◽  
Parkinson Disease ◽  
Brain Stimulation ◽  
Spontaneous Speech ◽  
Active Electrode ◽  
Fiber Tract ◽  
Speech Performance ◽  
Stn Dbs ◽  
Left Electrode ◽  
Deep Brain

OBJECTIVEPatients with Parkinson disease (PD) who undergo subthalamic nucleus (STN) deep brain stimulation (DBS) often develop a deterioration in speech performance, but there is no clear consensus on the specific effects seen or the mechanism involved and little description of the impact of DBS on conversational speech. Furthermore, there has been no fiber tract connectivity analysis to identify the structures potentially modulated by DBS to cause such deficits. The main objective of this study was to quantify spontaneous speech performance and identify potential involvement of the dentatorubrothalamic tract (DRTt) in patients who underwent STN DBS, because this tract has been implicated in speech deterioration.METHODSSpontaneous speech samples were obtained with STN DBS in both on and off modes in 35 patients with PD and assessed across multiple domains. Diffusion tensor imaging tractography seeded from the therapeutic DBS contacts was performed to identify the fiber tracts involved and, specifically, the DRTt. The position of active electrode contacts was assessed relative to that of the STN.RESULTSFifteen patients with akinetic-rigid (AR) PD and 20 with tremor-dominant (TD) PD subtypes were identified. In the AR-PD subgroup of patients, in whom there was DRTt involvement, 71% demonstrated much better overall speech and largely improved or unchanged fluency in the DBS-off condition. In patients with TD PD with DRTt involvement, 50% demonstrated better overall speech in the off condition, and equivocal results regarding improved or worsened fluency were found. When there was minimal DRTt involvement, 75% of patients with AR PD had better overall speech in the DBS-on condition and better or minimal fluency changes. Similarly, 83% of patients with TD PD with minimal DRTt involvement had better or minimal overall speech and fluency changes in the on condition. More medially placed left electrode contacts were associated with more DRTt involvement in 77% of patients (10 of 13).CONCLUSIONSTo the authors' knowledge, this is the first study to have investigated a specific fiber tract involved in STN DBS in different subtypes of PD relative to its impact on spontaneous speech. At optimal therapeutic programming of STN DBS, overall spontaneous speech and fluency were affected more negatively in patients with AR PD than in those with TD PD when there was DRTt involvement. After fiber tract analysis and modeling, it was found that medially positioned left electrode contacts more often involved fibers of the DRTt. If possible, avoidance of the DRTt by using active electrode contacts that are positioned less medially, specifically in patients with AR PD, might result in less speech deterioration.

scholarly journals A Deep Brain Stimulation Trial Period for Treating Chronic Pain

2020 ◽  
Vol 9 (10) ◽  
pp. 3155
Author(s):  
Prasad Shirvalkar ◽  
Kristin K. Sellers ◽  
Ashlyn Schmitgen ◽  
Jordan Prosky ◽  
Isabella Joseph ◽  
...  
Keyword(s):  
Chronic Pain ◽  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Electrical Contacts ◽  
Trial Period ◽  
External Stimulation ◽  
Stimulation Trial ◽  
Implanted Electrodes ◽  
Brain Target ◽  
Deep Brain

Early studies of deep brain stimulation (DBS) for various neurological disorders involved a temporary trial period where implanted electrodes were externalized, in which the electrical contacts exiting the patient’s brain are connected to external stimulation equipment, so that stimulation efficacy could be determined before permanent implant. As the optimal brain target sites for various diseases (i.e., Parkinson’s disease, essential tremor) became better established, such trial periods have fallen out of favor. However, deep brain stimulation trial periods are experiencing a modern resurgence for at least two reasons: (1) studies of newer indications such as depression or chronic pain aim to identify new targets and (2) a growing interest in adaptive DBS tools necessitates neurophysiological recordings, which are often done in the peri-surgical period. In this review, we consider the possible approaches, benefits, and risks of such inpatient trial periods with a specific focus on developing new DBS therapies for chronic pain.

Does Navigated Transcranial Stimulation Increase the Accuracy of Tractography? A Prospective Clinical Trial Based on Intraoperative Motor Evoked Potential Monitoring During Deep Brain Stimulation

Neurosurgery ◽  
2015 ◽  
Vol 76 (6) ◽  
pp. 766-776 ◽  
Author(s):  
Marie-Therese Forster ◽  
Alexander Claudius Hoecker ◽  
Jun-Suk Kang ◽  
Johanna Quick ◽  
Volker Seifert ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Motor Cortex ◽  
Brain Stimulation ◽  
Evoked Potential ◽  
Motor Evoked Potential ◽  
Fiber Tracking ◽  
Active Electrode ◽  
Electrode Contact ◽  
Evoked Potential Monitoring ◽  
Deep Brain

AbstractBACKGROUND:Tractography based on diffusion tensor imaging has become a popular tool for delineating white matter tracts for neurosurgical procedures.OBJECTIVE:To explore whether navigated transcranial magnetic stimulation (nTMS) might increase the accuracy of fiber tracking.METHODS:Tractography was performed according to both anatomic delineation of the motor cortex (n = 14) and nTMS results (n = 9). After implantation of the definitive electrode, stimulation via the electrode was performed, defining a stimulation threshold for eliciting motor evoked potentials recorded during deep brain stimulation surgery. Others have shown that of arm and leg muscles. This threshold was correlated with the shortest distance between the active electrode contact and both fiber tracks. Results were evaluated by correlation to motor evoked potential monitoring during deep brain stimulation, a surgical procedure causing hardly any brain shift.RESULTS:Distances to fiber tracks clearly correlated with motor evoked potential thresholds. Tracks based on nTMS had a higher predictive value than tracks based on anatomic motor cortex definition (P < .001 and P = .005, respectively). However, target site, hemisphere, and active electrode contact did not influence this correlation.CONCLUSION:The implementation of tractography based on nTMS increases the accuracy of fiber tracking. Moreover, this combination of methods has the potential to become a supplemental tool for guiding electrode implantation.

scholarly journals Laser-driven Wireless Deep Brain Stimulation using Temporal Interference and Organic Electrolytic Photocapacitors

2021 ◽  
Author(s):  
Florian MISSEY ◽  
Mary Jocelyn DONAHUE ◽  
Pascal WEBER ◽  
Ibrahima NGOM ◽  
Emma ACERBO ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Brain Stimulation ◽  
Ex Vivo ◽  
Neuronal Response ◽  
Red Light ◽  
Animal Experiments ◽  
Target Area ◽  
Implanted Electrodes ◽  
Deep Brain

Deep brain stimulation (DBS) is a technique commonly used both in clinical and fundamental neurosciences. Classically, brain stimulation requires an implanted and wired electrode system to deliver stimulation directly to the target area. Although techniques such as temporal interference (TI) can provide stimulation at depth without involving any implanted electrodes, these methods still rely on a wired apparatus which limits free movement. Herein we report organic photocapacitors as untethered light-driven electrodes which convert deep-red light into electric current. Pairs of these ultrathin devices can be driven using lasers at two different frequencies to deliver stimulation at depth via temporally interfering fields. We validate this concept of laser TI stimulation using numerical modeling, ex vivo tests with phantom samples, and finally in vivo tests. Wireless organic photocapacitors are placed on the cortex and elicit stimulation in the hippocampus, while not delivering off-target stimulation in the cortex. This laser-driven wireless TI evoked a neuronal response at depth that is comparable to control experiments induced with deep brain stimulation protocols using implanted electrodes. Our work shows that a combination of these two techniques, temporal interference and organic electrolytic photocapacitors, provides a reliable way to target brain structures requiring neither deeply implanted electrodes nor tethered stimulator devices. The laser TI protocol demonstrated here address two of the most important drawbacks in the field of deep brain stimulation and thus holds potential to solve many issues in freely-moving animal experiments or for clinical chronic therapy application.

Distance between Active Electrode Contacts and Dentatorubrothalamic Tract in Patients with Habituation of Stimulation Effect of Deep Brain Stimulation in Essential Tremor

2017 ◽  
Vol 78 (04) ◽  
pp. 350-357 ◽  
Author(s):  
Kathrin Steib ◽  
Max Lange ◽  
Eva Rothenfusser ◽  
Claudia Fellner ◽  
Alexander Brawanski ◽  
...  
Keyword(s):  
Retrospective Study ◽  
Deep Brain Stimulation ◽  
Essential Tremor ◽  
Brain Stimulation ◽  
Fiber Tracking ◽  
Active Electrode ◽  
Main Target ◽  
Target Side ◽  
Deep Brain

Background Some patients under thalamic deep brain stimulation (DBS) for essential tremor (ET) experience habituation of tremor reduction. The nucleus ventralis intermedius (Vim) is the current main target side for ET in DBS. However, the dentatorubrothalamic tract (DRTT) is considered the relevant structure to stimulate. We investigated the distance between the active contact of the DBS electrode and the DRTT and compared this distance in patients with habituation of tremor reduction and good responders. Material and Methods In this retrospective study, we performed deterministic fiber tracking of the DRTT in 6 patients (12 hemispheres) with ET who underwent DBS in the Vim. We subsequently measured the distance between the active contact of the electrode and the ipsilateral DRTT in both hemispheres. The clinical tremor response of those 6 patients was analyzed accordingly. Results The distance between the active contact and the DRTT in patients with better and constant clinical tremor reduction was shorter (mean distance: 2.9 ± 2.2 mm standard deviation [SD]) than in patients who showed habituation of their response (mean distance: 6.1 ± 3.9 mm SD). After re-placement of a thalamic electrode inside the DRTT in one patient who experienced unsatisfying tremor reduction due to habituation of stimulation, the tremor alleviation was significant and persistent at a 13-month follow-up. Conclusion This retrospective analysis suggests that recurrence of ET tremor under chronic DBS might be associated with a larger distance between the DRTT and the active lead contact, in comparison with the smaller distances in patients with persistently good tremor control.

Long-term deep brain stimulation in a patient with essential tremor: clinical response and postmortem correlation with stimulator termination sites in ventral thalamus

2000 ◽  
Vol 93 (1) ◽  
pp. 140-144 ◽  
Author(s):  
John A. Boockvar ◽  
Albert Telfeian ◽  
Gordon H. Baltuch ◽  
Brett Skolnick ◽  
Tanya Simuni ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Essential Tremor ◽  
Brain Stimulation ◽  
Content Type ◽  
Tremor Suppression ◽  
Ventral Thalamus ◽  
Postmortem Studies ◽  
Motor Thalamus ◽  
Deep Brain

✓ Essential tremor can be suppressed with chronic, bilateral deep brain stimulation (DBS) of the ventralis intermedius nucleus (Vim), the cerebellar receiving area of the motor thalamus. The goal in this study was to correlate the location of the electrodes with the clinical efficacy of DBS in a patient with essential tremor. The authors report on a woman with essential tremor in whom chronic bilateral DBS directed to the ventral thalamus produced adequate tremor suppression until her death from unrelated causes 16 months after placement of the electrodes. Neuropathological postmortem studies of the brain in this patient demonstrated that both stimulators terminated in the Vim region of the thalamus, and that chronic DBS elicited minor reactive changes confined to the immediate vicinity of the electrode tracks. Although the authors could not identify neuropathological abnormalities specific to essential tremor, they believe that suppression of essential tremor by chronic DBS correlates with bilateral termination of the stimulators in the Vim region of the thalamus.

scholarly journals Electro-Quasistatic Simulations in Bio-Systems Engineering and Medical Engineering

2005 ◽  
Vol 3 ◽  
pp. 39-49 ◽  
Author(s):  
U. van Rienen ◽  
J. Flehr ◽  
U. Schreiber ◽  
S. Schulze ◽  
U. Gimsa ◽  
...  
Keyword(s):  
Deep Brain Stimulation ◽  
Systems Engineering ◽  
Brain Stimulation ◽  
Medical Engineering ◽  
Morbus Parkinson ◽  
Electric Activity ◽  
Surrounding Tissue ◽  
Auditory Nerves ◽  
Major Interest ◽  
Deep Brain

Abstract. Slowly varying electromagnetic fields play a key role in various applications in bio-systems and medical engineering. Examples are the electric activity of neurons on neurochips used as biosensors, the stimulating electric fields of implanted electrodes used for deep brain stimulation in patients with Morbus Parkinson and the stimulation of the auditory nerves in deaf patients, respectively. In order to simulate the neuronal activity on a chip it is necessary to couple Maxwell's and Hodgkin-Huxley's equations. First numerical results for a neuron coupling to a single electrode are presented. They show a promising qualitative agreement with the experimentally recorded signals. Further, simulations are presented on electrodes for deep brain stimulation in animal experiments where the question of electrode ageing and energy deposition in the surrounding tissue are of major interest. As a last example, electric simulations for a simple cochlea model are presented comparing the field in the skull bones for different electrode types and stimulations in different positions.

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