Variable frequency stimulation of subthalamic nucleus for freezing of gait in Parkinson's disease

Analysis of Variable Frequency Stimulation Sacral Neuromodulation for Different Genders: A Chinese Multicentric Prospective Clinical Study

AIM

Sacral neuromodulation (SNM) is widely recognized as the essential treatment modality for patients suffering from various lower urinary tract disorders, particularly overactive bladder (OAB). This prospective study recruited patients who underwent variable frequency SNM treatment at six Chinese medical centers, aiming to evaluate the gender-specific effects of this intervention and provide precise guidance on its application for clinical management.

METHODS

This prospective study was managed by Beijing Hospital, and six Chinese medical centers participated in this prospective research. Inclusion and exclusion criteria were established to screen patients based on the indication for SNM. During the research, all patients were required to record 72-h voiding diaries, urgency scores, and visual analogue scale (VAS) scores to reflect their disease symptoms. Additionally, subjective questionnaire surveys such as OAB symptom score (OABSS) and quality-of-life (Qol) score were recorded to reflect the patients' quality of life and treatment satisfaction.

RESULTS

In this study, 52 patients (male patients: 25; female patients: 27) with OAB symptoms agreed to undergo variable frequency stimulation SNM therapy and finally convert to Stage II. Regarding the baseline outcomes, no significant differences were observed between the male and female groups. In terms of postoperative indicators, male patients showed a greater improvement in Qol scores compared to their female counterparts (20.06 ± 13.12 vs. 40.83 ± 26.06, p = 0.005). The results from VAS scores indicated that pain remission was more pronounced in male patients than in female patients (0.31 ± 0.87 vs. 1.67 ± 2.16, p = 0.02). Importantly, there was a statistically significant disparity in urinary urgency between males and females (male patients: 1.19 ± 1.56; female patients: 2.17 ± 1.52, p = 0.04).

CONCLUSIONS

In our study, we found that variable frequency SNM treatment yielded sex-specific differences in therapeutic effects, with male patients having a better outcome in some metrics. This suggests that a patient's sex may influence when variable frequency SNM is used, and in the patient's follow-up.

TRIAL REGISTRATION

ClinicalTrials.gov identifier: ChiCTR2000036677.

Effects of subthalamic nucleus deep brain stimulation using different frequency programming paradigms on axial symptoms in advanced Parkinson's disease

BACKGROUND

In advanced Parkinson's disease (PD), axial symptoms are common and can be debilitating. Although deep brain stimulation (DBS) significantly improves motor symptoms, conventional high-frequency stimulation (HFS) has limited effectiveness in improving axial symptoms. In this study, we investigated the effects on multiple axial symptoms after DBS surgery with three different frequency programming paradigms comprising HFS, low-frequency stimulation (LFS), and variable-frequency stimulation (VFS).

METHODS

This study involved PD patients who had significant preoperative axial symptoms and underwent bilateral subthalamic nucleus (STN) DBS. Axial symptoms, motor symptoms, medications, and quality of life were evaluated preoperatively (baseline). One month after surgery, HFS was applied. At 6 months post-surgery, HFS assessments were performed, and HFS was switched to LFS. A further month later, we conducted LFS assessments and switched LFS to VFS. At 8 months after surgery, VFS assessments were performed.

RESULTS

Of the 21 PD patients initially enrolled, 16 patients were ultimately included in this study. Regarding HFS, all axial symptoms except for the Berg Balance Scale (p < 0.0001) did not improve compared with the baseline (all p > 0.05). As for LFS and VFS, all axial symptoms improved significantly compared with both the baseline and HFS (all p < 0.05). Moreover, motor symptoms and medications were significantly better than the baseline (all p < 0.05) after using LFS and VFS. Additionally, the quality of life of the PD patients after receiving LFS and VFS was significantly better than at the baseline and with HFS (all p < 0.0001).

CONCLUSION

Our findings indicate that HFS is ineffective at improving the majority of axial symptoms in advanced PD. However, both the LFS and VFS programming paradigms exhibit significant improvements in various axial symptoms.

Efficacy and Safety of Sacral Neuromodulation by Converting Constant Frequency Stimulation Into Variable Frequency Stimulation in Patients With Detrusor Overactivity and Impaired Contractility: A Single-Center Prospective Study

OBJECTIVES

In patients with detrusor overactivity with impaired contractility (DOIC), it is difficult to relieve abnormal lower urinary tract symptoms during both storage and voiding using sacral neuromodulation (SNM) with constant frequency stimulation (CFS). We sought to evaluate the efficacy and safety of SNM using variable frequency stimulation (VFS) in patients with DOIC by comparing it with outcomes of SNM with CFS.

MATERIALS AND METHODS

Between September 2020 and May 2021, we prospectively enrolled 20 patients with DOIC, confirmed on urodynamic examination, and administered SNM with VFS. The patients were followed up and required to maintain voiding diaries and record scale scores of overactive bladder symptoms, psychology and quality of life, uroflowmetry, ultrasonic postvoid residual urine, and adverse events at baseline and during the CFS and VFS phases.

RESULTS

The average testing phase was 26.3 ± 4.1 days. Compared with baseline values, overactive bladder symptom, psychologic health questionnaire, and quality of life scores, in addition to voiding frequency, urgency incontinence frequency, daily catheterization volume of voiding diary, and ultrasonic postvoid residual (PVR) decreased significantly during both the CFS and VFS phases (p < 0.05). The average voided volume, functional bladder capacity, and maximum urine flow rate significantly increased during the CFS and VFS phases (p < 0.05). In the VFS phase, voiding frequency, urgency incontinence frequency, daily catheterization volume of voiding diary, and ultrasonic PVR further decreased (p < 0.05), whereas functional bladder capacity, maximum urine flow rate, quality of life score, overactive bladder symptom score, and psychologic health questionnaire score further improved compared with results obtained in the CFS phase (p < 0.05). In the VFS phase, the success rate of further improvement of symptoms was 85.0%, and no new complications were noted.

CONCLUSIONS

SNM that converts CFS into VFS may be an effective treatment option for patients with DOIC, exhibiting no increase in adverse events.

Alternative patterns of deep brain stimulation in neurologic and neuropsychiatric disorders

Deep brain stimulation (DBS) is a widely used clinical therapy that modulates neuronal firing in subcortical structures, eliciting downstream network effects. Its effectiveness is determined by electrode geometry and location as well as adjustable stimulation parameters including pulse width, interstimulus interval, frequency, and amplitude. These parameters are often determined empirically during clinical or intraoperative programming and can be altered to an almost unlimited number of combinations. Conventional high-frequency stimulation uses a continuous high-frequency square-wave pulse (typically 130-160 Hz), but other stimulation patterns may prove efficacious, such as continuous or bursting theta-frequencies, variable frequencies, and coordinated reset stimulation. Here we summarize the current landscape and potential clinical applications for novel stimulation patterns.

Remote programming for subthalamic deep brain stimulation in Parkinson's disease

Introduction

Deep brain stimulation (DBS) of the subthalamic nucleus (STN) is effective for the treatment of Parkinson's disease (PD). Moreover, remote programming is widely used in Mainland China. This necessitates evaluating the ability of remote programming to achieve the ideal postoperative effect. Therefore, we aimed to retrospectively evaluate the effects of different programming modes on the effectiveness of STN-DBS 12 months postoperatively in patients with PD.

Methods

Clinical data were collected retrospectively, before and 12 months after surgery, in 83 patients with PD. Based on the programming modes voluntarily selected by the patients during 12 months postoperatively, they were divided into three groups, namely remote programming alone, hospital programming alone, and hospital + remote programming. We compared the programming data and the effects of different programming methods on STN-DBS-related improvements 12 months postoperatively among these groups. Furthermore, we analyzed STN-DBS-related improvements at 12 months postoperatively in 76 patients.

Results

The effectiveness of STN-DBS was not influenced by the three programming modes. The postoperative Movement Disorder Society Unified Parkinson's Disease Rating Scale scores did not reveal statistically significant differences between the remote alone and hospital alone programming groups, except for motor examination. The postoperative decline in the levodopa equivalent daily dose was most apparent in the hospital programming alone group. The programming frequency of the hospital + remote programming group was considerably higher than that of the remaining groups. Seventy-six patients with PD displayed good STN-DBS surgical efficacy.

Conclusion

Programming modes do not influence the short-term efficacy of STN-DBS, and remote programming can yield a satisfactory surgical effect.

Deep brain-machine interfaces: sensing and modulating the human deep brain

Different from conventional brain-machine interfaces that focus more on decoding the cerebral cortex, deep brain-machine interfaces enable interactions between external machines and deep brain structures. They sense and modulate deep brain neural activities, aiming at function restoration, device control and therapeutic improvements. In this article, we provide an overview of multiple deep brain recording and stimulation techniques that can serve as deep brain-machine interfaces. We highlight two widely used interface technologies, namely deep brain stimulation and stereotactic electroencephalography, for technical trends, clinical applications and brain connectivity research. We discuss the potential to develop closed-loop deep brain-machine interfaces and achieve more effective and applicable systems for the treatment of neurological and psychiatric disorders.

Past, Present, and Future of Deep Brain Stimulation: Hardware, Software, Imaging, Physiology and Novel Approaches

Deep brain stimulation (DBS) has advanced treatment options for a variety of neurologic and neuropsychiatric conditions. As the technology for DBS continues to progress, treatment efficacy will continue to improve and disease indications will expand. Hardware advances such as longer-lasting batteries will reduce the frequency of battery replacement and segmented leads will facilitate improvements in the effectiveness of stimulation and have the potential to minimize stimulation side effects. Targeting advances such as specialized imaging sequences and "connectomics" will facilitate improved accuracy for lead positioning and trajectory planning. Software advances such as closed-loop stimulation and remote programming will enable DBS to be a more personalized and accessible technology. The future of DBS continues to be promising and holds the potential to further improve quality of life. In this review we will address the past, present and future of DBS.

Adaptive, personalized closed-loop therapy for Parkinson's disease: biochemical, neurophysiological, and wearable sensing systems

INTRODUCTION

Motor complication management is one of the main unmet needs in Parkinson's disease patients.

AREAS COVERED

Among the most promising emerging approaches for handling motor complications in Parkinson's disease, adaptive deep brain stimulation strategies operating in closed-loop have emerged as pivotal to deliver sustained, near-to-physiological inputs to dysfunctional basal ganglia-cortical circuits over time. Existing sensing systems that can provide feedback signals to close the loop include biochemical-, neurophysiological- or wearable-sensors. Biochemical sensing allows to directly monitor the pharmacokinetic and pharmacodynamic of antiparkinsonian drugs and metabolites. Neurophysiological sensing relies on neurotechnologies to sense cortical or subcortical brain activity and extract real-time correlates of symptom intensity or symptom control during DBS. A more direct representation of the symptom state, particularly the phenomenological differentiation and quantification of motor symptoms, can be realized via wearable sensor technology.

EXPERT OPINION

Biochemical, neurophysiologic, and wearable-based biomarkers are promising technological tools that either individually or in combination could guide adaptive therapy for Parkinson's disease motor symptoms in the future.

New Frontiers for Deep Brain Stimulation: Directionality, Sensing Technologies, Remote Programming, Robotic Stereotactic Assistance, Asleep Procedures, and Connectomics

Over the last few years, while expanding its clinical indications from movement disorders to epilepsy and psychiatry, the field of deep brain stimulation (DBS) has seen significant innovations. Hardware developments have introduced directional leads to stimulate specific brain targets and sensing electrodes to determine optimal settings via feedback from local field potentials. In addition, variable-frequency stimulation and asynchronous high-frequency pulse trains have introduced new programming paradigms to efficiently desynchronize pathological neural circuitry and regulate dysfunctional brain networks not responsive to conventional settings. Overall, these innovations have provided clinicians with more anatomically accurate programming and closed-looped feedback to identify optimal strategies for neuromodulation. Simultaneously, software developments have simplified programming algorithms, introduced platforms for DBS remote management via telemedicine, and tools for estimating the volume of tissue activated within and outside the DBS targets. Finally, the surgical accuracy has improved thanks to intraoperative magnetic resonance or computerized tomography guidance, network-based imaging for DBS planning and targeting, and robotic-assisted surgery for ultra-accurate, millimetric lead placement. These technological and imaging advances have collectively optimized DBS outcomes and allowed “asleep” DBS procedures. Still, the short- and long-term outcomes of different implantable devices, surgical techniques, and asleep vs. awake procedures remain to be clarified. This expert review summarizes and critically discusses these recent innovations and their potential impact on the DBS field.

Quantified assessment of deep brain stimulation on Parkinson's patients with task fNIRS measurements and functional connectivity analysis: a pilot study

Background

Deep brain stimulation (DBS) has proved effective for Parkinson’s disease (PD), but the identification of stimulation parameters relies on doctors’ subjective judgment on patient behavior.

Methods

Five PD patients performed 10-meter walking tasks under different brain stimulation frequencies. During walking tests, a wearable functional near-infrared spectroscopy (fNIRS) system was used to measure the concentration change of oxygenated hemoglobin (△HbO₂) in prefrontal cortex, parietal lobe and occipital lobe. Brain functional connectivity and global efficiency were calculated to quantify the brain activities.

Results

We discovered that both the global and regional brain efficiency of all patients varied with stimulation parameters, and the DBS pattern enabling the highest brain efficiency was optimal for each patient, in accordance with the clinical assessments and DBS treatment decision made by the doctors.

Conclusions

Task fNIRS assessments and brain functional connectivity analysis promise a quantified and objective solution for patient-specific optimization of DBS treatment.

Trial registration

Name: Accurate treatment under the multidisciplinary cooperative diagnosis and treatment model of Parkinson’s disease. Registration number is ChiCTR1900022715. Date of registration is April 23, 2019.

Deep Brain Stimulation Initiative: Toward Innovative Technology, New Disease Indications, and Approaches to Current and Future Clinical Challenges in Neuromodulation Therapy

Deep brain stimulation (DBS) is one of the most important clinical therapies for neurological disorders. DBS also has great potential to become a great tool for clinical neuroscience research. Recently, the National Engineering Laboratory for Neuromodulation at Tsinghua University held an international Deep Brain Stimulation Initiative workshop to discuss the cutting-edge technological achievements and clinical applications of DBS. We specifically addressed new clinical approaches and challenges in DBS for movement disorders (Parkinson's disease and dystonia), clinical application toward neurorehabilitation for stroke, and the progress and challenges toward DBS for neuropsychiatric disorders. This review highlighted key developments in (1) neuroimaging, with advancements in 3-Tesla magnetic resonance imaging DBS compatibility for exploration of brain network mechanisms; (2) novel DBS recording capabilities for uncovering disease pathophysiology; and (3) overcoming global healthcare burdens with online-based DBS programming technology for connecting patient communities. The successful event marks a milestone for global collaborative opportunities in clinical development of neuromodulation to treat major neurological disorders.

Variable- versus constant-frequency sacral neuromodulation in black-zone overactive bladder patients: a study protocol for a multicenter, prospective, randomized, blind, self-controlled trial

Background

The curative effect of sacral neuromodulation (SNM), used to treat overactive bladder (OAB) patients, is definite. However, some patients still have recurrent symptoms after SNM and unsatisfactory symptom improvement after repeated adjustments of the stimulation parameters combined with oral drugs. These are referred to as black-zone OAB patients. The described SNM is the standard method, which involves a constant-frequency stimulation (CFS) of the patient's specific sacral nerve. A new treatment strategy, which combines the advantages of high-frequency and low-frequency stimulations to generate variable-frequency stimulation (VFS), has not yet undergone a formal randomized clinical trial. Therefore, we designed this clinical trial to evaluate the efficacy and safety of VFS-SNM and CFS-SNM in the treatment of black-zone OAB patients.

Methods

We designed a multicenter, prospective, randomized, blinded, self-controlled trial with a 12-week follow-up period. The trial randomly divides the enrolled patients into CFS-SNM and VFS-SNM groups. The main evaluation index is the comparative effectiveness of VFS-SNM and CFS-SNM at the last follow-up. The secondary evaluation indices include the change in the OAB symptom score, the quality of life (QOL) score, and the visual analog scale compared with the baseline period at each follow-up time point.

Discussion

Previous studies and our pre-experimental results suggest that black-zone OAB patients may benefit from VFS-SNM. Twelve weeks of VFS-SNM are effective in 40%, and the non-inferior cutoff value is 10% (80% power, 0.05 significance level, 20% loss to follow up). Thus, the calculated sample size is 37 cases each for CFS and VFS groups. The trial is expected to be carried out in 18 centers, but centers will be added or removed as appropriate depending on specific implementation conditions. Clinical researchers at each center will be responsible for screening qualified participants. This is the first randomized controlled trial to comprehensively evaluate the efficacy and safety of VFS-SNM in black-zone OAB patients, which will provide high-quality clinical evidence and may provide new clinical options for such patients.

Trial registration

Chinese Clinical Trial Registry: ChiCTR2000036677, registration date: 24 August 2020.

Variable frequency stimulation of sacral neuromodulation in black-zone overactive bladder patients: a case report

Overactive bladder (OAB) is a common urological disease, reducing patient quality of life (QoL). Sacral neuromodulation (SNM) is a treatment option used when conservative treatment is inadequate. However, constant frequency stimulation-SNM (CFS-SNM) may not be sufficiently effective in achieving targeted symptom reduction in some patients. For such black-zone patients, a different treatment strategy is needed. Variable frequency stimulation (VFS) has been used for deep-brain stimulation treatment in patients with Parkinson’s disease with positive outcomes. Accordingly, in this study, we hypothesized the promising outcomes of VFS-SNM in black-zone OAB patients. Here, we evaluated the efficacy and safety of VFS-SNM viz-a-viz CFS-SNM in a black-zone patient with refractory OAB whose frequent micturition symptoms were not relieved after undergoing traditional conservative treatment. A 50-year-old male patient was treated with CFS-SNM at our hospital in October 2016, but his symptoms recurred after administering multiple medications and program-controlled parameter adjustments. We then treated the patient with VFS-SNM in March 2020. A 2-week follow-up through telephonic interviews was conducted; the improvements in voiding symptoms were evaluated by calculating the OAB symptom score (OABSS) and OAB-related QoL (OAB-QoL) score. We observed that OABSS was significantly lower after VFS-SNM than after CFS-SNM. Further, we observed that VFS-SNM significantly improved daytime and nocturnal micturition frequency, as evident from the reduced OABSSs from after CFS-SNM to after VFS-SNM. The main reason for patient dissatisfaction after CFS-SNM was the increased average daily micturition frequency and urgency. VFS-SNM controlled the micturition frequency to within the patient’s acceptable range, significantly improving the patient’s QoL (40% improvement in OAB-QoL score). To the best of our knowledge, this is the first case report on the use of VFS-SNM with positive outcomes in a black-zone OAB patient, suggesting that VFS-SNM is not inferior to CFS-SNM in the treatment of black-zone patients.

Update on Current Technologies for Deep Brain Stimulation in Parkinson's Disease

Deep brain stimulation (DBS) is becoming increasingly central in the treatment of patients with Parkinson's disease and other movement disorders. Recent developments in DBS lead and implantable pulse generator design provide increased flexibility for programming, potentially improving the therapeutic benefit of stimulation. Directional DBS leads may increase the therapeutic window of stimulation by providing a means of avoiding current spread to structures that might give rise to stimulation-related side effects. Similarly, control of current to individual contacts on a DBS lead allows for shaping of the electric field produced between multiple active contacts. The following review aims to describe the recent developments in DBS system technology and the features of each commercially available DBS system. The advantages of each system are reviewed, and general considerations for choosing the most appropriate system are discussed.

A Novel DBS Paradigm for Axial Features in Parkinson's Disease: A Randomized Crossover Study

BACKGROUND

High-frequency (130-185 Hz) deep brain stimulation (DBS) of the subthalamic nucleus is more effective for appendicular than axial symptoms in Parkinson's disease (PD). Low-frequency (60-80 Hz) stimulation (LFS) may reduce gait/balance impairment but typically results in worsening appendicular symptoms. We created a "dual-frequency" programming paradigm (interleave-interlink, IL-IL) to address both axial and appendicular symptoms. In IL-IL, 2 overlapping LFS programs are applied to the DBS lead, with the overlapping area focused on the optimal cathode. The nonoverlapping area (LFS) is thought to reduce gait/balance impairment, whereas the overlapping area (high-frequency stimulation, HFS) aims to control appendicular symptoms.

METHODS

We performed a randomized, double-blind crossover trial comparing patients' previously optimized IL-IL and conventional HFS paradigms. Each arm was 2 weeks in duration. The primary outcome measure was the patient/caregiver Modified Clinical Global Impression Severity (CGI-S). Secondary outcome measures included blinded motor evaluations, timed tests, patient/caregiver questionnaires, and Personal KinetiGraphs (PKG).

RESULTS

Twenty-five patients were enrolled, and 20 completed. The patient/caregiver CGI-S for gait/balance (P = 0.01) and appendicular symptom control (P = 0.001), and the blinded rater MDS-UPDRS-III (-5.22, P = 0.02), CGI-S gait/balance (P = 0.01), and CGI-S speech (P = 0.02) were better while on IL-IL. Scores on Parkinson's Disease Quality of Life (P = 0.002) and Freezing-of-Gait Questionnaires (P = 0.04) were better on IL-IL. The Timed-Up-and-Go was 9.8% faster (P = 0.01), with 11.8% reduction in steps (P = 0.001) on IL-IL. There was no difference in PKG bradykinesia (P = 0.18) or tremor (P = 0.23) between paradigms.

CONCLUSIONS

Our results prompt consideration of this novel programming paradigm (IL-IL) for PD patients with axial symptom impairment as a new treatment option for both axial and appendicular symptoms. © 2020 International Parkinson and Movement Disorder Society.

Variable- versus constant-frequency deep-brain stimulation in patients with advanced Parkinson's disease: study protocol for a randomized controlled trial

BACKGROUND

Deep-brain stimulation targeting the subthalamic nucleus (STN) can be used to treat motor symptoms and dyskinesia in the advanced stages of Parkinson's disease (PD). High-frequency stimulation (HFS) of the STN can lead to consistent, long-term improvement of PD symptoms. However, the effects of HFS on the axial symptoms of PD, specifically freezing of gait, can be limited or cause further impairment. While this can be alleviated via relatively low-frequency stimulation (LFS) in selected patients, LFS does not control all motor symptoms of PD. Recently, the National Engineering Laboratory for Neuromodulation reported preliminary findings regarding an efficient way to combine the advantages of HFS and LFS to form variable-frequency stimulation (VFS). However, this novel therapeutic strategy has not been formally tested in a randomized trial.

METHODS/DESIGN

We propose a multicenter, double-blind clinical trial involving 11 study hospitals and an established deep-brain stimulation team. The participants will be divided into a VFS and a constant-frequency stimulation group. The primary outcome will be changes in stand-walk-sit task scores after 3 months of treatment in the "medication off" condition. Secondary outcome measures include specific item scores on the Freezing of Gait Questionnaire and quality of life. The aim of this trial is to investigate the efficacy and safety of VFS compared with constant-frequency stimulation.

DISCUSSION

This is the first randomized controlled trial to comprehensively evaluate the effectiveness and safety of VFS of the STN in patients with advanced PD. VFS may represent a new option for clinical treatment of PD in the future.

TRIAL REGISTRATION

ClinicalTrials.gov, NCT03053726. Registered on February 15, 2017.

An update on adaptive deep brain stimulation in Parkinson's disease

Advancing conventional open‐loop DBS as a therapy for PD is crucial for overcoming important issues such as the delicate balance between beneficial and adverse effects and limited battery longevity that are currently associated with treatment. Closed‐loop or adaptive DBS aims to overcome these limitations by real‐time adjustment of stimulation parameters based on continuous feedback input signals that are representative of the patient's clinical state. The focus of this update is to discuss the most recent developments regarding potential input signals and possible stimulation parameter modulation for adaptive DBS in PD. Potential input signals for adaptive DBS include basal ganglia local field potentials, cortical recordings (electrocorticography), wearable sensors, and eHealth and mHealth devices. Furthermore, adaptive DBS can be applied with different approaches of stimulation parameter modulation, the feasibility of which can be adapted depending on specific PD phenotypes. Implementation of technological developments like machine learning show potential in the design of such approaches; however, energy consumption deserves further attention. Furthermore, we discuss future considerations regarding the clinical implementation of adaptive DBS in PD. © 2018 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.

Deep Brain Stimulation at Variable Frequency to Improve Motor Outcomes in Parkinson's Disease

Introduction

Deep brain stimulation (DBS) with high frequency (HFS) is a well-established therapy for Parkinson's disease (PD); however, low frequency DBS (LFS) may control axial symptoms including freezing of gait (FOG). We conducted a pilot safety and feasibility study to examine if a novel DBS paradigm of variable frequency stimulation (VFS) that combined HFS and LFS would capture a broader set of motor symptoms.

Methods

Four PD patients with bilateral STN DBS and FOG were enrolled. A UPDRS III and 10 m timed up and go (TUG) task were performed off medications-off DBS and then one hour after HFS and one hour after VFS programming.

Results

The UPDRS III motor score improved by additional 14% during VFS setting when compared to HFS. VFS also increased gait speed (mean change 45%) and reduced the number of freezing episodes (mean change 58%).

Conclusions

VFS improves UPDRS and FOG in PD when compared to HFS.Copyright © 2018 International Parkinson and Movement Disorder Society.

Design of a novel stimulation system with time-varying paradigms for investigating new modes of high frequency stimulation in brain

Background

Deep brain stimulation (DBS) has shown wide clinical applications for treating various disorders of central nervous system. High frequency stimulation (HFS) of pulses with a constant intensity and a constant frequency is typically used in DBS. However, new stimulation paradigms with time-varying parameters provide a prospective direction for DBS developments. To meet the research demands for time-varying stimulations, we designed a new stimulation system with a technique of LabVIEW-based virtual instrument.

Methods

The system included a LabVIEW program, a NI data acquisition card, and an analog stimulus isolator. The output waveforms of the system were measured to verify the time-varying parameters. Preliminary animal experiments were run by delivering the HFS sequences with time-varying parameters to the hippocampal CA1 region of anesthetized rats.

Results

Verification results showed that the stimulation system was able to generate pulse sequences with ramped intensity and hyperbolic frequency accurately. Application of the time-varying HFS sequences to the axons of pyramidal cells in the hippocampal CA1 region resulted in neuronal responses different from those induced by HFS with constant parameters. The results indicated important modulations of time-varying stimulations to the neuronal activity that could prevent the stimulation from inducing over-synchronized firing of population neurons.

Conclusions

The stimulation system provides a useful technique for investigating diverse stimulation paradigms for the development of new DBS treatments.

Chinese expert consensus on programming deep brain stimulation for patients with Parkinson's disease

Background

Deep Brain Stimulation (DBS) therapy for the treatment of Parkinson’s Disease (PD) is now a well-established option for some patients. Postoperative standardized programming processes can improve the level of postoperative management and programming, relieve symptoms and improve quality of life.

Main body

In order to improve the quality of the programming, the experts on DBS and PD in neurology and neurosurgery in China reviewed the relevant literatures and combined their own experiences and developed this expert consensus on the programming of deep brain stimulation in patients with PD in China.

Conclusion

This Chinese expert consensus on postoperative programming can standardize and improve postoperative management and programming of DBS for PD.

Vagus nerve stimulation balanced disrupted default-mode network and salience network in a postsurgical epileptic patient

INTRODUCTION

In recent years, treatment of intractable epilepsy has become more challenging, due to an increase in resistance to antiepileptic drugs, as well as diminished success following resection surgery. Here, we present the case of a 19-year old epileptic patient who received vagus nerve stimulation (VNS) following unsuccessful left parietal-occipital lesion-resection surgery, with results indicating an approximate 50% reduction in seizure frequency and a much longer seizure-free interictal phase.

MATERIALS AND METHODS

Using resting-state functional magnetic resonance imaging, we measured the changes in resting-state brain networks between pre-VNS treatment and 6 months post-VNS, from the perspective of regional and global variations, using regional homogeneity and large-scale functional connectives (seeding posterior cingulate cortex and anterior cingulate cortex), respectively.

RESULTS

After 6 months of VNS therapy, the resting-state brain networks were slightly reorganized in regional homogeneity, mainly in large-scale functional connectivity, where excessive activation of the salience network was suppressed, while at the same time the suppressed default-mode network was activated.

CONCLUSION

With regard to resting-state brain networks, we propose a hypothesis based on this single case study that VNS acts on intractable epilepsy by modulating the balance between salience and default-mode networks through the integral hub of the anterior cingulate cortex.