Integration of brain-computer interfaces with sacral nerve stimulation: a vision for closed-loop, volitional control of bladder function in neurogenic patients through real-time cortical signal modulation and peripheral neuro-stimulation

Sacral nerve stimulation (SNS) and brain-computer interfaces (BCI) are emerging neuromodulation therapies that offer innovative solutions for chronic neurological disorders. SNS, primarily used in the management of conditions such as urinary incontinence and chronic pelvic pain, demonstrates significant therapeutic potential. In contrast, BCIs are rapidly advancing in their ability to restore lost motor functions and improve the quality of life of patients with severe neurological impairments, such as spinal cord injury and stroke. The integration of SNS and BCI technologies presents a promising avenue for enhancing neuromodulation outcomes by leveraging the potential of both systems. This article explores the combined operation of SNS and BCI, addressing current challenges, future directions, and the potential for these combined therapies to revolutionise the field of functional neuromodulation.

Hypoglossal nerve stimulator on extraoral radiography and cone beam computed tomography scan: Case report

BACKGROUND

The hypoglossal nerve stimulator (HNS) device has been employed in some patients with refractory or unsatisfactory outcomes to chronic obstructive sleep apnea management. The objective of this article is to increase recognition of the radiologic appearances of this device within the head and neck region, as seen on extraoral radiographic and cone beam computed tomography (CBCT) images.

CLINICAL PRESENTATION

A 55-year-old man, refractory to a multitude of apneic medical therapies, underwent a series of preorthognathic radiologic studies. Notably, an implanted HNS lead and ribbon electrodes appeared as hyperdense structures on the panoramic radiograph, lateral cephalogram, and CBCT scan.

CONCLUSION

This article provides various radiologic views of the primary components of an HNS. Clinicians should be able to recognize the presence of neurostimulator devices used for management of chronic sleep apnea within the radiologic field of view of examinations of the head and neck.

Reporting guidelines for randomised controlled trial reports of implantable neurostimulation devices: the CONSORT-iNeurostim extension

Background

The Consolidated Standards of Reporting Trials (CONSORT) statement has improved the quality of reporting of randomised trials. Extensions to the CONSORT statement are often needed to address specific issues of trial reporting, including those relevant to particular types of interventions. Methodological and reporting deficiencies in clinical trials of implantable neurostimulation devices are common. The CONSORT-iNeurostim extension is a new reporting guideline for randomised controlled trials evaluating implantable neurostimulation devices.

Methods

CONSORT-iNeurostim was developed using the EQUATOR methodological framework including a literature review and expert consultation to generate an initial list of candidate items. The candidate items were included in a two-round Delphi survey, discussed at an international consensus meeting (42 stakeholders including healthcare professionals, methodologists, journal editors and industry representatives from the United States, United Kingdom, Netherlands and other countries), and refined through a checklist pilot (18 stakeholders).

Findings

The initial extension item list included 49 candidate items relevant to CONSORT-iNeurostim. We received 132 responses in the first round of the Delphi survey and 99 responses in the second round. Participants suggested an additional 20 candidate items for CONSORT-iNeurostim during the first round of the survey, and those achieving initial consensus were discussed at the consensus meeting. The CONSORT-iNeurostim extension includes 7 new checklist items, including one item for reporting the neurostimulation intervention comprising a separate checklist of 14 items.

Interpretation

The CONSORT-iNeurostim extension will promote increased transparency, clarity, and completeness of trial reports of implantable neurostimulation devices. It will assist journal editors, peer-reviewers, and readers to better interpret the appropriateness and generalisability of the methods used and reported outcomes.

Funding

Abbott, Boston Scientific Corp., Mainstay Medical, Medtronic Ltd, Nevro Corp. and Saluda Medical.

Reporting guidelines for protocols of randomised controlled trials of implantable neurostimulation devices: the SPIRIT-iNeurostim extension

Background

The Standard Protocol Items: Recommendations for Interventional Trials (SPIRIT) statement has improved the quality of reporting of randomised trial protocols. Extensions to the SPIRIT statement are needed to address specific issues of trial protocol reporting, including those relevant to particular types of interventions. Methodological and reporting deficiencies in protocols of clinical trials of implantable neurostimulation devices are common. The SPIRIT-iNeurostim extension is a new reporting guideline for randomised controlled trial protocols evaluating implantable neurostimulation devices.

Methods

SPIRIT-iNeurostim was developed using the EQUATOR methodological framework including a literature review and expert consultation to generate an initial list of candidate items. The candidate items were included in a two-round Delphi survey, discussed at an international consensus meeting (42 stakeholders including healthcare professionals, methodologists, journal editors and industry representatives from the United States, United Kingdom, Netherlands and other countries), and refined through a checklist pilot (18 stakeholders).

Findings

The initial extension item list included 42 candidate items relevant to SPIRIT-iNeurostim. We received 132 responses in the first round of the Delphi survey and 99 responses in the second round. Participants suggested an additional 14 candidate items for SPIRIT-iNeurostim during the first round of the survey, and those achieving initial consensus were discussed at the consensus meeting. The SPIRIT-iNeurostim extension includes 5 new checklist items, including one item for reporting the neurostimulation intervention comprising a separate checklist of 14 items.

Interpretation

The SPIRIT-iNeurostim extension will help to promote increased transparency, clarity, and completeness of reporting trial protocols evaluating implantable neurostimulation devices. It will assist journal editors, peer-reviewers, and readers to better interpret the appropriateness and generalisability of the methods used for a planned clinical trial.

Funding

Abbott, Boston Scientific Corp., Mainstay Medical, Medtronic Ltd, Nevro Corp., and Saluda Medical.

Reduced thalamic activity in ADHD under ABR forward masking conditions

Attention-deficit hyperactivity disorder (ADHD) is a common chronic neurodevelopmental disorder characterized by symptoms of inattention, overactivity, and/or impulsiveness. The prevalence of ADHD varies in different settings and there have been voices raised to call for more objective measures in order to avoid over- and underdiagnosing of ADHD. Auditory Brainstem Response (ABR) is a method where click shaped sounds evoke potentials that are recorder from electrodes on the skull of a patient. The aim of this study was to explore possible alterations in the ABR of 29 patients with ADHD compared to 39 healthy controls. We used a forward masked sound. We found differences in ABR that correspond to the thalamic area. The thalamus seems to play an active role in regulation of activity level in ADHD. More research is needed to draw any further conclusions on using ABR as an objective measurement to detect ADHD.

Atypical refractory occipital neuralgia treated with a unilateral dual-lead occipital nerve stimulator: a case report

Aim: To describe the successful treatment of atypical occipital neuralgia (ON) using a unilateral dual-lead occipital nerve stimulator.Setting: Outpatient clinic/operating room.Patient: A 53-year-old male with atypical ON.Case description: Patient was previously diagnosed with treatment-refractory left-sided trigeminal neuralgia with atypical occipital distribution. On presentation, his symptoms were consistent with ON with distribution to the left fronto-orbital area. He received a left-sided nerve stimulator implant targeting both the greater and lesser occipital nerves.Results: Patient reported pain relief from a numerical rating scale 10/10 to 3-4/10.Conclusion: ON with referred ipsilateral trigeminal distribution should be considered when patients present with simultaneous facial and occipital pain. Further, a dual-lead unilateral stimulator approach may be a viable treatment.

Effect of direct voltage induction by low-frequency security systems on neurostimulator lead

Low-frequency (LF) security systems, such as antitheft electronic article surveillance (EAS) gates emit strong magnetic fields that could potentially interfere with neurostimulator operation. Some patients reported pain and shocking sensations near EAS gates, even after they turned off their pulse generator. To investigate the direct voltage induction of EAS systems on neurostimulator leads, we evaluated voltages induced by two EAS systems (14 kHz continuous wave or 58 kHz pulsed) on a 40 cm sacral neurostimulator lead formed in a circular loop attached to a pulse generator that was turned off. The lead and neurostimulator were mounted in a saline-filled rectangular phantom placed within electromagnetic fields emitted by EAS systems. The measured voltage waveforms were applied to computational models of spinal nerve axons to predict whether these voltages may evoke action potentials. Additional in vitro testing was performed on the semicircular lead geometry, to study the effect of lead geometry on EAS induced voltages. While standard neurostimulator testing per ISO 14708-3:2017 recommends electromagnetic compatibility testing with LF magnetic fields for induction of malfunctions of the active electronic circuitry while generating intended stimulating pulses, our results show that close to the EAS antenna frames, the induced voltage on the lead could be strong enough to evoke action potentials, even with the pulse generator turned off. This work suggests that patient reports of pain and shocking sensations when near EAS systems could also be correlated with the direct EAS-induced voltage on neurostimulator lead.

The Untold Story of Occipital Nerve Stimulation in Patients With Cluster Headache: Surgical Technique in Relation to Clinical Efficacy

OBJECTIVES

Approximately one in every 1000 adults experiences cluster headache (CH). Although occipital nerve stimulation (ONS) appears encouraging in treatment for most patients with refractory CH, some patients do not reach adequate pain relief with ONS. A reason for failure of ONS might be anatomical variations and different surgical approaches. Therefore, an extensive literature analysis was performed, and cadaveric experimentation was combined with our clinical experience to provide a standardized proposal for ONS and obtain optimal management of patients with refractory CH.

MATERIALS AND METHODS

Data from 36 articles published between 1998 and 2023 were analyzed to retrieve information on the anatomical landmarks and surgical technique of ONS. For the cadaveric experimentation (N = 1), two electrodes were inserted from the region over the foramen magnum and projected toward the lower third of the mastoid process.

RESULTS

The existence of multiple approaches of ONS has been confirmed by the present analysis. Discrepancies have been found in the anatomical locations and corresponding landmarks of the greater and lesser occipital nerve. The surgical approaches differed in patient positioning, electrode placement, and imaging techniques, with an overall efficacy range of 35.7% to 90%.

CONCLUSIONS

Reports on the surgical approach of ONS remain contradictory, hence emphasizing the need for standardization. Only if all implanting physicians perform the ONS surgery using a standardized protocol, can future data be combined and outcomes compared and analyzed.

The influence of methylphenidate on auditory brainstem response patients with attention deficit hyperactivity disorder; an exploratory study

Background

Attention-deficit hyperactivity disorder (ADHD), characterized by periods of inattention, overactivity, and impulsiveness, is the most prevalent neurodevelopmental disorder among children. Auditory Brainstem Response (ABR) is a technique in which clickshaped sounds elicit potentials that are recorded from electrodes placed on a patient's skull. Extant research indicates that ABR is frequently affected in neurodevelopmental disorders such as ADHD. Methylphenidate (MPH), a psychostimulant, is often prescribed to children with ADHD as a first-line pharmacological treatment. The aim of this study was to explore the effects of Methylphenidate treatment on previously observed amplitude alterations in the ABR of patients with ADHD.

Methods

We recruited 32 drug-naïve children and adolescents (19 males and 13 females; mean age 11 years) diagnosed with ADHD and 35 health controls (15 males and 20 females; mean age 12 years). The ADHD group was treated with Methylphenidate, and ABR was recorded before treatment and at a steady state of medical treatment.

Results

Medicated ADHD patients exhibited increased activity in the right side ABR in Wave VI.

Conclusions

A significant increase in activity was found in a part of the ABR thought to correspond to the thalamic area in medicated ADHD patients compared to the same area of non-medicated ADHD patients. The results add to the growing body of research suggesting that specific ABR peaks correlate to certain psychiatric symptoms.

The Use of Salvage Procedures for Wound Complications in Neuromodulation

OBJECTIVE

Wound complications are a prevalent concern for neuromodulation procedures. While removal of the device was recommended, attempts to salvage expensive hardware have become commonplace. We examine our management in wound issues to aid in providing guidance for these situations.

METHODS

We identified 40 patients over an 8-year period in a large neuromodulation practice, who underwent washout or partial salvage of hardware. We examined the efficacy of washout and partial explants on the ability to salvage the implants. Covariates including age, sex, body mass index, smoking status, anticoagulation, and device type were considered.

RESULTS

There were 29 washouts and 10 partial hardware removal cases. Washouts were successful in 15/29 cases (51.7%), partial hardware removal was successful in 2/10 cases (20%), and removal with replacement was not successful (0 of 1). Washouts tended to be more successful than partial removal procedures (P = 0.08). In cases of successful washout, the average duration between infectious symptoms and washout was 7.27 ± 2.19 days. None of the demographic variables were associated with increased likelihood of washout failure.

CONCLUSIONS

Our results demonstrate a higher rate of washout failure in those who underwent partial device removal and in the presence of purulence at the surgical site. Further investigation must be conducted to determine the instances in which hardware removal is indicated to prevent failure or removal due to infection. Identification of these parameters will optimize therapeutic benefit and long-term financial impact.

Advances in applications of head mounted devices (HMDs): Physical techniques for drug delivery and neuromodulation

Head-mounted medical devices (HMDs) are disruptive inventions representing laboratories and clinical institutions worldwide are climbing the apexes of brain science. These complex devices are inextricably linked with a wide range knowledge containing the Physics, Imaging, Biomedical engineering, Biology and Pharmacology, particularly could be specifically designed for individuals, and finally exerting integrated bio-effect. The salient characteristics of them are non-invasive intervening in human brain's physiological structures, and alterating the biological process, such as thermal ablating the tumor, opening the BBB to deliver drugs and neuromodulating to enhance cognitive performance or manipulate prosthetic. The increasing demand and universally accepted of them have set off a dramatic upsurge in HMDs' studies, seminal applications of them span from clinical use to psychiatric disorders and neurological modulation. With subsequent pre-clinical studies and human trials emerging, the mechanisms of transcranial stimulation methods of them were widely studied, and could be basically came down to three notable approach: magnetic, electrical and ultrasonic stimulation. This review provides a comprehensive overviews of their stimulating mechanisms, and recent advances in clinic and military. We described the potential impact of HMDs on brain science, and current challenges to extensively adopt them as promising alternative treating tools.

Pre-deployment assessment of an AI model to assist radiologists in chest X-ray detection and identification of lead-less implanted electronic devices for pre-MRI safety screening: realized implementation needs and proposed operational solutions

Purpose

Chest X-ray (CXR) use in pre-MRI safety screening, such as for lead-less implanted electronic device (LLIED) recognition, is common. To assist CXR interpretation, we "pre-deployed" an artificial intelligence (AI) model to assess (1) accuracies in LLIED-type (and consequently safety-level) identification, (2) safety implications of LLIED nondetections or misidentifications, (3) infrastructural or workflow requirements, and (4) demands related to model adaptation to real-world conditions.

Approach

A two-tier cascading methodology for LLIED detection/localization and identification on a frontal CXR was applied to evaluate the performance of the original nine-class AI model. With the unexpected early appearance of LLIED types during simulated real-world trialing, retraining of a newer 12-class version preceded retrialing. A zero footprint (ZF) graphical user interface (GUI)/viewer with DICOM-based output was developed for inference-result display and adjudication, supporting end-user engagement and model continuous learning and/or modernization.

Results

During model testing or trialing using both the nine-class and 12-class models, robust detection/localization was consistently 100%, with mAP 0.99 from fivefold cross-validation. Safety-level categorization was high during both testing ( AUC ≥ 0.98 and ≥ 0.99 , respectively) and trialing (accuracy 98% and 97%, respectively). LLIED-type identifications by the two models during testing (1) were 98.9% and 99.5% overall correct and (2) consistently showed AUC ≥ 0.92 (1.00 for 8/9 and 9/12 LLIED-types, respectively). Pre-deployment trialing of both models demonstrated overall type-identification accuracies of 94.5% and 95%, respectively. Of the small number of misidentifications, none involved MRI-stringently conditional or MRI-unsafe types of LLIEDs. Optimized ZF GUI/viewer operations led to greater user-friendliness for radiologist engagement.

Conclusions

Our LLIED-related AI methodology supports (1) 100% detection sensitivity, (2) high identification (including MRI-safety) accuracy, and (3) future model deployment with facilitated inference-result display and adjudication for ongoing model adaptation to future real-world experiences.

Low-Noise Amplifier for Deep-Brain Stimulation (DBS)

Deep-brain stimulation (DBS) is an emerging research topic aiming to improve the quality of life of patients with brain diseases, and a great deal of effort has been focused on the development of implantable devices. This paper presents a low-noise amplifier (LNA) for the acquisition of biopotentials on DBS. This electronic module was designed in a low-voltage/low-power CMOS process, targeting implantable applications. The measurement results showed a gain of 38.6 dB and a −3 dB bandwidth of 2.3 kHz. The measurements also showed a power consumption of 2.8 μW. Simulations showed an input-referred noise of 6.2 μVRMS. The LNA occupies a microdevice area of 122 μm × 283 μm, supporting its application in implanted systems.

Space invader: pleural penetration of a hypoglossal nerve stimulator sensor lead

The mainstay of treatment for obstructive sleep apnea (OSA) is positive airway pressure (PAP). PAP therapy may be difficult to tolerate for some patients which may compromise adherence, requiring alternative therapies. Hypoglossal nerve stimulation (HGNS) has become an option for those who meet implantation criteria. Implantation of the device is an ambulatory surgical procedure and is generally well-tolerated, though rare adverse events have been reported. We report an unusual complication of HGNS in a patient who had initial success with this therapy. After three years of treatment, the sensor lead penetrated into the pleural space. Components of the HGNS were explanted, and a new sensor lead and generator were reimplanted. The new device was activated, and therapy was successfully resumed. This case demonstrates that there is a potential for a delayed complication of sensor lead penetration into the pleural space which has only rarely been reported.

Peripheral Nerve Stimulation for Occipital Neuralgia

Background

Chronic headaches are the second most prevalent disease and second most common cause for years lived with disability worldwide. Occipital neuralgia can cause headaches or be present in addition to other more prevalent causes of headache. If these headaches fail to respond to conservative and pharmacological therapy, physicians proceed to more invasive treatments, starting with infiltration of the greater occipital nerve with local anesthetic with or without corticosteroids, followed by nerve ablation or stimulation. Occipital nerve stimulation gained more popularity as the technology improved and more pain physicians received training on interventional procedures.

Methods

In this manuscript, we are presenting our experience with ultrasound-guided implant of occipital nerve stimulators using peripheral nerve stimulator systems. After confirming appropriateness of treatment by a successful occipital nerve block (i.e., resulting in >50% relief in patients’ pain intensity), we implanted five stimulator systems in three patients (two bilateral).

Results

We followed these patients for an average of eight months, and the average pain reduction was ∼50%. We did not observe any adverse events during or immediately after surgery. One patient developed an adverse reaction to the adhesive of the battery transmitter, but it was not severe enough to stop her from using the stimulator.

Conclusions

Considering the ease of implant and minimal side effects, implant of peripheral nerve stimulators to stimulate the occipital nerve is a promising treatment modality for patients with chronic headache who present with features of occipital neuralgia. However, wider use of this treatment modality is subject to further studies.