Choice of Implantable Pulse Generators for Deep Brain Stimulation: An Overview of Clinical Practice.

INTRODUCTION: The success of deep brain stimulation (DBS) treatment depends on several factors, including proper patient selection, accurate electrode placement, and adequate stimulation settings. Another factor that may impact long-term satisfaction and therapy outcomes is the type of implantable pulse generator (IPG) used: rechargeable or non-rechargeable. However, there are currently no guidelines on the choice of IPG type. The present study investigates the current practices, opinions, and factors DBS clinicians consider when choosing an IPG for their patients. METHODS: Between December 2021 and June 2022, we sent a structured questionnaire with 42 questions to DBS experts of two international, functional neurosurgery societies. The questionnaire included a rating scale where participants could rate the factors influencing their choice of IPG type and their satisfaction with certain IPG aspects. Additionally, we presented four clinical case scenarios to assess preference of choice of IPG-type in each case. RESULTS: Eighty-seven participants from 30 different countries completed the questionnaire. The three most relevant factors for IPG choice were "existing social support," "cognitive status," and "patient age." Most participants believed that patients valued avoiding repetitive replacement surgeries more than the burden of regularly recharging the IPG. Participants reported that they implanted the same amount of rechargeable as non-rechargeable IPGs for primary DBS insertions and 20% converted non-rechargeable to rechargeable IPGs during IPG replacements. Most participants estimated that rechargeable was the more cost-effective option. CONCLUSION: This present study shows that the decision-making of the choice of IPG is very individualized. We identified the key factors influencing the physician's choice of IPG. Compared to patient-centric studies, clinicians may value different aspects. Therefore, clinicians should rely not only on their opinion but also counsel patients on different types of IPGs and consider the patient's preferences. Uniform global guidelines on IPG choice may not represent regional or national differences in the healthcare systems.

Beyond implantation effect? Long-term seizure reduction and freedom following intracranial monitoring without additional surgical interventions.

The term 'implantation effect' is used to describe an immediate and transient improvement in seizure frequency following an intracranial study for seizure onset localization. We conducted a retrospective analysis of 190 consecutive patients undergoing intracranial electroencephalogram (EEG) monitoring, of whom 41 had no subsequent resection/ablation/stimulation; 33 had adequate data and follow-up time available for analysis. Analysis of seizure frequency following an intracranial study showed 36% (12/33) responder rate (>50% seizure reduction) at one year, decreasing and stabilizing at 20% from year 4 onwards. In addition, we describe three patients (9%) who had long term seizure freedom of more than five years following electrode implantation alone, two of whom had thalamic depth electrodes. Electrode implantation perhaps leads to a neuromodulatory effect sufficient enough to disrupt epileptogenic networks. Rarely, this may be significant enough to even result in long term seizure freedom, as seen in our three patients.

Fixed-Life or Rechargeable Battery for Deep Brain Stimulation: A Prospective Long-Term Study of Patient's Preferences.

INTRODUCTION: Deep brain stimulation (DBS) is an established treatment for movement disorders. We have previously shown that in our practice, the majority of adult patients prefer fixed-life implantable pulse generators (IPGs), although rechargeable batteries are increasingly used. The aim of this study was to evaluate patients' long-term satisfaction with their choice of battery and factors that influence their decision. METHODS: Thirty patients with DBS were given a questionnaire to assess long-term satisfaction and experience with the type of battery they had chosen. RESULTS: Twenty-six patients completed the survey. The mean age was 67.7 ± 7.3 years, and mean follow-up was 18.0 ± 7.2 months. The indications for DBS were Parkinson's disease (76.9%), tremor (11.5%) and dystonia (11.5%). Eleven patients (42.5%) had chosen the rechargeable battery. All patients were still happy with their choices and would not change the type of battery if they had the chance to do so. However, in patients who chose the fixed-life battery, concern about the size of battery rose from 6.7% pre-operatively to 60% on long-term post-operative follow-up. In patients who chose the rechargeable battery, concern about the need to recharge the battery did not change, remaining low postoperatively. Interestingly, even though the main reason cited for choosing the fixed-life battery was the convenience and concern about forgetting to recharge the battery, patients who had chosen a rechargeable IPG did not experience this problem. CONCLUSION: Patients and caregivers should be involved in the choice of battery, as each type of IPG has its own advantages and disadvantages. Long-term evaluation of patient's experience and satisfaction with battery of choice revealed that size of the IPG, need for further replacement surgeries and need for recharging remain matters of major concern. Although preoperatively often underestimated, the size of the battery seems to be an important factor in long-term satisfaction.

Patient Experience with Rechargeable Implantable Pulse Generator Deep Brain Stimulation for Movement Disorders.

BACKGROUND/AIMS: Nonrechargeable deep brain stimulation implantable pulse generators (IPGs) for movement disorders require surgical replacement every few years due to battery depletion. Rechargeable IPGs reduce frequency of replacement surgeries and inherent risks of complications but require frequent recharging. Here, we evaluate patient experience with rechargeable IPGs and define predictive characteristics for higher satisfaction. METHODS: We contacted all patients implanted with rechargeable IPGs at a single center in a survey-based study. We analyzed patient satisfaction with respect to age, diagnosis, target, charging duration, and body mass index. We tabulated hardware-related adverse events. RESULTS: Dystonia patients had significantly higher satisfaction than Parkinson's disease patients in recharging, display, programmer, and training domains. Common positive responses were "fewer surgeries" and "small size." Common negative responses were "difficulty finding the right position to recharge" and "need to recharge every day." Hardware-related adverse events occurred in 21 of 59 participants. CONCLUSION: Patient experience with rechargeable IPGs was largely positive; however, frustrations with recharging and adverse events were common. Dystonia diagnosis was most predictive of high satisfaction across multiple categories, potentially related to expected long disease duration with need for numerous IPG replacements.

Fixed-Life or Rechargeable Battery for Deep Brain Stimulation: Which Do Patients Prefer?

BACKGROUND: Deep brain stimulation (DBS) is increasingly used to treat a wide variety of neurological and psychiatric disorders. Implantable pulse generators (implantable pulse generators/batteries) for DBS were originally only available as a nonrechargeable option. However, there is now a choice between fixed-life and rechargeable batteries, with each having their own advantages and disadvantages. The extent of patient involvement in the choice of battery and the factors that matter to them have not been well studied. METHODS: Thirty consecutive adult patients with movement disorders attending a pre-DBS clinic were offered a choice of fixed-life or rechargeable battery and completed a questionnaire after the consultation on which factors influenced their decision. RESULTS: Nineteen patients (63%) chose the fixed-life battery and 11 patients (37%) chose the rechargeable battery. There were no significant differences in age, sex, underlying disease, disease duration or Unified Parkinson's Disease Rating Scale (UPDRS) (part 3) score (for patients with Parkinson disease) between those who chose the fixed-life vs. rechargeable battery. Most patients were not concerned about the size of the battery. Equal numbers were concerned about surgery to replace the battery, and less than half were concerned about the need to recharge the battery. More than half of patients felt that an acceptable charging frequency was monthly or yearly, and all patients felt that an acceptable charging duration was less than 1 hour, with half of all patients choosing less than 30 min. The main reasons cited for choosing the fixed-life battery were convenience and concern about forgetting to recharge the battery. The main reason for choosing the rechargeable battery was the avoidance of further surgery. DISCUSSION: Most patients in this adult cohort with movement disorders chose the fixed-life battery. The better lifestyle associated with a fixed-life battery is a major factor influencing their choice. Rechargeable batteries may be more acceptable if the recharging process is improved, more convenient, and discreet. CONFLICT OF INTEREST: The authors' institution has received educational grants from Medtronic, Abbott, and Boston Scientific companies.

Neuroversion: using electroconvulsive therapy as a bridge to deep brain stimulation implantation.

Parkinson's disease (PD) is a movement disorder with significant neuropsychiatric comorbidities. Electroconvulsive therapy (ECT) is effective in treating these neuropsychiatric symptoms; however, clinicians are reluctant to use ECT in patients with deep brain stimulation (DBS) implantations for fear of damaging the device, as well as potential cognitive side effects. Right unilateral ultra-brief pulse (RUL UBP) ECT has a more favorable cognitive side-effect profile yet has never been reported in PD patients with DBS implants. We present a case series of three patients with a history of PD that all presented with psychiatric decompensation immediately prior to planned DBS surgery. All three patients had DBS electrode(s) in place at the time and an acute course of ECT was utilized in a novel method to "bridge" these individuals to neurosurgery. The patients all experienced symptom resolution (psychosis and/or depression and/or anxiety) without apparent cognitive side effects. This case series not only illustrates that right unilateral ultra-brief pulse can be utilized in patients with DBS electrodes but also illustrates that this intervention can be utilized as a neuromodulatory "bridge", where nonoperative surgical candidates with unstable psychiatric symptoms can be converted to operative candidates in a manner similar to electrical cardioversion.

Psychological impact of surveillance in patients with a defibrillator lead under advisory: a prospective evaluation.

BACKGROUND: Implantable cardioverter defibrillator (ICD) leads are subject to technical failures and the impact of the resulting public advisories on patient welfare is unclear. The psychological status of patients who received an advisory for their Medtronic Fidelis ICD lead (Medtronic Inc., Minneapolis, MN, USA) and followed either by self-surveillance for alarm or home monitoring with CareLink was evaluated prospectively and compared to patients with ICDs not under advisory. METHODS: One hundred sixty consecutive consenting patients (90 alarms, 24 Carelinks, 46 controls) were recruited within 1.5 years of advisory notification. Advisory patients were seen immediately before being told that the automatic lead surveillance utilized since the advisory had been inadequate in warning of impending fracture, as well as 1 and 6 months after programming was optimized. Depression, anxiety, quality of life (QoL), and ICD-related concerns were assessed. RESULTS: Symptoms of depression and state anxiety were experienced by 31% and 48% of patients, respectively. QoL was impaired on all subscales. No significant group differences in distress and ICD-related concerns emerged at baseline or at follow-up. At baseline, alarm patients reported greater limitations because of body pain compared to controls (P < 0.05). All patients showed a significant reduction in body pain-related QoL at the final versus first two evaluations (P < 0.001). Advisory patients were significantly less satisfied with surveillance at follow-up than at baseline (P < 0.05). CONCLUSIONS: There was limited evidence for worse psychosocial functioning in those at risk for ICD lead fracture, irrespective of surveillance method. However, many control and advisory patients experienced chronic distress for which counseling may prove beneficial.

Pilot study of deep brain stimulation in refractory obsessive-compulsive disorder ethnic Chinese patients.

AIMS: Deep brain stimulation (DBS) of the ventral capsule/ventral striatum (VC/VS) is a promising alternative to ablative surgery in treatment of refractory obsessive-compulsive disorder (OCD). A pilot study was conducted to assess 15-month outcomes of DBS in patients with refractory OCD in Taiwan. METHODS: Four adult patients with a 3-year or more history of refractory OCD (Yale-Brown Obsessive-Compulsive Scale [Y-BOCS] score of at least 28) met the criteria for DBS surgery. DBS electrodes were implanted bilaterally in the VC/VS. Stimulation was adjusted for therapeutic benefit and absence of adverse effects. Psychiatric evaluation was conducted preoperatively, postoperatively, and at follow up at every 3 months for 15 months. Primary outcome measure was Y-BOCS. Secondary outcomes included the Hamilton Depression Rating Scale (HAM-D), and the Global Assessment of Function Scale. RESULTS: Mean severity of OCD was a Y-BOCS score of 36.3 ± 2.1. At the end of 15 months' follow up, there was a 33.06% decrease in OCD severity (P = 0.001). Similar findings were seen for HAM-D (32.51% reduction, P = 0.005), and Global Assessment of Function Scale (31.03% increase, P = 0.026). In terms of adverse effects, two patients suffered from hypomania episodes after several weeks of DBS stimulation, and one had transient hypomania-like syndrome during DBS initial programming. One patient (Case 1) had an allergic reaction to implantation of the pulse generator in the chest, and another patient (Case 3) exhibited vertigo. CONCLUSIONS: We confirm that DBS of the VC/VS appears to be beneficial for improvements in function and mood among patients with treatment-resistant OCD. Compared to previous studies examining the therapeutic effects of DBS, no serious adverse effects were observed.

Psychological adjustment in ICD patients living with advisory fidelis leads.

UNLABELLED: Psychological Adjustment and Fidelis ICD Leads. INTRODUCTION: Implantable cardioverter defibrillators (ICD) advisory notices present treatment dilemmas for physicians and patients. On one side, the risk of device malfunction and the likely severity of clinical sequelae have to be estimated. This estimate has to be weighed against the risks of surgery to replace the advisory component. It is unclear whether there is important psychological morbidity associated with living with an ICD under advisory and whether this should be factored into decision making. The study had 2 objectives: (1) to examine whether there is adverse psychological adjustment when an ICD is under advisory, and (2) to assess the psychological sequel of advisory ICD component malfunction. METHODS: This study focused on the Sprint Fidelis advisory. All patients in our practice who still had an in service Medtronic Fidelis lead were included in the study. Three groups were compared: advisory group but no fracture (n = 249), advisory group with lead fracture (n = 24), and a control group (n = 143). For both objectives, we used a general anxiety and depression instrument and also device-specific measures of psychological well being. RESULTS AND CONCLUSIONS: First, there was no evidence of differences in the psychological functioning of patients at risk of ICD lead malfunction compared to a control group. Second, patients who had experienced an ICD lead fracture had adverse psychological morbidity compared to control patients, and this appeared, primarily, to be related to receiving inappropriate shock(s) at the time of the fracture.

Patient-reported outcomes in Danish implantable cardioverter defibrillator patients with a Sprint Fidelis lead advisory notification.

AIMS: Few studies have investigated the association between implantable cardioverter defibrillators (ICDs) and lead advisory notifications and patient-reported outcomes (PROs). We examined (i) whether the mode used to inform patients about a device advisory is associated with PROs, and (ii) whether patients with a lead subject to a device advisory report poorer PROs than non-advisory controls. METHODS AND RESULTS: Patients (n= 207) implanted with an ICD at Aarhus University Hospital, Denmark, with a Sprint Fidelis lead subject to an advisory and a non-advisory control group (n= 510), completed a set of standardized PRO measures. A Bonferroni correction was applied to all statistical PRO comparisons to adjust for multiple comparisons, with a P-value of 0.0038 (0.05/13 PROs) indicating statistical significance. Device advisory patients did not differ significantly on PROs according to mode of notification (all P-values >0.0038). They also did not differ significantly from controls on mean scores of depression, anxiety, device acceptance, and health status (all P > 0.0038). Differences were only found on ICD concerns (P< 0.0001) and on mental health status (P = 0.003), with advisory patients reporting fewer ICD concerns and a better mental health status than non-advisory controls. CONCLUSIONS: The mode used to inform ICD patients about the advisory was not associated with PROs, nor was the overall well-being of device advisory patients impaired compared to non-advisory controls. These results indicate that ICD patients are generally able to cope with a device advisory.

Psychological effects of implantable cardioverter-defibrillator leads under advisory.

BACKGROUND: Automatic implantable cardioverter-defibrillators (ICDs) are standard therapy for patients at high risk of sudden cardiac death. Device implantation is a stressful event that has been associated with patient and anticipatory anxiety. While the psychological effects of normally functioning ICDs are known, only a dearth of literature evaluates how a warning about the potential for malfunction of an ICD lead, related to a device advisory, influences the degree of psychological distress. These effects are evaluated in a patient population with the Medtronic Sprint Fidelis defibrillation lead 6949 (Medtronic, Minneapolis, MN, USA). METHODS: A sample of 413 patients were studied. Groups included 158 with an advisory Medtronic 6949 and 255 with an ICD that had no current advisories. Patients were administered a validated disease-specific metric assessing concerns over ICDs, as well as a demographics questionnaire. The primary outcome was the total score on the ICD concerns (ICDC). Analysis was with one-way Analysis of Variance with preplanned orthogonal contrasts and multivariate regression. RESULTS: The advisory group tended to have higher numbers of high school and college graduates. The average length of device implant in the nonadvisory group was higher at 4.29 years versus 3.99 years in the advisory group (t = 0.901, P ≤ 0.5). A higher percentage of those with an advisory experienced more shocks (39% vs 32%; z =-1.51, P ≤ 0.5). Average ICDC scores in the advisory group with previous shock were significantly higher than in the nonadvisory group with prior shock ([27.7 standard deviation (SD) ± 14.5] vs [18.5 SD ± 12.5], P = 0.0001) . Average ICDC score in the advisory group without shock was also significantly elevated compared to the nonadvisory group (18.5 SD ± 14.5 vs 10.8, SD ± 12.5, P = 0.0001). There was a significant effect of having an advisory on total ICDC scores (F = 21.32, P ≤ 0.0001). History of shock also significantly increased total ICDC scores (F = 20.07, P ≤ 0.0001). In multivariate regression, presence of Fidelis lead and history of shock were predictors for increased ICDC scores (R(2) = 0.158, F = 38.88, P = 0.0001). When controlling for shock history, presence of Fidelis lead remained an independent predictor of elevated ICDC scores (R(2) = 0.125, F = 59.30, P ≤ 0.0001). CONCLUSIONS: Our study attempts to address some of the psychological differences between participants with advisory and nonadvisory leads. Higher scores on the ICDC were found in our advisory group. While statistically significant, it is entirely unclear if these scale elevations are clinically significant or if directed counseling at this stage may reduce these elevations. This raises the suspicion that directed counseling be undertaken for patients with future advisories.

Patient preferences for next generation neural prostheses to restore bladder function.

STUDY DESIGN: A survey administered to 66 individuals with spinal cord injury (SCI) implementing a choice-based conjoint (CBC) analysis. Six attributes with three levels each were defined and used to generate choice sets with treatment scenarios. Patients were asked to choose the scenario that they preferred most. OBJECTIVES: To determine the utility weights for treatment characteristics as well as the overall preference for the three types of neural prostheses (NP), that is Brindley, rhizotomy-free Brindley, and pudendal nerve stimulation. Earlier studies have revealed the importance of restoration of bladder function, but no studies have been performed to determine the importance of NP features. SETTING: Two academic affiliated medical systems' SCI outpatient and inpatient rehabilitation programs, Cleveland, OH. METHODS: CBC analysis followed by multinomial logit modeling. Individual part-worth utilities were estimated using hierarchical Bayes. RESULTS: Side effects had the greatest significant impact on subject choices, followed by the effectiveness on continence and voiding. NPs with rhizotomy-free sacral root stimulation were preferred (45% first choice) over pudendal afferent nerve stimulation (39% second choice) and sacral root stimulation with rhizotomy (53% third choice). Almost 20% did not want to have an NP at all times. CONCLUSION: CBC has shown to be a valuable tool to support design choices. The data showed that persons would prefer a bladder NP with minimally invasive electrodes, which would give them complete bladder function, with no side effects and that can be operated by pushing a button and they do not have to recharge themselves.

Dissociable neural effects of long-term stimulus-reward pairing in macaque visual cortex.

It has been proposed that perceptual learning may occur through a reinforcement process, in which consistently pairing stimuli with reward is sufficient for learning. We tested whether stimulus-reward pairing is sufficient to increase the sensorial representation of a stimulus by recording local field potentials (LFPs) in macaque extrastriate area V4 with chronically implanted electrodes. Two oriented gratings were repeatedly presented; one was paired with a fluid reward, whereas no reward was given at any other time. During the course of conditioning the LFP increased for the rewarded compared to the unrewarded orientation. The time course of the effect of stimulus-reward pairing and its reversal differed between an early and late interval of the LFP response: a fast change in the later part of the neural response that was dissociated from a slower change in the early part of the response. The fast change of the late interval LFP suggests that this late LFP change is related to enhanced attention during the presentation of the rewarded stimulus. The slower time course of the early interval response suggests an effect of sensorial learning. Thus, simple stimulus-reward pairing is sufficient to strengthen stimulus representations in visual cortex and does this by means of two dissociable mechanisms.

Attitude towards redundant leads and the practice of lead extractions: a European survey.

This survey has compared attitudes towards (endocardial) lead extraction, among European electrophysiology centres, with special attention paid to 'redundant leads'. The main findings of this survey are: (i) most of the centres performing lead extractions do so in low volume even though the number of implants may be high. (ii) Approaches to the practice of lead extraction are based largely on clinical experience and individual sentiment but not on a rigorous evidence based. (iii) Traction alone or in combination with extraction tools (but not laser) are commonly used for extraction. (iv) The perception of need for involvement of cardio-thoracic surgeon varies.

Changes in cardiac anxiety and self-care practices in heart failure patients following implantation of wireless hemodynamic monitoring sensors.

BACKGROUND: Wireless implantable hemodynamic monitors assist cardiac care providers in tailoring medication regimens to reduce chronic heart failure hospital admissions and to improve patient quality of life. Previous research exists to support wireless implantable hemodynamic monitors favorable impact on medical endpoints but, however, their psychological and behavioral effects have not yet been established. The purpose of this pilot study was to investigate patient psychological and behavioral changes after receiving the wireless implantable hemodynamic monitor. METHODS: Patients with heart failure (n=26) who were implanted with wireless implantable hemodynamic monitor sensors completed the Cardiac Anxiety Questionnaire and Self-Care of Heart Failure Index version 6.2 at pre-implant and at one-month post-implant, as well as an initial demographic questionnaire. RESULTS: Heart failure patients who received a wireless implantable hemodynamic monitor experienced a significant reduction in cardiac anxiety, t(25)=2.93, p=0.007, z=-0.46, d=0.58, driven by a reduction in fear of their condition, t(25)=2.26, p=0.03, z=-0.42, d=0.44. Increases in self-care behaviors fell short of significance t(25)=1.67, p=0.11, but showed a medium effect size, d=0.33. CONCLUSION: Heart failure patients who received a wireless implantable hemodynamic monitor reported significantly reduced cardiac fear, indicating that wireless implantable hemodynamic monitor technology may produce a collateral benefit in psychological effects. Patient self-care may also benefit but the current study was under-powered to reach statistical significance. Patient education about psychological and behavioral aspects of the wireless implantable hemodynamic monitor implant may yield increased patient engagement and broader health benefits if these results are confirmed in a larger study.

Changes in Physiological and Pathological Behaviours Produced by Deep Microelectrode Implantation Surgery in Rats: A Temporal Analysis.

Physiological behaviours such as the sleep-wake cycle and exploratory behaviours are important parameters in intact and sham-operated animals and are usually thought to be unaffected by experimental protocols in which neurosurgery is performed. However, there is insufficient evidence in the literature on the behavioural and cognitive effects observed after deep microelectrode implantation surgery in animal models of neurological diseases. Similarly, in studies that utilize animal models of neurological diseases, the impact of surgery on the pathological phenomena being studied is often minimized. Based on these considerations, we performed a temporal analysis of the effects of deep microelectrode implantation surgery in the hippocampus of rats on quiet wakefulness, sleep, and exploratory activity and the pathological behaviours such as convulsive seizures according to the Racine scale. Male Wistar rats (210-300 g) were used and grouped in sham and epileptic animals. Single doses of pilocarpine hydrochloride (2.4 mg/2 µl; i.c.v.) were administered to the animals to generate spontaneous and recurrent seizures. Deep microelectrode implantation surgeries in both groups and analysis of Fast ripples were performed. Physiological and pathological behaviours were recorded through direct video monitoring of animals (24/7). Our principal findings showed that in epileptic animals, one of the main behaviours affected by surgery is sleep; as a consequence of this behavioural change, a decrease in exploratory activity was also found as well as the mean time spent daily in seizures of scale 4 and the number of seizure events of scales 4 and 5 was increased after surgery. No significant correlations between the occurrence of FR and seizure events of scale 4 (rho 0.63, p value 0.25) or 5 (rho -0.7, p value 0.18) were observed. In conclusion, microelectrode implantation surgeries modified some physiological and pathological behaviours; therefore, it is important to consider this fact when it is working with animal models.

Harmonization of pipeline for detection of HFOs in a rat model of post-traumatic epilepsy in preclinical multicenter study on post-traumatic epileptogenesis.

Studies of chronic epilepsy show pathological high frequency oscillations (HFOs) are associated with brain areas capable of generating epileptic seizures. Only a few of these studies have focused on HFOs during the development of epilepsy, but results suggest pathological HFOs could be a biomarker of epileptogenesis. The Epilepsy Bioinformatics Study for Antiepileptogenic Therapy" (EpiBioS4Rx) is a multi-center project designed to identify biomarkers of epileptogenesis after a traumatic brain injury (TBI) and evaluate treatments that could modify or prevent the development of post-traumatic epilepsy. One goal of the EpiBioS4Rx project is to assess whether HFOs could be a biomarker of post-traumatic epileptogenesis. The current study describes the work towards this goal, including the development of common surgical procedures and EEG protocols, an interim analysis of the EEG for HFOs, and identifying issues that need to be addressed for a robust biomarker analysis. At three participating sites - University of Eastern Finland (UEF), Monash University in Melbourne (Melbourne) and University of California, Los Angeles (UCLA) - TBI was induced in adult male Sprague-Dawley rats by lateral fluid-percussion injury. After injury and in sham-operated controls, rats were implanted with screw and microwire electrodes positioned in neocortex and hippocampus to record EEG. A separate group of rats had serial magnetic resonance imaging after injury and then implanted with electrodes at 6 months. Recordings 28 days post-injury were available from UEF and UCLA, but not Melbourne due to technical issues with their EEG files. Analysis of recordings from 4 rats - UEF and UCLA each had one TBI and one sham-operated control - showed EEG contained evidence of HFOs. Computer-automated algorithms detected a total of 1,819 putative HFOs and of these only 40 events (2%) were detected by all three sites. Manual review of all events verified 130 events as HFO and the remainder as false positives. Review of the 40 events detected by all three sites was associated with 88% agreement. This initial report from the EpiBioS4Rx Consortium demonstrates the standardization of EEG electrode placements, recording protocol and long-term EEG monitoring, and differences in detection algorithm HFO results between sites. Additional work on detection strategy, detection algorithm performance, and training in HFO review will be performed to establish a robust, preclinical evaluation of HFOs as a biomarker of post-traumatic epileptogenesis.

Control of a visual keyboard using an electrocorticographic brain-computer interface.

OBJECTIVE: Brain-computer interfaces (BCIs) are devices that enable severely disabled people to communicate and interact with their environments using their brain waves. Most studies investigating BCI in humans have used scalp EEG as the source of electrical signals and focused on motor control of prostheses or computer cursors on a screen. The authors hypothesize that the use of brain signals obtained directly from the cortical surface will more effectively control a communication/spelling task compared to scalp EEG. METHODS: A total of 6 patients with medically intractable epilepsy were tested for the ability to control a visual keyboard using electrocorticographic (ECOG) signals. ECOG data collected during a P300 visual task paradigm were preprocessed and used to train a linear classifier to subsequently predict the intended target letters. RESULTS: The classifier was able to predict the intended target character at or near 100% accuracy using fewer than 15 stimulation sequences in 5 of the 6 people tested. ECOG data from electrodes outside the language cortex contributed to the classifier and enabled participants to write words on a visual keyboard. CONCLUSIONS: This is a novel finding because previous invasive BCI research in humans used signals exclusively from the motor cortex to control a computer cursor or prosthetic device. These results demonstrate that ECOG signals from electrodes both overlying and outside the language cortex can reliably control a visual keyboard to generate language output without voice or limb movements.