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The efficacy of non-invasive brain stimulation interventions in obsessive-compulsive disorder management: A network meta-analysis of randomized controlled trials.

Non-invasive brain stimulation (NIBS) has been widely used as an alternative treatment for obsessive compulsive disorder (OCD). However, the most effective NIBS parameters are unclear. To compare the efficacy of NIBS in OCD. We conducted a systematic review and network meta-analyses (NMA) to combine direct and indirect comparisons of NIBS.Systematic searches were conducted in Cochrane CENTRAL, EMBASE, PubMed, and Web of Science from inception to June 20, 2025. Forty-two randomized sham-controlled trials (n = 1456) were included. All statistical analyses were conducted with R statistical software. Bayesian NMAs mainly using the BUGSnet package and gemtc package. Five NIBS protocols produced statistically significant reductions in Yale-Brown Obsessive Compulsive Scale (Y-BOCS) scores compared with sham stimulation: high-frequency rTMS over the FzFCz (Hf-rTMS-FzFCz; MD -11.77, 95% CrI -20.62 to -3.09), low-frequency rTMS over F3F4 (Lf-rTMS-F3F4; MD -9.93, 95% CrI -18.07 to -1.65), low-frequency rTMS over FCz (Lf-rTMS-FCz; MD -3.25, 95% CrI -6.06 to -0.40), high-frequency deep TMS over FzFC (Hf-dTMS-FzFC; MD -6.48, 95% CrI -12.32 to -0.50), and 2 mA anodal tDCS over F3 with cathodal over Fp2 (MD -9.34, 95% CrI -16.01 to -3.03).For secondary outcomes, high-frequency deep rTMS over FzFCz produced the largest reduction both in depressive symptoms (SMD -1.24, 95% CrI -1.92 to -0.55) and anxiety scores (SMD -1.88, 95% CrI -2.62 to -1.11), but had no effect on Clinical Global Impression-Severity (CGI-S) scores.Specific NIBS protocols are safe and effective adjunctive treatments for OCD, with promising yet inconclusive improvements in comorbid depressive symptoms. Further high-quality, head-to-head trials are needed.

Humans

Assessing the effects of non-invasive transcranial electrical stimulation (tACS and tDCS) on electrophysiological sleep parameters - a systematic review.

Transcranial electrical stimulation (tES), including transcranial direct current stimulation (tDCS) and transcranial alternating current stimulation (tACS), is considered a safe method to modulate cortical activity and endogenous brain oscillations. Given the therapeutic potential of tES across various clinical conditions and the central role of sleep in restoration and memory consolidation, numerous studies have investigated its effects on sleep and sleep-related parameters, yielding inconsistent results. This systematic review provides an up-to-date synthesis of 51 studies assessing the impact of tES on objectively measured electrophysiological sleep outcomes in both healthy individuals and clinical populations. The reviewed studies demonstrate heterogeneous effects, reflecting substantial variability in study designs. Nonetheless, consistent trends emerge, including reduced NREM1 and increases in total sleep time, NREM2, and NREM3 following tES. Moreover, slow-oscillatory tES increased slow-wave power during sleep. Here we show that tES, particularly slow-oscillatory tES, may positively influence sleep architecture and continuity by modulating endogenous brain oscillations. However, due to heterogeneous stimulation protocols, inconsistent findings, the limited number of significant effects and substantial risk of bias the current evidence remains inconclusive. Well-designed, large-scale trials targeting specific sleep outcomes are needed to clarify the therapeutic potential of tES.

Humans

Effects of anodal transcranial direct current stimulation over the right primary motor cortex on a sequential motor finger tapping task in developmental stuttering.

INTRODUCTION: This study investigates the impact of anodal transcranial direct current stimulation (tDCS) on non-speech sequential motor practice in adults who stutter (AWS), compared to non-stuttering controls (ANS). Recent research has explored the effects of tDCS on speech fluency in stuttering. However, its effect on non-speech motor tasks has not yet been studied. METHODS: 20 AWS and 30 ANS right-handed participants were randomly assigned to anodal or sham tDCS conditions, performing a sequential finger tapping task. We targeted over the right primary motor cortex, stimulating at 2 mA for 20 min. Sequence duration and reaction time were analyzed. RESULTS: AWS analysis revealed that the anodal condition had significantly slower reaction times in the second half of the task compared to sham. For sequence durations, AWS in the anodal condition had slower overall sequence durations than the sham condition. However, there were no block-by-block differences in sequence duration. When comparing AWS and ANS, no significant differences were observed for sequence duration. However, there were significant differences in reaction time between AWS and ANS, specifically in earlier blocks. Additionally, there was no significant Group × Condition interaction. DISCUSSION: The findings suggest that anodal stimulation impeded finger sequencing in AWS, showing overall slower sequence durations and a diminishing effect on reaction times in the second half of the experiment, suggesting anodal tDCS may interact uniquely with the neural mechanisms in stuttering. Future studies should explore the effects of anodal tDCS on non-speech motor tasks to gain a broader understanding of its impact on motor control and motor learning.

Humans

A single session of high-definition transcranial direct current stimulation does not modulate effects of knee two-point discrimination training or sensorimotor function in healthy adults: Double-blind randomised controlled trial.

BACKGROUND: Benefits of sensory-training interventions on sensorimotor outcomes are inconsistent, and it is unclear whether transcranial direct current stimulation (tDCS) can enhance proprioception, which is fundamental to neuromuscular control. Existing evidence is dominated by upper-limb studies, so transferability to the knee is unclear. This study investigated whether a single session of anodal high-definition (HD)-tDCS, alone or combined with brief two-point discrimination (TPD) training, enhances knee sensorimotor function and performance in healthy adults. METHODS: In a double-blind randomised-controlled trial, 57 healthy participants received (1) 20-min, 1&#xa0;mA anodal HD-tDCS over the knee primary somatosensory (S1) map or sham stimulation, and (2) 15-min knee TPD training or no training. Knee somatosensory, sensorimotor, and functional performance measures were assessed pre- and immediately post-intervention. Three-way mixed-design ANOVAs, equivalence testing (smallest effect size of interest &#x3b7;2&#xa0;=&#xa0;0.02), Bayes factors, and linear mixed-effects models quantified effects. RESULTS: HD-tDCS, TPD training, and their sequential combination had no effect on any outcome measure (p&#xa0;&#x2265;&#xa0;0.05; &#x3b7;2&#xa0;&#x2264;&#xa0;0.015). Confidence intervals spanned equivalence bounds, and equivalence testing results were non-significant (p&#xa0;&#x2265;&#xa0;0.05). Bayes factors (<0.33) showed moderate evidence for the null (no effect). Mixed-effects modelling attributed &#x2264;8% of total variance to intervention fixed effects, with the remainder captured by participant-level random effects. CONCLUSION: A single 20-minute session of 1&#xa0;mA HD-tDCS, with or without brief TPD training, does not acutely modify knee somatosensory, sensorimotor, or functional performance in healthy adults. Existing evidence at the hand may not translate to the lower limb. Future work should investigate higher-dose, multi-session, task-concurrent, or network-targeted strategies in clinical populations.

Humans

Modulating sentence comprehension in people with aphasia through anodal tDCS: A double-blind randomized cross-over study.

This double-blind randomized cross-over study investigated the effects of perilesional anodal transcranial direct current stimulation (AtDCS) combined with speech-language therapy on sentence comprehension in eight individuals with chronic nonfluent agrammatic aphasia. The behavioral therapy consisted of an intensive comprehension treatment including drilling in sentence-to-picture matching and Mapping Therapy. Each participant underwent both the anodal tDCS and sham stimulation conditions (five received sham first followed by real stimulation, and the remaining three the reverse sequence), with each condition paired with the same behavioral treatment and separated by a four-month washout period. Stimulation was applied over the perilesional area (left BA6) for 20&#x202f;min during daily 40-min therapy sessions over four consecutive weeks. Sentence comprehension was assessed with the RiComprendo battery and functional communication with the Communicative Effectiveness Index (CETI). Data were analyzed using paired t-tests, Bayesian analyses, and linear mixed-effects models to control for baseline performance and individual variability. Both stimulation conditions produced significant pre-to-post improvements in sentence comprehension, particularly for syntactically complex structures such as passives and center-embedded object relatives. However, gains were overall greater following AtDCS, as reflected in larger effect sizes, stronger Bayes factors, and a significant treatment effect in the mixed-effects models. Only the AtDCS condition yielded significant improvements in self-perceived comprehension abilities on the CETI. These findings suggest that AtDCS over perilesional cortical areas may boost the effects of traditional language therapy on sentence comprehension, supporting its feasibility and potential as an adjuvant intervention in post-stroke aphasia rehabilitation.

Humans

Exercise with motor cortex high-definition transcranial direct current stimulation enhances cardiovascular efficiency and lower-limb function in multiple sclerosis: A crossover, double-blind, and proof-of-principle study.

Combining exercise with high-definition transcranial direct current stimulation (HD-tDCS) could offer a strategy to help people with Multiple Sclerosis improve outcomes. In this crossover study, participants with MS (Expanded Disability Status Scale &#x2265;3.0, n&#x202f;=&#x202f;12) and controls (n&#x202f;=&#x202f;10) completed baseline testing, followed by three randomized experimental conditions: 1) exercise+active HD-tDCS; 2) exercise+sham HD-tDCS; and 3) HD-tDCS alone. Exercise performance metrics [heart rate, work rate, heart rate-to-work rate (HR/WR) ratio, and perceived exertion] were compared across the exercise conditions. Secondary outcomes included the Symbol Digit Modalities Test (SDMT), Timed 25-Foot Walk (T25F), Nine-Hole Peg Test (9HPT), and acute symptom ratings (fatigue and pain), assessed pre-, immediately post-, and 1h-Post. Cardiovascular efficiency (HR/WR ratio) significantly improved during exercise+HD-tDCS compared to exercise alone, particularly in older MS participants (p&#x202f;=&#x202f;0.010). SDMT declined immediately post HD-tDCS alone, 1h-post-exercise alone, and at both time points during exercise+active HD-tDCS (p&#x202f;<&#x202f;0.05). Both groups increased walking speed only post-exercise+active HD-tDCS, while no condition affected upper-limb function (p&#x202f;<&#x202f;0.05). These results are in line with the tDCS literature in the general population, suggesting that tDCS improves exercise performance and selectively improves engaged motor function. The trade-off between physical and cognitive outcomes underscores the importance of personalized neuromodulation strategies in neurorehabilitation to maximize therapeutic benefits while minimizing adverse effects, and warrants further large-scale, long-term investigations of this approach in MS.

Humans

Navigated repetitive transcranial magnetic stimulation for post-stroke recovery: A systematic review and meta-analysis of randomized controlled trials.

Repetitive transcranial magnetic stimulation (rTMS) is a subcategory of non-invasive brain stimulation (NIBS), used to modulate brain plasticity and improve post-stroke recovery. Neuronavigation is used to improve the accuracy of stimulation with the aim of achieving a superior clinical outcome than with conventional targeting. The objective of this review is to evaluate the efficacy of navigated rTMS in subacute and chronic stroke patients in comparison to sham stimulation. We conducted a systematic-review and meta-analysis of randomized controlled trials (RCTs) identified from Pubmed, Scopus and Cochrane CENTRAL. Trials employing neuronavigated rTMS were included of these five types; high and low frequency rTMS, intermittent and continuous theta-burst stimulation (TBS) and Hebbian-type stimulation. 13 RCTs were included after a screening of 1900 studies. 606 patients receiving either active (n&#xa0;=&#xa0;360) or sham stimulation (n&#xa0;=&#xa0;246) were assessed. The pooled standardized mean difference (SMD) favored rTMS over sham SMD&#xa0;=&#xa0;0.4 (95&#xa0;%CI: 0.11-0.69), with moderate heterogeneity I2&#xa0;=&#xa0;55&#xa0;%. Among stimulation modalities, continuous TBS showed the largest pooled effect. rTMS was also associated with significant improvements in disability-related outcomes, SMD&#xa0;=&#xa0;0.61 (95&#xa0;% CI 0.14-1.08). Navigated rTMS is associated with modest but significant improvements in motor and disability outcomes in subacute and chronic stroke. Large comparative trials are required to clarify the potential added value over conventional targeting approaches.

Humans

A systematic review of macaque brain stimulation: Trends and future directions.

Neurostimulation techniques can powerfully modulate neural circuit activity and provide causal insights into the relationship between brain function and behavior. Macaque monkeys have long been a key animal model for brain stimulation studies. While stimulating the macaque brain with one or a few electrodes has already taught us much about brain function and dysfunction, recent technological advances promise a future with more precise stimulation using many more electrodes. However, such possibilities also increase the number of choices an experimenter has when designing their study. We can learn from a rich past, but a comprehensive overview of which brain regions have been studied and with what stimulation parameters is lacking. Here, we present a PRISMA-compliant systematic review of 734 macaque brain stimulation studies using electrical and/or optogenetic stimulation. We find a striking bias in which brain areas have traditionally been stimulated: a mere 10 brain regions account for half of all studies, with the remainder of studies investigating approximately 150 other areas. Across studies, stimulation frequency robustly predicted direct behavioral effects independent of brain region, while amplitude did not. Future studies could more systematically explore less studied regions through lower stimulation frequencies (e.g., 20-50&#x202f;Hz) alongside established ranges (&#x223c;200&#x202f;Hz). Tools such as fMRI or optical imaging can capture neural circuit engagement evoked by these frequencies, even when behavioral effects are absent or remain subtle. Our synthesis offers a guide towards the next steps in high-channel-count, high-precision stimulation approaches.

Animals

Transcranial Magnetic Stimulation for Patients with Exposure Therapy Resistant Obsessive-Compulsive Disorder (TETRO): Study Protocol for a Multicenter Randomized Controlled Trial.

BACKGROUND: Obsessive-compulsive disorder (OCD) is a disabling mental disorder, characterized by obsessions, compulsions, and substantial morbidity. Approximately 50% of adults with OCD fail to achieve satisfactory outcomes from first-line treatments, such as exposure therapy with response prevention (ERP), with or without medication. This leads to chronic social, educational, and occupational impairment. While invasive procedures such as deep brain stimulation are available for severe, treatment-refractory cases, a need remains for less invasive alternatives. Repetitive transcranial magnetic stimulation (rTMS), a noninvasive intervention, shows promise in reducing OCD symptoms. Unlike in depression, rTMS is not yet reimbursed for OCD in the Dutch healthcare system. OBJECTIVE: This study examines the efficacy and cost-effectiveness of low-frequency (1Hz) rTMS targeting the presupplementary motor area (pre-SMA) compared to sham rTMS as an adjuvant treatment to ERP in adults with OCD with inadequate response to first-line treatment. METHODS: A total of 250 adults with OCD will be enrolled in this multicenter randomized controlled trial. Participants will be randomly assigned to ERP combined with either active or sham 1Hz rTMS over the pre-SMA. Treatment is administered 4 times weekly for at least 5 weeks (20 rTMS-ERP sessions), with optional extension of 1 to 2 weeks, up to 28 rTMS-ERP sessions. Clinical assessments occur at baseline, weekly during treatment, posttreatment, and at 3, 6, and 12 months follow-up. Participants undergo pre- and posttreatment (functional) (MRI) scans, including a symptom provocation task. Blood sampling takes place pre- and posttreatment and at 3-month follow-up. The primary outcome is OCD severity at posttreatment, as measured by the Yale-Brown Obsessive-Compulsive Scale (Y-BOCS). Secondary outcomes include functional improvement, quality of life, and societal costs. Pretreatment symptom profiles, genotype, and brain network topology will be analyzed as predictors of response and relapse risk. Pre-to-post treatment change in blood-based and magnetic resonance (MR)-based neuroplasticity markers will help explore differential mechanisms between ERP alone and combined rTMS-ERP. We expect that the verum rTMS protocol will be cost-effective compared to sham-rTMS. RESULTS: Recruitment started in April 2022, and as of February 2026, 201 participants have been enrolled. Posttreatment assessments are projected to be completed in December 2026, with final one-year follow-up evaluations anticipated by the end of 2027. CONCLUSIONS: To our knowledge, this study is the first adequately powered randomized controlled trial examining efficacy, cost-effectiveness, and mechanism of action of rTMS for OCD as adjuvant therapy to ERP. In case of efficacy and/or cost-effectiveness, it will pave the way for rTMS as insured health care for adults with OCD in the Netherlands, and possibly other European countries. Furthermore, this trial will provide insight into the mechanisms of treatment response to intensive ERP, with and without adjunctive rTMS, as well as potential side effects, individual variability, and long-term outcomes in adults with OCD.

Humans

Six weeks of isometric resistance training led to evidence of corticospinal but not reticulospinal adaptation in previously untrained adult males.

The latest hypothesis regarding the source of enhanced neural activation from resistance training is the reticulospinal rather than the corticospinal tract, based on invasive animal and emerging human data. The present study employed a six-week isometric resistance training intervention in a randomized controlled design to address this knowledge gap. Thirty-nine healthy, untrained males (age ~23 y, sustained contraction group n = 13, explosive contraction group n = 9, control group n = 17) underwent neuromuscular and electrophysiological testing and completed all study requirements. Maximal isometric torque (MVC) and rate of torque development (RTD) were measured during a familiarization session as well as before and after the six-week period. Transcranial magnetic stimulation was used to assess motor-evoked potential (MEP) area and silent period duration while subjects contracted to 10% of MVC. Loud sound (120&#xa0;dB) was used to modulate MEP area and reaction time to visual stimuli during the StartReact test. Only the intervention groups demonstrated significant improvements in MVC (27%) and RTD (60%) (both P < 0.01), along with reduced MEP area (-&#xa0;21%) and silent period duration (-&#xa0;23%) (both P < 0.01). The sustained contraction group showed reduced modulation of reaction time and increased MEP suppression due to loud sound. Short-term resistance training seemed to reduce cortical inhibition and corticospinal excitability in both training groups. The study showed conflicting changes in measures purported to evaluate reticulospinal functioning. It is recommended to examine different forms of resistance training and longer training exposure in future.

Humans

A status update on the unkept promise of high-frequency spinal cord stimulation for treatment-refractory chronic migraine.

INTRODUCTION: Chronic migraine (CM) refractory to conventional pharmacotherapy (r-CM) remains a debilitating neurological condition with limited therapeutic options. High-frequency spinal cord stimulation at 10 kilohertz (HF-SCS) has recently emerged as a distinct neuromodulatory paradigm for this patient population. Unlike traditional spinal cord stimulation, HF-SCS operates above the frequency range that generates paresthesia, thereby eliminating stimulation-induced sensation while potentially engaging unique analgesic mechanisms. AREAS COVERED: This focused narrative review synthesizes the available clinical evidence, technical considerations, and mechanistic hypotheses specifically pertaining to cervical HF-SCS for refractory chronic migraine (r-CM). The authors further provide their expert perspectives on the future of this technology as a treatment option for refractory chronic migraine. EXPERT OPINION: Current data from prospective open-label studies and retrospective case series suggest that cervical HF-SCS may reduce monthly migraine days, facilitate conversion from chronic to episodic migraine patterns in some implanted patients, and may improve headache-related disability and quality of life over at least 52&#x2009;weeks of follow-up. The paresthesia-free nature of HF-SCS confers a distinct advantage for both patient tolerability and future trial design, as it permits sham-controlled methodologies that have historically been impossible with conventional neurostimulation. However, these findings remain preliminary and should be considered hypothesis-generating pending confirmation in adequately powered randomized sham-controlled trials.

Humans

Dissociable neural mechanisms of cognitive enhancement through transcranial stimulation and behavioral training.

BACKGROUND: Transcranial direct current stimulation (tDCS) and adaptive working memory (WM) training are promising cognitive enhancement approaches; however, their neural mechanisms and potential synergies remain poorly understood. OBJECTIVE: We directly compared how tDCS and WM training modulate neural oscillations during WM performance and examined whether combining both interventions produces additive effects. METHODS: We randomized 112 healthy adults into four groups: control (sham tDCS&#xa0;+&#xa0;non-adaptive 1-back), tDCS-only (active tDCS&#xa0;+&#xa0;non-adaptive 1-back), training-only (sham tDCS&#xa0;+&#xa0;adaptive n-back training), or combined (active tDCS&#xa0;+&#xa0;adaptive training). Participants underwent five daily intervention sessions. We recorded high-density EEG during transfer n-back tasks at baseline, post-intervention, and one-week follow-up. RESULTS: All active interventions improved WM performance relative to the control group, with the combined group showing the largest gains (n-back accuracy: +15.6% vs.&#xa0;+&#xa0;10.1% tDCS-only, +9.7% training-only, +0.7% control; all p&#xa0;<&#xa0;0.001). Critically, tDCS selectively increased gamma-band (30-50&#xa0;Hz) power in the frontal and parietal regions (cluster p&#xa0;=&#xa0;0.018, d&#xa0;>&#xa0;1.0), whereas WM training enhanced frontal theta-band (4-8&#xa0;Hz) power and theta-gamma phase-amplitude coupling (both cluster p&#xa0;<&#xa0;0.012, d&#xa0;>&#xa0;0.85). The combined group exhibited both neural signatures. Brain-behavior correlations revealed dissociable relationships: gamma increases predicted n-back accuracy improvements (r&#xa0;=&#xa0;0.61, p&#xa0;<&#xa0;0.001), whereas theta enhancements correlated with operation span gains (r&#xa0;=&#xa0;0.58, p&#xa0;=&#xa0;0.002). CONCLUSIONS: tDCS and WM training enhance cognition through distinct yet complementary neural mechanisms: tDCS via gamma-mediated cortical excitability and WM training via theta-mediated cognitive control. These findings provide neurophysiological evidence for multimodal enhancement strategies that target parallel pathways within WM networks.

Humans

Deep brain stimulation for Tourette syndrome: a systematic review and meta-analysis.

Deep brain stimulation (DBS) has emerged as a promising neuromodulatory therapy for patients with refractory Tourette syndrome (TS). Various brain targets-including the globus pallidus internus (GPi) and several thalamic nuclei-have been explored, yet the comparative efficacy of DBS in different targets remain unclear. This meta-analysis aims to evaluate the clinical efficacy of DBS in TS and assess symptom improvements across different stimulation targets. A systematic search of PubMed, Embase, and Web of Science identified studies published between October 2014 and September 2025. Study quality was assessed using the French and Gronseth classification system. Outcomes of interest included pre- and postoperative scores on the Yale Global Tic Severity Scale (YGTSS) and Yale-Brown Obsessive Compulsive Scale (YBOCS). A total of 22 studies involving 358 patients were included in this meta-analysis. Mean YGTSS scores decreased from 69.19&#x2009;&#xb1;&#x2009;18.04 preoperatively to 35.88&#x2009;&#xb1;&#x2009;17.23 postoperatively. There was an average 48% reduction in YGTSS scores. DBS led to a substantial reduction in tic severity (YGTSS: GPi, SMD&#x2009;=&#x2009;2.29, P&#x2009;<&#x2009;0.00001; thalamus, SMD&#x2009;=&#x2009;2.33, P&#x2009;<&#x2009;0.0001). Within the GPi subgroup, stimulation of the anteromedial GPi (amGPi) resulted in significantly better benefits (SMD&#x2009;=&#x2009;3.01, P&#x2009;<&#x2009;0.00001) compared to the posterior-ventrolateral GPi (pvlGPi), which did not reach statistical significance (SMD&#x2009;=&#x2009;1.23, P&#x2009;=&#x2009;0.05). YBOCS scores decreased from a mean of 17.38&#x2009;&#xb1;&#x2009;6.15 preoperatively to 9.16&#x2009;&#xb1;&#x2009;4.12 postoperatively. The average reduction in YBOCS scores was 47%. Obsessive-compulsive disorder (OCD) symptoms also showed significant improvement following DBS (overall YBOCS, SMD&#x2009;=&#x2009;0.94, P&#x2009;<&#x2009;0.00001; amGPi, SMD&#x2009;=&#x2009;1.49, P&#x2009;=&#x2009;0.004; pvlGPi, SMD&#x2009;=&#x2009;0.72; P&#x2009;=&#x2009;0.006). DBS is an effective and target-sensitive intervention for TS, alleviating both motor tics and obsessive-compulsive symptoms. Compared to therapies such as pvlGPi and thalamic-DBS, amGPi-DBS may demonstrate greater therapeutic potential compared with pvlGPi-DBS, suggesting its potential advantage in modulating the associated circuits involved in the pathophysiology of TS.

Humans

Theta-range SEEG stimulation for intracranial mapping: extending conventional 1-Hz and 50-Hz protocols.

OBJECTIVE: Electrical brain stimulations (EBS) are central to epileptic network identification and functional mapping during stereo-electroencephalography, yet stimulation frequencies remain empirical, and standardized across patients and brain regions, producing false negatives and false positives, and potentially compromising surgical outcome. We prospectively investigated theta-range EBS (7&#xa0;Hz) in the temporal lobe, a prominent physiological frequency band in this region, and compared it with conventional 1-Hz and 50-Hz protocols. METHODS: We analyzed 1,408 temporal EBS in 25 drug-resistant epileptic patients. Epileptic responses (afterdischarges, seizures) and clinical signs were assessed across the epileptic network and temporal structures (amygdala, hippocampus, neocortex, parahippocampal gyrus, white matter), and confronted to stimulation parameters (frequency, intensity, duration, total charge). RESULTS: At matched intensity and duration, 7-Hz EBS were associated with a higher occurrence of afterdischarges and clinical signs than 1-Hz EBS in several temporal structures. Effects on usual seizure induction were less consistent. Comparisons with 50&#xa0;Hz showed no systematic significant differences, with responses observed at one or both frequencies depending on structure and outcome. When controlling for total charge, frequency-related differences were attenuated. Some effects were sporadically observed at both intermediate frequency and charge quantity. CONCLUSIONS: EBS responses emerge from the interaction between all electrical parameters and anatomical location and local excitability, and can hardly be disentangled. However, 7-Hz EBS can provide complementary clinical information during temporal-lobe mapping, with a targeted approach. SIGNIFICANCE: These findings support targeted evaluation of broader stimulation parameter spaces, including intermediate frequencies, rather than routine reliance on fixed low- and high-frequency protocols alone.

Humans

Choice of Anesthesia in Microelectrode Recording-guided Deep Brain Stimulation Surgery for Parkinson's Disease (CHAMPION): A Noninferiority Randomized Controlled Trial.

BACKGROUND: Deep brain stimulation for Parkinson's disease is often performed under conscious sedation or general anesthesia. However, anesthetic agents may influence intraoperative microelectrode recording, and the optimal anesthesia method for microelectrode recording remains unclear. This study compared general anesthesia and conscious sedation in preserving microelectrode recording signal intensity during deep brain stimulation. METHODS: In this prospective, noninferiority randomized controlled trial, patients with Parkinson's disease (United Kingdom Brain Bank criteria) undergoing elective bilateral surgery were randomized 1:1 to the conscious sedation or the general anesthesia group. During surgery, a desflurane anesthetic titrated against the quality of the electrophysiologic signal was applied in the general anesthesia group, whereas patients in the conscious sedation group received dexmedetomidine anesthesia. The primary outcome was the proportion of patients with high-quality microelectrode recording (normalized root mean square greater than 2.0), assessed postoperatively off-line. Secondary outcomes included operation and recording duration, 6-month clinical efficacy, and complication rates. RESULTS: Of 188 randomized patients (94 general anesthesia, 93 conscious sedation), desflurane anesthesia was noninferior for high normalized root mean square proportion (89.4% vs . 90.3%; difference, -0.96%; 95% CI, -9.62 to 7.70). The general anesthesia group had shorter operative time (difference, -9.07&#x2009;min; 95% CI, -13.99 to -4.14; P < 0.001). At 6 months, changes in Unified Parkinson's Disease Rating Scale score (difference, -2.50; 95% CI, -7.20 to 2.20; P = 0.297), levodopa equivalent daily dose (difference, -58.4&#x2009;mg; 95% CI, -133.56 to 16.75; P = 0.128), and complication rates (general anesthesia: 10.9% vs . conscious sedation: 8.9%; P = 0.655) were comparable between the groups. CONCLUSIONS: General anesthesia is noninferior to conscious sedation for microelectrode-guided subthalamic nucleus deep brain stimulation, providing equivalent signal intensity and clinical outcomes while improving procedural efficiency, supporting its use as a valid clinical option.

Humans

Individual differences in brain dynamics across a social cognition network induced by cortico-cerebellar tDCS in adults with autism spectrum disorder (ASD).

Autism spectrum disorder (ASD) is a neurodevelopmental condition with core diagnostic domains of social communication impairments, restricted interests and repetitive behaviors. Idiosyncratic brain organization is a potential hallmark of ASD. Previous transcranial direct current stimulation (tDCS) studies often targeted dorsolateral prefrontal cortex, with changes oin brain dynamics averaged across the cohort. We utilized a magnetoencephalographic (MEG) array to characterize individual differences in brain dynamics induced by cortico-cerebellar tDCS across nodes of a social cognition network. A randomized, sham-controlled, double-blind, within-subject clinical trial was conducted in a cohort of 24 young adults with ASD or high autistic traits. Two separate sessions of computerized social learning activities were combined with verum/sham tDCS, with anodal electrode over right temporoparietal junction (TPJ) and cathode on right deltoid. Following stimulation, theta- and alpha-band activity were evaluated within nodes of a social cognition network: bilateral TPJ, fusiform, medial prefrontal cortex and Crus I/II of cerebellum. Idiosyncratic participant-specific up- and down-regulation of theta- and alpha-band activity occurred across the network. Activity in right Crus I/II, a region inundated by the stimulation current, strongly correlated with the change of activity summed across all cerebral cortical nodes in theta- but not alpha-band. Intrinsic theta-band activity is believed to mediate input/output relationships in cerebellar cortex and to drive synaptic plasticity. These results suggest that theta-band stimulation of cerebellar cortex might be an effective therapy for individuals on the autism spectrum who present with cerebellar hyperactivity.

Humans

Transient acoustic stimulation induces time-dependent synaptic remodeling and enhancement of auditory nerve output after threshold recovery.

BACKGROUND: Acoustic stress can alter cochlear function even in the absence of permanent threshold elevation; however, synaptic consequences of transient acoustic stimulation remain incompletely understood. OBJECTIVE: This study aimed to investigate whether transient acoustic stimulation induces changes in the auditory nerve output and cochlear ribbon synapse morphology following hearing threshold recovery. METHODS: Young adult CBA/CaJ mice were exposed to band-limited acoustic stimulation (45-2,000&#xa0;Hz, 95&#xa0;dB SPL, 2&#xa0;h). Auditory brainstem responses (ABRs), hair cell and spiral ganglion neuron survival, and synaptic morphology were evaluated before exposure and up to 2&#xa0;weeks post-exposure. RESULTS: ABR thresholds were transiently elevated immediately after exposure but largely recovered by 1&#xa0;day post-exposure. In contrast, ABR wave I amplitudes significantly increased after threshold recovery across multiple test frequencies. Ribbon-associated puncta in both inner and outer hair cell regions exhibited biphasic temporal changes, with an initial decrease immediately after exposure followed by an increase at 1&#xa0;day post-exposure. The ribbon-associated punctal area also increased after exposure and remained elevated at later post-exposure time points. No significant loss of hair cells or spiral ganglion neurons was observed. Exploratory genomic analysis suggested enrichment of pathways related to metabolic defense and cellular stress responses. CONCLUSIONS: Transient acoustic stimulation induces time-dependent synaptic remodeling and enhancement of peripheral auditory nerve output without overt cellular degeneration. These findings support a model in which early cochlear responses to acoustic perturbation include adaptive synaptic plasticity and gain regulation, extending current concepts of noise-induced cochlear change beyond irreversible synaptic loss.

Animals

Assessment of Surgical Salvage Outcomes for Exposed Cranial Neuromodulating Devices.

OBJECTIVES: Implanted neuromodulating devices (NMDs) such as cochlear implants (CIs) and deep brain stimulators (DBSs) are commonly used in modern medicine. Rarely, complications arise post-operatively, including hardware exposure. Traditional teaching suggests that these devices require removal if exposed; however, surgical salvage is a high risk, high reward alternative. We review our single institution experience managing NMD exposure with surgical salvage. METHODS: Retrospective chart review was performed on individuals who had a NMD implanted and underwent an attempt at surgical salvage for exposure during the study period (January 01, 2021 through December 31, 2023). Study outcome success was defined as maintaining a functional NMD 1&#x2009;year after salvage was attempted. Surgical techniques associated with successful salvage were compared. RESULTS: Nine of 729 patients (1.2%) implanted with NMDs experienced hardware exposure during this 2-year study period. Nine subjects were referred for NMD salvage; however, only 6 of 9 subjects (66.7%, CI&#x2009;=&#x2009;3; DBS&#x2009;=&#x2009;3) underwent NMD salvage attempts. Four of the subjects had successful salvage demonstrated successful salvage with a functioning NMD and without wound healing concerns 1&#x2009;year after their salvage procedure. CONCLUSIONS: Classic teaching states that exposed NMDs require explantation. However, this approach necessarily imposes time without benefit from the NMD between explantation and reimplantation. Our experience demonstrates that surgical salvage can be a successful alternative for the majority (66.7%) of individuals.

Humans