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Introduction: Perinatal stroke (PS) is a focal vascular brain injury and the leading cause of hemiparetic cerebral palsy. Motor impairments last a lifetime but treatments are limited. Transcranial direct-current stimulation (tDCS) may enhance motor learning in adults but tDCS effects on motor learning are less studied in children. Imaging-based simulations of tDCS-induced electric fields (EF) suggest differences in the developing brain compared to adults but have not been applied to common pediatric disease states. We created estimates of tDCS-induced EF strength using five tDCS montages targeting the motor system in children with PS [arterial ischemic stroke (AIS) or periventricular infarction (PVI)] and typically developing controls (TDC) aged 6-19 years to explore associates between simulation values and underlying anatomy. Methods: Simulations were performed using SimNIBS https://simnibs.github.io/simnibs/build/html/index.html using T1, T2, and diffusion-weighted images. After tissue segmentation and tetrahedral mesh generation, tDCS-induced EF was estimated based on the finite element model (FEM). Five 1mA tDCS montages targeting motor function in the paretic (non-dominant) hand were simulated. Estimates of peak EF strength, EF angle, field focality, and mean EF in motor cortex (M1) were extracted for each montage and compared between groups. Results: Simulations for eighty-three children were successfully completed (21 AIS, 30 PVI, 32 TDC). Conventional tDCS montages utilizing anodes over lesioned cortex had higher peak EF strength values for the AIS group compared to TDC. These montages showed lower mean EF strength within target M1 regions suggesting that peaks were not necessarily localized to motor network-related targets. EF angle was lower for TDC compared to PS groups for a subset of montages. Montages using anodes over lesioned cortex were more sensitive to variations in underlying anatomy (lesion and tissue volumes) than those using cathodes over non-lesioned cortex. Discussion: Individualized patient-centered tDCS EF simulations are prudent for clinical trial planning and may provide insight into the efficacy of tDCS interventions in children with PS. [ABSTRACT FROM AUTHOR]

• Application of anodal tDCS concurrent to surgical training enhances unimanual skill acquisition compared to training alone. • Changes in delta EEG activity in the sensorimotor network are associated with surgical skill improvement. • EEG patterns of unimanual and bimanual surgical skill performance differ, primarily within the parietal cortex. • Anodal tDCS modulated alpha frequency band activity during bimanual surgical skill performance. Transcranial direct-current stimulation (tDCS), an increasingly applied form of non-invasive brain stimulation, can augment the acquisition of motor skills. Motor learning investigations of tDCS are limited to simple skills, where mechanisms are increasingly understood. Investigations of meaningful, complex motor skills possessed by humans, such as surgical skills, are limited. This replication and extension of our previous findings used electroencephalography (EEG) to determine how tDCS and complex surgical training alters electrical activity in the sensorimotor network to enhance complex surgical skill acquisition. In twenty-two participants, EEG was recorded during baseline performance of simulation-based laparoscopic surgical skills. Participants were randomized to receive 20 min of primary motor cortex targeting anodal tDCS or sham concurrent to 1 h of surgical skill training. EEG was reassessed following training, during a post-training repetition of the surgical tasks. Our results replicated our previous study suggesting that compared to sham, anodal tDCS enhanced the acquisition of unimanual surgical skill. Surgical training modulated delta frequency band activity in sensorimotor regions. Next, the performance of unimanual and bimanual skills evoked unique EEG profiles, primarily within the beta frequency-band in parietal regions. Finally, tDCS-paired surgical training independently modulated delta and alpha frequency-bands in sensorimotor regions. Application of tDCS during surgical skill training is feasible, safe and tolerable. In conclusion, we are the first to explore electrical brain activity during performance of surgical skills, how electrical activity may change during surgical training and how tDCS alters the brain to enhance skill acquisition. The results provide preliminary evidence of neural markers that can be targeted by neuromodulation to optimize complex surgical training. [ABSTRACT FROM AUTHOR]

Background Recent changes in surgical training environments may have limited opportunities for trainees to gain proficiency in skill. Complex skills such as neurosurgery require extended periods of training. Methods to enhance surgical training are required to overcome duty-hour restrictions, to ensure the acquisition of skill proficiency. Transcranial direct-current stimulation (tDCS) can enhance motor skill learning, but is untested in surgical procedural training. We aimed to determine the effects of tDCS on simulation-based neurosurgical skill acquisition. Methods Medical students were trained to acquire tumor resection skills using a virtual reality neurosurgical simulator. The primary outcome of change in tumor resection was scored at baseline, over 8 repetitions, post-training, and again at 6 weeks. Participants received anodal tDCS or sham over the primary motor cortex. Secondary outcomes included changes in brain resected, resection effectiveness, duration of excessive forces (EF) applied, and resection efficiency. Additional outcomes included tDCS tolerability. Results Twenty-two students consented to participate, with no dropouts over the course of the trial. Participants receiving tDCS intervention increased the amount of tumor resected, increased the effectiveness of resection, reduced the duration of EF applied, and improved resection efficiency. Little or no decay was observed at 6 weeks in both groups. No adverse events were documented, and sensation severity did not differ between stimulation groups. Conclusions The addition of tDCS to neurosurgical training may enhance skill acquisition in a simulation-based environment. Trials of additional skills in high-skill residents, and translation to nonsimulated performance are needed to determine the potential utility of tDCS in surgical training. [ABSTRACT FROM AUTHOR]

Introduction Perinatal stroke causes hemiparetic cerebral palsy (CP) and lifelong disability. Treatments are limited but non-invasive brain stimulation, such as transcranial direct-current stimulation (tDCS) can alter cortical excitability, providing a unique opportunity for therapeutic neuromodulation in CP. We have demonstrated that application of tDCS can enhance motor skill acquisition in children. Growing evidence suggests that tDCS is safe in pediatrics, however refined forms of stimulation such as high-definition (HD)-tDCS have not been applied in children. The KINARM robot objectively quantifies sensorimotor function and holds potential to examine functional changes associated with tDCS-paired motor learning. We aimed to characterize changes in sensorimotor function induced by tDCS and HD-tDCS paired motor learning in children. We hypothesized that application of tDCS and HD-tDCS will improve motor function (visually-guided reaching; VGR), but only tDCS will improve sensory function (position matching). Methods AMPED (Accelerated motor learning in pediatrics) is a randomized, sham-controlled trial (ClinicalTrials.gov: NCT03193580). Healthy, right-handed children (12–18y) were recruited. A validated 4-stage KINARM protocol and a series of motor function assessments [Purdue Pegboard Test (PPT), Jebsen Taylor Test, and Serial Reaction Time Task] were completed at baseline, post-training, and six weeks later. Participants were randomized to receive sham tDCS, anodal tDCS, or anodal HD-tDCS targeting the right primary motor cortex. Over five consecutive days, participants trained their left hand on the PPT during stimulation. Safety and tolerability was assessed daily. Group differences were explored using repeated measure ANOVA with post hoc correcting for multiple comparisons. Results To date, 15 of 24 participants have completed the study (median 16.4y, range 12–18y, 67% female). Blinded interim analysis of cases grouped by intervention (group A, B, C) was performed on an exploratory basis. All participants improved their left hand PPT scores ( p  < 0.001) regardless of intervention. The mean improvement in left hand PPT scores was 3.93 ± 1.33 pegs and was comparable across the groups: A 4.33 ± 1.78, B 3.08 ± 1.15, C 3.67 ± 1.18. No difference was observed between the groups. Right hand PPT scores increased (Group A p = 0.009) or were unchanged (both p > 0.06). Position matching performance did not change from baseline to post-training. Group A demonstrated improvements in left hand reaction (p = 0.03) and movement time (p = 0.04) in VGR tasks between baseline and post-training. All procedures were well tolerated with no adverse events reported. Conclusion Application of tDCS and HD-tDCS in healthy children is safe, feasible, and tolerable. Sensorimotor function may be altered by tDCS and HD-tDCS paired with motor training. Optimizing tDCS and HD-tDCS protocols while exploring mechanisms of action is essential to advance therapeutic applications of tDCS in children with CP and other motor disabilities. [ABSTRACT FROM AUTHOR]

Introduction Perinatal stroke is the leading cause of hemiparetic cerebral palsy (CP). We have shown non-invasive brain stimulation enhances motor learning in healthy and hemiparetic children using transcranial-direct-current-stimulation (tDCS). High-definition (HD-tDCS) may offer additional potential but is unstudied in pediatrics. Motor maps are individualized representations of primary motor cortex (M1) topography measurable with single pulse TMS. Advances in MRI-guided imaging and robotic TMS may facilitate rapid and accurate motor mapping. How motor maps are altered by motor learning and tDCS are unknown. We aimed to determine the effects of tDCS/HD-tDCS enhanced motor learning on motor maps in children, hypothesizing tDCS-enhanced learning is associated with motor map enlargement. Methods AMPED (Accelerated Motor learning in PEDiatrics) is a randomized, sham-controlled trial (NCT03193580). Participants are healthy, right handed children aged 12–18 years. TMS motor mapping is performed using neuronavigated (Brainisght2), robotic (Axilum) TMS. A 10 × 10, 7 mm grid is placed over M1 with 4 stimulations per point generating motor evoked potentials (MEP) of individual hand muscles. Primary outcome is motor map area (volume, center of gravity, cortical excitability are secondary). Motor function is assessed with Purdue Pegboard (primary), Jebsen-Taylor Test, and Serial Reaction Time Task. Participants are randomized into three groups: right M1 1 mA tDCS, HD-tDCS, or sham. All practiced the PPT daily (8 trails) during stimulation with the left hand for 5 consecutive days. Safety and tolerability is assessed daily. All outcomes are repeated on day 5 and at 6 weeks. Two-way repeated measure ANOVA examined changes in performance and motor maps across groups and sessions. Results Fifteen of 24 participants have completed the study (median age 16.4, 67% female). Blinded interim analysis grouped interventions as A, B, or C. PPT scores improved across all groups (p < 0.001) mean improvement was 3.93(SD:1.3) and comparable across groups: A 4.3(SD 1.7), B 3.1(SD 1.2), C 3.7(SD 1.2). Motor maps were obtained without complication except two subjects could not complete bi-hemispheric mapping due to time constraints. Motor map outcomes differed at baseline between hemispheres −109.31 mm 2 (SD 675.46). Following intervention, map area decreased in group C(−147 ± 65.7), p < 0.04) but change in area was not different between groups. Similar findings were observed for secondary outcomes. Procedures were well tolerated with no adverse events. Conclusion Trials combining tDCS or HD-tDCS enhanced motor learning with robotic TMS motor mapping are feasible in children. Completion of the sample will determine how HD-tDCS enhancement of motor learning compares to tDCS, with potential to advance therapeutic applications in children with CP. [ABSTRACT FROM AUTHOR]