Mean Radial Error Research Articles

Accuracy and Workflow Improvements for Responsive Neurostimulation Hippocampal Depth Electrode Placement Using Robotic Stereotaxy.

Background: Robotic stereotaxy is increasingly common in epilepsy surgery for the implantation of stereo-electroencephalography (sEEG) electrodes for intracranial seizure monitoring. The use of robots is also gaining popularity for permanent stereotactic lead implantation applications such as in deep brain stimulation and responsive neurostimulation (RNS) procedures.Objective: We describe the evolution of our robotic stereotactic implantation technique for placement of occipital-approach hippocampal RNS depth leads.Methods: We performed a retrospective review of 10 consecutive patients who underwent robotic RNS hippocampal depth electrode implantation. Accuracy of depth lead implantation was measured by registering intraoperative post-implantation fluoroscopic CT images and post-operative CT scans with the stereotactic plan to measure implantation accuracy. Seizure data were also collected from the RNS devices and analyzed to obtain initial seizure control outcome estimates.Results: Ten patients underwent occipital-approach hippocampal RNS depth electrode placement for medically refractory epilepsy. A total of 18 depth electrodes were included in the analysis. Six patients (10 electrodes) were implanted in the supine position, with mean target radial error of 1.9 ± 0.9 mm (mean ± SD). Four patients (8 electrodes) were implanted in the prone position, with mean radial error of 0.8 ± 0.3 mm. The radial error was significantly smaller when electrodes were implanted in the prone position compared to the supine position (p = 0.002). Early results (median follow-up time 7.4 months) demonstrate mean seizure frequency reduction of 26% (n = 8), with 37.5% achieving ≥50% reduction in seizure frequency as measured by RNS long episode counts.Conclusion: Prone positioning for robotic implantation of occipital-approach hippocampal RNS depth electrodes led to lower radial target error compared to supine positioning. The robotic platform offers a number of workflow advantages over traditional frame-based approaches, including parallel rather than serial operation in a bilateral case, decreased concern regarding human error in setting frame coordinates, and surgeon comfort.

Enhanced intelligent driver model for two-dimensional motion planning in mixed traffic

This study aims to model two-dimensional (lateral and longitudinal) motion of an Ego Vehicle (EV). Intelligent Driver Model (IDM) is enhanced for this purpose. All the surrounding obstacles (vehicles and road boundaries) are considered as stimuli that elicit driver’s reactions (lateral and longitudinal accelerations). A Virtual LiDAR sensor on the EV perceives the surrounding. Proximity and speed are used to compute longitudinal and lateral components of average relative velocity. A new formulation is presented to compute the effective gap considering all the surrounding obstacles. It is composed of four components: front, rear, left, and right. The former two affect longitudinal acceleration, while the latter two influence lateral acceleration of the EV. A discretionary lane-change model is also developed to account for the driver’s deliberate (not just mandatory) lateral movements. A total of 13 model parameters are used, of which eight are newly introduced. These model parameters are calibrated using 1050 human-driven car trajectories from Next Generation SIMulation dataset. Taguchi’s fractional factorial design principle is used to optimize the parameters. Gray relational analysis indicated that the three newly introduced parameters to be the three most influential parameters. Validation using another 450 car trajectories resulted in a mean radial error of 3.97 m over a horizon of 10 s. The performance measures of two-dimensional motion planning (model error, longitudinal error, and mixed gap error) are found to be better than those reported in the literature. The developed human-like AV-IDM offers a proof of concept.

The Effects of Target Location Upon Throwing Velocity and Accuracy in Experienced Female Handball Players.

The purpose of this study was to investigate the effect on throwing performance (velocity and accuracy) of experienced female handball players when throwing at four different targets in a handball goal. Thirteen experienced female handball players (age 18.2 ± 1.7 years, height 1.7 ± 0.10 m, mass 68.1 ± 19.6 kg, and training experience 9.5 ± 3.7 years) performed 10 throws from a 7 m distance at each corner of the handball goal with maximal effort. Maximal ball velocity was recorded with a radar gun together with mean radial error, centroid error, and bivariate variable error, as measurements of accuracy. The main findings were that the ball velocity was higher when throwing at targets at the ipsilateral side, compared with the contralateral side, while throwing consistency (bivariate variable error) decreased when throwing at the contralateral side upper corner. No velocity-accuracy trade-off was found between the four targets. Based upon the findings, it is suggested that players throw to the (upper) ipsilateral side of the goal when performing a penalty throw, dependent on the goalkeepers’ position, since the ball velocity is the highest here, without losing accuracy. This gives the goalkeeper less time to react and stop the ball, thereby giving the player the highest chance of scoring.

Deep Brain Stimulation Lead Implantation Using a Customized Rapidly Manufactured Stereotactic Fixture with Submillimetric Euclidean Accuracy

Background: The microTargeting^TM Microtable^TM Platform is a novel stereotactic system that can be more rapidly fabricated than currently available 3D-printed alternatives. We present the first case series of patients who underwent deep brain stimulation (DBS) surgery guided by this platform and demonstrate its in vivo accuracy. Methods: Ten patients underwent DBS at a single institution by the senior author and 15 leads were placed. The mean age was 69.1 years; four were female. The ventralis intermedius nucleus was targeted for patients with essential tremor and the subthalamic nucleus was targeted for patients with Parkinson’s disease. Results: Nine DBS leads in 6 patients were appropriately imaged to enable measurement of accuracy. The mean Euclidean electrode placement error (EPE) was 0.97 ± 0.37 mm, and the mean radial error was 0.80 ± 0.41 mm (n = 9). In the subset of CT scans performed greater than 1 month postoperatively (n = 3), the mean Euclidean EPE was 0.75 ± 0.17 mm and the mean radial error was 0.69 ± 0.17 mm. There were no surgical complications. Conclusion: The Microtable^TM platform is capable of submillimetric accuracy in patients undergoing stereotactic surgery. It has achieved clinical efficacy in our patients without surgical complications and has demonstrated the potential for superior accuracy compared to both traditional stereotactic frames and other common frameless systems.

Kinaesthetic imagery ability moderates the effect of an AO+MI intervention on golf putt performance: A pilot study

BackgroundPrevious research has established that motor imagery (MI) and action observation (AO) independently enhance the performance and learning of motor skills. Recent studies have demonstrated that combining AO and MI (AO + MI) elicits increased activity in motor regions of the brain and enhances performance more than either AO or MI alone. Kinesthetic imagery (KI) ability refers to the ease with which one can sense their own body and imagine how a movement feels during a task (Malouin et al., 2007). KI ability may be of particular importance when engaging with AO + MI as the provision of an external visual stimulus through AO renders the visual component of MI redundant. ObjectiveThe current study aims to add to the emerging body of behavioural evidence demonstrating the performance benefits of AO + MI by exploring the effect of an AO + MI intervention on golf putting performance, as well as exploring the role that KI ability represents in AO + MI effectiveness. MethodRight-handed male golfers (N = 44) of varying skill level performed twenty 15-foot putts before and after a 3.5 min AO + MI intervention (AO + MI group; mean handicap = 7.5, SD = 4.3) or a similarly timed passive reading task (Control group; mean handicap = 11.5, SD = 5.4). Using the MIQ-3 questionnaire, participants in both experimental groups were classified according to kinesthetic imagery ability where: a mean score ≥6 were classified as good imagers. Performance accuracy was measured using mean radial error (MRE), precision was quantified via bivariate error (BVE) and putter kinematics were recorded by SAM Puttlab. ResultsResults from a series of ANCOVAs indicate that good kinesthetic imagers who received the AO + MI intervention were significantly more precise (BVRE) on the putting task than good kinesthetic imagers in the Control group (p = 0.041, d = 0.678). Good kinesthetic imagers in the intervention group also significantly outperformed good kinesthetic imagers in the control group on a measure of speed control (SD of error scores along the axis of progression) in golf putting (p = 0.041). ConclusionsOur results suggest that the presence of AO with MI increases the relevance of kinesthetic cues, that good kinesthetic imagers are able to utilise for subsequent performance benefits during the putting task. We discuss the increased importance of kinesthetic awareness/feel following the intervention as an explanation for such improvements in performance.

Frameless Robot-Assisted Deep Brain Stimulation Surgery: An Initial Experience.

Modern robotic-assist surgical systems have revolutionized stereotaxy for a variety of procedures by increasing operative efficiency while preserving and even improving accuracy and safety. However, experience with robotic systems in deep brain stimulation (DBS) surgery is scarce. To present an initial series of DBS surgery performed utilizing a frameless robotic solution for image-guided stereotaxy, and report on operative efficiency, stereotactic accuracy, and complications. This study included the initial 20 consecutive patients undergoing bilateral robot-assisted DBS. The prior 20 nonrobotic, frameless cohort of DBS cases was sampled as a baseline historic control. For both cohorts, patient demographic and clinical data were collected including postoperative complications. Intraoperative duration and number of Microelectrode recording (MER) and final lead passes were recorded. For the robot-assisted cohort, 2D radial errors were calculated. Mean case times (total operating room, anesthesia, and operative times) were all significantly decreased in the robot-assisted cohort (all P-values<.02) compared to frameless DBS. When looking at trends in case times, operative efficiency improved over time in the robot-assisted cohort across all time assessment points. Mean radial error in the robot-assisted cohort was 1.40±0.11mm, and mean depth error was 1.05±0.18mm. There was a significant decrease in the average number of MER passes in the robot-assisted cohort (1.05) compared to the nonrobotic cohort (1.45, P<.001). This is the first report of application of frameless robotic-assistance with the Mazor Renaissance platform (Mazor Robotics Ltd, Caesarea, Israel) for DBS surgery, and our findings reveal that an initial experience is safe and can have a positive impact on operative efficiency, accuracy, and safety.

Effects of Ego-Depletion and State Anxiety on Performance Changes in Dart-Throwing Tasks: A Latent Curve Model Approach Reporting Trial Data for Human Participants.

This study examined the effects ego depletion (ED) and state anxiety (SA)have on performance changes in dart-throwing, a perceptual-motor task, using a Latent Curve Model (LCM). Twenty-two men, who had never played darts before, were recruited and randomly assigned to two counterbalanced groups: Group A was exposed first to ED and then to non-ED (NED), and Group B was exposed first to NED and then to ED. We found that the number of trials had a non-linear effect on darts performance, which improved as the number of trials increased before declining again; that is, mean radial error decreased first and then increased. Therefore, motor performance was sustained in the form of a quadratic curve as the number of task executions increased. In general, the higher the degree of ED and SA, the greater the negative effect on performance. However, this phenomenon was observed only in the early-phase trials, and the interacting influence of ED and SA appeared in the late-phase trials. Thus, this study demonstrated that ED and SA have direct effects on performance curves in early-phase trials only, and that their interacting influence appears in late-phase trials.

Evaluating the role of 1.5 T quantitative susceptibility mapping for subthalamic nucleus targeting in deep brain stimulation surgery

Background and purposeQuantitative susceptibility mapping (QSM) has been shown to be valuable in direct targeting for subthalamic nucleus (STN) DBS, given its higher quality of contrast between the STN border and adjacent anatomical structures. The objective is to demonstrate the feasibility of using 1.5T QSM for direct targeting in STN DBS planning. Material and methodsEleven patients underwent MRI acquisitions using a 1.5T scanner, including multi-echo gradient echo sequences for generating QSM images. 22 STN targets were planned with direct targeting method using QSM images by one stereotactic neurosurgeon and indirect targeting method using standard protocol by a second stereotactic neurosurgeon. The two physicians were blinded to each other's results. ResultsThe mean coordinates for the STN using direct targeting relative to the mid-commissural point (MCP) was 11.41±2.43mm lateral, 2.48±0.53mm posterior and 4.45±0.95mm inferior. The mean coordinates for the STN using indirect targeting was 11.79±2.51mm lateral, 2.55±0.54mm posterior, and 4.84±1.03mm inferior. The mean (±SEM) radial error between the direct and indirect target was 0.67±0.14mm. In cases where DBS electrodes were implanted, the radial difference between the indirect and actual target (1.19±0.30mm) was statistically equivalent to the radial difference between the direct and actual target (1.0±0.27mm). ConclusionsDirect targeting of the STN for DBS implantation using 1.5T QSM was found to be statistically equivalent to standard protocol surgery planning. This may offer a simpler, more intuitive alternative for DBS surgery planning at centers with 1.5T MRIs.

Reliability of 3D dental and skeletal landmarks on CBCT images.

To quantify reliability of three-dimensional skeletal landmarks and a comprehensive set of dental landmarks in cone-beam computed tomography (CBCT) and to determine the shapes of envelope of error. Three judges located 31 skeletal landmarks and 60 dental landmarks on the pre- and posttreatment CBCT images of 22 patients. Landmark error was determined by calculating the distance of deviation of landmark locations around their average. Standard deviation and mean radial spherical error were calculated. Scatterplots were constructed to characterize envelope of error. The midline landmarks of the cranial base were highly reliable. Bilateral skeletal landmarks tended to have larger error than midline landmarks. Among the nonconventional landmarks, fronto-zygomatic suture, condyle, and mental foramen showed relatively high reliability. However, foramen spinosum and temporal fossa showed larger errors. Gonion was the least reliable landmark. Most dental landmarks were located more reliably than skeletal landmarks. The highest reliability was found at incisal edges. Mesiobuccal cusp of first molars also showed high reliability. There were differences in the size and shape of the distributions of errors of different landmarks. Most landmarks showed elongated envelopes. Bilateral structures tended to show greater errors than midline structures. Most dental landmarks were more reliable than skeletal landmarks.

Efficacy of Combined General, Special, and Specific Resistance Training on Pace Bowling Skill in Club-Standard Cricketers.

Feros, SA, Young, WB, and O'Brien, BJ. Efficacy of combined general, special, and specific resistance training on pace bowling skill in club-standard cricketers. J Strength Cond Res 34(9): 2596-2607, 2020-This study investigated the efficacy of combined "general," "special," and "specific" resistance training on pace bowling skill. Twelve male, club-standard pace bowlers were randomly allocated to a combined resistance training (CRT) program or traditional cricket training (TCT) program for 8 weeks. The CRT group (n = 6) trained with 300, 250-g, and standard cricket balls; performed 20-m sprints with +20% and +15% body mass resistance (but also unresisted); and completed chin-up and pull-up training. The TCT group (n = 6) trained with standard balls and performed unresisted 20-m sprints. No statistically significant GROUP × TIME interactions were identified. The CRT group demonstrated a "clear moderate" enhancement in peak ball release speed (mean ±95% confidence limits [CLs]: 1.2 ± 1.5 m·s, d = 0.66 ± 0.83), a "clear large" increase in mean radial error (mean ±95% CLs: 7.1 ± 6.5 cm, d = 0.94 ± 0.87), and a "clear large" rise in bivariate variable error (mean ±95% CLs: 7.2 ± 7.8 cm, d = 0.97 ± 1.05). The TCT group exhibited "unclear" changes across all pace bowling skill measures. Both groups displayed "unclear" changes in approach speed, 20-m sprint time, and 1 repetition maximum pull-up strength. In 8 weeks, the CRT program improved peak ball release speed, but at the cost of poorer bowling accuracy and consistency of bowling accuracy. These findings could be attributed to bowling with the heavier balls. The inclusion of "specific" resistance training does not seem to be effective in enhancing all-round pace bowling skill in club-standard cricketers.

SPEED-ACCURACY TRADEOFF OF INSTEP KICK IN YOUNG SOCCER PLAYERS

The speed-accuracy trade-off of fast movements acts inversely and as such is known as the Fitts's law. The aim of this study is to determine how instep kick (IK) speed grading instructions affect the instep kick speed and accuracy. The primary hypothesis assumes that a complex motor task such as IK has an inverse relation between speed and accuracy, and the secondary hypothesis assumes that the applied speed grading instructions are sensitive. The research involved 13 male players, the average age of 15 years (±1.6). The experimental protocol included the execution of IK at five different speeds, determined by verbal instructions to respondents. For assessment of kicking accuracy, we observed the following dependent variables: mean radial error (MRE), bivariate variable error (BVE), and centroid radial error (CRE). Comparative analysis has shown that higher accuracy (reduced MRE) and kicking consistency (reduced BVE) are achieved under lower kicking speeds, but these effects were not achieved in regard to CRE. Subsequent analyses have shown that MRE has a tendency towards a significant difference between the slowest and fastest kicks (p=0.068-0.075), while in the case of BVE it has been found that there are differences between the slowest and all other speed levels (p≤0.05). The main findings of this study have indicated a partial existence (two of three variables) of an inverse relationship between speed and accuracy in complex motor tasks such as IK (multi-joint and discrete motion).

Prediction of China’s Energy Consumption Based on Robust Principal Component Analysis and PSO-LSSVM Optimized by the Tabu Search Algorithm

China’s energy consumption issues are closely associated with global climate issues, and the scale of energy consumption, peak energy consumption, and consumption investment are all the focus of national attention. In order to forecast the amount of energy consumption of China accurately, this article selected GDP, population, industrial structure and energy consumption structure, energy intensity, total imports and exports, fixed asset investment, energy efficiency, urbanization, the level of consumption, and fixed investment in the energy industry as a preliminary set of factors; Secondly, we corrected the traditional principal component analysis (PCA) algorithm from the perspective of eliminating “bad points” and then judged a “bad spot” sample based on signal reconstruction ideas. Based on the above content, we put forward a robust principal component analysis (RPCA) algorithm and chose the first five principal components as main factors affecting energy consumption, including: GDP, population, industrial structure and energy consumption structure, urbanization; Then, we applied the Tabu search (TS) algorithm to the least square to support vector machine (LSSVM) optimized by the particle swarm optimization (PSO) algorithm to forecast China’s energy consumption. We collected data from 1996 to 2010 as a training set and from 2010 to 2016 as the test set. For easy comparison, the sample data was input into the LSSVM algorithm and the PSO-LSSVM algorithm at the same time. We used statistical indicators including goodness of fit determination coefficient (R2), the root means square error (RMSE), and the mean radial error (MRE) to compare the training results of the three forecasting models, which demonstrated that the proposed TS-PSO-LSSVM forecasting model had higher prediction accuracy, generalization ability, and higher training speed. Finally, the TS-PSO-LSSVM forecasting model was applied to forecast the energy consumption of China from 2017 to 2030. According to predictions, we found that China shows a gradual increase in energy consumption trends from 2017 to 2030 and will breakthrough 6000 million tons in 2030. However, the growth rate is gradually tightening and China’s energy consumption economy will transfer to a state of diminishing returns around 2026, which guides China to put more emphasis on the field of energy investment.

How much trunk control is affected in adults with moderate-to-severe cerebral palsy?

Trunk control (TC) impairment is a typical feature in individuals with cerebral palsy (CP), but there are lack of methods that allow to quantify the extent to which static and dynamic TC is impaired in adults with moderate-to-severe CP. Thus, the aims of this study were to analyze the reliability of a posturography protocol to assess TC in adults with CP, and quantify their degree of TC impairment compared to a control sample of adults without CP. Forty-seven adults with moderate-to-severe CP and nineteen control participants were assessed via a protocol of static and dynamic seated trunk tasks, performed on a stable and an unstable surface placed on a force-plate. The mean radial error was the primary variable measured. A large percentage of CP participants successfully completed the static and dynamic conditions on the stable surface (static: 93.6%; dynamic: 91.5–72.3%); however, this percentage decreased considerably on the unstable surface (51.1–34.0%). The posturography protocol displayed good reliability in adults with CP (0.89 ≤ ICC ≤ 0.95; 15.2% ≤ SEM ≤ 20.7%). Adults with CP displayed significantly decreased TC in 4/5 tasks on the stable seat, particularly in dynamic conditions (1.71 ≤ dg ≤ 1.91). Our results confirmed that TC is significantly affected in CP adults compared with controls without CP of similar age, but they present more difficulties to perform dynamic tasks. Thus, it would be recommend including dynamic in addition to static conditions to obtain a comprehensive assessment of TC impairment in adults with moderate-to-severe CP. Additional, these results encourage practitioners to design dynamic activities that challenge trunk control for rehabilitations/training programs.

The Effect of Virtual Reality Training on Learning and Kinematics Characteristics of Dart Throwing

Background: Numerous studies proposed the improvement of movement skills on sport-context by virtual reality interaction. Objectives: The purpose of this study was investigating the effect of virtual reality on dart throwing performance and kinematics. Methods: A total of 24 healthy junior high school boy students (aged = 13.54, SD = 0.50) participated in a virtual reality game of dart throwing in the Iranian academic year of 1396-97. We investigated the mean radial error and bivariate variable error to measure performance outcomes, and preparation time, throwing time, maximum flexion angle, release time angle, and angular velocity to measure movement kinematics. The X-box Kinect (Microsoft, USA) body movement track, standard dart board (unicorn ELIPSE HD) and Casio High-Speed camera (EX-ZR1000, China) sampling at 240 Hz were used to measure performance and capture dominant upper limb motion during dart throwing play. Before exporting data to SPSS 25, Kinovea and MATLAB R2015b were used to analyze videos and smoothing data. Repeated measure ANOVA was used to analyze variables separately. Results: The results showed that virtual reality intervention was significantly effective on performance and movement kinematics. Mean radial error (P = 0.004) decreased from 19.67 ± 6.20 in the pre-test to 17.46 ± 5.81 in the acquisition, and 14.75 ± 4.01 in the post-test. Bivariate variable error (P = 0.001) decreased from 11.46 ± 1.21 in the pre-test to 11.20 ± 1.56 in the acquisition, and 10.03 ± 1.11 in the post-test. Other kinematics factors showed the significant difference in phases. Conclusions: These findings suggest that virtual reality can be applied as an effective instrument in discrete motor skill learning.

Aircraft positioning using PPP method in GLONASS system

PurposeThe purpose of the study is focused on implementation of Global Navigation Satellite System (GLONASS) technique in civil aviation for recovery of aircraft position using Precise Point Positioning (PPP) method in kinematic mode.Design/methodology/approachThe aircraft coordinates of Cessna 172 plane in XYZ geocentric frame were obtained based on GLONASS code and phase observations for PPP method. The numerical computations were executed in post-processing mode in the RTKPOST module in RTKLIB program. The mathematical scheme of equation observation of PPP method was solved using Kalman filter in stochastic processing.FindingsIn paper, the average accuracy of aircraft position is about 0.308 m for X coordinate, 0.274 m for Y coordinate, 0.379 m for Z coordinate. In case of the mean radial spherical error (MRSE) parameter, the average value equals to 0.562 m. In paper, the accuracy of aircraft position in BLh geodesic frame were also showed and described.Research limitations/implicationsThe PPP method can be applied for determination the coordinates of receiver, receiver clock bias, Zenith Wet Delay (ZWD) parameter and ambiguity term for each satellite.Practical implicationsThe PPP method is a new technique for aircraft positioning in air navigation. The PPP method can be also used in receiver autonomous integrity monitoring (RAIM) module in aircraft-based augmentation system (ABAS) system in air transport. The typical accuracy for recovery the aircraft position is about cm ÷ dm level using the PPP method.Social implicationsThe paper is destined for people who work in area of geodesy, navigation, aviation and air transport.Originality/valueThe work presents the original research results of implementation the GLONASS satellite technique for recovery the aircraft position in civil aviation. Currently, the presented research PPP method is used in precise positioning of aircraft in air navigation based on global positioning system and GLONASS solutions.

Robot-guided pediatric stereoelectroencephalography: single-institution experience.

OBJECTIVEStereoelectroencephalography (SEEG) has increased in popularity for localization of epileptogenic zones in drug-resistant epilepsy because safety, accuracy, and efficacy have been well established in both adult and pediatric populations. Development of robot-guidance technology has greatly enhanced the efficiency of this procedure, without sacrificing safety or precision. To date there have been very limited reports of the use of this new technology in children. The authors present their initial experience using the ROSA platform for robot-guided SEEG in a pediatric population.METHODSBetween February 2016 and October 2017, 20 consecutive patients underwent robot-guided SEEG with the ROSA robotic guidance platform as part of ongoing seizure localization and workup for medically refractory epilepsy of several different etiologies. Medical and surgical history, imaging and trajectory plans, as well as operative records were analyzed retrospectively for surgical accuracy, efficiency, safety, and epilepsy outcomes.RESULTSA total of 222 leads were placed in 20 patients, with an average of 11.1 leads per patient. The mean total case time (± SD) was 297.95 (± 52.96) minutes and the mean operating time per lead was 10.98 minutes/lead, with improvements in total (33.36 minutes/lead vs 21.76 minutes/lead) and operative (13.84 minutes/lead vs 7.06 minutes/lead) case times/lead over the course of the study. The mean radial error was 1.75 (± 0.94 mm). Clinically useful data were obtained from SEEG in 95% of cases, and epilepsy surgery was indicated and performed in 95% of patients. In patients who underwent definitive epilepsy surgery with at least a 3-month follow-up, 50% achieved an Engel class I result (seizure freedom). There were no postoperative complications associated with SEEG placement and monitoring.CONCLUSIONSIn this study, the authors demonstrate that rapid adoption of robot-guided SEEG is possible even at a SEEG-naïve institution, with minimal learning curve. Use of robot guidance for SEEG can lead to significantly decreased operating times while maintaining safety, the overall goals of identification of epileptogenic zones, and improved epilepsy outcomes.

Relationship Between Selected Physical Qualities, Bowling Kinematics, and Pace Bowling Skill in Club-Standard Cricketers.

Feros, SA, Young, WB, and O'Brien, BJ. Relationship between selected physical qualities, bowling kinematics, and pace bowling skill in club-standard cricketers. J Strength Cond Res 33(10): 2812-2825, 2019-Although strength and conditioning of cricket pace bowlers has become more specialized in recent times, little is understood about the interplay between physical capacities, pace bowling kinematics, and pace bowling skill measures. This study sought to determine these interrelationships. Thirty-one male club-standard pace bowlers completed 3 test sessions on separate occasions 4-7 days apart. The first testing session comprised an 8-over pace bowling assessment, where bowling skill and selected bowling kinematics were measured. A physical test battery was completed over the remaining 2 sessions. Peak and mean ball release (BR) speed were related with 1 repetition maximum pull-up strength (rs = 0.56, p = 0.005) and correlated with 20-m sprint time (rs = -0.42, p = 0.022; rs = -0.37, p = 0.044, respectively). Mean radial error was associated with 10-m and 20-m sprint times (rs = 0.41, p = 0.030; rs = 0.38, p = 0.037, respectively), and correlated with height and peak power from 3 countermovement jumps (CMJs) (rs = -0.39, p = 0.036; rs = -0.41, p = 0.031, respectively), and mean peak power from 20 CMJs (rs = -0.45, p = 0.020). Bivariate variable error was correlated with front-leg extension angle at BR (rs = 0.41, p = 0.036), and also with approach speed (rs = -0.36, p = 0.050). These relationships may assist strength and conditioning coaches in designing more effective training programs to enhance bowling speed and accuracy. Training interventions are warranted, however, to validate these associations.

Kicking Performance in Young U9 to U20 Soccer Players: Assessment of Velocity and Accuracy Simultaneously

ABSTRACTPurpose: The purpose of this study was to compare the kicking performance of young soccer players in the U9 to U20 age groups. Method: Three hundred and sixty-six Brazilian players were evaluated on an official pitch using three-dimensional kinematics to measure (300 Hz) ball velocity (Vball), foot velocity (Vfoot), Vball/Vfoot ratio, last stride length, and distance between the support foot and the ball. Simultaneously, a two-dimensional procedure was also conducted to compute (60 Hz) the mean radial error, bivariate variable error, and accuracy. Possible age-related differences were assessed through one-way analysis of variance and magnitude-based inferences. Results: Ball velocity increased by 103% (p < .001, η2 = .39) from the U11 age group (48.54 ± 8.31 km/hr) to the U20 age group (98.74 ± 16.35 km/hr). Foot velocity presented a 59% increase (p < .001, η2 = .32) from the U11 age group (49.08 ± 5.16 km/hr) to U20 (78.24 ± 9.49 km/hr). This finding was due to improvement in the quality of foot–ball impact (Vball/Vfoot ratio) from U11 (0.99 ± 0.13 a.u.) to U20 (1.26 ± 0.11 a.u.; p < .001, η2 = .25). Parameters such as mean radial error and accuracy appeared to be impaired during the growth spurt (U13–U15). Last stride length was correlated, low to moderately high, with Vball in all age groups (r = .36–.79). Conclusions: In summary, we concluded that simple biomechanical parameters of kicking performance presented distinct development. These results suggest that different training strategies specific for each age group could be applied. We provide predictive equations to aid coaches in the long-term monitoring process to develop the kick in soccer or search for talented young players.

Automated detection of foveal center in SD-OCT images using the saliency of retinal thickness maps.

To develop an automated method based on saliency map of the retinal thickness map to determine foveal center in spectral-domain optical coherence tomography (SD-OCT) images. This paper proposes an automatic method for the detection of the foveal center in SD-OCT images. Initially, a retinal thickness map is generated by considering the axial distance between the internal limiting membrane (ILM) and the Bruch's membrane (BM). Both the ILM and BM boundaries are automatically segmented by a known retinal segmentation technique. The macular foveal region is identified as a salient feature in the retinal thickness map, and segmented by the saliency detection method based on a human vision attention model. Finally, the foveal center is identified by searching for the lowest point from the determined macular fovea region. Experimental results in 39 scans from 35 healthy eyes and 58 scans from 29 eyes diagnosed with several stages of age-related macular degeneration (AMD), from mild or intermediate stages to severe dry or wet stages, demonstrated that the proposed method achieves good performance. The mean radial distance error of the automatically detected foveal center locations when compared to consensus manual determination established by repeated sessions from two expert readers was 52 ± 56 μm for the normal eyes and 73 ± 63 μm for AMD eyes. The proposed algorithm was more effective for detecting the foveal center automatically in SD-OCT images than the state-of-art methods.

Examining Impulse-Variability Theory and the Speed-Accuracy Trade-Off in Children's Overarm Throwing Performance.

This study examined variability in throwing speed and spatial error to test the prediction of an inverted-U function (i.e., impulse-variability [IV] theory) and the speed-accuracy trade-off. Forty-five 9- to 11-year-old children were instructed to throw at a specified percentage of maximum speed (45%, 65%, 85%, and 100%) and hit the wall target. Results indicated no statistically significant differences in variable error across the target conditions (p = .72), failing to support the inverted-U hypothesis. Spatial accuracy results indicated no statistically significant differences with mean radial error (p = .18), centroid radial error (p = .13), and bivariate variable error (p = .08) also failing to support the speed-accuracy trade-off in overarm throwing. As neither throwing performance variability nor accuracy changed across percentages of maximum speed in this sample of children as well as in a previous adult sample, current policy and practices of practitioners may need to be reevaluated.