Visuomotor Integration Research Articles

Center of Pressure Feedback Modulates the Entrainment of Voluntary Sway to the Motion of a Visual Target

Visually guided weight shifting is widely employed in balance rehabilitation, but the underlying visuo-motor integration process leading to balance improvement is still unclear. In this study, we investigated the role of center of pressure (CoP) feedback on the entrainment of active voluntary sway to a moving visual target and on sway’s dynamic stability as a function of target predictability. Fifteen young and healthy adult volunteers (height 175 ± 7 cm, body mass 69 ± 12 kg, age 32 ± 5 years) tracked a vertically moving visual target by shifting their body weight antero-posteriorly under two target motion and feedback conditions, namely, predictable and less predictable target motion, with or without visual CoP feedback. Results revealed lower coherence, less gain, and longer phase lag when tracking the less predictable compared to the predictable target motion. Feedback did not affect CoP-target coherence, but feedback removal resulted in greater target overshooting and a shorter phase lag when tracking the less predictable target. These adaptations did not affect the dynamic stability of voluntary sway. It was concluded that CoP feedback improves spatial perception at the cost of time delays, particularly when tracking a less predictable moving target.

An Investigation of Brain Functional Connectivity by Form of Craniosynostosis.

Long-term neurocognitive sequelae of nonsyndromic craniosynostosis (NSC) patients are just beginning to be clarified. This study uses functional MRI (fMRI) to determine if there is evidence of altered brain functional connectivity in NSC, and whether these aberrations vary by form of synostosis. Twenty adolescent participants with surgically treated NSC (10 sagittal synostosis, 5 right unilateral coronal synostosis [UCS], 5 metopic synostosis [MSO]) were individually matched to controls by age, gender, and handedness. A subgroup of MSO was classified as severe metopic synostosis (SMS) based on the endocranial bifrontal angle. Resting state fMRI was acquired in a 3T Siemens TIM Trio scanner (Erlangen, Germany), and data were motion corrected and then analyzed with BioImage Suite (Yale School of Medicine). Resulting group-level t-maps were cluster corrected with nonparametric permutation tests. A region of interest analysis was performed based on the left Brodmann's Areas 7, 39, and 40. Sagittal synostosis had decreased whole-brain intrinsic connectivity compared to controls in the superior parietal lobules and the angular gyrus (P = 0.071). Unilateral coronal synostosis had decreased intrinsic connectivity throughout the prefrontal cortex (P = 0.031). The MSO cohort did not have significant findings on intrinsic connectivity, but the SMS subgroup had significantly decreased connectivity among multiple subcortical structures. Sagittal synostosis had decreased connectivity in regions associated with visuomotor integration and attention, while UCS had decreased connectivity in circuits crucial in executive function and cognition. Finally, severity of metopic synostosis may influence the degree of neurocognitive aberration. This study provides data suggestive of long-term sequelae of NSC that varies by suture type, which may underlie different phenotypes of neurocognitive impairment.

S7A-19 SESSION 7A: SAGITTAL SYNOSTOSIS LONG-TERM NEUROCOGNITIVE OUTCOMES IN SAGITTAL SYNOSTOSIS: THE IMPACT OF REOPERATION

Introduction: Optimal age at surgery in nonsyndromic sagittal craniosynostosis (NSC) continues to be debated. This study examined the impact of reoperation on neurocognitive outcome in children with NSC using comprehensive neurocognitive testing. Methods: Forty-seven school-age children (age 5–16 years) with NSC who underwent whole-vault cranioplasty were included in this analysis. Twenty-four participants underwent early surgery (operated at age 6 months or younger; mean age at surgery 4.8 months), and 23 participants underwent later surgery (operated at age greater than 6 months; mean age at surgery 14.3 months). Participants were administered a battery of standardized neuropsychological testing (Wechsler Abbreviated Scale of Intelligence, Wechsler Fundamentals, Beery-Buktenica Visual Motor Integration) to measure neurocognitive outcomes. Results: Thirteen out of the 47 participants underwent a reoperation (27.7%); 11 out of the 13 reoperations were minor revisions while 2 reoperations were cranioplasties. Of the two participants who underwent major revisions, one was in the early surgery and the other was in the late surgery group. Reoperation rate was not statistically greater in those patients who had early surgery when compared to late surgery. Later surgery patients did not perform statistically better than early first surgery patients, even when the early surgery patients underwent reoperation, on any outcome measure of neurocognitive function, including IQ, academic achievement, visuomotor integration, executive function, and behavior (p>0.05 for all). Comparing reoperated early surgery patients with non-reoperated late surgery patients, reoperated early surgery patients scored significantly higher on word reading, reading comprehension, spelling, numerical operations, and visuomotor integration (p<0.05), and had fewer indicators of suspected learning disabilities compared to non-reoperated late surgery patients. Conclusion: Reoperation rate after whole vault cranioplasty was observed to be 27.7%, with few cases of repeat cranioplasty (4.3% of all patients). Operated and reoperated early surgery patients performed better in IQ, academic achievement, and visuomotor integration compared with non-reoperated late surgery patients. This provides evidence that whole-vault cranioplasty before 6 months of age is associated with better neurocognitive outcome compared to after 6 months of age, even when early surgery requires a reoperation.

Worse global intellectual and worse neuropsychological functioning in preterm-born children at preschool age: a meta-analysis.

Preterm births (<32weeks of gestational age) are associated with cognitive problems that are difficult to diagnose in infancy but potentially detectable at preschool age. This review aimed to evaluate the extent to which total intelligence quotient (IQ) and neuropsychological functions at ages three to five years differ between children born at <32weeks gestational age or<1500g birth weight and children born at term. The secondary aim was to determine whether cognitive performance differs between extremely preterm (EPT)/extremely low birth weight (ELBW) children and very preterm (VPT) or very low birth weight (VLBW) children. PubMed and PsycINFO databases were searched for cohort studies comparing IQ and neuropsychological functions in term-born and preterm-born children born after 1994. At ages three to five years, preterm-born children, compared with term-born ones, had worse IQ mean score (d=-0.77 [95% confidence interval -0.88 to -0.66]), attention, memory, visuomotor integration skill and executive functions. No differences were found between VPT/VLBW and EPT/ELBW children. Preterm-born children showed poorer IQ and neuropsychological functions compared with term-born subjects already at preschool age. The extent of differences is similar to that detected at a later age.

A comparison study assessing neuropsychological outcome of patients with post-operative pediatric cerebellar mutism syndrome and matched controls after proton radiation therapy.

Post-operative pediatric cerebellar mutism syndrome (CMS), characterized by mutism, ataxia/hypotonia, and emotional lability, can result in long-term deficits following resection of posterior fossa (PF) tumors. This longitudinal study compared neuropsychological outcomes of pediatric patients with post-operative CMS to a matched control patient group without CMS. Fifty-eight PF tumor patients received post-surgical proton radiation therapy (PRT) and testing at baseline and at ≥ 1-year post-PRT over a 10-year period. Of these, 18 (31%) had post-operative CMS with baseline and follow-up neuropsychological test data. Those participants were matched to 18 controls by tumor location, age, gender, and handedness; no significant group differences were found at baseline for clinical/demographic variables. Total mean age at baseline was 7.26years (SD = 4.42); mean follow-up interval was 3.26years (SD = 2.24). Areas assessed: overall intelligence, expressive and receptive vocabulary, visuomotor integration, fine motor speed, inhibition, emotional control, depression, and anxiety. Patients were 52% male; 86% medulloblastoma/14% ependymoma; 86% craniospinal irradiation/14% focal radiation; and 86% chemotherapy. No group differences were found between most mean baseline scores; expressive vocabulary and fine motor speed were significantly lower in the post-operative CMS group (p< 0.05). Mean change scores revealed no significant differences for the sample; scores were within the normal range except fine motor skills were impaired for both groups. Longitudinal neuropsychological outcomes for post-operative pediatric CMS patients did not differ significantly from matched controls without this condition. Patients were in the normal range in all areas except fine motor speed, which was impaired for both groups independent of CMS diagnosis.

Assessment tool for visual perception deficits in cerebral visual impairment: reliability and validity.

To evaluate the reliability and validity of the Children's Visual Impairment Test for 3- to 6-year-olds (CVIT 3-6). Reliability was assessed via test-retest correlation and intraclass correlation coefficient (ICC) in typically developing children, children with cerebral visual impairment (CVI), intellectual impairment, and simulated impaired vision (validation groups n=59, mean developmental age=4y 10mo, 27 females, 32 males). Internal validity was evaluated with a confirmatory factor analysis on the normative sample (n=301, median age=4y 8mo,SD=9.7mo, 148 females, 153 males). External validity was assessed by correlating performance on CVIT 3-6 with L94, the Beery-Buktenica Developmental Test of Visuo-Motor Integration (Beery-VMI), the Freiburg Vision Test, the revised Snijders-Oomen Nonverbal Intelligence Test for children between 2years 6months and 7-years-old (SON-R 2.5-7), and the Social Responsiveness Scale (SRS) questionnaire and bycomparing performance between validation groups. We observed very good test-retest reliability (r=0.82, p<0.001, ICC=0.80) and confirmed the hypothesized factor structure (comparative fit index=1; Tucker-Lewis index=1.045). We found high correlations with tests with a strong visual perception component (L94: r=0.74, p<0.001; SON-R 2.5-7: r=0.37, p=0.01) and low correlations with other tests (Beery-VMI: r=0.25, p=0.09; SRS: r=0-0.26, p=0.09). Lowest scores were observed for children with CVIcompared to the other validation groups (F[3,44]=5.1, p=0.003). CVIT 3-6 is grounded in knowledge of visual perception. The tool specifically measures CVI-related visual perception deficits and is not mediated by intellectual abilities or low visual acuity. Evidence for good test-retest reliability of the Children's Visual Impairment Test for 3- to 6-year-olds (CVIT 3-6). Factor structure of normative data reflects CVIT 3-6's foundations in vision science. CVIT 3-6 specifically measures visual perception impairments. CVIT 3-6 performance is not influenced by intelligence or low visual acuity.

Alterations in the Structural and Functional Connectivity of the Visuomotor Network of Children With Periventricular Leukomalacia

Children born preterm with periventricular leukomalacia (PVL) demonstrate increased difficulties with tasks requiring visuomotor integration. The visuomotor integration network encompasses brain regions within frontal, parietal, and occipital cortices. Because of their proximity to the lateral ventricle the underlying white matter pathways are at a high risk of damage following PVL-related hypoxic-ischemic white matter injury. This study provides an exploratory analysis of the structural and functional connections within the visuomotor integration network, along with an a priori evaluation of the superior longitudinal fasciculus, inferior fronto-occipital fasciculus, and frontal aslant tract. For each pathway, tracts within both hemispheres revealed decreased volume and number of reconstructed fibers and an increase in quantitative anisotropy and generalized fractional anisotropy. The connectivity results also indicate that there may be changes to both the structural integrity and functional integration of neural networks involved with visuomotor integration functions in children with PVL.

Predictive and reactive reward signals conveyed by climbing fiber inputs to cerebellar Purkinje cells.

There is increasing evidence for a cerebellar contribution to cognitive processing, but the specific input pathways conveying this information remain unclear. We probed the role of climbing fiber inputs to Purkinje cells in generating and evaluating predictions about associations between motor actions, sensory stimuli and reward. We trained mice to perform a visuomotor integration task to receive a reward and interleaved cued and random rewards between task trials. Using two-photon calcium imaging and Neuropixels probe recordings of Purkinje cell activity, we show that climbing fibers signal reward expectation, delivery and omission. These signals map onto cerebellar microzones, with reward delivery activating some microzones and suppressing others, and with reward omission activating both reward-activated and reward-suppressed microzones. Moreover, responses to predictable rewards are progressively suppressed during learning. Our findings elucidate a specific input pathway for cerebellar contributions to reward signaling and provide a mechanistic link between cerebellar activity and the creation and evaluation of predictions.

Action Observation for Neurorehabilitation in Apraxia.

Neurorehabilitation and brain stimulation studies of post-stroke patients suggest that action-observation effects can lead to rapid improvements in the recovery of motor functions and long-term motor cortical reorganization. Apraxia is a clinically important disorder characterized by marked impairment in representing and performing skillful movements [gestures], which limits many daily activities and impedes independent functioning. Recent clinical research has revealed errors of visuo-motor integration in patients with apraxia. This paper presents a rehabilitative perspective focusing on the possibility of action observation as a therapeutic treatment for patients with apraxia. This perspective also outlines impacts on neurorehabilitation and brain repair following the reinforcement of the perceptual-motor coupling. To date, interventions based primarily on action observation in apraxia have not been undertaken.

Brain-Inspired Coding of Robot Body Schema Through Visuo-Motor Integration of Touched Events.

Representing objects in space is difficult because sensorimotor events are anchored in different reference frames, which can be either eye-, arm-, or target-centered. In the brain, Gain-Field (GF) neurons in the parietal cortex are involved in computing the necessary spatial transformations for aligning the tactile, visual and proprioceptive signals. In reaching tasks, these GF neurons exploit a mechanism based on multiplicative interaction for binding simultaneously touched events from the hand with visual and proprioception information.By doing so, they can infer new reference frames to represent dynamically the location of the body parts in the visual space (i.e., the body schema) and nearby targets (i.e., its peripersonal space). In this line, we propose a neural model based on GF neurons for integrating tactile events with arm postures and visual locations for constructing hand- and target-centered receptive fields in the visual space. In robotic experiments using an artificial skin, we show how our neural architecture reproduces the behaviors of parietal neurons (1) for encoding dynamically the body schema of our robotic arm without any visual tags on it and (2) for estimating the relative orientation and distance of targets to it. We demonstrate how tactile information facilitates the integration of visual and proprioceptive signals in order to construct the body space.

Bidirectional and co-developing associations of cognitive, mathematics, and literacy skills during kindergarten

This study of children from two U. S. states examined associations among four cognitive and academic skills: executive function (EF), visuo-motor integration, mathematics assessed with applied problems, and letter-word knowledge. Before (T1) and after (T2) kindergarten, children (N = 555) were assessed using the Head-Toes-Knees-Shoulders (HTKS) EF task, the Beery-Buktenica test of Visuo-motor Integration (Beery VMI), and Woodcock-Johnson subtests of Applied problems and Letter-word identification. Bidirectional analyses showed that all T1 skills predicted at least one other skill, with T1 HTKS and T1 Applied problems predicting all skills. In addition, improving from T1 to T2 in Applied problems was associated with improvements in all skills using random effects analyses, based on differences between children nested in kindergarten classrooms. This overall pattern of results was confirmed using fixed effects analyses, which examined only within-child variability. We conclude that multiple skills undergird early mathematics learning and vice versa.

Impairment of cognitive function in ornithine transcarbamylase deficiency is global rather than domain-specific and is associated with disease onset, sex, maximum ammonium, and number of hyperammonemic events.

Beginning in 2006, the Urea Cycle Disorders Consortium (UCDC) has conducted a longitudinal study of eight inherited deficiencies of enzymes and transporters of the urea cycle, including 444 individuals with ornithine transcarbamylase deficiency (OTCD), of whom 300 (67 males, 233 females) received psychological evaluation. In a cross-sectional study (age range, 3-71 years), analysis of covariance (ANCOVA) determined the association between outcomes in five cognitive domains (global intelligence, executive functions, memory, visuomotor integration, visual perception) and sex, age at testing and timing of disease onset defined as early onset (≤28 days; EO), late onset (LO), or asymptomatic (AS). The dataset of 183 subjects with complete datasets (31 males, 152 females) revealed underrepresentation of EO subjects (2 males, 4 females), who were excluded from the ANCOVA. Although mean scores of LO and AS individuals were within 1 SD of the population norm, AS subjects attained significantly higher scores than LO subjects and males higher scores than females. Correlations between cognitive domains were high, particularly intelligence proved to be a distinguished indicator for cognitive functioning. Maximum plasma ammonium concentration and intelligence correlated significantly higher in EO (r = -0.47) than in LO subjects (r = 0.04). Correlation between the number of hyperammonemic events and intelligence scores were similar for EO (r = -0.30) and LO (r = -0.26) individuals. The number of clinical symptoms was significantly associated with intelligence (r = -0.28) but not with scores in other domains. Results suggest that OTCD has a global impact on cognitive functioning rather than a specific effect on distinct cognitive domains.

Adaptive functioning in children with neurofibromatosis type 1: relationship to cognition, behavior, and magnetic resonance imaging.

To characterize the adaptive behavior profile of children with neurofibromatosis type 1 (NF1) and determine its relationship to neuropsychological functioning and non-neoplastic T2-weighted hyperintense brain lesions on brain magnetic resonance imaging (MRI). In this cross-sectional study, we retrospectively reviewed neuropsychological reports from 104 children with NF1 (56 males, 48 females; mean age 10y 4mo; standard deviation [SD] 3y 4mo; range 3y 5mo-17y 6mo), and extracted data from a range of cognitive and behavioral measures, including the Adaptive Behavior Assessment System (ABAS). Brain MRI was retrospectively reviewed in 42 individuals. Adaptive Behavior Assessment System scores were continuously distributed and pathologically shifted by 0.79 to 1.26SD across Conceptual, Social, and Practical domains, and 46.5% of individuals had a composite score in the borderline or impaired range. Impairment in adaptive functioning was correlated with deficits in executive function (r=-9.543, p<0.001), externalizing problems (r=-0.366, p<0.001), and attention (r=-9.467, p=0.001). Cluster analysis revealed three distinct phenotypic subgroups, one of which exhibited normal cognitive ability, but impaired adaptive functioning, with persistent deficits in executive function, behavioral problems, and attention-deficit/hyperactivity disorder symptomatology. There was no relationship between ABAS scores and the number or location of unidentified bright objects. Adaptive functioning deficits are common among children with NF1 and are associated with impairment in other cognitive/behavioral domains, independent of general cognitive ability. Deficits in adaptive behavior are common in children with neurofibromatosis type 1 (NF1). Poor adaptive functioning is associated with impairments in executive function, externalizing behaviors, and attention, regardless of cognitive ability. The presence or location of unidentified bright objects do not predict adaptive behavior skills in children with NF1.

Visuoperceptual Impairment in Children with NF1: From Early Visual Processing to Procedural Strategies.

Visual-spatial impairment has long been considered a hallmark feature of neurofibromatosis type 1 (NF1). No study investigating the cognitive and neuropsychological profile of NF1 used the Rey Complex Figure Test (RCFT) task as the primary measure of visual-perceptual abilities taking into consideration all functions involved including the strategic processing style. We compared 18 children with NF1, 17 siblings (S), and 18 typically developing children (TD) at intelligence scale and RCFT copy, recall, and recognition trials; we also evaluated the copy strategy as a measure of a visual-processing style. Children with NF1 had normal total IQ, with cognitive weaknesses in the perceptual organization and working memory in line with the existing literature. At the RCFT copy, immediate and delay recall scores are significantly lower in NF1 than S and TD, while recognition is in the normal range in all groups. Copy style was poor and less efficient in children with NF1 and correlated to copy and recall ability, but the effect of the group in the RCFT copy and recall remained significantly controlling for strategic approach. The present study confirms visuospatial impairment in children with NF1, due to a deficit in perceptual analysis of shape and their spatial features, in visuomotor integration efficiency and strategies, in recall memory, while recognition memory is preserved. A more configural/holistic style may facilitate both the visual-perceptual and visuomotor ability and the recall process. Visuoperceptual impairment in NF1 seems to be a unified process from early visual processing to higher order functions (planning, strategy, and executive functioning).

Mathematical skills in children with pilocytic astrocytoma.

Pediatric patients with circumscribed cerebellar pilocytic astrocytoma (PA) tumors generally perform within the normal range on neuropsychological tests after a complete tumor resection. The outcome in academically relevant abilities such as mathematics, which in adults involve some cerebellar functions, is however much less understood. The aim of this study is to retrospectively investigate the neuroplasticity of mathematical skills and associated cognitive functions following cerebellar resection of PA in pediatric patients. Twenty-two children (mean age = 11.2+1.8), including 11 PA patients (females = 6) and 11 healthy controls (females = 6), were administered a battery of mathematical (MaT) and neuropsychological tests. Single-case statistical analyses were carried out (Crawford's t) as well as between-group comparisons (Wilcoxon test). Spearman correlations between MaT and neuropsychological tests were calculated. Thirty-six percent of the patients showed difficulties in some mathematical tasks, 50% of them within a broader cognitive deficit. Verbal working memory was associated with MaT performance both in patients and controls while, crucially, visuospatial memory, and visual-motor integration were associated with MaT in patients only. Among patients, MaT correlated negatively with tumor size and positively with the interval surgery test. The results evince an overall recovery of mathematical abilities despite PA in the majority of patients. This functional reestablishment is supported by visuospatial and visuomotor integration functions that contribute to set up emerging mathematical skills in these patients. Higher levels of compensation are found in more developed tumors as compared to smaller ones.

Plasticity, innateness, and the path to language in the primate brain

AbstractMany researchers consider language to be definitionally unique to humans. However, increasing evidence suggests that language emerged via a series of adaptations to neural systems supporting earlier capacities for visuomotor integration and manual action. This paper reviews comparative neuroscience evidence for the evolutionary progression of these adaptations. An outstanding question is how to mechanistically explain the emergence of new capacities from pre-existing circuitry. One possibility is that human brains may have undergone selection for greater plasticity, reducing the extent to which brain organization is hard-wired and increasing the extent to which it is shaped by socially transmitted, learned behaviors. Mutations that made these new abilities easier or faster to learn would have undergone positive selection, and over time, the neural changes once associated with individual neural plasticity would tend to become heritable, innate, and fixed. Clearly, though, language is not entirely “innate;” it does not emerge without the requisite environmental input and experience. Thus, a mechanistic explanation for the evolution of language must address the inherent trade-off between the evolutionary pressure for underlying neural systems to be flexible and sensitive to environmental input vs. the tendency over time for continually adaptive behaviors to become reliably expressed in an early-emerging, canalized, less flexible manner.

Impaired performance of patients with writer’s cramp in complex fine motor tasks

ObjectiveWriter’s cramp (WC) is a task-specific focal dystonia. WC is characterized by involuntary contractions of muscles of the hand and arm during handwriting, resulting in impaired writing with exaggerated finger forces. The generalization of symptoms to other fine motor tasks is widely discussed. The aim of the study was to determine affected fine motor aspects with an extensive testing battery. MethodsTwelve people with WC and twelve healthy controls were examined. Performance in the Jebsen-Taylor Hand Function Test, Nine-Hole-Peg Test and 2-point discrimination was evaluated. To analyze object manipulation skills, we examined grip forces, temporal measures and other aspects of force control during (1) lifting actions with variations of weight and surface (2) cyclic movements (3) visuomotor tracking (4) fast force changes and (5) grip strength. In addition, correlation between the dependent variables of the fine motor tasks and the handwriting deficits was assessed. ResultsWC patients had impaired performance in the visuomotor tracking task (root mean square error (RMSE), p = 0.03 and time lag, p = 0.05) and the fast force changes (frequency, p = 0.01). There were no statistically significant group differences in the other tasks. We found a correlation between the RMSE of the tracking task and the time needed to write the test sentence (r = 0.643, p = 0.01). ConclusionWC patients revealed abnormalities in complex fine motor performance in tasks with high demands on coordination and visual components, specifically in tracking and fast force changes. SignificanceThis suggests a deficit in visuomotor integration, coordination and cognitive aspects related to movement processing particularly with respect to low forces. These insights may prove useful in the development of targeted training approaches.

Distortion of Visuo-Motor Temporal Integration in Apraxia: Evidence From Delayed Visual Feedback Detection Tasks and Voxel-Based Lesion-Symptom Mapping.

Limb apraxia is a higher brain dysfunction that typically occurs after left hemispheric stroke and its cause cannot be explained by sensory disturbance or motor paralysis. The comparison of motor signals and visual feedback to generate errors, i.e., visuo-motor integration, is important in motor control and motor learning, which may be impaired in apraxia. However, in apraxia after stroke, it is unknown whether there is a specific deficit in visuo-motor temporal integration compared to visuo-tactile and visuo-proprioceptive temporal integration. We examined the precision of visuo-motor temporal integration and sensory-sensory (visuo-tactile and visuo-proprioception) temporal integration in apraxia after stroke by using a delayed visual feedback detection task with three different conditions (tactile, passive movement, and active movement). The delay detection threshold and the probability curve for delay detection obtained in this task were quantitative indicators of the respective temporal integration functions. In addition, we performed subtraction and voxel-based lesion-symptom mapping to identify the brain lesions responsible for apraxia and deficits in visuo-motor temporal integration. The behavioral experiments showed that the delay detection threshold was extended and that the probability curve for delay detection was less steep in apraxic patients compared to controls (pseudo-apraxic patients and unaffected patients), only for the active movement condition, and not for the tactile and passive movement conditions. Furthermore, the severity of apraxia was significantly correlated with the delay detection threshold and the steepness of the probability curve in the active movement condition. These results indicated that multisensory (i.e., visual, tactile, and proprioception) feedback was normally temporally integrated, but motor prediction and visual feedback were not correctly temporally integrated in apraxic patients. That is, apraxic patients had difficulties with visuo-motor temporal integration. Lesion analyses revealed that both apraxia and the distortion of visuo-motor temporal integration were associated with lesions in the fronto-parietal motor network, including the left inferior parietal lobule and left inferior frontal gyrus. We suppose that damage to the left inferior fronto-parietal network could cause deficits in motor prediction for visuo-motor temporal integration, but not for sensory-sensory (visuo-tactile and visuo-proprioception) temporal integration, leading to the distortion of visuo-motor temporal integration in patients with apraxia.

Cortical morphology, epileptiform discharges, and neuropsychological performance in BECTS.

The aim of this study was to understand the relationship between cortical morphology, centrotemporal spike (CTS), and neuropsychological functioning in children with BECTS compared to their typically developing peers. To examine whole-brain differences in cortical thickness between groups, a general linear model approach was applied to T1-weighted structural magnetic resonance imaging (MRI) in children with BECTS and typically developing children. Further region-of-interest (ROI) analyses were performed to examine the effects of frequency and lateralization of CTS. In addition, the relationship between Processing Speed Index (PSI) and cortical thickness was investigated. Twenty-three patients with BECTS and thirty-two controls were included. There was no statistically significant difference in global cortical thickness between groups. With ROI analyses, we found significantly thinner cortex within right pars opercularis when comparing children with right predominant CTS, and with very frequent right CTS (>10/min) to the control group (P=0.028 and P=0.026, respectively). A statistically significant interaction of group (controls vs BECTS) and PSI was seen in bilateral frontal and right superior parietal cortices, indicating a positive relationship between cortical thickness and PSI in healthy controls but not BECTS. A region of cortex where right CTS may originate was thinner in BECTS compared to children without BECTS. Typically developing children with faster processing speed had thicker cortices in regions supporting visuomotor integration, motor, and executive function, but this relationship was not observed in BECTS. These results suggest that BECTS is associated with atypical cortical morphology that may underlie poorer neuropsychological performance.

Manual Dexterity Is a Strong Predictor of Visuo-Motor Temporal Integration in Children.

Although visuo-motor temporal integration in children is suggested to be related to motor control and motor learning, its relevance is still unclear. On the other hand, visuo-motor temporal integration ability undergoes developmental changes with age. In the current correlational study, we measured manual dexterity and visuo-motor temporal integration ability in 132 children with typical development (age, 4–15 years) and investigated the relationship between the two functions. The Movement Assessment Battery for Children-2nd edition was used as an indicator of manual dexterity. The delay detection threshold (DDT) and steepness of the probability curve for delay detection, which was measured by the delayed visual feedback detection task for self-generated movement, were used as indices of the visuo-motor temporal integration ability. The results indicated significant correlations between manual dexterity/age and DDT/steepness of the probability curve for delay detection. In addition, hierarchical multiple regression analysis showed that both manual dexterity and age significantly contributed to visuo-motor temporal integration, indicating a better fit than when only age was employed as an independent variable. Importantly, there was no interaction effect between age and manual dexterity. These findings were the first to suggest that manual dexterity is a significant predictor of visuo-motor temporal integration ability in children, regardless of age. The present study validated the important relationship between visuo-motor temporal integration and manual dexterity in children. Considering the limitations of the current study, including the non-homogeneous sample, further studies are still warranted to validate the results.