Quantification of hand functional recovery in spinal cord injury patients.

STUDY DESIGN: A prospective cohort study. OBJECTIVES: To examine the use of a circle-tracing task in quantifying hand functional recovery in cervical spinal cord injury patients. METHODS: Ten cervical spinal cord injury (SCI) patients and 10 healthy age-matched controls performed a circle-tracing task, using a computerized tablet at the beginning of the study and after 4 weeks. Data relative to performance accuracy as well as pen pressure throughout the performances were collected, and clinical assessment for all patients was performed at the beginning and at the end of the study. RESULTS: Significant differences were found in pen pressure profiles in the SCI patients between the initial assessment and after 4 weeks of assessment. SCI patients, when compared with controls, apply less pressure during the execution, though no significant differences were found for the other parameters. Examination of pen pressure profiles of both controls and SCI patients reveals that, in addition to the lower pressure registered, SCI patients present a more oscillating pressure profile which is direction-dependent. No significant correlations were found between clinical assessments and pen pressure, both within the initial assessment as well as after 4 weeks. CONCLUSIONS: This study emphasizes the potential of simple computerized means for quantifying upper limb functions in SCI patients. These results of this study could be helpful for both highlighting specific functional deficits in patients as well tailoring specific interventions.

The Best of Two Different Visual Instructions in Improving Precision Ball-Throwing and Standing Long Jump Performances in Primary School Children.

Two observational learning approaches have been shown to be successful in improving children's motor performances: one is "technique-focused", another is "goal-focused". In this study, we sought to compare the effectiveness of these two strategies, thus testing for the more efficient method of observational learning to enhance motor skills in primary school children. To this end, two experiments were designed. Experiment 1 involved a precision ball throwing task. Experiment 2 involved a standing long jump task. A total of 792 subjects (aged 6-11) participated in this study and were divided into technique-focus (Experiment 1 n = 200; Experiment 2 n = 66), goal-focus (Experiment 1 n = 195; Experiment 2 n = 68), and control groups (Experiment 1 n = 199; Experiment 2 n = 64). The experiments were divided into pretest, practice, and retention phases. During the practice phase, the technique-focus and goal-focus groups were given different visual instructions on how to perform the task. The results showed that children aged 10-11 belonging to the technique-focus group performed significantly better in the practice phase than both the goal-focus and the control group (p < 0.001), but only for the precision ball throwing task. These findings could be useful for training adaptation in the context of motor learning and skills acquisition.

Crosstalk between Gross and Fine Motor Domains during Late Childhood: The Influence of Gross Motor Training on Fine Motor Performances in Primary School Children.

Gross and fine motor competence have a close relationship during development and are shown to correlate to some extent. However, the study of the interaction between these domains still requires further insights. In this study, we investigated the developmental changes in overall motor skills as well as the effects of gross motor training programs on fine motor skills in children (aged 6-11, n = 240). Fine motor skills were assessed before and after gross motor intervention using the Box and Block Test. The gross motor intervention was based on the Test of Gross Motor Development-3rd Edition. Results showed that gross and fine motor skills correlate across all years of primary school, both significantly improving with age. Finally, the gross motor intervention appeared to not influence fine motor skills. Our findings show that during primary school age, overall motor development is continuous, but non-linear. From age nine onward, there seems to be a major step-up in overall motor competence, of which teachers/educators should be aware of in order to design motor educational programs accordingly. While gross and fine motor domains might be functionally integrated to enhance children's motor performances, further research is needed to clarify the effect of gross motor practice on fine motor performances.

Examining modifications of execution strategies during a continuous task.

How strategies are formulated during a performance is an important aspect of motor control. Knowledge of the strategy employed in a task may help subjects achieve better performances, as it would help to evidence other possible strategies that could be used as well as help perfect a certain strategy. We sought to investigate how much of a performance is conditioned by the initial state and whether behavior throughout the performance is modified within a short timescale. In other words, we focus on the process of execution and not on the outcome. To this scope we used a repeated continuous circle tracing task. Performances were decomposed into different components (i.e., execution variables) whose combination is able to numerically determine movement outcome. By identifying execution variables of speed and duration, we created an execution space and a solution manifold (i.e., combinations of execution variables yielding zero discrepancy from the desired outcome) and divided the subjects according to their initial performance in that space into speed preference, duration preference, and no-preference groups. We demonstrated that specific strategies may be identified in a continuous task, and strategies remain relatively stable throughout the performance. Moreover, as performances remained stable, the initial location in the execution space can be used to determine the subject's strategy. Finally, contrary to other studies, we demonstrated that, in a continuous task, performances were associated with reduced exploration of the execution space.

Circle drawing and tracing dataset for evaluation of fine motor control.

We introduce a motion dataset from healthy human subjects (n = 125) performing two fine motor control tasks on a graphic tablet, namely circle drawing and circle tracing. The article reports the methods and materials used to capture the motion data. The method for data acquisition is the same as the one used to investigate some aspects of fine motor control in healthy subjects in the paper by Cohen et al. (2018) "Precision in drawing and tracing tasks: Different measures for different aspects of fine motor control" (https://doi.org/10.1016/j.humov.2018.08.004) [1]. The dataset shared here contains new raw files of the two-dimensional motion data, as well information on the participants (gender, age, laterality index). These data could be instrumental for assessing other aspects of fine motor control, such as speed-accuracy tradeoff, speed-curvature power law, etc., and/or test machine learning algorithms for e.g., task classification.

An Inertial Measurement Unit-Based Wireless System for Shoulder Motion Assessment in Patients with Cervical Spinal Cord Injury: A Validation Pilot Study in a Clinical Setting.

Residual motion of upper limbs in individuals who experienced cervical spinal cord injury (CSCI) is vital to achieve functional independence. Several interventions were developed to restore shoulder range of motion (ROM) in CSCI patients. However, shoulder ROM assessment in clinical practice is commonly limited to use of a simple goniometer. Conventional goniometric measurements are operator-dependent and require significant time and effort. Therefore, innovative technology for supporting medical personnel in objectively and reliably measuring the efficacy of treatments for shoulder ROM in CSCI patients would be extremely desirable. This study evaluated the validity of a customized wireless wearable sensors (Inertial Measurement Units-IMUs) system for shoulder ROM assessment in CSCI patients in clinical setting. Eight CSCI patients and eight healthy controls performed four shoulder movements (forward flexion, abduction, and internal and external rotation) with dominant arm. Every movement was evaluated with a goniometer by different testers and with the IMU system at the same time. Validity was evaluated by comparing IMUs and goniometer measurements using Intraclass Correlation Coefficient (ICC) and Limits of Agreement (LOA). inter-tester reliability of IMUs and goniometer measurements was also investigated. Preliminary results provide essential information on the accuracy of the proposed wireless wearable sensors system in acquiring objective measurements of the shoulder movements in CSCI patients.

Future Portrait of the Athletic Brain: Mechanistic Understanding of Human Sport Performance Via Animal Neurophysiology of Motor Behavior.

Sport performances are often showcases of skilled motor control. Efforts to understand the neural processes subserving such movements may teach us about general principles of behavior, similarly to how studies on neurological patients have guided early work in cognitive neuroscience. While investigations on non-human animal models offer valuable information on the neural dynamics of skilled motor control that is still difficult to obtain from humans, sport sciences have paid relatively little attention to these mechanisms. Similarly, knowledge emerging from the study of sport performance could inspire innovative experiments in animal neurophysiology, but the latter has been only partially applied. Here, we advocate that fostering interactions between these two seemingly distant fields, i.e., animal neurophysiology and sport sciences, may lead to mutual benefits. For instance, recording and manipulating the activity from neurons of behaving animals offer a unique viewpoint on the computations for motor control, with potentially untapped relevance for motor skills development in athletes. To stimulate such transdisciplinary dialog, in the present article, we also discuss steps for the reverse translation of sport sciences findings to animal models and the evaluation of comparability between animal models of a given sport and athletes. In the final section of the article, we envision that some approaches developed for animal neurophysiology could translate to sport sciences anytime soon (e.g., advanced tracking methods) or in the future (e.g., novel brain stimulation techniques) and could be used to monitor and manipulate motor skills, with implications for human performance extending well beyond sport.

Visuomotor perturbation in a continuous circle tracing task: novel approach for quantifying motor adaptation.

The study of motor adaptation certainly has advanced greatly through the years and helped to shed light on the mechanisms of motor learning. Most paradigms used to study adaptation employ a discrete approach, where people adapt in successive attempts. Continuous tasks on the other hand, while known to possess different characteristics than discrete ones, have received little attention regarding the study motor adaptation. In this paper, we test for adaptation using a continuous circle tracing task with a visuomotor gain perturbation. To examine the feasibility of this task, 45 normal subjects divided into 3 groups were tested for adaptation, aftereffects, and generalization. All subjects exhibited a gradual adaptation when faced with a perturbation as well as opposite aftereffects once the perturbation was removed. Aftereffects tended to persist unless veridical feedback was given. The task generalized well both in size and in space. We believe that this task, by being continuous, could allow for a thorough investigation of visuomotor adaptation to gain perturbations in particular, and perhaps be expanded to other types of adaptations as well, especially when used alongside discrete tasks.

The Less You Are, the More You Are Helped: Effect of Kinesio Tape on Temporal Coordination.

We investigated whether a relationship exists between the inherent timing skill of subject and the magnitude of effect of KT on timing performance by expanding the examination of the dataset described in our previous work. Healthy subjects, tested with and without KT (NKT), performed sets of repetitive wrist's flexion-extensions (IWFEs) with the dominant limb (DL) and the non-dominant limb (NDL) in a synchronization-continuation task at two inter-onset intervals (IOIs): 550-ms and 800-ms. Standard deviation (SD) of IWFEs was used to measure the unevenness of performance. Different patterns of response to KT were observed based on the participant's inherent precision. In the NDL the effect of KT was found significantly higher in the subgroups of individuals having SDNKT of IWFEs>38 ms (p=0.0024) in the 800-ms IOI or SDNKT of IWFEs>19 ms (p=0.0004) in the 550-ms IOI. In the DL the effect of KT was not influenced by the inherent timing skill. We propose KT to be tested for restoring motor control on subjects experiencing sensorimotor disorders associated with intense repetitive training. Also, our findings suggest that care should be taken when using groups of healthy subjects to test the effect of KT.

Precision in drawing and tracing tasks: Different measures for different aspects of fine motor control.

Drawing and tracing tasks, by being relatively easy to execute and evaluate, have been incorporated in many paradigms used to study motor control. While these tasks are helpful when examining various aspects relative to the performance, the relationship in proficiency between these tasks was not evaluated to our knowledge. Seeing that drawing is thought to be an internally cued and tracing an externally cued task, differences in performances are to be expected. In this study, a quantitative evaluation of the precision of circle drawing and tracing, and spiral tracing was made on 150 healthy subjects. Our results show that, while precision is correlated when repeating drawing circles, tracing spirals, or tracing circles as well as between tracing spirals and tracing circles; there is no correlation when subjects performed drawing circles and tracing spirals or between drawing and tracing of circles. These results suggest that this lack of correlation is task dependent and not shape dependent. We suggest that the evaluation of fine motor control should include both a tracing and a drawing task, taking in consideration the precision in each task. We believe that this approach could help not only to evaluate fine motor control more accurately, but also to identify subjects who are more reliant on either internal or external cueing and to what extent.

Deletion of the endogenous TrkB.T1 receptor isoform restores the number of hippocampal CA1 parvalbumin-positive neurons and rescues long-term potentiation in pre-symptomatic mSOD1(G93A) ALS mice.

Amyotrophic lateral sclerosis (ALS) causes rapidly progressive paralysis and death within 5 years from diagnosis due to degeneration of the motor circuits. However, a significant population of ALS patients also shows cognitive impairments and progressive hippocampal pathology. Likewise, the mutant SOD1(G93A) mouse model of ALS (mSOD1), in addition to loss of spinal motor neurons, displays altered spatial behavior and hippocampal abnormalities including loss of parvalbumin-positive interneurons (PVi) and enhanced long-term potentiation (LTP). However, the cellular and molecular mechanisms underlying these morpho-functional features are not well understood. Since removal of TrkB.T1, a receptor isoform of the brain-derived neurotrophic factor, can partially rescue the phenotype of the mSOD1 mice, here we tested whether removal of TrkB.T1 can normalize the number of PVi and the LTP in this model. Stereological analysis of hippocampal PVi in control, TrkB.T1-/-, mSOD1, and mSOD1 mice deficient for TrkB.T1 (mSOD1/T1-/-) showed that deletion of TrkB.T1 restored the number of PVi to physiological level in the mSOD1 hippocampus. The rescue of PVi neuron number is paralleled by a normalization of high-frequency stimulation-induced LTP in the pre-symptomatic mSOD1/T1-/- mice. Our experiments identified TrkB.T1 as a cellular player involved in the homeostasis of parvalbumin expressing interneurons and, in the context of murine ALS, show that TrkB.T1 is involved in the mechanism underlying structural and functional hippocampal degeneration. These findings have potential implications for hippocampal degeneration and cognitive impairments reported in ALS patients at early stages of the disease.

The effect of fidget spinners on fine motor control.

Fidgeting, defined as the generation of small movements through nervousness or impatience, is one of cardinal characteristic of ADHD. While fidgeting is, by definition, a motor experience still nothing is known about the effects of fidgeting on motor control. Some forms of fidgeting involve also the manipulation of external objects which, through repetition, may become automatic and second nature. Both repetition and practice are important for the acquisition of motor skills and, therefore, it is plausible that the repetitive manipulation of objects may influence motor control and performance. As such, fidget spinners, by being diffuse and prone to repetitive usage, may represent interesting tool for improving motor control. In this study we examine the effect of fidget spinners on fine motor control, evaluated by a spiral-tracing task. We show that the use of fidget spinner indeed seems to have a favorable effect on fine motor control, at least in the short term, although this effect does not seem to be in any way inherent to fidget spinners themselves as much as to object manipulation in general. However, due to their widespread usage, fidget spinner may have the advantage of being an enjoyable means for improving fine motor control.

3D reconstruction of human movement in a single projection by dynamic marker scaling.

The three dimensional (3D) reconstruction of movement from videos is widely utilized as a method for spatial analysis of movement. Several approaches exist for a 3D reconstruction of movement using 2D video projection, most of them require the use of at least two cameras as well as the application of relatively complex algorithms. While a few approaches also exist for 3D reconstruction of movement with a single camera, they are not widely implemented due to tedious and complicated methods of calibration. Here we propose a simple method that allows for a 3D reconstruction of movement by using a single projection and three calibration markers. Such approach is made possible by tracking the change in diameter of a moving spherical marker within a 2D projection. In order to test our model, we compared kinematic results obtained with this model to those with the commonly used approach of two cameras and Direct Linear Transformation (DLT). Our results show that such approach appears to be in line with the DLT method for 3D reconstruction and kinematic analysis. The simplicity of this method may render it approachable for both clinical use as well as in uncontrolled environments.

Neural plasticity and network remodeling: From concepts to pathology.

Neuroplasticity has been subject to a great deal of research in the last century. Recently, significant emphasis has been placed on the global effect of localized plastic changes throughout the central nervous system, and on how these changes integrate in a pathological context. Specifically, alterations of network functionality have been described in various pathological contexts to which corresponding structural alterations have been proposed. However, considering the amount of literature and the different pathological contexts, an integration of this information is still lacking. In this paper we will review the concepts of neural plasticity as well as their repercussions on network remodeling and provide a possible explanation to how these two concepts relate to each other. We will further examine how alterations in different pathological contexts may relate to each other and will discuss the concept of plasticity diseases, its models and implications.

Acetylcholine, GABA and neuronal networks: a working hypothesis for compensations in the dystrophic brain.

Duchenne muscular dystrophy (DMD), a genetic disease arising from a mutation in the dystrophin gene, is characterized by muscle failure and is often associated with cognitive deficits. Studies of the dystrophic brain on the murine mdx model of DMD provide evidence of morphological and functional alterations in the central nervous system (CNS) possibly compatible with the cognitive impairment seen in DMD. However, while some of the alterations reported are a direct consequence of the absence of dystrophin, others seem to be associated only indirectly. In this review we reevaluate the literature in order to formulate a possible explanation for the cognitive impairments associated with DMD. We present a working hypothesis, demonstrated as an integrated neuronal network model, according to which within the cascade of events leading to cognitive impairments there are compensatory mechanisms aimed to maintain functional stability via perpetual adjustments of excitatory and inhibitory components. Such ongoing compensatory response creates continuous perturbations that disrupt neuronal functionality in terms of network efficiency. We have theorized that in this process acetylcholine and network oscillations play a central role. A better understating of these mechanisms could provide a useful diagnostic index of the disease's progression and, perhaps, the correct counterbalance of this process might help to prevent deterioration of the CNS in DMD. Furthermore, the involvement of compensatory mechanisms in the CNS could be extended beyond DMD and possibly help to clarify other physio-pathological processes of the CNS.

Modulation of isochronous movements in a flexible environment: links between motion and auditory experience.

The ability to perform isochronous movements while listening to a rhythmic auditory stimulus requires a flexible process that integrates timing information with movement. Here, we explored how non-temporal and temporal characteristics of an auditory stimulus (presence, interval occupancy, and tempo) affect motor performance. These characteristics were chosen on the basis of their ability to modulate the precision and accuracy of synchronized movements. Subjects have participated in sessions in which they performed sets of repeated isochronous wrist's flexion-extensions under various conditions. The conditions were chosen on the basis of the defined characteristics. Kinematic parameters were evaluated during each session, and temporal parameters were analyzed. In order to study the effects of the auditory stimulus, we have minimized all other sensory information that could interfere with its perception or affect the performance of repeated isochronous movements. The present study shows that the distinct characteristics of an auditory stimulus significantly influence isochronous movements by altering their duration. Results provide evidence for an adaptable control of timing in the audio-motor coupling for isochronous movements. This flexibility would make plausible the use of different encoding strategies to adapt audio-motor coupling for specific tasks.