Quantifying motor adaptation in a sport-specific table tennis setting

Studies on motor adaptation aim to better understand the remarkable, largely implicit capacity of humans to adjust to changing environmental conditions. So far, this phenomenon has mainly been investigated in highly controlled laboratory setting, allowing only limited conclusions and consequences for everyday life scenarios. Natural movement tasks performed under externally valid conditions would provide important support on the transferability of recent laboratory findings. Therefore, one major goal of the current study was to create and assess a new table tennis paradigm mapping motor adaptation in a more natural and sport-specific setting. High-speed cinematographic measurements were used to determine target accuracy in a motor adaptation table tennis paradigm in 30 right-handed participants. In addition, we investigated if motor adaptation was affected by temporal order of perturbations (serial vs. random practice). In summary, we were able to confirm and reproduce typical motor adaptation effects in a sport-specific setting. We found, according to previous findings, an increase in target errors with perturbation onset that decreased during motor adaptation. Furthermore, we observed an increase in target errors with perturbation offset (after-effect) that decrease subsequently during washout phase. More importantly, this motor adaptation phenomenon did not differ when comparing serial vs. random perturbation conditions.

EEG Analysis in Coincident Timing Task Towards Motor Rehabilitation

The identification of specific components in EEG signals is often key when designing EEG-based brain-computer interfaces (BCIs), and a good understanding of the factors that elicit such components can be helpful when it comes to precise, energy-efficient and time-accurate actuation of exoskeletons. CNVs (Contingent Negative Variations), ERDs or ERSs (Event-Related Desynchronizations/Synchronizations) as well as ErrPs (Error-Related Potentials) are particularly important components can be identified during motor tasks and related to specific events in a Coincident Timing (CT) task. This work investigates offline EEG signals acquired during an upper limb CT task and analyzes the task protocol with the purpose of correlating the aforementioned EEG features to movement onset. CNVs and ERD/ERS were successfully identified after averaging multiple trials, and it was further concluded that complementary information about muscle activity (via EMG) as well as video tracking of arm movement play a critical role in the synchronization of EEG components with movement onset. The framework for EEG analysis presented in this paper allows for future development of a BCI on top of this CT task capable of assessing motor learning and actuating an exoskeleton to enable faster motor rehabilitation.

Constraint-Induced Movement Therapy in multiple sclerosis: Safety and three-dimensional kinematic analysis of upper limb activity. A randomized single-blind pilot study

BACKGROUND

There are few evidences on safety of Constraint-Induced Movement Therapy (CIMT), as well as its effects in neurological conditions, including multiple sclerosis (MS).

OBJECTIVE

To evaluate safety and effectiveness of a 2-week CIMT protocol on upper limb activity of progressive MS patients through a three-dimensional (3D) kinematic analysis.

METHODS

In this randomized single-blind pilot study, we randomly allocated patients affected by progressive MS reporting a reduced use of one upper limb into two different groups: CIMT group (less affected limb blocked by a splint) and control group (undergoing bi-manual treatment). Primary outcome was CIMT safety. Furthermore, we assessed CIMT effects through clinical outcomes (hand grip strength, HGS, and 9 Hole Peg Test, 9HPT) and 3D kinematic analysis (normalized jerk, number of movement units, going phase duration, mean velocity, endpoint error). All evaluations were performed at baseline (T0) and after 2 weeks of treatment (T1) for both arms in both groups.

RESULTS

Ten MS patients, mean aged 51.0±7.7 years, were randomly allocated in the 2 groups. After treatment, no differences were found in the blocked arm. Furthermore, CIMT group showed significant improvements in clinical and kinematic parameters.

CONCLUSIONS

CIMT might be considered a safe and effective technique in MS patients.

Transcranial direct current stimulation (tDCS) for upper limb rehabilitation after stroke: future directions

Transcranial Direct Current Stimulation (tDCS) is a potentially useful tool to improve upper limb rehabilitation outcomes after stroke, although its effects in this regard have shown to be limited so far. Additional increases in effectiveness of tDCS in upper limb rehabilitation after stroke may for example be achieved by (1) applying a more focal stimulation approach like high definition tDCS (HD-tDCS), (2) involving functional imaging techniques during stimulation to identify target areas more exactly, (3) applying tDCS during Electroencephalography (EEG) (EEG-tDCS), (4) focusing on an effective upper limb rehabilitation strategy as an effective base treatment after stroke. Perhaps going even beyond the application of tDCS and applying alternative stimulation techniques such as transcranial Alternating Current Stimulation (tACS) or transcranial Random Noise Stimulation (tRNS) will further increase effectiveness of upper limb rehabilitation after stroke.

Improved Learning a Coincident Timing Task With a Predictable Resisting Force

The present study analyzes the learning in a coincident timing task with force perturbation. We aimed to verify whether a predictable load (constant spring) applied to hand movements could facilitate learning and, thus, performance improvement with respect to movements without any external load and an unpredictable load to perform a coincident timing task with a few number of repetitions (n = 28) under acquisition and transfer phases. The results showed that the group with a predictable load had a significant better performance with lower percentage of errors and smaller time variance in the acquisition and transfer phase. The groups with no load and unpredictable load had a similar performance in the transfer phase. It can be concluded that adding a predictable force to the coincident timing task results in performance improvement. Therefore, learning to reach a target at a correct time could be improved with the application of predictable external loads.

Does kinematics add meaningful information to clinical assessment in post-stroke upper limb rehabilitation? A case report

[Purpose] The aims of this case study were to: (a) quantify the impairment and activity restriction of the upper limb in a hemiparetic patient; (b) quantitatively evaluate rehabilitation program effectiveness; and (c) discuss whether more clinically meaningful information can be gained with the use of kinematic analysis in addition to clinical assessment. The rehabilitation program consisted of the combined use of different traditional physiotherapy techniques, occupational therapy sessions, and the so-called task-oriented approach. [Subject and Methods] Subject was a one hemiplegic patient. The patient was assessed at the beginning and after 1 month of daily rehabilitation using the Medical Research Council scale, Nine Hole Peg Test, Motor Evaluation Scale for Upper Extremity in Stroke Patients, and Hand Grip Dynamometer test as well as a kinematic analysis using an optoelectronic system. [Results] After treatment, significant improvements were evident in terms of total movement duration, movement completion velocity, and some smoothness parameters. [Conclusion] Our case report showed that the integration of clinical assessment with kinematic evaluation appears to be useful for quantitatively assessing performance changes.

The Neural Mechanism Exploration of Adaptive Motor Control: Dynamical Economic Cell Allocation in the Primary Motor Cortex

Adaptive flexibility is of significance for the smooth and efficient movements in goal attainment. However, the underlying work mechanism of the cerebral cortex in adaptive motor control still remains unclear. How does the cerebral cortex organize and coordinate the activity of a large population of cells in the implementation of various motor strategies? To explore this issue, single-unit activities from the M1 region and kinematic data were recorded simultaneously in monkeys performing 3D reach-to-grasp tasks with different perturbations. Varying motor control strategies were employed and achieved in different perturbed tasks, via the dynamic allocation of cells to modulate specific movement parameters. An economic principle was proposed for the first time to describe a basic rule for cell allocation in the primary motor cortex. This principle, defined as the Dynamic Economic Cell Allocation Mechanism (DECAM), guarantees benefit maximization in cell allocation under limited neuronal resources, and avoids committing resources to uneconomic investments for unreliable factors with no or little revenue. That is to say, the cells recruited are always preferentially allocated to those factors with reliable return; otherwise, the cells are dispatched to respond to other factors about task. The findings of this study might partially reveal the working mechanisms underlying the role of the cerebral cortex in adaptive motor control, wherein is also of significance for the design of future intelligent brain-machine interfaces and rehabilitation device.

Quantification of long-term effects of botulinum injection in a case of cerebral palsy affecting the upper limb movement

OBJECTIVE

The aim of this work was to put into evidence the long-lasting modification induced by botulinum toxin injection and rehabilitative treatment on motor control.

METHODS

In this contribution, we report the case of a female child showing hemiplegia, due to cerebral palsy. She underwent botulinum injection, followed by physical and occupational therapy. We quantified the biomechanical, cerebral and occupational aspects of her impaired upper limb, also dynamically, with respect to her pre- and post-treatment condition.

RESULTS

Small long-lasting improvements--induced on biomechanics by botulinum injection--triggered wide cerebral modification, well reflected in improved contextual movements and motor strategy.

CONCLUSION

These results provide evidences that small modifications in the end-effector performance often imply cerebral modifications and improvement in finalized motor strategy.

Neuromuscular taping for the upper limb in Cerebral Palsy: A case study in a patient with hemiplegia

OBJECTIVE

To assess quantitatively the effects of Neuromuscular Taping (NMT) on the upper limb in a female child with left hemiplegia, due to Cerebral Palsy (CP).

METHODS

The patient underwent NMT on cervical level, shoulder and hand only of the plegic upper limb, followed by physical therapy. Kinematic data of upper limbs during reaching task were collected before (PRE) and after 2 weeks of treatment (POST).

RESULTS

After the intervention, the affected limb improved in terms of movement duration, Average Jerk and Number of Unit Movements indices, indicating a faster, smoother and less segmented movement. Improvements appeared at the ranges of motion of the upper limb joints, both at shoulder and elbow joints. No significant changes were globally displayed for the unaffected arm.

CONCLUSION

NMT seems to be a promising intervention for improving upper limb movement in patients with CP. Further investigations are certainly needed to assess effectively the effects of the intervention in this pathological state.