Spontaneity competes with intention to influence the coordination dynamics of interpersonal performance tendencies

Research has shown that spontaneous visual coupling supports frequency entrainment, phase attraction, and intermittent interpersonal coordination when co-actors are switched from a no-vision (NV) to vision (V) context. In two experiments, co-actors started in a NV context while producing the same or different amplitude movements. The same amplitude resulted in similar self-paced frequencies, while different amplitudes resulted in disparate frequencies. In experiment 1, co-actors were instructed to maintain amplitude while receiving no instructions to coordinate their actions. Frequency and phase entrainment was limited in the V context even when co-actors started the NV context with the same amplitude. In experiment 2, co-actors were instructed to maintain amplitude and intentionally coordinate together, but not at a specific pattern. Significant frequency modulations occurred to maintain amplitude as the co-actors sought to coordinate their actions. With the open-ended instructions, co-actors produced in-phase and anti-phase coordination along with intermittent performance exhibited by shifts between a variety of stable relative phase patterns. The proposed hypotheses and findings are discussed within the context of a shared manifold representation for joint action contexts, with the coordination dynamics expressed by the HKB model of relative phase serving to conceptualization the representations in the shared manifold.

Post-stroke deficits in the anticipatory control and bimanual coordination during naturalistic cooperative bimanual action

BACKGROUND

Unilateral stroke leads to asymmetric deficits in movement performance; yet its effects on naturalistic bimanual actions, a key aspect of everyday functions, are understudied. Particularly, how naturalistic bimanual actions that require the two hands to cooperatively interact with each other while manipulating a single common object are planned, executed, and coordinated after stroke is not known. In the present study, we compared the anticipatory planning, execution, and coordination of force between individuals with left and right hemisphere stroke and neurotypical controls in a naturalistic bimanual common-goal task, lifting a box.

METHOD

Thirty-three individuals with chronic stroke (15 LCVA, 18 RCVA) and 8 neurotypical age-matched controls used both hands to lift a box fitted with force transducers under unweighted and weighted conditions. Primary dependent variables included measures of anticipation (peak grip and load force rate), execution (peak grip force, load force), and measures of within-hand (grip-load force coordination) and between-hand coordination (force rate cross-correlations). Primary analyses were performed using linear mixed effects modeling. Exploratory backward stepwise regression examined predictors of individual variability within participants with stroke.

RESULTS

Participants with stroke, particularly the RCVA group, showed impaired scaling of grip and load force rates with the addition of weight, indicating deficits in anticipatory control. While there were no group differences in peak grip force, participants with stroke showed significant impairments in peak load force and in grip-load force coordination with specific deficits in the evolution of load force prior to object lift-off. Finally, there were differences in spatial coordination of load force rates for participants with stroke, and especially the RCVA group, as compared to controls. Unimanual motor performance of the paretic arm and hemisphere of lesion (right hemisphere) were the key predictors of impairments in anticipatory planning of grip force and bimanual coordination among participants with stroke.

CONCLUSIONS

These results suggest that individuals with stroke, particularly those with right hemisphere damage, have impairments in anticipatory planning and interlimb coordination of symmetric cooperative bimanual tasks.

Bimanual movements in children with cerebral palsy: a systematic review of instrumented assessments

BACKGROUND

Assessment of bimanual movements, which are frequently impaired in children with cerebral palsy, is highly challenging in clinical practice. Instrumented measures have been developed to evaluate and help to understand impaired upper limb movement during bimanual tasks in these children. The aim of this review was to report instrumented measurement tools (3D motion analysis, sensors, etc.) used for bimanual task movement analysis, and the metrological properties of the measures in children with cerebral palsy.

METHODS

A systematic review was conducted (Prospero CRD42022308517). PubMed, Web of Science, Cochrane and Scopus databases were searched with relevant keywords and inclusion/exclusion criteria. Article quality and biomechanical methods were evaluated with a customized scale and metrological properties with the COSMIN checklist.

RESULTS

In total, 452 children, mostly with unilateral cerebral palsy, mean age 10.9 (SD 3.2) years, underwent quantitative bimanual assessments in the 31 included studies (mean quality score 22/32 points [SD 4.7]). The tools used were 3D motion analysis (n = 26), accelerometers (n = 2), and other instruments (cube, digitizer, etc.) (n = 3). Children performed 1-5 bimanual tasks in laboratory settings, mostly activities of daily living or game scenarios. Analyses focused mostly on spatiotemporal variables, 6 of which were specifically developed for bilateral measures (task completion time, goal synchronization, movement overlap time, interlimb coupling, continuous relative phase and asynchrony). These instrumented measurements had moderate to good discriminant and convergent validity, but reliability and responsiveness assessments were lacking.

CONCLUSIONS

A large number of quantitative bimanual assessments involving different tools, bimanual tasks and specific variables developed to evaluate bimanual function were found. Development of other relevant variables and validation of these tools are needed to further determine their usefulness, both as research outcomes and to guide therapies in clinical practice. Future research, involving younger children and real-life assessments, will improve our understanding of bimanual function in children with cerebral palsy.

Motor patterns of the impaired upper limb in children with unilateral cerebral palsy performing bimanual tasks

BACKGROUND

Upper limb movement patterns have not yet been identified in bimanual conditions despite the difficulties children with unilateral cerebral palsy have performing bimanual activities. The aim was to identify specific motor patterns from kinematic deviations during bimanual tasks in this population.

METHODS

Twenty children with unilateral cerebral palsy and 20 age-matched, typically developing children performed the five tasks of a 3D bimanual protocol. To evaluate upper limb kinematic deviations, 10 Arm Variable Scores were calculated for the affected /non-dominant upper limb of each participant for each task. Sparse K-means cluster analysis was applied to the 50 Arm Variable Scores of all the children to identify motor patterns and determining variables. Clinical tests of impairment (muscle strength, selectivity, spasticity) and function (Assisting hand assessment, Abilhand-Kids) were compared between the clusters obtained.

FINDINGS

Three different motor patterns were identified using the data from all the children: mild, proximal-distal and proximal-distal with trunk. The most important cluster determinants were the Arm Variable Scores for pronation-supination and wrist extension. In the cerebral palsy group, scores of impairments (p < .01) and function (Assisting Hand Assessment [p < .001] and Abilhand-Kids [p = .004]) differed for each motor pattern. Supination and wrist extension deviations differed significantly between the groups (p < .001).

INTERPRETATION

During performance of bimanual tasks, children with unilateral cerebral palsy used distinct motor patterns that each corresponded to a specific clinical profile. Elbow-wrist deviations were the largest and most decisive and were specific to the cerebral palsy group: they should be the target of interventions to enhance bimanual function.

CLINICALTRIALS

gov identifier: NCT03888443.

Bimanual motor skill learning with robotics in chronic stroke: comparison between minimally impaired and moderately impaired patients, and healthy individuals

Background

Most activities of daily life (ADL) require cooperative bimanual movements. A unilateral stroke may severely impair bimanual ADL. How patients with stroke (re)learn to coordinate their upper limbs (ULs) is largely unknown. The objectives are to determine whether patients with chronic supratentorial stroke could achieve bimanual motor skill learning (bim-MSkL) and to compare bim-MSkL between patients and healthy individuals (HIs).

Methods

Twenty-four patients and ten HIs trained over 3 consecutive days on an asymmetrical bimanual coordination task (CIRCUIT) implemented as a serious game in the REAplan® robot. With a common cursor controlled by coordinated movements of the ULs through robotic handles, they performed as many laps as possible (speed constraint) on the CIRCUIT while keeping the cursor within the track (accuracy constraint). The primary outcome was a bimanual speed/accuracy trade-off (biSAT), we used a bimanual coordination factor (biCO) and bimanual forces (biFOP) for the secondary outcomes. Several clinical scales were used to evaluate motor and cognitive functions.

Results

Overall, the patients showed improvements on biSAT and biCO. Based on biSAT progression, the HI achieved a larger bim-MSkL than the patients with mild to moderate impairment (Fugl-Meyer Assessment Upper Extremity (FMA-UE): 28–55, n = 15) but not significantly different from those with minimal motor impairment (FMA-UE: 66, n = 9). There was a significant positive correlation between biSAT evolution and the FMA-UE and Stroke Impact Scale.

Conclusions

Both HI and patients with chronic stroke training on a robotic device achieved bim-MSkL, although the more impaired patients were less efficient. Bim-MSkL with REAplan® may be interesting for neurorehabilitation after stroke.

Trial registration: ClinicalTrial.gov identifier: NCT03974750. Registered 05 June 2019. https://clinicaltrials.gov/ct2/show/NCT03974750?cond=NCT03974750&draw=2&rank=1

Supplementary Information

The online version contains supplementary material available at 10.1186/s12984-022-01009-3.

Left hemisphere damage produces deficits in predictive control of bilateral coordination

Previous research has demonstrated hemisphere-specific motor deficits in ipsilesional and contralesional unimanual movements in patients with hemiparetic stroke due to MCA infarct. Due to the importance of bilateral motor actions on activities of daily living, we now examine how bilateral coordination may be differentially affected by right or left hemisphere stroke. To avoid the caveat of simply adding unimanual deficits in assessing bimanual coordination, we designed a unique task that requires spatiotemporal coordination features that do not exist in unimanual movements. Participants with unilateral left (LHD) or right hemisphere damage (RHD) and age-matched controls moved a virtual rectangle (bar) from a midline start position to a midline target. Movement along the long axis of the bar was redundant to the task, such that the bar remained in the center of and parallel to an imaginary line connecting each hand. Thus, to maintain midline position of the bar, movements of one hand closer to or further away from the bar midline required simultaneous, but oppositely directed displacements with the other hand. Our findings indicate that left (LHD), but not right (RHD) hemisphere-damaged patients showed poor interlimb coordination, reflected by significantly lower correlations between displacements of each hand along the bar axis. These left hemisphere-specific deficits were only apparent prior to peak velocity, likely reflecting predictive control of interlimb coordination. In contrast, the RHD group bilateral coordination was not significantly different than that of the control group. We conclude that predictive mechanisms that govern bilateral coordination are dependent on left hemisphere mechanisms. These findings indicate that assessment and training in cooperative bimanual tasks should be considered as part of an intervention framework for post-stroke physical rehabilitation.

The probability of choosing both hands depends on an interaction between motor capacity and limb-specific control in chronic stroke

A goal of rehabilitation after stroke is to promote pre-stroke levels of arm use for every day, frequently bimanual, functional activities. We reasoned that, after a stroke, the choice to use one or both hands for bimanual tasks might depend not only on residual motor capacity, but also the specialized demands imposed by the task on the paretic hand. To capture spontaneous, task-specific choices, we covertly observed 50 pre-stroke right-handed chronic stroke survivors (25 each of left, LHD, and right-hemisphere damage, RHD) and 11 age-similar control adults and recorded their hand use strategies for two pairs of bimanual tasks with distinct demands: one with greater precision requirements (photo-album tasks), and another with greater stabilization requirements (letter-envelope tasks). The primary outcome was the choice to use one or both hands. Logistic regression was used to test the two hypotheses that the probability of choosing a bimanual strategy would be greater in those with less severe motor impairment and also in those with LHD. When collapsed across the four tasks, we found support for these hypotheses. Notably, however, the influence of these factors on bimanual choice varied based on task demands. For the photo-album pair, the probability of a bimanual strategy was greater for those with LHD compared to RHD, regardless of the degree of motor impairment. For the letter-envelope pair, we found a significant interaction between impairment and side of lesion in determining the likelihood of choosing both hands. Therefore, the manner in which side of lesion moderates the effect of impairment on hand use depends on the task.

Transient changes in paretic and non-paretic isometric force control during bimanual submaximal and maximal contractions

Purpose

The purpose of this study was to investigate transient bimanual effects on the force control capabilities of the paretic and non-paretic arms in individuals post stroke across submaximal and maximal force control tasks.

Methods

Fourteen chronic stroke patients (mean age = 63.8 ± 15.9; stroke duration = 38.7 ± 45.2 months) completed two isometric force control tasks: (a) submaximal control and (b) maximal sustained force production. Participants executed both tasks with their wrist and fingers extending across unimanual (paretic and non-paretic arms) and bimanual conditions. Mean force, force variability using coefficient of variation, force regularity using sample entropy were calculated for each condition.

Results

During the submaximal force control tasks (i.e., 5, 25, and 50% of maximum voluntary contraction), the asymmetrical mean force between the paretic and non-paretic arms decreased from unimanual to bimanual conditions. The asymmetry of force variability and regularity between the two arms while executing unimanual force control tended to decrease in the bimanual condition because of greater increases in the force variability and regularity for the non-paretic arm than those for the paretic arm. During the maximal sustained force production tasks (i.e., 100% of maximum voluntary contraction), the paretic arm increased maximal forces and decreased force variability in the bimanual condition, whereas the non-paretic arm reduced maximal forces and elevated force variability from unimanual to bimanual conditions.

Conclusions

The current findings support a proposition that repetitive bimanual isometric training with higher execution intensity may facilitate progress toward stroke motor recovery.

The effects of speed of execution on upper-limb kinematics in activities of daily living with respect to age

In this study, 26 young, 16 older adults ≤ 66a, and 22 older adults ≥ 67a were examined in a set of neuropsychological tests and the kinematics in two different activities of daily living (ADL) were assessed. Half of the participants performed the ADL in a natural speed, the other half as fast as possible. The performance in the Trail Making Task B revealed an increased slope after 67 years of age. When executed in a natural speed, ADL kinematics were comparable. When executed as fast as possible, almost all kinematic parameters showed significant group and speed differences and revealed group × speed interactions. Models of multiple linear regression predicting ADL trial durations showed similar strategies in the young and older adults < 67a. Factors were the general movement speed, the travelled path lengths, and the simultaneous use of both hands. In the older adults ≥ 67a, factors were the general movement speed, the travelled path length, and the activity level (during the task execution). A principal component analysis supported these findings by revealing two underlying components: movement strategy and age-dependent decline in primarily executive functions, where the ADL trial duration had comparable loadings on both components. These results in association with the accelerated decline in executive functions found in the oldest group suggest that deterioration of ADL with age is particularly caused by specific age-dependent changes in cognitive capacities.

Differential control of task and null space variability in response to changes in task difficulty when learning a bimanual steering task

The presence of motor redundancy means that movement variability can be split into a 'task-space' component that affects task performance, and a 'null space' component which has no effect on task performance. While the control of task-space variability during learning is essential, because it is directly linked to performance, how the nervous system controls null space variability during learning has not been well understood. One factor that has been hypothesized to govern the change in null space variability with learning is task difficulty, but this has not been directly tested. Here, we examined how task difficulty influences the change in null space variability with learning. Healthy, college-aged participants (N = 36) performed a bimanual steering task, where they steered a cursor through a smooth W-shaped track of a certain width as quickly as possible while attempting to keep the cursor within the track. Task difficulty was altered by changing the track width and participants were split into one of the three groups based on the track width that they practiced on-wide, narrow, or progressive (where the width of the track progressively changed from wide to narrow over practice). The redundancy in this task arose from the fact that the position of the cursor was defined as the average position of the two hands. Results showed that movement time depended on task difficulty, but all groups were able to decrease their movement time with practice. Learning was associated with a reduction in null space variability in all groups, but critically, there was no effect of task difficulty. Further analyses showed that while the task-space variability showed an expected speed-accuracy tradeoff with movement time, the null space variability showed a qualitatively different pattern. These results suggest differential control of task and null space variability in response to changes in task difficulty with learning, and may reflect a strong preference to minimize overall movement variability during learning.

The effects of unimanual and bimanual massed practice on upper limb function in adults with cervical spinal cord injury: a systematic review

BACKGROUND

Individuals with cervical spinal cord injury (cSCI) have identified improving upper limb function as their most important rehabilitation goal. Unimanual massed practice (UMP) and bimanual massed practice (BMP) may help achieve this.

OBJECTIVES

To evaluate and compare the effects of UMP and BMP on upper limb function in adults with cSCI.

DATA SOURCES

Cochrane Central Register of Controlled Trials, PubMed, CINAHL, Web of Science and PEDro until April 2016.

STUDY SELECTION

Studies investigating the effects of UMP and/or BMP on upper limb function in adults with cSCI.

DATA EXTRACTION AND SYNTHESIS

Data was extracted using a standardised form. Studies were appraised using a modified version of the Cochrane risk of bias tool. The findings were qualitatively synthesised.

RESULTS

Five randomised controlled trials and 2 case studies were included. Six studies included UMP, three included BMP, and two compared these approaches. Overall the studies reported that UMP and BMP improved upper limb function, particularly when combined with electrical stimulation, with no clear differences between UMP and BMP. These findings should be interpreted with caution however, as 6 studies presented a high or unclear risk of bias for all functional upper limb outcome measures included, and the remaining study was a small pilot study with no control group.

CONCLUSION

Although the findings of the included studies support the use of UMP and BMP in adults with cSCI, only 7 studies, all with significant limitations, were included; hence robust conclusions cannot be drawn and further research is warranted. PROSPERO registration number: CRD42016037365.

Shared right-hemispheric representations of sensorimotor goals in dynamic task environments

Functional behaviour affords that we form goals to integrate sensory information about the world around us with suitable motor actions, such as when we plan to grab an object with a hand. However, much research has tested grasping in static scenarios where goals are pursued with repetitive movements, whereas dynamic contexts require goals to be pursued even when changes in the environment require a change in the actions to attain them. To study grasp goals in dynamic environments here, we employed a task where the goal remained the same but the execution of the movement changed; we primed participants to grasp objects either with their right or left hand, and occasionally they had to switch to grasping with both. Switch costs should be minimal if grasp goal representations were used continuously, for example, within the left dominant hemisphere. But remapped or re-computed goal representations should delay movements. We found that switching from right-hand grasping to bimanual grasping delayed reaction times but switching from left-hand grasping to bimanual grasping did not. Further, control experiments showed that the lateralized switch costs were not caused by asymmetric inhibition between hemispheres or switches between usual and unusual tasks. Our results show that the left hemisphere does not serve a general role of sensorimotor grasp goal representation. Instead, sensorimotor grasp goals appear to be represented at intermediate levels of abstraction, downstream from cognitive task representations, yet upstream from the control of the grasping effectors.

Solo versus joint bimanual coordination

Understanding the differences between solo and joint action control is an important goal in psychology. The present study represented a novel approach in which participants performed a bimanual finger oscillation task, either alone or in pairs. It was hypothesized that performance of this task relies heavily on attention and utilizes two independent processes that differentially affect solo and joint performance. One process attempts to align the fingers correctly regardless of oscillation speed, and this is reflected in an alignment error evident even at slow oscillations. A second process attempts to minimize the time lag between the fingers as the oscillation speed increases, reflected in a temporal error indexed by the rate of error increase with increasing movement speed. In three experiments, alignment and temporal error in the finger oscillation task were compared in solo and joint actors. Overall, solo actors had much lower alignment error than joint actors. Solo actors also showed a reduction in temporal error when the fingers moved in a symmetrical rather than parallel fashion, consistent with previous research showing an increase in error with increasing movement speed. However, the effect of symmetry on temporal error did not occur with joint actors. Similar results were found with one hand inverted, suggesting that the pattern of results was not due to the use of homologous muscles. To test the role of visual feedback, we examined the effect of denying visual feedback to one of the actors in the joint condition. Paradoxically, under these conditions, there was lower temporal error in the symmetrical condition. These results are interpreted in terms of the organization of solo versus joint actions and the control of bimanual tasks in general.

The Effect of Bimanual Training with or Without Constraint on Hand Functions in Children with Unilateral Cerebral Palsy: A Non-Randomized Clinical Trial

AIM

To compare the effect of bimanual training with or without constraint on manual functions in children with unilateral cerebral palsy (UCP).

METHODS

Seventeen children aged 6-11 years with UCP participated in one of two intensive therapeutic camps: bimanual (n = 9) incorporating one hour of constraint ("Hybrid") or Bimanual (n = 8). Each camp met for 2 weeks, 5 days per week for 6 hours each day. The Assisting Hand Assessment (AHA) and the Jebsen Taylor Test of Hand Function (JTTHF) examined bimanual and unimanual functions pre, post- and 3-months post-intervention.

RESULTS

A significant improvement was noted in AHA scores for both groups between the pre-, post- and three months post-intervention [Hybrid (F2; 16 = 85.5, p < 0.01); Bimanual (F2; 16 = 15.4, p < 0.01)] with no significant differences between groups over time (F2; 30 = 0.74, p = 0.48). For the JTTHF, a significant improvement was noted in the affected hand following the Hybrid program (F2; 30 = 7.45, p = 0.01), while following the Bimanual program a significant difference was noted only in the less-affected hand (F2; 16 = 6.02, p < 0.01].

CONCLUSION

Both interventions Hybrid and Bimanual were similarly effective for improving use of the affected hand in bimanual tasks. The unique contribution of each intervention, the Hybrid program on the affected and the Bimanual on the less-affected side, warrants further examination.

Towards assessing corticospinal excitability bilaterally: Validation of a double-coil TMS method

BACKGROUND

For several decades, Transcranial magnetic stimulation (TMS) has been used to monitor corticospinal excitability (CSE) changes in various contexts. Habitually, single-coil TMS is applied over one primary motor cortex (M1), eliciting motor-evoked potentials (MEPs) in a contralateral limb muscle, usually a hand effector. However, in many situations, it would be useful to obtain MEPs in both hands simultaneously, to track CSE bilaterally. Such an approach requires stimulating both M1 concurrently while avoiding interference between the two descending stimuli.

NEW METHOD

We examined MEPs obtained at rest using a double-coil TMS approach where the two M1 are stimulated with a 1ms inter-pulse interval (double-coil_1ms). MEPs were acquired using double-coil_1ms (MEP_double) or single-coil (MEP_single) TMS, at five different intensities of stimulation (100, 115, 130, 145 or 160% of the resting motor threshold, rMT). Given the 1ms inter-pulse interval in double-coil_1ms trials, MEP_double were either evoked by a 1st (MEP_double-1) or a 2nd (MEP_double-2) TMS pulse.

RESULTS

All MEP_TYPE (MEP_TYPE=MEP_single, MEP_double-1 and MEP_double-2) were equivalent, regardless of the hand within which they were elicited, the intensity of stimulation or the pulse order.

COMPARISON WITH EXISTING METHOD

This method allows one to observe state-related CSE changes for the two hands simultaneously on a trial-by-trial basis.

CONCLUSION

These results infer the absence of any neural interactions between the two cortico-spinal volleys with double-coil_1ms TMS. Hence, this technique can be reliably used to assess CSE bilaterally, opening new research perspectives for scientists interested in physiological markers of activity in the motor output system.

Impaired Voluntary Movement Control and Its Rehabilitation in Cerebral Palsy

Cerebral palsy is caused by early damage to the developing brain, as the most common pediatric neurological disorder. Hemiplegia (unilateral spastic cerebral palsy) is the most common subtype, and the resulting impairments, lateralized to one body side, especially affect the upper extremity, limiting daily function. This chapter first describes the pathophysiology and mechanisms underlying impaired upper extremity control of cerebral palsy. It will be shown that the severity of impaired hand function closely relates to the integrity of the corticospinal tract innervating the affected hand. It will also shown that the developing corticospinal tract can reorganize its connectivity depending on the timing and location of CNS injury, which also has implications for the severity of hand impairments and rehabilitation. The mechanisms underlying impaired motor function will be highlighted, including deficits in movement execution and planning and sensorimotor integration. It will be shown that despite having unimanual hand impairments, bimanual movement control deficits and mirror movements also impact function. Evidence for motor learning-based therapies including Constraint-Induced Movement Therapy and Bimanual Training, and the possible pathophysiological predictors of treatment outcome and plasticity will be described. Finally, future directions for rehabilitations will be presented.

The influence of a constraint and bimanual training program using a variety of modalities on endurance and on the cardiac autonomic regulation system of children with unilateral cerebral palsy: A self-control clinical trial

BACKGROUND

An intensive hybrid program, combining constraint with bimanual training, improves upper extremity function as well as walking endurance of children with unilateral cerebral palsy (UCP). Endurance improvement may be associated with the cardiac autonomic regulation system (CARS) adaptation, known to be impaired among these children.

OBJECTIVE

To examine the influence of an intensive hybrid program on CARS, walking endurance and the correlation with upper extremity function of children with UCP.

METHODS

Twenty-four children aged 6-10 years with UCP participated in a hybrid program, 10 days, 6 hours per day. Data were collected pre-, post- and 3-months post-intervention. Main outcome measures included the Polar RS800CX for heart rate (HR) and heart rate variability (HRV) data, the 6-Minute Walk Test (6MWT) for endurance, and the Assisting Hand Assessment (AHA) and Jebsen-Taylor Test of Hand Function (JTTHF) for bimanual and unimanual function.

RESULTS

A significant reduction in HR and an increase in HRV at post- and 3-month post-intervention was noted (χ22= 8.3, p = 0.016) along with a significant increase in 6MWT with a median increase of 81 meters (χ22= 11.0, p = 0.004) at the same interval. A significant improvement was noted in unimanual and bimanual performance following the intervention.

CONCLUSIONS

An intensive hybrid program effectively improved CARS function as well as walking endurance and upper extremity function in children with UCP (213).

Both hands at work: the effect of aging on upper-limb kinematics in a multi-step activity of daily living

The kinematic performance of basic motor tasks shows a clear decrease with advancing age. This study examined if the rules known from such tasks can be generalized to activities of daily living. We examined the end-effector kinematics of 13 young and 13 elderly participants in the multi-step activity of daily living of tea-making. Furthermore, we analyzed bimanual behavior and hand dominance in the task using different conditions of execution. The elderly sample took substantially longer to complete the activity (almost 50%) with longer trajectories compared with the young sample. Models of multiple linear regression revealed that the longer trajectories prolonged the trial duration in both groups, and while movement speed influenced the trial duration of young participants, phases of inactivity negatively affected how long the activity took the elderly subjects. No differences were found regarding bimanual performance or hand dominance. We assume that in self-paced activities of daily living, the age-dependent differences in the kinematics are more likely to be based on the higher cognitive demands of the task rather than on pure motor capability. Furthermore, it seems that not all of the rules known from basic motor tasks can be generalized to activities of daily living.

Control of Cycling Limb Movements: Aspects for Rehabilitation

Walking, swimming, cycling, and running are cyclic movements that are often performed in training programs or rehabilitation protocols by athletes or people with neuromotor disorders. The muscular and kinematic activities that are acquired during cyclic movements reveal control principles, especially for the optimization and stabilization of motor performance, for a given criterion in rehabilitation processes. The influence of external loads and resistive forces on limb movements should be considered in rehabilitation protocols and when assessing physical activity levels or defining activity patterns for the artificial control of limb movements. This chapter focuses on special cyclic limb movements: lower and upper limb cycling. Two aspects of this research and applications are discussed. First, variances of movement patterns are examined at different levels of the motor system (endpoint, joint configuration, muscle) during unimanual right and left arm cycling and bimanual cycling movements. Second, it is shown that the muscle activity patterns that are acquired during lower and upper limb cycling in able-bodied people may be used to define and improve stimulation patterns for functional electrical stimulation-driven cycling movements in spinal cord-injured individuals. This report also discusses the advantages of the application and control of these types of movements for the rehabilitation of people with paralyzed limbs.

The Influence of a Constraint and Bimanual Training Program Using a Variety of Modalities, on Upper Extremity Functions and Gait Parameters Among Children with Hemiparetic Cerebral Palsy: A Case Series

AIM

To assess the influence of an intensive combined constraint and bimanual upper extremity (UE) training program using a variety of modalities including the fitness room and pool, on UE functions as well as the effects of the program on gait parameters among children with hemiparetic cerebral palsy.

METHODS

Ten children ages 6-10 years participated in the program for 2 weeks, 5 days per week for 6 hr each day. Data from the Assisting Hand Assessment (AHA) for bimanual function , the Jebsen-Taylor Test of Hand Function (JTTHF) for unimanual function, the six-minute walk test (6MWT), and the temporal-spatial aspects of gait using the GAITRite walkway were collected prior to, immediately post and 3-months post-intervention.

RESULTS

A significant improvement was noted in both unimanual as well as bimanual UE performance; A significant improvement in the 6MWT was noted, from a median of 442 meter [range: 294-558] at baseline to 466 [432-592] post intervention and 528 [425-609] after 3 months (p = .03).

CONCLUSION

Combining intensive practice in a variety of modalities, although targeting to the UE is associated with substantial improvement both in the upper as well as in the lower extremity function.

Mirror movements in unilateral spastic cerebral palsy: Specific negative impact on bimanual activities of daily living

AIM

Mirror movements are involuntary movements of the other hand during voluntary unimanual movements. Some, but not all children with unilateral spastic cerebral palsy (USCP) show this phenomenon. In this observational study, we investigated whether these mirror movements have a specific negative impact on bimanual activities of daily living.

METHODS

Eighteen children (six girls; age range, 6-16 years; mean age, 12 years 1 month; SD, 3 years 3 month) with USCP, nine with and nine without mirror movements, underwent the Jebsen Taylor Hand Function Test (unimanual capacity) and the Assisting Hand Assessment (bimanual performance). In addition, we measured the time the participants needed for the completion of five activities we had identified as particularly difficult for children with mirror movements.

RESULTS

Multivariate analysis demonstrated that mirror movements indeed have a specific negative impact on bimanual performance (Assisting Hand Assessment) and on the time needed for the completion of these five particularly difficult activities. This effect was independent from unimanual capacity.

CONCLUSION

Functional therapies in children with USCP and mirror movements should address this phenomenon.

Effects of botulinum toxin A and/or bimanual task-oriented therapy on upper extremity impairments in unilateral Cerebral Palsy: an explorative study

OBJECTIVE

This study reports on the effects of botulinum toxin A (BoNT-A) injections in the upper extremity (UE) of children with unilateral Cerebral Palsy (uCP) combined with bimanual task oriented therapy (BITT) or either treatment modality performed separately on UE range of motion (ROM), spasticity and (functional) strength.

METHODS

Thirty-five children, mean age 7.14 years (SD 2.63) of whom 11 had a Manual Ability Classification Score (MACS) I, 15 MACS II and 9 MACS III, participated. The trial started with four study groups: BoNT-A-only (n = 5), BITT-only (n = 11), BoNT-A + BITT (n = 13), and control (n = 6). Twenty-two children were randomized and, due to recruitment problems 13 children received their parents' preferred treatment: BoNT-A + BITT or BITT-only. Three comparisons were analysed: BITT (BoNT-A + BITT and BITT-only; n = 24) versus no BITT (BoNT-A-only and control; n = 11), BoNT-A (BoNT-A-only and BoNT-A + BITT; n = 18) versus no BoNT-A (BITT-only and control; n = 17), and the additional effect of BoNT-A (BoNT-A + BITT versus BITT-only).

RESULTS

BoNT-A significantly decreased key grip strength and finger flexion tone, had a clinically relevant (additional) positive effect on active thumb abduction and supination and a significantly negative effect on unilateral functional strength. BITT + BoNT-A significantly increased active supination. BITT reduced elbow flexor tone and BITT-only resulted in more improvement than BoNT-A + BITT in functional unimanual and, to a lesser extent, in bimanual grip strength.

CONCLUSIONS

In comparison with BoNT-A + BITT, BITT-only gives more improvement on functional grip strength and, therefore, could possibly increase bimanual performance. In this case, the (additional) role of BoNT-A may be an increase in active supination and thumb abduction.

Inter-limb coupling during diadochokinesis in Parkinson's and Huntington's disease

Patients with neurodegenerative diseases often exhibit deficits in bimanual coordination. One characteristic of bimanual movements is inter-limb coupling. It is the property of motor performance harmonization between hands during a bimanual task. The objective of this study was to identify whether spatial and temporal inter-limb coupling occurred in Parkinson's disease (PD) and Huntington's disease (HD) patients. Twenty-three PD patients and 15 healthy controls were tested. Data from 12 choreic HD patients were also taken from a databank. Participants were asked to perform a unimanual and bimanual rapid repetitive diadochokinesis task. The difference between hands in mean amplitude and mean duration of cycles was computed in the unimanual and bimanual tasks for each group. Results show that healthy controls exhibited temporal and spatial inter-limb coupling during the bimanual diadochokinesis task. Conversely, PD and HD patients exhibited temporal inter-limb coupling; but failed to exhibit spatial inter-limb coupling during the bimanual diadochokinesis task. Furthermore, HD patients exhibited reduced levels of structural coupling compared to controls and PD patients. These results suggest that alterations in basal ganglia-thalamo-cortical networks due to PD and HD do not affect temporal inter-limb coupling. However, common pathophysiological changes related to PD and HD may cause altered spatial inter-limb coupling during a rapid repetitive bimanual diadochokinesis task.

Consistently modeling the same movement strategy is more important than model skill level in observational learning contexts

The experiment undertaken was designed to elucidate the impact of model skill level on observational learning processes. The task was bimanual circle tracing with a 90° relative phase lead of one hand over the other hand. Observer groups watched videos of either an instruction model, a discovery model, or a skilled model. The instruction and skilled model always performed the task with the same movement strategy, the right-arm traced clockwise and the left-arm counterclockwise around circle templates with the right-arm leading. The discovery model used several movement strategies (tracing-direction/hand-lead) during practice. Observation of the instruction and skilled model provided a significant benefit compared to the discovery model when performing the 90° relative phase pattern in a post-observation test. The observers of the discovery model had significant room for improvement and benefited from post-observation practice of the 90° pattern. The benefit of a model is found in the consistency with which that model uses the same movement strategy, and not within the skill level of the model. It is the consistency in strategy modeled that allows observers to develop an abstract perceptual representation of the task that can be implemented into a coordinated action. Theoretically, the results show that movement strategy information (relative motion direction, hand lead) and relative phase information can be detected through visual perception processes and be successfully mapped to outgoing motor commands within an observational learning context.

Practicing a matching movement with a mirror in individuals with spastic hemiplegia

This experimental study aimed to determine the effect of practicing a position matching task with (mirror) visual feedback of the less-impaired arm on the matching accuracy of the impaired arm in children and adolescents with spastic hemiparetic cerebral palsy. Practice consisted of 40 trials of bimanual target matching, where one group received regular visual feedback and a second group received mirror visual feedback of the less-impaired arm. On three occasions (pre, post, and after a 1-week-retention) position sense (matching accuracy measured as the endpoint error in cm) of the impaired arm was tested with a unimanual and bimanual matching task, performed without any visual information of either hand. Matching accuracy of the impaired arm was better in the post-test than in the pre-test, but this improvement was similar for both practice groups. In the retention-test, accuracy had returned to pre-test-level, which might be ascribed to the short duration of the practice period. These outcomes suggest that practicing a matching task with visual feedback of the less-impaired arm might help to improve the matching accuracy of the impaired arm in individuals with spastic hemiparetic cerebral palsy.