Bilateral Hand Movements Research Articles

Method of Electrical Muscle Stimulation to Improve Hand-eye Coordination Training in Gaming

Hand-eye coordination refers to the harmonization between visual information and hand movements. In this coordination, the information perceived by the eyes is used to guide the movements of the hands. In many games, hand-eye coordination is important for the player's experience. However, when players are faced with an unfamiliar activity, it can be a challenge to develop hand-eye coordination in a short period. This study proposes a method for hand-eye coordination training in gaming using Electrical Muscle Stimulation (EMS). By employing EMS, it is possible to enhance attention distribution during bilateral hand movements and improve hand-eye coordination, potentially enabling individuals to train hand coordination skills in a shorter period. To test the feasibility and effectiveness of our method, we first tested participants for attentional switching while wearing the EMS device to ensure that it did not negatively affect participants. Sixteen participants were then trained in hand-eye coordination with and without EMS, and the effects of the training were tested in a customized game and a real music game. The results showed that participants trained with EMS showed more significant improvements in scores and accuracy than those without EMS in both the custom game and the real game. We also conducted a retained effect experiment, which confirmed that participants retained the training effect one week after training. Thus, our study shows the possibility of using EMS as a new medium for training hand-eye coordination in games.

Neurophysiological Oscillatory Mechanisms Underlying the Effect of Mirror Visual Feedback-Induced Illusion of Hand Movements on Nociception and Cortical Activation.

Mirror Visual Feedback (MVF)-induced illusion of hand movements produces beneficial effects in patients with chronic pain. However, neurophysiological mechanisms underlying these effects are poorly known. In this preliminary study, we test the novel hypothesis that such an MVF-induced movement illusion may exert its effects by changing the activity in midline cortical areas associated with pain processing. Electrical stimuli with individually fixed intensity were applied to the left hand of healthy adults to produce painful and non-painful sensations during unilateral right-hand movements with such an MVF illusion and right and bilateral hand movements without MVF. During these events, electroencephalographic (EEG) activity was recorded from 64 scalp electrodes. Event-related desynchronization (ERD) of EEG alpha rhythms (8-12 Hz) indexed the neurophysiological oscillatory mechanisms inducing cortical activation. Compared to the painful sensations, the non-painful sensations were specifically characterized by (1) lower alpha ERD estimated in the cortical midline, angular gyrus, and lateral parietal regions during the experimental condition with MVF and (2) higher alpha ERD estimated in the lateral prefrontal and parietal regions during the control conditions without MVF. These preliminary results suggest that the MVF-induced movement illusion may affect nociception and neurophysiological oscillatory mechanisms, reducing the activation in cortical limbic and default mode regions.

Neural coordination of bilateral hand movements: evidence for an involvement of brainstem motor centres.

Bilateral hand movements are assumed to be coordinated by a neural coupling mechanism. Neural coupling is experimentally reflected in complex electromyographic (EMG) responses in the forearm muscles of both sides to unilateral electrical arm nerve stimulation (ES). The aim of this study was to examine a potential involvement of the reticulospinal system in neural coupling by the application of loud acoustic stimuli (LAS) known to activate neurons of this system. LAS, ES and combined LAS/ES were applied to healthy subjects during visually guided bilateral hand flexion-extension movements. Muscle responses to the different stimuli were evaluated by electrophysiological recordings. Unilateral electrical ulnar nerve stimulation resulted in neural coupling responses in the forearm extensors (FE) of both sides. Interestingly, LAS evoked bilateral EMG responses that were similar in their configuration to those induced by ES. The presence of startles was associated with a shift of the onset and enhanced amplitude of LAS-induced coupling-like responses. Upon combined LAS/ES application, ES facilitated ipsilateral startles and coupling-like responses. Modulation of coupling-like responses by startles, the similarity of the responses to ES and LAS, and their interaction following combined stimulation suggests that both responses are mediated by the reticulospinal system. Our findings provide novel indirect evidence that the reticulospinal system is involved in the neural coupling of hand movements. This becomes clinically relevant in subjects with a damaged corticospinal system where a dominant reticulospinal system leads to involuntary limb coupling, referred to as associated movements. KEY POINTS: Automatic coordination of hand movements is assumed to be mediated by a neural coupling mechanism reflected by bilateral reflex responses in forearm muscles to unilateral electrical arm nerve stimulation (ES). Loud acoustic stimuli (LAS) were applied to assess a potential involvement of the reticulospinal system in the neural coupling mechanism. LAS evoked a bilateral reflex response in the forearm extensors that was similar to the neural coupling response to ES, and which could be separated from the acoustic startle response. Combined application of LAS and ES resulted in a facilitation of startle and coupling-like responses ipsilateral to ES, thus indicating an interaction of afferences from both stimuli. These novel findings provide indirect evidence that the reticulospinal system is a key motor structure for the coupling of bilateral hand movements.

Differential contribution of sensorimotor cortex and subthalamic nucleus to unimanual and bimanual hand movements.

Why does unilateral deep brain stimulation improve motor function bilaterally? To address this clinical observation, we collected parallel neural recordings from sensorimotor cortex (SMC) and the subthalamic nucleus (STN) during repetitive ipsilateral, contralateral, and bilateral hand movements in patients with Parkinson's disease. We used a cross-validated electrode-wise encoding model to map electromyography data to the neural signals. Electrodes in the STN encoded movement at a comparable level for both hands, whereas SMC electrodes displayed a strong contralateral bias. To examine representational overlap across the two hands, we trained the model with data from one condition (contralateral hand) and used the trained weights to predict neural activity for movements produced with the other hand (ipsilateral hand). Overall, between-hand generalization was poor, and this limitation was evident in both regions. A similar method was used to probe representational overlap across different task contexts (unimanual vs. bimanual). Task context was more important for the STN compared to the SMC indicating that neural activity in the STN showed greater divergence between the unimanual and bimanual conditions. These results indicate that SMC activity is strongly lateralized and relatively context-free, whereas the STN integrates contextual information with the ongoing behavior.

Abstract 25 — Remitting Seronegative Symmetric Synovitis with Pitting Edema (RS3PE) in Dialysis Patient

Background Remitting seronegative symmetrical synovitis with pitting edema (RS3PE) syndrome is characterized by acute symmetrical synovitis, and pitting edema involving, the dorsal part of hands and feet. It affects more men aged more than 50 years. The inflammatory markers are usually elevated, with negative rheumatoid factor. The underlying etiology is not clear but has been associated with drugs exposure, infections, malignancy in 30% of cases, and coexist with other autoimmune diseases. The clinical course is benign with significant improvement to low-dose prednisolone therapy for 2 to 3 months. It has been rarely reported in dialysis patients. Methods and case description A 54 years old male, known to have long standing uncontrolled diabetes mellitus, hypertension, chronic kidney disease and diabetic retinopathy. Recently, he was treated for left foot cellulitis and advanced renal failure (813 micromol/L) initiated on hemodialysis. He presented one week later with progressive painful bilateral upper limb and lower limb pitting edema, with limited range of movement in hands and reduce urine output. He was resumed on hemodialysis for management of volume overload. Despite removal of almost 12 liters of fluids during consecutive dialysis sessions and improvement of lower limb edema, his bilateral hand edema was persistence with pain and limited movement. Further investigations were done to evaluate for rheumatological condition. Results Hand X ray was normal and ultrasound of the hand revealed features of synovitis, diffuse subcutaneous oedema and possible cellulitis. He was started on IV antibiotics without major improvement and blood culture was negative. CT chest showed left pleural effusion. The ESR was elevated 120, while serology for HBV. HCV, HIV, and parvovirus were negative. In addition, the autoimmune workup were negative (CCP, RF, ANA, ANCA, C3, C4, ACEI). He was diagnosed with remitting seronegative symmetric synovitis with pitting edema (RS3PE). He was treated with IV hydrocortisone once 100 mg, followed by oral prednisolone 10 mg for 5 days with dramatic improvement in bilateral hand edema and movement. He had hyperglycemia steroid related managed with adjustment of insulin therapy. At follow up in 1 week, patient regain full function of both hands, and he was on regular hemodialysis trice per week. Conclusion RS3PE is rare in hemodialysis patients, with favorable response to steroid therapy. We used shorter duration of 5 days steroid therapy with complete recovery and no recurrence at 1 year follow up. Screening for underlying autoimmune, infection or malignancy in RS3PE is essential.

Effect of Visual Feedback on Behavioral Control and Functional Activity During Bilateral Hand Movement.

Previous researches state vision as a vital source of information for movement control and more precisely for accurate hand movement. Further, fine bimanual motor activity may be associated with various oscillatory activities within distinct brain areas and inter-hemispheric interactions. However, neural coordination among the distinct brain areas responsible to enhance motor accuracy is still not adequate. In the current study, we investigated task-dependent modulation by simultaneously measuring high time resolution electroencephalogram (EEG), electromyogram (EMG) and force along with bi-manual and unimanual motor tasks. The errors were controlled using visual feedback. To complete the unimanual tasks, the participant was asked to grip the strain gauge using the index finger and thumb of the right hand thereby exerting force on the connected visual feedback system. Whereas the bi-manual task involved finger abduction of the left index finger in two contractions along with visual feedback system and at the same time the right hand gripped using definite force on two conditions that whether visual feedback existed or not for the right hand. Primarily, the existence of visual feedback for the right hand significantly decreased brain network global and local efficiency in theta and alpha bands when compared with the elimination of visual feedback using twenty participants. Brain network activity in theta and alpha bands coordinates to facilitate fine hand movement. The findings may provide new neurological insight on virtual reality auxiliary equipment and participants with neurological disorders that cause movement errors requiring accurate motor training. The current study investigates task-dependent modulation by simultaneously measuring high time resolution electroencephalogram, electromyogram and force along with bi-manual and unimanual motor tasks. The findings show that visual feedback for right hand decreases the force root mean square error of right hand. Visual feedback for right hand decreases local and global efficiency of brain network in theta and alpha bands.

Alpha and beta neural oscillations differentially reflect age-related differences in bilateral coordination

Bilateral in-phase (IP) and anti-phase (AP) movements represent two fundamental modes of bilateral coordination that are essential for daily living. Although previous studies have shown that aging is behaviorally associated with decline in bilateral coordination, especially in AP movements, the underlying neural mechanisms remain unclear. Here, we use kinematic measurements and electroencephalography to compare motor performance of young and older adults executing bilateral IP and AP hand movements. On the behavioral level, inter-limb synchronization was reduced during AP movements compared to IP and this reduction was stronger in the older adults. On the neural level, we found interactions between group and condition for task-related power change in different frequency bands. The interaction was driven by smaller alpha power decreases over the non-dominant cortical motor area in young adults during IP movements and larger beta power decreases over the midline region in older adults during AP movements. In addition, the decrease in inter-limb synchronization during AP movements was predicted by stronger directional connectivity in the beta-band: an effect more pronounced in older adults. Our results therefore show that age-related differences in the two bilateral coordination modes are reflected on the neural level by differences in alpha and beta oscillatory power as well as interhemispheric directional connectivity.

Bimanual motor performance in everyday life activities of children with hemiplegic cerebral palsy.

Motor impairments in children with cerebral palsy significantly reduce their ability to learn and adapt bimanual actions into their life roles. The current evidence on bimanual coordination performance in children with hemiplegic cerebral palsy were mostly drawn from kinematic studies. Whether these kinematic findings on bimanual motor performance can be observed when performing daily life activities in a natural environment is not clear. Further, there is no evidence what and how the verbal prompting influences bilateral motor performance. We intend to explore its role on bimanual motor performance as well. This study aimed to investigate the bimanual motor performance in everyday life activities of children with hemiplegic cerebral palsy and the role of verbal prompts in facilitating affected hand use. This is an observational study. Local medical center and community. Twenty-five children with hemiplegic cerebral palsy and 25 age-matched typically developing children. The Observation-based Test of Capacity, Performance, and Developmental Disregard and Melbourne Assessment 2 were used to assess the quantitative and qualitative use of hands in everyday activities. Children with hemiplegic cerebral palsy, demonstrated different motor coordination patterns in daily bimanual activities compared with their counterparts. With verbal prompts, children with hemiplegic cerebral palsy significantly increased the use of their affected hands in bimanual activities. However, the increases were observed only in basic motor components, such as reaching and grasping, and not in complex motor components such as manipulation. These findings will assist researchers and clinicians to develop and refine intervention programs that maximize rehabilitation benefits in improving bimanual hand coordination performance for children with hemiplegic cerebral palsy. This study increased our understanding of bimanual motor performance of children with hemiplegic cerebral palsy in everyday life activities. The results demonstrated children with cerebral palsy rely more on their less-affected hand to perform bimanual activities with or without verbal prompts. Incorporating bimanual activities and verbal prompts during intervention may only be effective on facilitating basic hand movements but not on improving complex movements of affected hands. Further research is needed to explore other intervention strategies to facilitate complex bilateral hand movements.

Dissociating the causal role of left and right dorsal premotor cortices in planning and executing bimanual movements – A neuro-navigated rTMS study

BackgroundThe dorsal premotor cortex (PMd) is a key region in bimanual coordination. However, causal evidence linking PMd functionality during motor planning and execution to movement quality is lacking. ObjectiveWe investigated how left (PMdL) and right PMd (PMdR) are causally involved in planning and executing bimanual movements, using short-train repetitive transcranial magnetic stimulation (rTMS). Additionally, we explored to what extent the observed rTMS-induced modulation of performance could be explained by rTMS-induced modulation of PMd-M1 interhemispheric interactions (IHI). MethodsTwenty healthy adults (mean age ± SD = 22.85 ± 3.73 years) participated in two sessions, in which either PMdL or PMdR was targeted with rTMS (10 Hz) in a pseudo-randomized design. PMd functionality was transiently modulated during the planning or execution of a complex bimanual task, whereby the participant was asked to track a moving dot by controlling two dials. The effect of rTMS on several performance measures was investigated. Concurrently, rTMS-induced modulation of PMd-M1 IHI was measured using a dual-coil paradigm, and associated with the rTMS-induced performance modulation. ResultsrTMS over PMdL during planning increased bilateral hand movement speed (p = 0.03), thereby improving movement accuracy (p = 0.02). In contrast, rTMS over PMdR during both planning and execution induced deterioration of movement stability (p = 0.04). rTMS-induced modulation of PMd-M1 IHI during planning did not predict rTMS-induced performance modulation. ConclusionThe current findings support the growing evidence on PMdL dominance during motor planning, as PMdL was crucially involved in planning the speed of each hand, subserving bimanual coordination accuracy. Moreover, the current results suggest that PMdR fulfills a role in continuous adjustment processes of movement.

Attention-dependent switching between intrinsic-muscle and extrinsic-visual coordinates during bimanual movements.

Inter-limb coordination is achieved through multiple levels of motor control based on intrinsic-muscle and extrinsic-visual coordinates. Online visual feedback affects which of these coordinates is dominant, and visual perception is involved in the switching of motor coordination across the two hands; however, it remains unclear whether there is any role for attention in inter-limb coordination. Therefore, we evaluated the effects of attention on the dominance of intrinsic-muscle and extrinsic-visual coordinates by investigating inter-limb interference in the right or left hand during bimanual reaching movements, as induced by visual perturbations. We first showed an effect of differences in online visual feedback on bimanual coordination (Experiment 1). We then revealed that attention to visual cursors that directly affected the hand movement led to the dominance of the intrinsic-muscle coordinates, which synchronized homologous muscle activities. In contrast, attention to an integrated visual object controlled by bilateral hand movements was associated with a preference for extrinsic-visual coordinates to synchronize bilateral movement directions (Experiment 2). Thus, attention-dependent switching between intrinsic-muscle and extrinsic-visual coordinates was observed during bimanual movements; extrinsic-visual coordinates may enable goal-directed bimanual movements at least for particular task requirements.

Cortical neural activity evoked by bilateral and unilateral mirror therapy after stroke

ObjectiveThis study aimed to investigate the differential effects of bilateral and unilateral mirror therapy (MT) on motor cortical activations in stroke patients by magnetoencephalography (MEG). MethodsSixteen stroke patients and 16 right-handed healthy volunteers were recruited. All participants were required to perform 4 conditions: resting, no mirror with bilateral hand movements (Bilateral-No mirror), mirror with bilateral hand movements (Bilateral-Mirror) and mirror with unilateral hand movements (Unilateral-Mirror). Beta oscillatory activities in the primary motor cortex (M1) were collected during each condition using MEG. The percentage change of beta oscillatory activity was calculated for each condition to correct the baseline differences. ResultsIn the stroke group, the percentage change of M1 beta oscillatory activity significantly decreased more in the Bilateral-Mirror condition than in the Bilateral-No mirror and Unilateral-Mirror conditions. In the healthy group, no significant differences in the percentage change of beta oscillatory activity were found among the 3 conditions. Further, a significant difference in the percentage change of beta oscillatory activity only in the Bilateral-Mirror condition was found between the 2 groups. ConclusionsThis study provides new information on the differential cortical activations modulated by bilateral and unilateral MT. SignificanceBilateral MT led to greater M1 neural activities than unilateral MT and bilateral movements without a mirror in stroke patients.

The Motor Cortex Has Independent Representations for Ipsilateral and Contralateral Arm Movements But Correlated Representations for Grasping

Motor commands for the arm and hand generally arise from the contralateral motor cortex, where most of the relevant corticospinal tract originates. However, the ipsilateral motor cortex shows activity related to arm movement despite the lack of direct connections. The extent to which the activity related to ipsilateral movement is independent from that related to contralateral movement is unclear based on conflicting conclusions in prior work. Here we investigate bilateral arm and hand movement tasks completed by two human subjects with intracortical microelectrode arrays implanted in the left hand and arm area of the motor cortex. Neural activity was recorded while they attempted to perform arm and hand movements in a virtual environment. This enabled us to quantify the strength and independence of motor cortical activity related to continuous movements of each arm. We also investigated the subjects' ability to control both arms through a brain-computer interface. Through a number of experiments, we found that ipsilateral arm movement was represented independently of, but more weakly than, contralateral arm movement. However, the representation of grasping was correlated between the two hands. This difference between hand and arm representation was unexpected and poses new questions about the different ways the motor cortex controls the hands and arms.

Differential neural coordination of bilateral hand and finger movements.

Cooperative hand movements (e.g., opening a bottle) require a close coordination of the hands. This is reflected in a neural coupling between the two sides. The aim of this study was to investigate in how far neural coupling is present not only during bilateral hand but also during bilateral finger movements. For this purpose unilateral mechanical and electrical nerve stimuli were delivered during bilateral sequentially and synchronously performed finger movements on a keyboard and, for comparison, during bilateral hand flexion movements. Electromyographic (EMG) activity and reflex responses in forearm flexor and extensor muscles of both sides were recorded and analyzed. Confounding EMG activity related to hand movements during the finger task was limited by wrist fixating braces. During the hand flexion task, complex reflex responses appeared in the forearm muscles of both sides to unilateral stimulation of the ulnar nerve (mean latency 57 ms), reflecting neural coupling between the two hands. In contrast, during the bilateral finger movement task, unilateral electrical nerve or mechanical stimulation of the right index finger was followed by dominant ipsilateral reflex responses (latency 45 and 58 ms, respectively). The results indicate that in contrast to the coupled hand movements, finger movements may not be coupled but can move independently on each side. Functionally this makes sense because during most activities of daily living, a close cooperation of the hands but not of individual fingers is needed. This independence of individual finger movements may rely on strong, specific, contralateral cortico‐motoneuronal control.

Coordination of bilateral synchronous and asynchronous hand movements

This study deals with the coordination of bilateral synchronous and asynchronous hand movements. Cooperative hand movements (e.g. opening a bottle) were shown to be coordinated by a neural coupling, reflected in the appearance of reflex responses in forearm muscles of both sides to unilateral arm nerve stimulation. The mechanical effect of this neural coupling was investigated during bilateral synchronous and asynchronous sinusoidal tracking tasks. During the synchronous tracking task, right handed corrective movements were mirrored by the left hand, suggesting a neural coupling. During the asynchronous tracking task, large non-coupled bilateral corrective hand movements dominated. The findings indicate that during synchronous hand movements an automatic coordination of bilateral hand movements occurs. In contrast, asynchronous tasks require independent hand movements. These appear to be visually guided and voluntarily controlled, leading to larger movement errors and corrections.

Neuromagnetic Decoding of Simultaneous Bilateral Hand Movements for Multidimensional Brain-Machine Interfaces.

To provide multidimensional control, we describe the first reported decoding of bilateral hand movements by using single-trial magnetoencephalography signals as a new approach to enhance a user's ability to interact with a complex environment through a multidimensional brain-machine interface. Ten healthy participants performed or imagined four types of bilateral hand movements during neuromagnetic measurements. By applying a support vector machine (SVM) method to classify the four movements regarding the sensor data obtained from the sensorimotor area, we found the mean accuracy of a two-class classification using the amplitudes of neuromagnetic fields to be particularly suitable for real-time applications, with accuracies comparable to those obtained in previous studies involving unilateral movement. The sensor data from over the sensorimotor cortex showed discriminative time-series waveforms and time-frequency maps in the bilateral hemispheres according to the four tasks. Furthermore, we used four-class classification algorithms based on the SVM method to decode all types of bilateral movements. Our results provided further proof that the slow components of neuromagnetic fields carry sufficient neural information to classify even bilateral hand movements and demonstrated the potential utility of decoding bilateral movements for engineering purposes such as multidimensional motor control.

THE PREVALENCE OF CARPAL TUNNEL SYNDROME AMONG FEMALE DAIRY MILKERS

Introduction: Occupation-related Carpal tunnel syndrome represents one of the major health problems among workers in various occupations throughout the world that possess a complex symptoms resulting from compressing the median nerve at the carpal tunnel. Farmers in Egypt are known to use the traditional manual milking of their cattle which needs bilateral repetitive hand movements. Aim of the work: To determine the prevalence and severity of CTS among farmers who performed hand-milking task of cattle and correlate these findings with working years and work duration per hours. Materials and methods: A structured questionnaire was used to determine demographics; work history, present medications and history of any chronic illness. Clinical examination for CTS symptoms as nocturnal exacerbation, Phalen sign, Tinel sign, sensory hyperalgesia, thenar atrophy and thenar weakness. Electrophysiologic studies were done for 240 female farmers, where half of them were milking their cattle manually the other half is used as control. Both groups are matched for age, and Body Mass Index (BMI). Results: The prevalence and clinical severity of CTS were significantly higher among female farmers who milk their cattle than non milkers in both hands (P<0.001), The median nerve motor and sensory conductive study was significantly higher among milkers than non milkers farmers (P value<0.001). The electrophysiological findings were significantly correlated with the longer years of work and longer working hours. Conclusion: These findings suggest that CTS is a significant occupational health issue for farmers that continue the traditional methods of manual milking. Introduction of automated milking machines may help to reduce this problem among the coming generations of the Egyptian farmers who represents a noticeable part of our community

Arthrogryposis multiplex congenita in an adult patient cohort: What are the limitations in activities in daily life?

Arthrogryposis multiplex congenita (AMC) is a clinical diagnosis characterized by the presence of at least two joint contractures at birth. Causes of AMC are numerous involving CNS, neuromuscular system, connective and bone tissue. This study is the first to describe disability patterns of a cohort of adults with AMC. Thirty-nine patients (age 33.8 ± 11.5 years; 23 females) underwent between 2010 and 2016 a 4 day evaluation in the PMR ward during the multidisciplinary consultations for AMC at the Reference Centre of Congenital Anomalies in Grenoble: 25 with amyoplasia, 8 with distal arthrogryposis (DA), and 6 with other atypical diseases. All underwent the following functional assessments: functional independence measure (FIM) scale, functional ambulance classification (FAC) modified, six-minute walk test (SMWT), and a battery of functional tests for the upper limb (reaching, grasping, and pinches). Most patients suffering from AMC had modified independence, with an average FIM= 113.8 ± 12.3 (min = 71, max = 126, median = 117). Nearly all subjects had satisfactory Cognitive-FIM (34.9, min = 33, max = 35), while motor items of the FIM were altered (motor-FIM =78.4, min = 36, max = 91) especially bathing (5.9), upper body dressing (5.7), lower body dressing (5.3), toileting (5.4) and stairs (5.3). Regarding mobility limitation, the mean FAC score was 6.1/8. Only 34 patients could complete SMWT, with a limited mean distance: 338.6 ± 134 m (min = 100 m, max = 700 m). Walking was a major activity limitation for many patients, 28 patients needed to walk slowly on plain ground with surveillance or technical aids, 3 patients couldn’t walk. Regarding the upper limb, they could achieve 11.0 ± 5.5 of 16 tasks testing reaching movements (min = 1, max = 16), and 17.9 ± 6.8 of 22 tasks testing bilateral fine hand and finger movements (min = 0, max = 22). Activity limitations tended to be less severe in patients with DA. Despite obvious disabilities, most persons with AMC can live independently with few technical aids and compensations. Rehabilitation options were proposed accordingly, and patients’ satisfaction for this expert evaluation was high.

Supplementary Motor Complex and Disturbed Motor Control - a Retrospective Clinical and Lesion Analysis of Patients after Anterior Cerebral Artery Stroke.

Both the supplementary motor complex (SMC), consisting of the supplementary motor area (SMA) proper, the pre-SMA, and the supplementary eye field, and the rostral cingulate cortex are supplied by the anterior cerebral artery (ACA) and are involved in higher motor control. The Bereitschaftspotential (BP) originates from the SMC and reflects cognitive preparation processes before volitional movements. ACA strokes may lead to impaired motor control in the absence of limb weakness and evoke an alien hand syndrome (AHS) in its extreme form. To characterize the clinical spectrum of disturbed motor control after ACA strokes, including signs attributable to AHS and to identify the underlying neuroanatomical correlates. A clinical assessment focusing on signs of disturbed motor control including intermanual conflict (i.e., bilateral hand movements directed at opposite purposes), lack of self-initiated movements, exaggerated grasping, motor perseverations, mirror movements, and gait apraxia was performed. Symptoms were grouped into (A) AHS-specific and (B) non-AHS-specific signs of upper limbs, and (C) gait apraxia. Lesion summation mapping was applied to the patients' MRI or CT scans to reveal associated lesion patterns. The BP was recorded in two patients. Ten patients with ACA strokes (nine unilateral, one bilateral; mean age: 74.2 years; median NIH-SS at admission: 13.0) were included in this case series. In the acute stage, all cases had marked difficulties to perform volitional hand movements, while movements in response to external stimuli were preserved. In the chronic stage (median follow-up: 83.5 days) initiation of voluntary movements improved, although all patients showed persistent signs of disturbed motor control. Impaired motor control is predominantly associated with damaged voxels within the SMC and the anterior and medial cingulate cortex, while lesions within the pre-SMA are specifically related to AHS. No BP was detected over the damaged hemisphere. ACA strokes involving the premotor cortices, particularly the pre-SMA, are associated with AHS-specific signs. In the acute phase, motor behavior is characterized by the inability to carry out self-initiated movements. Motor control deficits may persist to a variable degree beyond the acute phase. Alterations of the BP point to an underlying SMC dysfunction in AHS.

Operative skill: quantifying surgeon's response to tissue properties

BackgroundThe aim of this study was to investigate how tissue characteristics influence psychomotor planning and performance during a suturing task. Our hypothesis was that participants would alter their technique based on tissue type with each subsequent stitch placed while suturing. Materials and methodsSurgical attendings (n = 6), residents (n = 4), and medical students (n = 5) performed three interrupted sutures on different simulated materials as follows: foam (dense connective tissue), rubber balloons (artery), and tissue paper (friable tissue). An optical motion tracking system captured performance data from participants' bilateral hand movements. Path length and suture time were segmented by each individual stitch placed to investigate changes to psychomotor performance with subsequent stitch placements. Repeated measures analysis of variance was used to evaluate for main effects of stitch order on path length and suture time and interactions between stitch order, material, and experience. ResultsWhen participants sutured the tissue paper, they changed their procedure time (F(4,44) = 5.14, P = 0.017) and path length (F(4,44) = 4.64, P = 0.003) in a linear fashion with the first stitch on the tissue paper having the longest procedure time and path length. Participants did not change their path lengths and procedure times when placing subsequent stitches in the foam (P = 0.910) and balloon materials (P = 0.769). ConclusionsThis study demonstrates quantifiable real-time adaptation by participants to material characteristics during a suturing task. Participants improved their motion-based performance with each subsequent stitch placement indicating changes in psychomotor planning or performance. This adaptation did not occur with the less difficult tasks. Motion capture technology is a promising method for investigating surgical performance and how surgeons adapt to operative complexity.

Investigating the neural architecture of handedness.

FRONTIERS COMMENTARY article Front. Psychol., 11 February 2015 Volume 6 - 2015 | https://doi.org/10.3389/fpsyg.2015.00148