Intact Arm Research Articles

Examining Item Position Effect on Reliability Coefficients of Multiple Choice Physics Achievement Test

This study explored the effect of changes in item sequence on test reliability coefficients (test-retest and Kuder Richardson 20) and student’s achievement in multiple-choice physics tests in Senior Secondary School II in Taraba State. The study adopted repeated measures two-group within-subject experimental research design. The research collected data in order to answer three research questions and test one hypothesis. The sample comprised 450 senior secondary II Physics students (male = 303 and female = 147 ) drawn from population of Physics students in Taraba State. Multi stage sampling technique was employed to randomly select twelve schools from three Local Government Areas of the three Senatorial Districts of Taraba State, and an intact arm of SS II from each of the sampled schools was used. Two parallel 40-items Physics Achievement Test developed by the researcher were used for data collection. The resulting data were collated and analysed using descriptive statistics and t-test. Results showed that reliability coefficients obtained from the two formats were quite comparable. However, the finding revealed that there is significant difference between the students mean achievement score in the format A and Format B of the physics achievement test (t = 4.409 , df = 898, p < 0.05, two-tailed). Sequels to the findings, it is concluded that changes in item sequence has no effect on the reliability coefficients, but students will perform better in physics achievement test if the test items are arranged randomly than in descending order of difficulty.

Feasibility Evaluation of Online Classification-based Control for Gross Movement in a 2-DoF Prosthetic Arm.

Regression and classification models have been extensively studied to exploit the myoelectric and kinematic input information from the residual limb for the control of multiple degree-of-freedom (DoF) powered prostheses. The gross movement control of above-elbow prostheses is mainly based on regression models which map the available inputs to continuous prosthetic poses. However, the regression output is sensitive to the variation in the input signal. The myoelectric signal variation is usually large due to unintentional muscle contractions, which can deteriorate the user-in-the-loop performance with respect to the offline analysis. Alternatively, the classification models offer the advantage of being more robust to the input signal variation, but they were predominantly used for fine motor functions such as grasping. For gross motor functions, the discrete output may cause issues. Therefore, this work attempts to investigate the feasibility of utilising the classification model to control a 2-DoF transhumeral prosthesis for gross movement. The performance of 6 able-bodied subjects was evaluated in performing reaching and orientation matching tasks with a prosthetic arm in a virtual reality environment. The results were compared with the case of using their intact arms and existing results using the regression model. Our findings indicate that the classification-based method provides comparable performance to the regression model, making it a potential alternative for gross arm movement in multi-DoF prosthetic arms.

Non-Paretic Arm Motor Deficit and Recovery as a Function of Damage Lateralization after Stroke: Biomechanical Study

The aim was to study the dependence of post stroke motor impairments of the paretic and the intact arm of lesion lateralization and paresis severity. The influence of lateralization of the lesion and the severity of paresis on the recovery of motor functions after rehabilitation using a hand exoskeleton controlled by a brain-computer interface was also studied. The study included 24 patients, 12 with left hemisphere involvement and 12 with right hemisphere involvement. Each group included 6 patients with moderate paresis and 6 patients with severe paresis. As motor tests, isolated movements in the joints of the paretic and intact hands were used before and after the rehabilitation course. Joint torque and motion isolation degree were used to assess motor function. It is shown that the muscle moments of the intact arm are greater in the case of damage to the left hemisphere; the asymmetry of the moments in the joints in this case was more pronounced than in the case of damage to the right hemisphere. This may be due to a greater imbalance in the activity of the hemispheres. The effectiveness of rehabilitation was manifested in: 1) an increase in moments in the joints in both paretic and intact hands; 2) an increase in the symmetry of the biomechanical parameters of the paretic and intact hands, which may indicate the restoration of the balance of the activity of the hemispheres. Biomechanical analysis of isolated movements allows suggests the pronation-supination in the vertical position of the arm as a sensitive indicator of motor function recovery after stroke.

Functional Specialization and Arm Length in Octopus bimaculoides

Although the functional specialization of octopus arms may seem unlikely due to the appearance of radial symmetry, there is significant evidence for preferential arm use in various species of octopus. For example, in O. maya, O. digueti, and O. vulgaris, the anterior arms are utilized more frequently for grasping prey and exploring (Lee, 1992; Voight, 1992; Byrne et al., 2006), while posterior arms are more frequently utilized for crawling in O. vulgaris (Levy et al., 2015). Additionally, O. aculeatus and O. marginatus preferentially use two of their posterior-most arms during camouflage walking (Huffard et al., 2005). Mazzolai and colleagues (2013) established a link between arm morphology and specialization, demonstrating that the longest arm was preferentially used in reaching movements in O. vulgaris. Given these observed functional differences and the potential for morphology to provide further insight into octopus arm specialization, the goal of this study was to determine if morphological differences exist between different arm identities (L1-L4, R1-R4) in O. bimaculoides. To test this hypothesis, the relationship between arm length and other factors including: arm identity, body mass, sex, anterior versus posterior location, and left versus right side was analyzed statistically. The data set included 111 intact arms from 22 wild-caught specimens of O. bimaculoides (11 males and 11 females). Simple linear regressions were performed to test for a relationship between these morphological features and arm length and an analysis of covariance was performed to test for differences in arm length by arm identity. Mass demonstrated a significant linear relationship with arm length and a one-way ANOVA demonstrated that arm identity is significantly correlated with arm length. Moreover, an analysis of covariance found that independent of mass, arm identity has a significant linear relationship with arm length. Thus, despite an overall appearance of radial symmetry, arms of different identities do not have statistically equivalent lengths in O. bimaculoides. Furthermore, differences in arm length do not appear to be related to sex, anterior versus posterior location, or left or right side. These results call into question the existing practice of treating all octopus arms as equivalent by either using a single arm measurement as representative of all eight, or calculating an average length, and suggest that morphological analyses of specific arm identities may be more informative. Further investigation into the functional specialization and morphology of octopus arms is warranted.

Coral defences: the perilous transition of juvenile crown-of-thorns starfish to corallivory

The transition from the post-settlement herbivorous juvenile to the coral-eating stage of crown-of-thorns starfish (COTS) is a fundamental step to seed population outbreaks that decimate tropical coral reefs. How the highly cryptic juveniles fare during this transition is poorly understood. We show that the juveniles are vulnerable to attack by coral during this ontogenetic diet shift to coral prey. We monitored the condition, growth, and survival of juvenile COTS during the first 3.5 mo on a diet of Acropora sp. In initial encounters, juveniles often withdrew their arms to avoid the defensive nematocysts of the corals. Within the first 67 d of being offered coral, 37.8% of the juveniles experienced various levels of sublethal and lethal damage. Damaged arms were reduced to ~65.4% of the length of an intact arm, but most injured juveniles were able to regenerate their arms with an average predicted recovery time of ~4 mo. Although sublethal damage slowed the growth of injured juveniles, their capacity to regenerate is likely to contribute to the success of this highly prolific species. Despite being the prey of COTS, coral can influence the survival of juveniles, and potentially reduce their ecological impact by prolonging their growth to reproductive maturity, delaying their transition into a coral predator, and thereby hindering recruitment into the adult population.

Upper extremity prosthetic selection influences loading of transhumeral osseointegrated systems.

Percutaneous osseointegrated (OI) implants are increasingly viable as an alternative to socket suspension of prosthetic limbs. Upper extremity prostheses have also become more complex to better replicate hand and arm function and attempt to recreate pre-amputation functional levels. With more functionality comes heavier devices that put more stress on the bone-implant interface, which could be an issue for implant stability. This study quantified transhumeral loading at defined amputation levels using four simulated prosthetic limb-types: (1) body powered hook, (2) myoelectric hook, (3) myoelectric hand, and (4) advanced prosthetic limb. Computational models were constructed to replicate the weight distribution of each prosthesis type, then applied to motion capture data collected during Advanced Activities of Daily Living (AADLs). For activities that did not include a handheld weight, the body powered prosthesis bending moments were 13–33% (range of means for each activity across amputation levels) of the intact arm moments (reference 100%), torsional moments were 12–15%, and axial pullout forces were 30–40% of the intact case (p≤0.001). The myoelectric hook and hand bending moments were 60–99%, torsional moments were 44–97%, and axial pullout forces were 62–101% of the intact case. The advanced prosthesis bending moments were 177–201%, torsional moments were 164–326%, and axial pullout forces were 133–185% of the intact case (p≤0.001). The addition of a handheld weight for briefcase carry and jug lift activities reduced the overall impact of the prosthetic model itself, where the body powered forces and moments were much closer to those of the intact model, and more complex prostheses further increased forces and moments beyond the intact arm levels. These results reveal a ranked order in loading magnitude according to complexity of the prosthetic device, and highlight the importance of considering the patient’s desired terminal device when planning post-operative percutaneous OI rehabilitation and training.

Effect of sublethal predation on reproductive output of the crown-of-thorns starfish Acanthaster sp., with an overview of arm damage

The extreme reproductive potential of the crown-of-thorns starfish (CoTS) Acanthaster sp. is a key trait used to explain their population outbreaks. Despite their highly defended morphology, sublethal predation is prevalent, as documented here for 2 outbreak populations in the Great Barrier Reef: Davies Reef and Lynch's Reef (arm damage 73.0 and 58.3%, respectively). It is not known how this trauma affects reproductive potential as a quantitative change in gonad production. We investigated the variability in gonad weight in the arms of uninjured CoTS. For CoTS with injured arms, we assessed the impact of arm injury and regeneration on gonad development at the level of the whole individual and among arms. The gonad index (GI) was lower in CoTS with 3 or more injured arms on Davies Reef, but not Lynch's Reef. At the level of individual arms, arm damage (25-100% of individual arm lost at Davies Reef and 10-100% at Lynch's Reef) resulted in a lower gonad weight compared to intact arms. Arms regenerating following total arm loss had a lower gonad weight than intact arms, even for arms that were 50-74% (Davies Reef) and 75-99% regenerated (Lynch's Reef). For uninjured CoTS, we show strong support for GI estimates based on extrapolation from one arm, and that inclusion of more than 4 arms resulted in marginal reduction in error. It is clear that sublethal injury can have a significant effect on gonad production in CoTS, with implications for population control given the reproductive potential of this species.

A Cortico- Basal Ganglia Model for choosing an optimal rehabilitation strategy in Hemiparetic Stroke

To facilitate the selection of an optimal therapy for a stroke patient with upper extremity hemiparesis, we propose a cortico-basal ganglia model capable of performing reaching tasks under normal and stroke conditions. The model contains two hemispherical systems, each organized into an outer sensory-motor cortical loop and an inner basal ganglia (BG) loop, controlling their respective hands. The model is trained to simulate two therapeutic approaches: the constraint induced movement therapy (CIMT) in which the intact is arrested, and Bimanual Reaching in which the movements of the intact arm are found to aid the affected arm. Which of these apparently mutually conflicting approaches is right for a given patient? Based on our study on the effect of lesion size on arm performance, we hypothesize that the choice of the therapy depends on the lesion size. Whereas bimanual reaching is more suitable for smaller lesion size, CIMT is preferred in case of larger lesion sizes. By virtue of the model’s ability to capture the experimental results effectively, we believe that it can serve as a benchmark for the development and testing of various rehabilitation strategies for stroke.

Investigation of relations between selective motor control and edinburgh visual gait score for children with cerebral palsy

Gait is an autonomic process consisting of coordinated movements of the upper extremities, lower extremities, trunk and pelvis. However, researches regarding effects of upper extremity problems on gait parameters are limited.The aim of this study was to investigate the effects of arm swing on spatiotemporal characteristics of gait in individuals with unilateral transhumeral amputations.A total of 25 unilateral transhumeral amputees and 25 healthy subjects were included. Information on the demographic features of individuals, amputations, and prosthetic devices were recorded. Spatiotemporal characteristics of gait were obtained using the GAITRite electronic walkway, and the arm swing was evaluated with the two video-cameras and analyzed using the Dartfish Pro Suite 7 software.The groups were similar regarding their age, height and weight. Mean duration from the amputation was 14.91 ± 10.90 years, and the mean weight of the prostheses was 1.44 ± 0.39 kg. Amputees had a less ambulatory arm swing on their amputated sides compared to their intact arms and healthy individuals. When the amputee group was compared to the healthy individuals, their step and stride lengths were shorter and their foot progression angle was higher, their gait velocity and cadence were lower than the healthy group.The reduction of arm swing on the amputated side in unilateral transhumeral amputees is thought to be due to (1) use of the contralateral side in functional activities, (2) restriction of shoulder joint movement of socket boundaries and (3) fixed mechanical elbow joint. It has been thought that a decrease in the arm swing during walking may lead to a decrease in step length, stride length, and gait velocity.

Characteristics of Phantom Limb Pain Alleviated with Virtual Reality Rehabilitation.

Neurorehabilitation techniques using virtual reality (VR) systems have recently become widespread as a rehabilitation method for restoring phantom limb movement and alleviating phantom limb pain (PLP). However, analgesic effects have varied between studies, possibly because of differences in the characteristics of PLP between patients (e.g., cramping, burning, shooting). We aimed to reveal the relationship between VR effects and PLP characteristics using an exploratory factor analysis. PLP characteristics of 19 patients were measured using the Short-Form McGill Pain Questionnaire (SF-MPQ), and all PLP patients performed the VR rehabilitation protocol for 20 minutes. During VR rehabilitation, mirror-reversed computer graphic images of an intact arm (the virtual phantom limb) were presented to patients via a head-mounted display, inducing the perception of voluntary execution of movements of their phantom limb when intending bimanual movements. VR rehabilitation significantly restored movement representation (P < 0.0001) quantified using the bimanual coupling effect and significantly alleviated PLP intensity (P < 0.0001). The factor analysis revealed that PLP characteristics could be divided into two factors: "somatosensory-related pain characteristics" and "kinesthesia-related pain characteristics." PLP alleviation via VR rehabilitation was significantly correlated with "kinesthesia-related pain characteristics" (r = 0.47, P = 0.02) but not "somatosensory-related pain characteristics" (r = 0.22, P = 0.17). The current findings indicate that VR rehabilitation may be particularly effective for PLP associated with distorted phantom limb movement and body representations (e.g., clamping, gnawing), compared with typical neuropathic sensations (e.g., shooting, burning, dysesthesia).

Effects of arm swing on spatiotemporal characteristics of gait in unilateral transhumeral amputees

BackgroundGait is an autonomic process consisting of coordinated movements of the upper extremities, lower extremities, trunk and pelvis. However, researches regarding effects of upper extremity problems on gait parameters are limited. Research questionThe aim of this study was to investigate the effects of arm swing on spatiotemporal characteristics of gait in individuals with unilateral transhumeral amputations. MethodsA total of 25 unilateral transhumeral amputees and 25 healthy subjects were included. Information on the demographic features of individuals, amputations, and prosthetic devices were recorded. Spatiotemporal characteristics of gait were obtained using the GAITRite electronic walkway, and the arm swing was evaluated with the two video-cameras and analyzed using the Dartfish Pro Suite 7 software. ResultsThe groups were similar regarding their age, height and weight. Mean duration from the amputation was 14.91 ± 10.90 years, and the mean weight of the prostheses was 1.44 ± 0.39 kg. Amputees had a less ambulatory arm swing on their amputated sides compared to their intact arms and healthy individuals. When the amputee group was compared to the healthy individuals, their step and stride lengths were shorter and their foot progression angle was higher, their gait velocity and cadence were lower than the healthy group. SignificanceThe reduction of arm swing on the amputated side in unilateral transhumeral amputees is thought to be due to (1) use of the contralateral side in functional activities, (2) restriction of shoulder joint movement of socket boundaries and (3) fixed mechanical elbow joint. It has been thought that a decrease in the arm swing during walking may lead to a decrease in step length, stride length, and gait velocity.

Upper Limb Prosthesis Control for High-Level Amputees via Myoelectric Recognition of Leg Gestures.

Recognition of motion intent via surface electromyography (EMG) has become increasingly practical for prosthesis control, but lacking residual muscle sites remains a major obstacle to its use by high-level amputees. Currently, there are few approaches to upper limb prosthesis control for individuals with amputations proximal to the elbow, all of which suffer from one or more of three primary problems: invasiveness, the need for intensive training, and lacking functionality. Using surface EMG sensors placed on the lower leg and a natural mapping between degrees of freedom of the leg and the arm, we tested a noninvasive control approach by which high-level amputees could control prosthetic elbow, wrist, and hand movements with minimal training. In this paper, we used able-bodied subjects to facilitate a direct comparison between control using intact arm and leg muscles. First, we found that foot gestures could be classified offline using time domain features and linear discriminant analysis with accuracy comparable to an equivalent system for recognizing arm movements. Second, we used the target achievement control test to evaluate real-time control performance in three and four degrees of freedom. After approximately 20 min of training, subjects tended to perform the task as well with the leg as with intact arm muscles, and performance overall was comparable to other control methods.

Biomechanical Assessment of Fugl-Meyer Score: The Case of One Post Stroke Patient Who has Undergone the Rehabilitation using Hand Exoskeleton Controlled by Brain-Computer Interface

Objective: The study is double aimed: 1) to propose a version of common protocol for an assessment of upper limb motor impairment with the use of biomechanical characteristics of Fugl-Meyer items and 2) to apply this protocol to assess an efficacy of rehabilitation using hand exoskeleton controlled by brain-computer interface during the late stage of post stroke recovery in patient with mild paresis.Methods: One patient, 62 years old man, 10 months after ischemic stroke was recruited in the rehabilitation procedure. The patient was instructed to perform one of three tasks: to relax and to imagine kinesthetically slow extension of either paretic (left) or intact (right) hand fingers. The recorded electroencephalography was analyzed and exoskeleton extended the patient's fingers if brain-computer interface classifier recognized the imagery of their extension. The patient performed 10 daily procedures, each including three 10-minute long sessions. 14 items of Fugl-Meyer scale, describing flexor synergy (domain II), extensor synergy (domain III), movement combining synergies (domain IV) and movement out of synergy (domain V) were evaluated by standard Fugl-Meyer scores. In addition to Fugl-Meyer assessment biomechanical analysis of each item was performed. The items were recorded by electromagnetic tracking system for both paretic and intact arms. All seven degrees of freedom in each arm were taken into account. Two types of biomechanical parameters were analyzed: 1) coordination between angular velocities and 2) maximal angular velocities corresponding to seven degrees of freedom of the arm.Results: Fugl-Meyer assessment revealed motor improvements for two items only, whereas biomechanical analysis for all 14 items considered.Conclusion: The use of Fugl-Meyer scale completed by biomechanical parameters of its’ items can be a version of common protocol for assessment of upper limb motor impairment, useful for obtaining a comparable data in different clinical studies.

Modified Constraint-Induced Movement Therapy for Persons with a Unilateral Upper Extremity Amputation

Rates of prosthetic device abandonment are highest among persons with upper extremity (UE) amputation and contribute to the occurrence of overuse injuries in the contralateral, intact arm. To reduce rates of abandonment, therapy that incorporates the prosthesis into activities of daily living (ADL) within home and work environments is vital. An underexplored type of therapy for persons with UE amputation is Modified Constraint Induced Movement therapy (mCIMT) which has been extensively studied in patients with chronic, subacute, and acute stroke. It has shown improved outcomes in body image, quality of life, independence in ADL, and skilled use and motor automaticity of the impaired extremity during self-care tasks. Stroke and unilateral UE amputation create similar neurological processes of cortical reorganization within the ipsilateral hemisphere and parietal areas. Using the affected UE facilitates cortical activation of the contralateral hemisphere as proficiency in the affected UE increases. This study describes a novel treatment approach based on mCIMT for unilateral UE prosthetic training including outcomes of two clinic cases.

Visualisation of upper limb activity using spirals: A new approach to the assessment of daily prosthesis usage.

Background:Current outcome measures used in upper limb myoelectric prosthesis studies include clinical tests of function and self-report questionnaires on real-world prosthesis use. Research in other cohorts has questioned both the validity of self-report as an activity assessment tool and the relationship between clinical functionality and real-world upper limb activity. Previously,1 we reported the first results of monitoring upper limb prosthesis use. However, the data visualisation technique used was limited in scope.Study Design:Methodology development.Objectives:To introduce two new methods for the analysis and display of upper limb activity monitoring data and to demonstrate the potential value of the approach with example real-world data.Methods:Upper limb activity monitors, worn on each wrist, recorded data on two anatomically intact participants and two prosthesis users over 1 week. Participants also filled in a diary to record upper limb activity. Data visualisation was carried out using histograms, and Archimedean spirals to illustrate temporal patterns of upper limb activity.Results:Anatomically intact participants’ activity was largely bilateral in nature, interspersed with frequent bursts of unilateral activity of each arm. At times when the prosthesis was worn prosthesis users showed very little unilateral use of the prosthesis (≈20–40 min/week compared to ≈350 min/week unilateral activity on each arm for anatomically intact participants), with consistent bias towards the intact arm throughout. The Archimedean spiral plots illustrated participant-specific patterns of non-use in prosthesis users.Conclusion:The data visualisation techniques allow detailed and objective assessment of temporal patterns in the upper limb activity of prosthesis users.Clinical relevanceActivity monitoring offers an objective method for the assessment of upper limb prosthesis users’ (PUs) activity outside of the clinic. By plotting data using Archimedean spirals, it is possible to visualise, in detail, the temporal patterns of upper limb activity. Further work is needed to explore the relationship between traditional functional outcome measures and real-world prosthesis activity.

Recovery of Proprioception in the Upper Extremity by Robotic Mirror Therapy: a Clinical Pilot Study for Proof of Concept.

A novel robotic mirror therapy system was recently developed to provide proprioceptive stimulus to the hemiplegic arm during a mirror therapy. Validation of the robotic mirror therapy system was performed to confirm its synchronicity prior to the clinical study. The mean error angle range between the intact arm and the robot was 1.97 to 4.59 degrees. A 56-year-old male who had right middle cerebral artery infarction 11 months ago received the robotic mirror therapy for ten 30-minute sessions during 2 weeks. Clinical evaluation and functional magnetic resonance imaging (fMRI) studies were performed before and after the intervention. At the follow-up evaluation, the thumb finding test score improved from 2 to 1 for eye level and from 3 to 1 for overhead level. The Albert's test score on the left side improved from 6 to 11. Improvements were sustained at 2-month follow-up. The fMRI during the passive motion revealed a considerable increase in brain activity at the lower part of the right superior parietal lobule, suggesting the possibility of proprioception enhancement. The robotic mirror therapy system may serve as a useful treatment method for patients with supratentorial stroke to facilitate recovery of proprioceptive deficit and hemineglect.

Restoring movement representation and alleviating phantom limb pain through short-term neurorehabilitation with a virtual reality system.

We developed a quantitative method to measure movement representations of a phantom upper limb using a bimanual circle-line coordination task (BCT). We investigated whether short-term neurorehabilitation with a virtual reality (VR) system would restore voluntary movement representations and alleviate phantom limb pain (PLP). Eight PLP patients were enrolled. In the BCT, they repeatedly drew vertical lines using the intact hand and intended to draw circles using the phantom limb. Drawing circles mentally using the phantom limb led to the emergence of an oval transfiguration of the vertical lines ('bimanual-coupling' effect). We quantitatively measured the degree of this bimanual-coupling effect as movement representations of the phantom limb before and immediately after short-term VR neurorehabilitation. This was achieved using an 11-point numerical rating scale (NRS) for PLP intensity and the Short-Form McGill Pain Questionnaire (SF-MPQ). During VR neurorehabilitation, patients wore a head-mounted display that showed a mirror-reversed computer graphic image of an intact arm (the virtual phantom limb). By intending to move both limbs simultaneously and similarly, the patients perceived voluntary execution of movement in their phantom limb. Short-term VR neurorehabilitation promptly restored voluntary movement representations in the BCT and alleviated PLP (NRS: p=0.015; 39.1±28.4% relief, SF-MPQ: p=0.015; 61.5±48.5% relief). Restoration of phantom limb movement representations and reduced PLP intensity were linearly correlated (p<0.05). VR rehabilitation may encourage patient's motivation and multimodal sensorimotor re-integration of a phantom limb and subsequently have a potent analgesic effect. There was no objective evidence that restoring movement representation by neurorehabilitation with virtual reality alleviated phantom limb pain. This study revealed quantitatively that restoring movement representation with virtual reality rehabilitation using a bimanual coordination task correlated with alleviation of phantom limb pain.

The kinematic portrait of a patient as an objective indicator of motor function in the process of neurorehabilitation with hand exoskeleton controlled by the brain – computer interface

The results of biomechanical analysis of the motor function of the arm of poststroke patient in the process of neuroreha bilitation with exoskeleton of the hand controlled by brain – computer interface are presented in this paper. At the beginning and end of the course it was registered the kinematic portrait of the patient– isolated random movements for each of the seven degrees of freedom as the paretic and intact arms. Angular accelerations were taken as an assessment of muscle forces, the number of reverse movements was taken as an assessment of joint spasticity, and the kinematic content of the movement as a description of pathological synergy arising after stroke. These parameters give an objective numerical asses sment of motor function as well as of rehabilitation technology effectiveness.

Designing and testing lightweight shoulder prostheses with hybrid actuators for movements involved in typical activities of daily living and impact absorption.

Unlike forearm amputees, transhumeral amputees have residual stumps that are too small to provide a sufficient range of operation for their prosthetic parts to perform usual activities of daily living. Furthermore, it is difficult for small residual stumps to provide sufficient impact absorption for safe manipulation in daily living, as intact arms do. Therefore, substitution of upper limb function in transhumeral amputees requires a sufficient range of motion and sufficient viscoelasticity for shoulder prostheses under critical weight and dimension constraints. We propose the use of two different types of actuators, ie, pneumatic elastic actuators (PEAs) and servo motors. PEAs offer high power-to-weight performance and have intrinsic viscoelasticity in comparison with motors or standard industrial pneumatic cylinder actuators. However, the usefulness of PEAs in large working spaces is limited because of their short strokes. Servo motors, in contrast, can be used to achieve large ranges of motion. In this study, the relationship between the force and stroke of PEAs was investigated. The impact absorption of both types of actuators was measured using a single degree-of-freedom prototype to evaluate actuator compliance for safety purposes. Based on the fundamental properties of the actuators identified, a four degree-of-freedom robotic arm is proposed for prosthetic use. The configuration of the actuators and functional parts was designed to achieve a specified range of motion and torque calculated from the results of a simulation of typical movements performed in usual activities of daily living. Our experimental results showed that the requirements for the shoulder prostheses could be satisfied.

Forcing the shift of the crossover site to proximal regions in wheat chromosomes.

Terminal deletions obligate the first crossover to be formed in more proximal positions. This increases the recombination rate in intercalary intervals but not in the proximity of the centromere. Crossovers are not uniformly distributed along chromosomes in wheat. They take place preferentially in distal positions. The effect of the chromosomal architecture on crossover positioning has been analyzed from the chiasmate bonds at metaphase I formed by the truncated arms of 51 terminal deletion lines of eight wheat chromosomes. Chromosome 4A and the B genome chromosomes, in their standard or truncated conformation, and their arms, were identified by C-banding. Chromosomes studied show a similar chiasma distribution. Reduction of the size of the truncated arms is accompanied by a gradual decrease of the chiasma frequency in chromosome arms 1BL, 3BS, 3BL, 4BL, 5BS, 5BL, 6BL, 7BS, 7BL and 4AL. In chromosome arm 1BS, most chiasmata are concentrated in the distal half of the satellite and, in 4AS, in the distal 24 %. The arms 2BS, 2BL and 6BS do not show a simple decreasing gradient of the recombination rate, the chiasma frequency increases in subdistal intervals compared to more distal regions. Although terminal deletions usually induce an increase of chiasma frequency in intercalary regions, the level of intact chromosome arms is maintained in only a few deletion lines. Truncated arms containing only the 20 % proximal of the intact arm do not form chiasmata. The relationships of chiasma positioning with chromatin structure and genome organization is discussed.