Dexterous Hand Research Articles

Functional Electrical Stimulation and Brain-Machine Interfaces for Simultaneous Control of Wrist and Finger Flexion.

Brain-machine interface (BMI) controlled functional electrical stimulation (FES) is a promising treatment to restore hand movements to people with cervical spinal cord injury. Recent intracortical BMIs have shown unprecedented successes in decoding user intentions, however the hand movements restored by FES have largely been limited to predetermined grasps. Restoring dexterous hand movements will require continuous control of many biomechanically linked degrees-of-freedom in the hand, such as wrist and finger flexion, that would form the basis of those movements. Here we investigate the ability to restore simultaneous wrist and finger flexion, which would enable grasping with a controlled hand posture and assist in manipulating objects once grasped. We demonstrate that intramuscular FES can enable monkeys with temporarily paralyzed hands to move their fingers and wrist across a functional range of motion, spanning an average 88.6 degrees at the metacarpophalangeal joint flexion and 71.3 degrees of wrist flexion, and intramuscular FES can control both joints simultaneously in a real-time task. Additionally, we demonstrate a monkey using an intracortical BMI to control the wrist and finger flexion in a virtual hand, both before and after the hand is temporarily paralyzed, even achieving success rates and acquisition times equivalent to able-bodied control with BMI control after temporary paralysis in two sessions. Together, this outlines a method using an artificial brain-to-body interface that could restore continuous wrist and finger movements after spinal cord injury.

2210 The adjustable Transobturator male system (ATOMS) for urinary incontinence: 9 year sub analysis within the geriatric population

Abstract Introduction The ongoing rise in prostate cancer rates and consequent prostatectomy have led to an increase in rates of male stress urinary incontinence. ATOMS is an adjustable sling requiring no manual input and suitable for frailer patients. We investigated the long term efficacy of the ATOMsin managing SUI and performed a sub-analysis within the geriatric population (aged 75+). Method 69 men (mean: 70.2, range 50–81) underwent an ATOMS insertion between 2015–2019. Follow up data for up to 9 years were analysed (mean: 5.8, range 5–9 years). Out of the 69 men in the original cohort, 19 were aged 75+ (mean: 76.5, range: 75–81). 17 had SUI post radical prostatectomy, 1 post TURP and 1 post AP resection. Results Out of the 19 men, 14 (74%) were dry post ATOMsimplant insertion (ie using maximum one pad per day for reassurance). This rate is lower compared with the original cohort (79.7%). The average number of top ups to achieve dryness was 3 (same as the initial cohort). Out of the 14 men who remained incontinent in the initial cohort, 5 were 75+. Of these, 2 reported a significant improvement in their incontinence without meeting the ‘dry’ criteria. 1 had his ATOMsdevice removed due to infection. 1 was switched to an artificial urinary sphincter. 1 remains incontinent and is being managed with botox injections. There were no cases of mechanical failure. Conclusions ATOMS appears to be an efficacious and safe procedure in the geriatric population, with only marginal difference in dry rates compared to the non-geriatric cohort. The main benefit over an artificial sphincter is that it exerts a passive effect to prevent incontinence and requires no patient input for every void. This is especially prudent as geriatric patients may lose hand dexterity or cognitive ability over time.

Enhancing dexterous hand control: a distributed architecture for machine learning integration

Enhancing dexterous hand control: a distributed architecture for machine learning integration

Validation of the Kinematic Assessment Protocol Used in the Technology-Supported Neurorehabilitation System, Rehabilitation Technologies for Hand and Arm (R3THA™), in Children and Teenagers with Cerebral Palsy.

This study evaluates the R3THA™ assessment protocol (R3THA-AP™), a technology-supported testing module for personalized rehabilitation in children with cerebral palsy (CP). It focuses on the reliability and validity of the R3THA-AP in assessing hand and arm function, by comparing kinematic assessments with standard clinical assessments. Conducted during a 4-week summer camp, the study assessed the functional and impairment levels of children with CP aged 3-18. The findings suggest that R3THA is more reliable for children aged 8 and older, indicating that age significantly influences the protocol's effectiveness. The results also showed that the R3THA-AP's kinematic measurements of hand and wrist movements are positively correlated with the Box and Blocks Test Index (BBTI), reflecting hand function and dexterity. Additionally, the R3THA-AP's accuracy metrics for hand and wrist activities align with the Melbourne Assessment 2's Range of Motion (MA2-ROM) scores, suggesting a meaningful relationship between R3THA-AP data and clinical assessments of motor skills. However, no significant correlations were observed between the R3THA-AP and MA2's accuracy and dexterity measurements, indicating areas for further research. These findings validate the R3THA-AP's utility in assessing motor abilities in CP patients, supporting its integration into clinical practice.

The improved force/position hybrid control system for multi joint humanoid multi fingered dexterous hand

The improved force/position hybrid control system for multi joint humanoid multi fingered dexterous hand

Design of TCP-actuator-driven, soft-tendon-integrated anthropomorphic dexterous hand: SoroAgilHand-1

This paper presents the design, analysis, and development of a dexterous hand driven by TCP actuators, termed the SoroAgilHand-1. Using the elastic stress of the TCP array with the measured Young's modulus, a mapping model of the tendon-contracted length to the joint angle of the dexterous hand was developed and validated by the recorded trajectory of the thumb-index finger. We introduced a self-sensing model for the TCP array in the SoroAgilHand-1 system and established an integrated closed-loop control system using the tensile sensors and strain-measuring devices. Considering the Kapandji test and the Feix taxonomy, the grasping performance of SoroAgilHand-1 was evaluated using postures from the collected data. The experimental results show that the soft dexterous hand can achieve 33 grasping postures and pass the Kapandji test, implying that it fulfils the anthropomorphic design goal using TCP actuators. Moreover, based on the grabbing stability test from the Feix taxonomy, the finger-tip trajectory of the closed-loop controller for the driven TCP was significantly improved and exhibited greater stability than that in open-loop driving.

Caffeine, Alcohol, and Drug Use as Work Adjuncts Among Neurosurgeons. Prevalence, Contributing Factors, and Proposed Strategies

Neurosurgeons may resort to caffeine, alcohol, and various drugs to maintain peak performance as they grapple with work demands and escalated stress. The prevalence of this controversial strategy remains largely unexplored. An anonymous survey of 23 questions formulated by our research group was distributed through personal contacts and neurosurgical societies. Inquiries revolved around the use of medications and other substances for job-related reasons. Data were analyzed via regression and descriptive statistics in python. In total, 215 neurosurgeons (43 residents) were included, with 213 disclosing their gender (94 females). Out of all, 9.3% were <30, 38.1% were 30-39, 44.6% were 40-59, and 7.9% were >60years old. Most (70.7%) practiced in Europe, 18.6% in Asia, 6.5% in North and South America, and the rest in Africa or Australia. While 132 participants stated they consume caffeine to manage challenging schedules, drugs for cognitive and mood enhancement were utilized by 18 and 35 respectively. Alcohol was employed for stress relief by 28 with 4 reporting as heavy drinkers. Drugs posed a solution to sleep disorders for 82, and helped 8 others in strengthening their hand dexterity. Notably, 12 of those claiming drug use initiated it in medical school. Exercise, self-care activities, and relational support were the main alternatives sought. Ultimately, most responders recommended extending mental health assistance and raising awareness about drug use. Reflecting on our results on job-associated drug use by neurosurgeons, we propose the judicious use of pharmacological or nonpharmacological adjuncts, alongside the prioritization of neurosurgeons' well-being.

Theoretical proposal for restoration of hand motor function based on plasticity of motor-cortical interhemispheric interaction and its developmental rule.

After stroke, the poorer recovery of motor function of upper extremities compared to other body parts is a longstanding problem. Based on our recent functional MRI evidence on healthy volunteers, this perspective paper proposes systematic hand motor rehabilitation utilizing the plasticity of interhemispheric interaction between motor cortices and following its developmental rule. We first discuss the effectiveness of proprioceptive intervention on the paralyzed (immobile) hand synchronized with voluntary movement of the intact hand to induce muscle activity in the paretic hand. In healthy participants, we show that this bilateral proprioceptive-motor coupling intervention activates the bilateral motor cortices (= bilaterally active mode), facilitates interhemispheric motor-cortical functional connectivity, and augments muscle activity of the passively-moved hand. Next, we propose training both hands to perform different movements, which would be effective for stroke patients who becomes able to manage to move the paretic hand. This bilaterally different movement training may guide the motor cortices into left-right independent mode to improve interhemispheric inhibition and hand dexterity, because we have shown in healthy older adults that this training reactivates motor-cortical interhemispheric inhibition (= left-right independent mode) declined with age, and can improve hand dexterity. Transition of both motor cortices from the bilaterally active mode to the left-right independent mode is a developmental rule of hand motor function and a common feature of motor function recovery after stroke. Hence, incorporating the brain's inherent capacity for spontaneous recovery and adhering to developmental principles may be crucial considerations in designing effective rehabilitation strategies.

Stretchable glove for accurate and robust hand pose reconstruction based on comprehensive motion data

We propose a compact wearable glove capable of estimating both the finger bone lengths and the joint angles of the wearer with a simple stretch-based sensing mechanism. The soft sensing glove is designed to easily stretch and to be one-size-fits-all, both measuring the size of the hand and estimating the finger joint motions of the thumb, index, and middle fingers. The system was calibrated and evaluated using comprehensive hand motion data that reflect the extensive range of natural human hand motions and various anatomical structures. The data were collected with a custom motion-capture setup and transformed into the joint angles through our post-processing method. The glove system is capable of reconstructing arbitrary and even unconventional hand poses with accuracy and robustness, confirmed by evaluations on the estimation of bone lengths (mean error: 2.1 mm), joint angles (mean error: 4.16°), and fingertip positions (mean 3D error: 4.02 mm), and on overall hand pose reconstructions in various applications. The proposed glove allows us to take advantage of the dexterity of the human hand with potential applications, including but not limited to teleoperation of anthropomorphic robot hands or surgical robots, virtual and augmented reality, and collection of human motion data.

Imaging body-mind crosstalk in young adults

ObjectiveThere is evidence that complex relationships exist between motor functions, brain structure, and cognitive functions, particularly in the aging population. However, whether such relationships observed in older adults could extend to other age groups (e.g., younger adults) remains to be elucidated. Thus, the current study addressed this gap in the literature by investigating potential associations between motor functions, brain structure, and cognitive functions in a large cohort of young adults MethodsIn the current study, data from 910 participants (22–35 yr) were retrieved from the Human Connectome Project. Interactions between motor functions (i.e., cardiorespiratory fitness, gait speed, hand dexterity, and handgrip strength), brain structure (i.e., cortical thickness, surface area, and subcortical volumes), and cognitive functions were examined using linear mixed-effects models and mediation analyses. The performance of different machine-learning classifiers to discriminate young adults at three different levels (related to each motor function) was compared ResultsCardiorespiratory fitness and hand dexterity were positively associated with fluid and crystallized intelligence in young adults, whereas gait speed and handgrip strength were correlated with specific measures of fluid intelligence (e.g., inhibitory control, flexibility, sustained attention, and spatial orientation; false discovery rate [FDR] corrected, p < 0.05). The relationships between cardiorespiratory fitness and domains of cognitive function were mediated by surface area and cortical volume in regions involved in the default mode, sensorimotor, and limbic networks (FDR corrected, p < 0.05). Associations between handgrip strength and fluid intelligence were mediated by surface area and volume in regions involved in the salience and limbic networks (FDR corrected, p < 0.05). Four machine-learning classifiers with feature importance ranking were built to discriminate young adults with different levels of cardiorespiratory fitness (random forest), gait speed, hand dexterity (support vector machine with the radial kernel), and handgrip strength (artificial neural network) ConclusionsIn summary, similar to observations in older adults, the current study provides empirical evidence (i) that motor functions in young adults are positively related to specific measures of cognitive functions, and (ii) that such relationships are at least partially mediated by distinct brain structures. Furthermore, our analyses suggest that machine-learning classifier has a promising potential to be used as a classification tool and decision support for identifying populations with below-average motor and cognitive functions.

Cervical Spinal Cord Morphometrics in Degenerative Cervical Myelopathy: Quantification using Semi-automated Normalized Technique and Correlation with Neurological Dysfunctions

Degenerative cervical myelopathy (DCM) is characterized by spinal cord atrophy. Accurate estimation of spinal cord atrophy is key to the understanding of neurological diseases, including DCM. However, its clinical application is hampered by difficulties in its precise and consistent estimation due to significant variability in spinal cord morphometry along the cervical spine, both within and between individuals. To characterize morphometrics of the compressed spinal cord in DCM patients. We employed our semi-automated analysis framework that incorporates the Spinal Cord Toolbox (SCT) and a normalization approach to effectively address the challenges posed by cord compression in these patients. Additionally, we examined the clinical relevance of these morphometric measures to enhance our understanding of DCM pathophysiology. Prospective study. This study investigated 36 DCM patients and 31 healthy controls (HCs). Clinical scores including 9-hole peg test for hand dexterity, hand grip strength, balance, gait speed, modified Japanese Orthopaedic Association (mJOA) score, and imaging-based spinal cord morphometrics. Using the generic spine acquisition protocol and our semi-automated analysis pipeline, spinal cord morphometrics, including cross-sectional area (CSA), anterior-posterior (AP) and transverse (RL) diameters, eccentricity, and solidity, were estimated from sagittal T2w magnetic resonance imaging (MRI) images using the Spinal Cord Toolbox (SCT). Normalized metrics were extracted from the C1 to C7 vertebral levels and compared between DCM patients and HC. Morphometric data at regions of maximum spinal cord compression (MSCC) were correlated with the clinical scores. A subset of participants underwent follow-up scans at six months to monitor longitudinal changes in spinal cord atrophy. Spinal cord morphometric data were normalized against the healthy population morphometry (PAM50 database) and extracted for all participants. DCM patients showed a notable reduction in CSA, AP, and RL diameter across all vertebral levels compared to HC. MSCC metrics correlated significantly with clinical scores like dexterity, grip strength, and mJOA scores. Longitudinal analysis indicated a decrease in CSA and worsening clinical scores in DCM patients. Our processing pipeline offers a reliable method for assessing spinal cord compression in DCM patients. Normalized spinal cord morphometrics, particularly the CSA could have potential for monitoring DCM disease severity and progression, guiding treatment decisions. Furthermore, to our knowledge our study is the first to apply the generic spinal cord acquisition protocol, ensuring consistent imaging across different MRI scanners and settings. Coupled with our semi-automated analysis pipeline, this protocol is key for the detailed morphometric characterization of compressed spinal cords in patients with DCM, a disease that is both complex and heterogenous. This study was funded by the National Institute of Neurological Disorders and Stroke (NINDS) (K23:NS091430) and (R01: NS129852-01A1).

VR-HandNet: A Visually and Physically Plausible Hand Manipulation System in Virtual Reality.

This study aims to allow users to perform dexterous hand manipulation of objects in virtual environments with hand-held VR controllers. To this end, the VR controller is mapped to the virtual hand and the hand motions are dynamically synthesized when the virtual hand approaches an object. At each frame, given the information about the virtual hand, VR controller input, and hand-object spatial relations, the deep neural network determines the desired joint orientations of the virtual hand model in the next frame. The desired orientations are then converted into a set of torques acting on hand joints and applied to a physics simulation to determine the hand pose at the next frame. The deep neural network, named VR-HandNet, is trained with a reinforcement learning-based approach. Therefore, it can produce physically plausible hand motion since the trial-and-error training process can learn how the interaction between hand and object is performed under the environment that is simulated by a physics engine. Furthermore, we adopted an imitation learning paradigm to increase visual plausibility by mimicking the reference motion datasets. Through the ablation studies, we validated the proposed method is effectively constructed and successfully serves our design goal. A live demo is demonstrated in the supplementary video.

Multichannel Sensorimotor Integration with a Dexterous Artificial Hand

People use their hands for intricate tasks like playing musical instruments, employing myriad touch sensations to inform motor control. In contrast, current prosthetic hands lack comprehensive haptic feedback and exhibit rudimentary multitasking functionality. Limited research has explored the potential of upper limb amputees to feel, perceive, and respond to multiple channels of simultaneously activated haptic feedback to concurrently control the individual fingers of dexterous prosthetic hands. This study introduces a novel control architecture for three amputees and nine additional subjects to concurrently control individual fingers of an artificial hand using two channels of context-specific haptic feedback. Artificial neural networks (ANNs) recognize subjects’ electromyogram (EMG) patterns governing the artificial hand controller. ANNs also classify the directions objects slip across tactile sensors on the robotic fingertips, which are encoded via the vibration frequency of wearable vibrotactile actuators. Subjects implement control strategies with each finger simultaneously to prevent or permit slip as desired, achieving a 94.49% ± 8.79% overall success rate. Although no statistically significant difference exists between amputees’ and non-amputees’ success rates, amputees require more time to respond to simultaneous haptic feedback signals, suggesting a higher cognitive load. Nevertheless, amputees can accurately interpret multiple channels of nuanced haptic feedback to concurrently control individual robotic fingers, addressing the challenge of multitasking with dexterous prosthetic hands.

Effect of concurrent action observation, peripheral nerve stimulation and motor imagery on dexterity in patients after stroke: a pilot study

Research to improve and expand treatment options for motor impairment after stroke remains an important issue in rehabilitation as the reduced ability to move affected limbs is still a limiting factor in the selection of training content for stroke patients. The combination of action observation and peripheral nerve stimulation is a promising method for inducing increased excitability and plasticity in the primary motor cortex of healthy subjects. In addition, as reported in the literature, the use of action observation and motor imagery in conjunction has an advantage over the use of one or the other alone in terms of the activation of motor-related brain regions. The aim of the pilot study was thus to combine these findings into a multimodal approach and to evaluate the potential impact of the concurrent application of the three methods on dexterity in stroke patients. The paradigm developed accordingly was tested with 10 subacute patients, in whom hand dexterity, thumb-index pinch force and thumb tapping speed were measured for a baseline assessment and directly before and after the single intervention. During the 10-min session, patients were instructed to watch a repetitive thumb-index finger tapping movement displayed on a monitor and to imagine the sensations that would arise from physically performing the same motion. They were also repeatedly electrically stimulated at the wrist on the motorically more affected body side and asked to place their hand behind the monitor for the duration of the session to support integration of the displayed hand into their own body schema. The data provide a first indication of a possible immediate effect of a single application of this procedure on the dexterity in patients after stroke.

The future lies in a pair of tactile hands.

Advancing robot hand dexterity with optical tactile sensing raises questions about humanoid robotics.

Iron deficiency anemia in relation to pinch strength and hand dexterity in preschool children: a cross-sectional study

BackgroundIron deficiency anemia (IDA) constitutes a considerable nutritional problem in Egyptian preschool children. Moreover, IDA limits physical activity performance and interferes with children's development. Accordingly, we aim to investigate the correlation between IDA and hand dexterity and pinch grip strength in preschool children.ResultsThis observational cross-sectional study encompassed the participation of 87 children, comprising both genders, with an age range of 5–6 years. The cohort was initially stratified into three distinct groups: Group A comprised 36 non-anemic children, group B included 25 children with mild iron-deficiency anemia (IDA), and group C consisted of 26 children with moderate IDA. After group delineation, comprehensive laboratory analyses were performed on all participants to assess for IDA, involving a thorough examination of their complete blood picture, hemoglobin (Hb) levels, serum iron levels, and serum ferritin levels. The evaluative metrics employed in this study encompassed the Bruininks-Oseretsky Test of Motor Proficiency-Second Edition (BOT-2) and the Baseline Mechanical Pinch Gauge. These instruments were utilized to assess manual dexterity and pinch strength, specifically tip-to-tip and tripod strength. This investigation revealed a positive correlation between Hb, serum iron, and serum ferritin levels with both manual dexterity and pinch strength across all three groups.ConclusionThis study highlights that IDA negatively affects hand dexterity and pinch grip strength in preschool children. Managing IDA early is crucial for improving their physical performance and overall development.

Evaluating gloved hand performance based on the mechanical properties of the applied material

The hands are the most complex organs of the body for performing various activities. Therefore, it is critical to protect them against dangers. Protective gloves can reduce or prevent injuries, but they can downgrade hand performance in various aspects, including tactile sensitivity, strength, grip force and hand dexterity. In this study, eight protective gloves with different designs and materials were made. The study investigated the influence of the number of layers and several characteristics, e.g., mass per square meter, thickness, bending stiffness and compressibility, on the gloved hand performance regarding protection ability, tactile sensitivity, strength capability and manual dexterity. The results indicated that despite the improving effects of increasing layer thickness, weight, bending energy and compressibility on protection ability, the gloves diminish tactile sensitivity, grip and pinch force, and manual dexterity. Therefore, it is necessary to select an optimum design to ensure a satisfactory trade-off between protection and performance.

Mild Dehydration Triggered by Exercise Reduces Cognitive Performance in Children, But Does Not Affect Their Motor Skills

Objective Children face the risk of dehydration in varying amounts during the day due to reasons such as physical activity, sweating, eating salty foods and drinking carbonated beverages. It is assumed that dehydration can lead to impaired motor skills and cognitive performance since it affects brain function. However, inconsistencies in study results, test times and problems caused by heat stress make new research mandatory. In our research, we examined the effects of exercise-induced mild dehydration on motor skills and cognitive performance in active/sedentary boys who do/do not do regular physical activities in their daily lives. Methods The study included 112 boys who do regular physical activity (n:57; 12.40 ± 0.49age) and sedentary (n:55; 12.49 ± 0.50age). The children were given a 12-h hydration program. Mild dehydration was created by giving exercises after hydration measurements. In case of hydration and mild dehydration, Bruininks-Oseretsky Motor Proficiency and d2 attention test were applied to the children. For comparison, Repeated Measures ANOVA and Bonferroni post-hoc test was performed at the second level. Results According to the hydration and mild dehydration comparison results, there was no difference in total score of Fine Motor Skill Sensitivity, Fine Motor Skill Integration, Hand Dexterity and Bidirectional Coordination, Balance, Running Speed and Agility, Hand-Arm Coordination, Strength, and BOT-2 in children. There was a decrease in both groups in terms of Focused Attention, Processing Speed, Accuracy, Concentration Performance and Attention Span. Conclusion As a result, mild dehydration is associated with daily physical activity in children (physical education classes, etc.) or it can easily occur due to food/beverage preferences. It may affect children’s performance of school curriculum and extracurricular activities. It shows that maintaining optimal hydration is important.

Effect of Hand Dexterity Exercises on physical therapist students’ self-efficacy: A Randomized Clinical Trial

Effect of Hand Dexterity Exercises on physical therapist students’ self-efficacy: A Randomized Clinical Trial

Evidence-Based Physiotherapeutic Interventions Enhancing Hand Dexterity, Activities of Daily Living and Quality of Life of Parkinson's Disease Patients: A Systematic Review.

This systematic review primarily aims to identify the optimal physiotherapeutic intervention to improve hand dexterity in Parkinson's Disease (PD) patients. The secondary objectives were to identify the hand dexterity physiotherapeutic interventions available for PD patients, and to determine the quality of these interventions. Eight electronic databases were systematically searched to identify relevant randomized controlled trial full-text articles using the established search strategy. The primary outcomes of interest were measurements for hand dexterity and activities of daily living (ADL). A total of 11 studies comprising 647 participants with PD were included. Most studies had a high risk of performance bias and an unclear risk of selection bias. The intervention training period ranged from a single session to 12 weeks. Compared to their respective control group, eight out of 11 studies revealed significant results in hand dexterity, two out of three studies reported positive effects on ADL, four of seven studies showed significant improvements in upper limb motor performance, and two studies perceived positive benefits in terms of overall quality of life. Five out of 11 studies that recorded the occurrence of adverse events reported no adverse events post-intervention. The dearth of evidence made it difficult to support any one intervention as the best intervention when compared to the other PD treatments in upper limb rehabilitation. Regardless, a home-based dexterity rehabilitation programme is still a promising approach to enhance dexterity-related functional abilities.