Finger Coordination Research Articles

Learning to Play Guitar with Robotic Hands

AbstractPlaying the guitar is a dexterous human skill that poses significant challenges in computer graphics and robotics due to the precision required in finger positioning and coordination between hands. Current methods often rely on motion capture data to replicate specific guitar playing segments, which restricts the range of performances and demands intricate post‐processing. In this paper, we introduce a novel reinforcement learning model that can play the guitar using robotic hands, without the need for motion capture datasets, from input tablatures. To achieve this, we divide the simulation task for playing guitar into three stages. (a): for an input tablature, we first generate corresponding fingerings that align with human habits. (b): based on the generated fingerings as the guidance, we train a neural network for controlling the fingers of the left hand using deep reinforcement learning, and (c): we generate plucking movements for the right hand based on inverse kinematics according to the tablature. We evaluate our method by employing precision, recall, and F1 scores as quantitative metrics to thoroughly assess its performance in playing musical notes. In addition, we conduct qualitative analysis through user studies to evaluate the visual and auditory effects of guitar performance. The results demonstrate that our model excels in playing most moderately difficult and easier musical pieces, accurately playing nearly all notes.

Development of a Device for Mirror Therapy

Previous research on the interconnections between brain activity and actions had led to the discovery of mirror neurons, neurons that have two particularly important roles: they mediate the imitation of movements based on visual information, and they underlie the understanding of actions. Mirror therapy is a relatively new, non-invasive therapy based on the use of visual feedback in recovery. Since 1996, it has been introduced in medical rehabilitation programmes, targeting conditions such as: hemiplegia after stroke, gait recovery after stroke, improvement of finger coordination in Parkinson's patients, reduction of phantom limb pain after amputations, and chronic pain from hand osteoarthritis, fibromyalgia, and complex regional pain syndrome. The device that is the subject of the present work presents a new constructive variant of the mirror box, which offers a much more efficient method of applying mirror therapy in various conditions, both at the level of the upper and lower limbs. The results of two assessments on the effectiveness of visual stimulation in recovery, carried out with the help of this device, first on the recovery of the hand functionality in subjects with hemiparesis after ischemic stroke and second assessment in the treatment of chronic pain of subjects with hand osteoarthritis will also be presented. Keywords: mirror therapy, visual feedback, neuroplasticity, kinesthetic memory, stroke, phantom limb pain

Robust tracking control of a minimal realization model of an impaired human hand for anthropomorphic coordination

Objective Physiologically relevant optimal controllers better represent the decision-making process of the central nervous system (CNS) with proper neural inputs and proprioceptor feedback. A biomechanical mathematical framework in the human palm reference frame was simulated using physiological dynamics to explore the biomechanics of movement coordination of fingers in a human hand.Method Physiological state space models include multiple zero eigenvalues, representing a redundant system. A fingertip trajectory tracking control paradigm is created by reducing the model order through the H∞ control paradigm. The external disturbances and sensory noise are included in the 21-Degrees-of-Freedom biomechanical model.Main Results An analysis is conducted on the flexion movement of the robotic finger when it is disrupted from its initial equilibrium position. The controller administers feedback force at the joints to control the movement of the robotic finger. A full order H∞ robust controller was developed, and the results were compared with the reduced-order model. The model order was reduced from 21 to 18 states. A reference trajectory is followed by the index finger in the minimal realization model, which is derived from the joint angular position profile. It stabilizes at a flexion angle of 1 rad/sec within 2 sec. Studying the simpler form of a model first gives a realistic view of the more complex model. This study has the potential to enhance our comprehension of anthropomorphic movement coordination in hands with impairments in kinesiology, ergonomics, assistive technology, and prosthetic devices.

Older individuals do not show task specific variations in EEG band power and finger force coordination.

Controlling and coordinating finger force is crucial for performing everyday tasks and maintaining functional independence. Aging naturally weakens neural, muscular, and musculoskeletal systems, leading to compromised hand motor function. This decline reduces cortical activity, finger force control and coordination in older adults. To investigate independently the EEG band power and finger force coordination in older individuals and compare the results with young healthy adults. Twenty healthy young adults aged 20-30 (26.96±2.68) and fourteen older adults aged 58-72 (62.57±3.58) participated in this study. Participants held the instrumented handle gently for five seconds then lifted and held it for an additional five seconds in the two conditions: fixed (thumb platform secured) and free condition (thumb platform may slide on slider). In the older individuals there was no difference observed in the finger force synergy indices, and EEG beta band power between the two task conditions. However, in the young group synergy indices and EEG beta band power were less in free condition compared to fixed condition. Additionally, in the fixed condition, older adults showed a reduced synergy indices and reduced EEG beta band power than the young adults. Older participants exhibited consistent synergy indices and beta band power across conditions, while young adults adjusted strategies based on tasks. Task-dependent finger force synergy indices were observed in young adults, contrasting with older individuals Additionally, it is suggested that EEG band power and synergy indices may be related, indicating potential associations between EEG activity and finger force coordination.

Test-Retest reliability and measurement error of the uncontrolled manifold analysis: A step towards the clinical translation

The uncontrolled manifold (UCM) analysis has gained broad application in biomechanics and neuroscience for investigating the structure of motor variability in functional tasks. The UCM utilizes inter-trial analysis to partition the variance of elemental variables (e.g., finger forces, joint angles) that affect (VORT) and do not affect (VUCM) a performance variable (e.g., total force, end-effector position). However, to facilitate the translation of UCM into clinical settings, it is crucial to demonstrate the reliability of UCM estimates: VORT, VUCM, and their normalized difference, ΔV. This study aimed to determine the test–retest reliability using the intraclass correlation coefficient (ICC3,K), Bland-Altman plots, the standard error of measurement (SEM), and the minimal detectable change (MDC) of UCM estimate. Fifteen healthy individuals (24.8 ± 1.2 yrs old) performed a finger coordination task, with sessions separated by one hour, one day, and one week. Excellent reliability was found for VORT (ICC3,K = 0.97) and VUCM (ICC3,K = 0.92), whereas good reliability was observed for ΔV (ICC3,K = 0.84). Bland-Altman plots reveled no systematic differences. SEM% values were 24.57 %, 26.80 % and 12.49 % for VORT, VUCM and ΔV respectively, while the normalized MDC% values were 68.12 %, 74.30 % and 34.61 % for VORT, VUCM and ΔV respectively. Our results support the use of UCM as a reliable method for investigating the structure of movement variability. The excellent measurement properties make the UCM a promising tool for tracking changes in motor behavior over time (i.e., effects of interventions in prospective studies).

Bimanual finger coordination in professional and amateur darbuka players

Professional hand percussionists who play the darbuka (a drum from the Middle East) show fast and stable bimanual finger coordination compared to amateur players. A cross-recurrence quantification analysis clarifies how stable bimanual coordination is achieved by dissociating stochastic noise and attractor strength in the dynamic system. This study employed a cross-recurrence quantification analysis to examine professional and amateur darbuka players’ fast and stable bimanual finger coordination. Eight professional and eight amateur percussion players participated in the study and played a darbuka with their right and left ring fingers, alternating as fast as possible for 12 s. We then analyzed the finger position data and calculated the stochastic noise and attractor strength from the density and the longest diagonal line in the recurrence plot, respectively. We used linear mixed-effects models to test whether stochastic noise and attractor strength differed between professional and amateur players. The results indicate that professional darbuka players achieve fast and stable bimanual finger coordination by enhancing attractor strength rather than reducing stochastic noise in the dynamic system.

Portable 3D-printed hand orthosis with spatial stiffness distribution personalized for assisting grasping in daily living.

Stroke survivors having limited finger coordination require an active hand orthosis to assist them with grasping tasks for daily activities. The orthosis should be portable for constant use; however, portability imposes constraints on the number, size, and weight of the actuators, which increase the difficulty of the design process. Therefore, a tradeoff exists between portability and the assistive force. In this study, a personalized spatial stiffness distribution design is presented for a portable and strengthful hand orthosis. The spatial stiffness distribution of the orthosis was optimized based on measurements of individual hand parameters to satisfy the functional requirements of achieving sufficient grip aperture in the pre-grasping phase and minimal assistive force in the grasping phase. Ten stroke survivors were recruited to evaluate the system. Sufficient grip aperture and high grip strength-to-weight ratio were achieved by the orthosis via a single motor. Moreover, the orthosis significantly restored the range of motion and improved the performance of daily activities. The proposed spatial stiffness distribution can suggest a design solution to make strengthful hand orthoses with reduced weight.

Developmental and acquired brain injury have opposite effects on finger coordination in children.

The ability to coordinate finger forces to dexterously perform tasks develops in children as they grow older. Following brain injury, either developmental (as in cerebral palsy-CP) or acquired (as in traumatic brain injury-TBI), this developmental trajectory will likely be impaired. In this study, we compared finger coordination in a group of children aged 4-12 with CP and TBI to a group of typically developing children using an isometric pressing task. As expected, deficits were observed in functional tests (Jebsen Taylor test of hand function, Box and Block test) for both groups, and children in both groups performed the pressing task less well than the control group. However, differing results were observed between the CP and TBI groups when using the uncontrolled manifold hypothesis to look at the synergy index. This index measures the relative amount of "good" (does not affect the outcome measure) and "bad" (does affect the outcome measure) variability, where in this case the outcome measure is the total force produced by the fingers. While children with CP were more variable in their performance, their synergy index was not significantly different from typically developing children, suggesting the development of compensatory strategies. In contrast, the children following TBI showed performance that got worse as a function of age (i.e., the older children with TBI performed worse than the younger children with TBI). These differences between the groups may be a result of different areas of brain injury typically observed in CP and TBI, and the different amount of time that has passed since the injury.

Humanlike spontaneous motion coordination of robotic fingers through spatial multi-input spike signal multiplexing

With advances in robotic technology, the complexity of control of robot has been increasing owing to fundamental signal bottlenecks and limited expressible logic state of the von Neumann architecture. Here, we demonstrate coordinated movement by a fully parallel-processable synaptic array with reduced control complexity. The synaptic array was fabricated by connecting eight ion-gel-based synaptic transistors to an ion gel dielectric. Parallel signal processing and multi-actuation control could be achieved by modulating the ionic movement. Through the integration of the synaptic array and a robotic hand, coordinated movement of the fingers was achieved with reduced control complexity by exploiting the advantages of parallel multiplexing and analog logic. The proposed synaptic control system provides considerable scope for the advancement of robotic control systems.

Laser-Actuated Multi-Fingered Hand for Dexterous Manipulation of Micro-Objects

Dexterous robotic manipulation refers to the coordination of multiple fingers or manipulators to grasp and manipulate a target object. In past decades, various achievements have been established in dexterous robotic manipulation in the physical world. However, such dexterous ability is rarely found in nano/micro manipulation, which is mainly due to the difficulty in developing actuators and sensors at a nano/micro-scale, as well as the dependence on the physical properties of objects. As a result, only limited and relatively simple micro-manipulation tasks such as pushing and picking have been realized so far. Here, we demonstrate a platform to achieve dexterous manipulation in the micro-world by developing a micro multi-fingered hand that is actuated by optical traps. The system consists of several micro laser-actuated fingers which are coordinated to function as a robotic micro-hand. Each micro-finger is configured with three degrees of freedom in a 2-dimensional space, and a system composed of coordinated micro-fingers can then be utilized for grasping, rotating, moving, and even levering and rolling of objects in micron scale. Thus, the proposed approach in this paper establishes a foundation in achieving dexterous robotic manipulation of objects at micron scale through the coordination of multiple micro fingers.

Beta rhythmicity in human motor cortex reflects neural population coupling that modulates subsequent finger coordination stability

Human behavior is not performed completely as desired, but is influenced by the inherent rhythmicity of the brain. Here we show that anti-phase bimanual coordination stability is regulated by the dynamics of pre-movement neural oscillations in bi-hemispheric primary motor cortices (M1) and supplementary motor area (SMA). In experiment 1, pre-movement bi-hemispheric M1 phase synchrony in beta-band (M1-M1 phase synchrony) was online estimated from 129-channel scalp electroencephalograms. Anti-phase bimanual tapping preceded by lower M1-M1 phase synchrony exhibited significantly longer duration than tapping preceded by higher M1-M1 phase synchrony. Further, the inter-individual variability of duration was explained by the interaction of pre-movement activities within the motor network; lower M1-M1 phase synchrony and spectral power at SMA were associated with longer duration. The necessity of cortical interaction for anti-phase maintenance was revealed by sham-controlled repetitive transcranial magnetic stimulation over SMA in another experiment. Our results demonstrate that pre-movement cortical oscillatory coupling within the motor network unknowingly influences bimanual coordination performance in humans after consolidation, suggesting the feasibility of augmenting human motor ability by covertly monitoring preparatory neural dynamics.

Remote assessment of hand dexterity: an quantitative method to reduce human error in occupational therapy

Dexterity is the coordination of hands and fingers with the eyes. Existing unilateral movements and dexterity tests use wearable devices for recording hand assessment. It is understandable that whenever some wired devices tag hands, the patient tends to be more conscious, which may not reflect the actual outcome. In this paper, using the finger-tap counter and loop-wire test, an attempt is made to evaluate unilateral movements and dexterity in adults of different age groups without using any wearable device. The test timings are recorded automatically with the help of the ATmega328p microcontroller and transferred to the clinician wirelessly via Bluetooth communication. Healthy 30 subjects between the age range (20–35, 36–50, 51–65, 66–80) were tested for finger-tap counter and loop-wire tests. The experiment is also tested for dominant and non-dominant hands for the same subjects. In this experiment, the result shows as the age increases, the trend in the assessment completion time and number of failures during the performance of the test increases. Female groups can perform both tests quicker than male groups with fewer errors irrespective of age group.

Tapping Performance of Professional and Amateur Darbuka Players.

Motor skills of professional musicians can be regarded as a model to investigate human skill acquisition after prolonged practice. Although rhythmic tapping skills of musicians such as drummers and pianists were investigated previously, the tapping performance of hand percussionists is still largely unknown. In this study, we investigated the tapping performance of professional and amateur darbuka players. Three tapping tasks were performed: single-, double-, and triple-finger tapping tasks. The participants were asked to tap as fast as possible for 12 s in the single-finger tapping task while they tapped as fast and alternate/even as possible in the double- and triple-finger tapping tasks. The tapping speed and variability of inter-tap interval (ITI) and tapping amplitude were assessed for each task. In the single-finger and triple-finger tapping tasks, there was no significant difference in the tapping speed between the professional and amateur darbuka players. In the double-finger tapping task, the tapping speed was significantly faster in the professional players than the amateur players. Interestingly, the professional players showed faster tapping speed in both familiar and unfamiliar patterns of finger coordination. The tapping speed of the double-finger tapping task was significantly correlated with the duration and the age of commencement of darbuka training. The professional players also showed less variability of ITI and tapping amplitude compared to the amateur players. These results suggest that prolonged practice of the hand percussion increases the performance stability and coordination speed of both familiar and unfamiliar patterns.

Performance of Bimanual Finger Coordination Tasks in Speakers Who Stutter

Stuttering is a neurodevelopmental speech disorder characterized by the symptoms of speech repetition, prolongation, and blocking. Stuttering-related dysfluency can be transiently alleviated by providing an external timing signal such as a metronome or the voice of another person. Therefore, the existence of a core motor timing deficit in stuttering has been speculated. If this is the case, then motoric behaviors other than speech should be disrupted in stuttering. This study examined motoric performance on four complex bimanual tasks in 37 adults who stutter and 31 fluent controls. Two tasks utilized bimanual rotation to examine motor dexterity, and two tasks used the bimanual mirror and parallel tapping movements to examine timing control ability. Video-based analyses were conducted to determine performance accuracy and speed. The results showed that individuals who stutter performed worse than fluent speakers on tapping tasks but not on bimanual rotation tasks. These results suggest stuttering is associated with timing control for general motor behavior.

Latrihal Media to Improve Fine Motor Ability in Student with Visual Impairment

The purpose of this study was to determine the use of latrihal media in improving fine motor skills in students with visual impairment. The methods used are lectures, demonstrations, and assignments. The subject of this research is 1 student with visual impairment at the special needs school, in Sumedang, West Java. The results showed that students experienced an increase in ability and had reached the Minimum Completeness Criteria of 65. In the initial ability, students get a score of 25 with a percentage of 25% and increase to a score of 72 with a percentage of 72%, so that there is an increase of 47%. Increased research is also indicated by the results of initial observations obtaining a score of 2 in the discipline aspect; a score of 1 on the conscientious aspect; score 1 on the aspect of concentration; and a score of 1 on the participatory aspect to a score of 3 on the discipline aspect; a score of 3 on the conscientious aspect; score 3 on the aspect of concentration; and a score of 3 on the aspect of participation in the final observation because students get direct experience using interesting media. This study demonstrates that the use of concrete learning media will make it easier to improve students' finger coordination skills. In addition, fine motor training media also makes it easier for teachers to guide students, especially for students with visual impairment.

Differential neural plasticity of individual fingers revealed by fMRI neurofeedback.

Previous work has shown that functional magnetic resonance imaging (fMRI) activity patterns associated with individual fingers can be shifted by temporary impairment of the hand. Here, we investigated whether these neural activity patterns could be modulated endogenously and whether any behavioral changes result from this modulation. We used decoded neurofeedback in healthy individuals to encourage participants to shift the neural activity pattern in sensorimotor cortex of the middle finger toward the index finger, and the ring finger toward the little finger. We first mapped the neural activity patterns for all fingers of the right hand in an fMRI pattern localizer session. Then, in three subsequent neurofeedback sessions, participants were rewarded after middle/ring finger presses according to their activity pattern overlap during each trial. A force-sensitive keyboard was used to ensure that participants were not altering their physical finger coordination patterns. We found evidence that participants could learn to shift the activity pattern of the ring finger but not of the middle finger. Increased variability of these activity patterns during the localizer session was associated with the ability of participants to modulate them using neurofeedback. Participants also showed an increased preference for the ring finger but not for the middle finger in a postneurofeedback motor task. Our results show that neural activity and behaviors associated with the ring finger are more readily modulated than those associated with the middle finger. These results have broader implications for rehabilitation of individual finger movements, which may be limited or enhanced by individual finger plasticity after neurological injury.NEW & NOTEWORTHY It may be possible to remobilize fingers after neurological injury by altering neural activity patterns. Toward this end, we examined whether finger-related neural activity patterns could be modified in healthy individuals without physical intervention, using fMRI neurofeedback. Our findings show that greater variability of neural patterns at baseline predicted a participant's ability to successfully shift these patterns. Because neural variability is common in individuals poststroke, this illustrates a potential clinical benefit of this procedure.

Biocultural evidence of precise manual activities in an Early Holocene individual of the high-altitude Peruvian Andes.

Cuncaicha, a rockshelter site in the southern Peruvian Andes, has yielded archaeological evidence for human occupation at high elevation (4,480 masl) during the Terminal Pleistocene (12,500-11,200 cal BP), Early Holocene (9,500-9,000 cal BP), and later periods. One of the excavated human burials (Feature 15-06), corresponding to a middle-aged female dated to ~8,500 cal BP, exhibits skeletal osteoarthritic lesions previously proposed to reflect habitual loading and specialized crafting labor. Three small tools found in association with this burial are hypothesized to be associated with precise manual dexterity. Here, we tested this functional hypothesis through the application of a novel multivariate methodology for the three-dimensional analysis of muscle attachment surfaces (entheses). This original approach has been recently validated on both lifelong-documented anthropological samples as well as experimental studies in nonhuman laboratory samples. Additionally, we analyzed the three-dimensional entheseal shape and resulting moment arms for muscle opponens pollicis. Results show that Cuncaicha individual 15-06 shows a distinctive entheseal pattern associated with habitual precision grasping via thumb-index finger coordination, which is shared exclusively with documented long-term precision workers from recent historical collections. The separate geometric morphometric analysis revealed that the individual's opponens pollicis enthesis presents a highly projecting morphology, which was found to strongly correlate with long joint moment arms (a fundamental component of force-producing capacity), closely resembling the form of Paleolithic hunter-gatherers from diverse geo-chronological contexts of Eurasia and North Africa. Overall, our findings provide the first biocultural evidence to confirm that the lifestyle of some of the earliest Andean inhabitants relied on habitual and forceful precision grasping tasks.

Kesulitan Menggenggam pada Proses Belajar Menulis dan Membaca Anak DCD

Although the learning process of writing involves all other supporting elements, such as stimulation from parents, the ability to coordinate fingers in grasping is a major aspect of the process. This study examines the causes of grasping difficulties as well as their relation to children's learning and writing processes. Analysis of this study using journal analysis. The findings show that Developmental Coordination Disorder (DCD) or poor motor skills are the main cause of difficulty grasping children. DCD levels were tested by Finger Tapping (FT), Curve Tracing (CT), and Paragraph Writing tests. Whereas 2 experimental tasks, Manik Threading and Per-Board were used to assess the FMS of reading children. This meta-analysis concludes that DCD influences the learning process of writing children and Fine Motor Performance is also related to the process of early reading for early childhood. Researcher's solution, recommends a comprehensive eye examination for children's eye and finger coordination and helps improve children's FMS, perform occupational therapy for children with DCD as well as continuous stimulus for children to train their fingers in the learning process of writing and early reading in children.

Concepts of Early Music Re-creation in Wanda Landowska’s Work

Concepts of Early Music Re-creation in Wanda Landowska’s Work

Differences of Smoothness and Coordination of the Fingers and Upper Extremities between Skilled and Non-skilled Players during Receiving the Basketball

Differences of Smoothness and Coordination of the Fingers and Upper Extremities between Skilled and Non-skilled Players during Receiving the Basketball