Evolution, biomechanics, and neurobiology converge to explain selective finger motor control.

Humans use their fingers to perform a variety of tasks, from simple grasping to manipulating objects, to typing and playing musical instruments, a variety wider than any other species. The more sophisticated the task, the more it involves individuated finger movements, those in which one or more selected fingers perform an intended action while the motion of other digits is constrained. Here we review the neurobiology of such individuated finger movements. We consider their evolutionary origins, the extent to which finger movements are in fact individuated, and the evolved features of neuromuscular control that both enable and limit individuation. We go on to discuss other features of motor control that combine with individuation to create dexterity, the impairment of individuation by disease, and the broad extent of capabilities that individuation confers on humans. We comment on the challenges facing the development of a truly dexterous bionic hand. We conclude by identifying topics for future investigation that will advance our understanding of how neural networks interact across multiple regions of the central nervous system to create individuated movements for the skills humans use to express their cognitive activity.

Explaining the influence of practice on the grooved pegboard times of older adults: role of force steadiness.

The purpose was to identify the variables that can explain the variance in the grooved pegboard times of older adults categorized as either fast or slow performers. Participants (n = 28; 60-83 years) completed two experimental sessions, before and after 6 practice sessions of the grooved pegboard test. The 2 groups were identified based on average pegboard times during the practice sessions. Average pegboard time during practice was 73 ± 11 s for the fast group and 85 ± 13 s for the slow group. Explanatory variables for the pegboard times before and after practice were the durations of 4 peg-manipulation phases and 12 measures of force steadiness (coefficient of variation [CV] for force) during isometric contractions with the index finger abductor and wrist extensor muscles. Time to complete the grooved pegboard test after practice decreased by 25 ± 11% for the fast group and by 28 ± 10% for the slow group. Multiple regression models explained more of the variance in the pegboard times for the fast group before practice (Adjusted R2 = 0.85) than after practice (R2 = 0.51), whereas the variance explained for the slow group was similar before (Adjusted R2 = 0.67) and after (Adjusted R2 = 0.64) practice. The explanatory variables differed between before and after practice for the fast group but only slightly for the slow group. These findings indicate that performance-based stratification of older adults can identify unique adjustments in motor function that are independent of chronological age.

Validity and reliability of the Duruöz Hand Index in patients with psoriatic arthritis.

OBJECTIVE: The Duruöz Hand Index (DHI) is a valuable scale developed for evaluating hand functions of patients with rheumatoid arthritis and subsequently proven to be valid and reliable in various diseases. This study aims to investigate the validity and reliability of the DHI in patients with psoriatic arthritis (PsA). METHODS: Patients diagnosed with PsA according to CASPAR criteria were enrolled. The demographic, clinical, and functional characteristics of patients were evaluated. Functional assessment was performed with DHI, Hand Functional Index, Health Assessment Questionnaire, and VAS-disability scale. C-reactive protein level, patients' and physicians' global VAS, swelling and tenderness of the hand joints, gross grip strength and thumb strength, and disease activity assessments were recorded as non-functional parameters related to active disease status. Reliability was assessed by internal consistency (with Cronbach's-a) and test-retest intraclass correlation coefficient. Face, content, convergent, and divergent validities were applied. RESULTS: One hundred and forty-four patients (74.3% female) were included in this study. The Cronbach's alpha coefficient was 0.963, and for the test-retest reliability of the DHI, the intraclass correlation coefficient was 0.904 (p < 0.001). DHI showed good correlations with the functional disability scales (Hand Functional Index, Health Assessment Questionnaire, VAS-disability), indicating its convergent validity and moderate to non-significant correlations with the non-functional parameters supporting its divergent validity. CONCLUSIONS: Despite the occurrence of significant deformities and functional loss in PsA patients, there is a noticeable absence of specific tools tailored for PsA. Considering the intricacies associated with skin, nail, tendon, entheseal involvement, and arthritis, there is a need for straightforward tools in both clinical practice and studies involving patients with PsA. The DHI is a valid and reliable scale to evaluate the functional disability of hands in patients with PsA.

Identifying the most representative actigraphy variables reflecting standardized hand function assessments for remote monitoring in children with unilateral cerebral palsy.

BACKGROUND: Accurate assessment of physical activity and motor function in children with cerebral palsy is crucial for determining the effectiveness of interventions. This study aimed to investigate the correlation between real-world activity monitoring outcomes and in-laboratory standardized hand function assessments in children with unilateral cerebral palsy. METHODS: Actigraphy data were collected over 3 days from children aged 4-12 years with unilateral cerebral palsy before in-laboratory assessments. To tackle the high dimensionality and collinearity of actigraphy variables, we first applied hierarchical clustering using the Pearson correlation coefficient as the distance metric and then performed a principal component analysis (PCA) to reduce the dimensionality of our data. RESULTS: Both hierarchical clustering and PCAs revealed a consistent pattern in which magnitude ratio variables (ln[affected side magnitude/less-affected side magnitude]) were more strongly associated with standardized assessments of hand function than with activity time and distance domain variables. Hierarchical clustering analysis identified two distinct clusters of actigraphy variables, with the second cluster primarily consisting of magnitude ratio variables that exhibited the strongest correlation with Melbourne Assessment 2, Pediatric Motor Activity Log, Assisting Hand Assessment, and Manual Ability Classification System level. Principal component 2, primarily representing the magnitude ratio domain, was positively associated with a meaningful portion of subcategories of standardized measures, whereas principal component 1, representing the activity time and distance component, showed limited associations. CONCLUSIONS: The magnitude ratio of actigraphy can provide additional objective information that complements in-laboratory hand function assessment outcomes in future studies of children with unilateral cerebral palsy. TRIAL REGISTRATION IN CLINICALTRIALS.GOV: NCT04904796 (registered prospectively; date of registration: 23/05/2021).

Hand function outcomes following surgical treatment of complete neonatal brachial plexus palsy.

PURPOSE: Although re-innervation of the hand is considered a priority in the treatment of infants with complete brachial plexus injury, there is currently a paucity of publications investigating hand function outcomes following primary nerve reconstruction in infants with neonatal brachial plexus palsy (NBPP). This study therefore aimed to evaluate hand function outcomes in a series of patients with complete NBPP. METHODS: This retrospective case series included all patients who underwent primary nerve surgery for complete neonatal brachial plexus palsy over an 8-year period. Outcomes were assessed using the Raimond Hand Scale. Classification of grade 3 or higher indicates a functional hand (assistance in bimanual activity). RESULTS: Nineteen patients with a complete NBPP underwent primary nerve reconstruction at a mean age of 3.7 months. Periodic clinical evaluations were performed until at least 4 years of age. According to the Raimondi hand scale, one patient did not recover (grade 0), three patients attained grade 1, four grade 2, ten grade 3, and in one grade 4. Overall hand functional recovery was achieved in 57.8% (11/19) of patients. CONCLUSION: Sufficient recovery of hand function to perform bimanual activity tasks in patients with complete NBPP lesions is possible and should be a priority in the surgical treatment of these infants.

Permanent deterioration of fine motor skills after the resection of tumors in the supplementary motor area.

Supplementary motor area syndrome (SMAS) represents a common neurosurgical sequela. The incidence and time frame of its occurrence have yet to be characterized after surgery for brain tumors. We examined patients suffering from a brain tumor preoperatively, postoperatively, and during follow-up examinations after three months, including fine motor skills testing and transcranial magnetic stimulation (TMS). 13 patients suffering from a tumor in the dorsal part of the superior frontal gyrus underwent preoperative, early postoperative, and 3-month follow-up testing of fine motor skills using the Jebsen-Taylor Hand Function Test (JHFT) and the Nine-Hole Peg Test (NHPT) consisting of 8 subtests for both upper extremities. They completed TMS for cortical motor function mapping. Test completion times (TCTs) were recorded and compared. No patient suffered from neurological deficits before surgery. On postoperative day one, we detected motor deficits in two patients, which remained clinically stable at a 3-month follow-up. Except for page-turning, every subtest indicated a significant worsening of function, reflected by longer TCTs (p < 0.05) in the postoperative examinations for the contralateral upper extremity (contralateral to the tumor manifestation). At 3-month follow-up examinations for the contralateral upper extremity, each subtest indicated significant worsening compared to the preoperative status despite improvement to the immediate postoperative level. We also detected significantly longer TCTs (p < 0.05) postoperatively in the ipsilateral upper extremity. This study suggests a long-term worsening of fine motor skills even three months after SMA tumor resection, indicating the necessity of targeted physical therapy for these patients.

Self-care and hand function in preschool children with unilateral or bilateral cerebral palsy: A cross-sectional study.

AIMS: To describe self-care capabilities among children with cerebral palsy (CP) and explore associations between self-care and hand function for children with unilateral cerebral palsy (UCP) and children with bilateral cerebral palsy (BCP) separately. METHOD: Cross-sectional data on self-care capabilities (Pediatric Evaluation of Disability Inventory, PEDI), manual abilities (Manual Ability Classification System, MACS) and hand use during bimanual performance (Assisting Hand Assessment, AHA; Both Hands Assessment, BoHA) were retrieved from the Norwegian Quality and Surveillance Registry for Cerebral Palsy (NorCP). Eighty-seven children with CP (UCP, n = 61, mean age 4 years 1 month, SD 1 year 3 months, range 56) or BCP (n = 26, mean age 4 years 4 months, SD 1 year, range 41), classified at MACS level I (n = 26), II (n = 40) or III (n = 21), were included. RESULTS: No significant differences in self-care capabilities were found between children with UCP and children with BCP. Analysis of variance showed significant differences in self-care between MACS levels for the whole group. No significant differences in self-care between MACS levels were observed for children with UCP (p = 0.36), but significant differences were found for those with BCP (p < 0.001). Whereas a small correlation (r = 0.3) between PEDI and AHA scores was found for children with UCP, a large correlation (r = 0.6) was found for those with BCP. Children with BCP with symmetric hand use during bimanual performance (BoHA) had higher PEDI scores than children with asymmetric hand use. CONCLUSION: Though children with UCP and children with BCP who were classified at MACS I-III exhibited similar self-care capabilities, the limited hand use seems to contribute differently between the two groups. The two different measures of hand use exhibit different associations with self-care capabilities for young children with UCP and BCP, respectively, and illustrate the need to treat UCP and BCP as two distinct groups, each requiring tailored interventions according to their specific needs.

A Sensor-Based Upper Limb Treatment in Hemiplegic Patients: Results from a Randomized Pilot Study.

In post-stroke patients, the disabling motor deficit mainly affects the upper limb. The focus of rehabilitation is improving upper limb function and reducing long-term disability. This study aims to evaluate the feasibility of using the Gloreha Aria (R-Lead), a sensor-based upper limb in-hospital rehabilitation, compared with conventional physiotherapist-led training in subacute hemiplegic patients. Twenty-one patients were recruited and randomised 1:1 to a sensor-based group (treatment group TG) or a conventional group (control group, CG). All patients performed 30 sessions of 30 min each of dedicated upper limb rehabilitation. The Fugl-Meyer Assessment for Upper Extremity (FMA-UE) was the primary evaluation., both as a motor score and as individual items. Secondary evaluations were Functional Independence Measure; global disability assessed with the Modified Barthel Index; Motor Evaluation Scale for UE in stroke; power grip; and arm, shoulder, and hand disability. All the enrolled patients, 10 in the TG and 11 in the CG, completed all hand rehabilitation sessions during their hospital stay without experiencing any adverse events. FMA-UE scores in upper limb motor function improved in both groups [delta change CG (11.8 ± 9.2) vs. TG (12.7 ± 8.6)]. The score at T1 for FMA joint pain (21.8 vs. 24 best score) suggests the use of the Gloreha Aria (R-Lead) as feasible in improving arm function abilities in post-stroke patients.

Effectiveness of a home training program on improving pinch force perception in older adults.

BACKGROUND: Hand function is reduced with aging which can lead to impairments in the performance of daily activities and eventually loss of independence. The ability to perceive the forces being applied to an object is an important component of hand control that also declines with age. However, the extent to which force perception can be improved through training remains largely unknown. PURPOSE: This study evaluated the effectiveness of a home-training program focused on improving force perception in older adults. STUDY DESIGN: Quasi-experimental - Uncontrolled trial. METHODS: Eleven independent, healthy adults (mean age: 77.2 ± 6.8 years) participated in a home-based sensorimotor hand training program 6 days/week for 6 weeks. Force perception, the primary outcome variable, was measured as the ability to reproduce a pinch force equal to 25% maximum voluntary contraction in the absence of visual feedback using either the ipsilateral remembered or contralateral concurrent (CC) hand. We also measured hand strength, dexterity, tactile acuity, and cognition before and after training. RESULTS: After the program was completed, participants showed a 35% reduction in absolute (p < 0.01, confidence interval (CI): [7.3, 33.2], effect sizes (ES): 0.87) and constant (p = 0.05, CI: [0.0, 34.9], ES: 0.79) force matching errors in the CC condition. Improvements in dominant hand dexterity (Purdue pegboard test) (p < 0.05, CI: [0.2, 2.4], ES: 0.60) and tactile sensitivity (JVP thresholds) (p < 0.05, CI: [-1.7, -0.1], ES: 0.94), as well as cognition (Trail Making Test B) (p < 0.05, CI: [-24,1. -1.6], ES: 0.30) were also observed post-training. CONCLUSIONS: The results suggest that home-hand training can be an effective way to improve force perception among older adults.

Effect of augmented reality-based rehabilitation of hand burns on hand function in children: A randomized controlled trial.

BACKGROUND: Despite the use of traditional rehabilitation methods, hand function may still remain impaired in children suffering from burn injuries. PURPOSE: This study aimed to assess the impact of implementing an augmented reality (AR) rehabilitation booklet designed for pediatric hand burn on their hand functionality. STUDY DESIGN: This was a randomized controlled trial. METHODS: Seventy-two children, aged 8-14 years with a hand burn, were randomly allocated into intervention (n = 36) and control (n = 36) groups. Children in the control group received routine rehabilitation program, while in the intervention group, children performed exercises using a printed booklet with related AR application. The Jebsen-Taylor Hand Function Test was completed before the intervention at the time of the patients' discharge and 1 month later. RESULTS: The results of analysis of covariance based on baseline- and fully-adjusted models showed significant intervention effect after discharge as well as after intervention for hand function (mean difference [95% confidence interval] for discharge: -8.2 [-15.0 to -1.4] and for after intervention: -74.0 [-88.8 to -59.1]) and the items (all p < 0.05), except for writing and lifting large light objects for both after discharge and after intervention measures (all p-value > 0.05). CONCLUSIONS: A significant decrease in the total time taking to complete the Jebsen-Taylor hand function test was observed in the intervention group compared to the control group 1 month after discharge. Rehabilitation of children with hand burns, using printed educational booklet with related AR application, improves their hand function.

The Corbett Targeted Coin Test: Reliability, criterion related validity, and normative data.

STUDY DESIGN: Clinical measurement. BACKGROUND: Many daily living tasks require in-hand manipulation (IHM). There is a gap in standardized assessment tools for measuring IHM. The Corbett Targeted Coin Test (CTCT) was designed to allow measurement of that fine motor skill. PURPOSE: 1) To evaluate the interrater, test-retest reliability, and validity of the CTCT, and 2) to establish adult norms for the CTCT. METHODS: Reliability and Validity - 30 participants (25 females, age range 21-45) were assessed with the Nine-Hole Peg test and CTCT consecutively by three researchers, then re-evaluated one week later on the CTCT; Reliability was determined using intraclass correlation (ICC2,k) between tests and across testers; Criterion-related validity was determined by comparing scores from nine-hole test and CTCT across testers using ICC2,k. Normative - 190 participants (147 females, age range 20-80) were assessed with the CTCT; mean and standard deviation for participants' scores were calculated by age groups and gender. RESULTS: Test-retest reliability: poor for the right hand (ICCs = -0.29 to 0.45), and poor-moderate for the left hand (ICCs = 0.17-0.56). Inter-rater reliability ranged from moderate to excellent (ICCs = 0.60-0.80). The agreement between CTCT scores and Nine-Hole Peg test was poor for the right (ICC = 0.02; 95% CI: [-0.06, 0.14]) and left hands (ICC = 0.06; 95% CI: [-0.08, 0.28]). CTCT normative data: 41-50 age group demonstrated the highest performance while the 71-80 age group demonstrated the lowest performance. Scores between genders were similar. DISCUSSION: The poor test-retest reliability of CTCT was probably due to practice effect, while interrater reliability indicated that the test can be administered by different testers without compromising the results. The poor validity between tools proves their different constructs. CONCLUSIONS: Use of the CTCT may add another dimension to assessment of dexterity and fine motor skills, specifically, in-hand manipulation, but needs further research on test-retest reliability.

Conservative management of hand impairment in children and adolescents with heritable disorders of connective tissue: A scoping review.

AIMS: To synthesize and critically appraise available interventions in the conservative management of hand impairment for children and adolescents with heritable disorders of connective tissue (HDCT). METHODS: A search of peer-reviewed literature and online platforms were included with data regarding hand impairment and function, conservative management and outcome measures extracted and appraised. Levels of evidence were applied to published literature. RESULTS: Ten peer-reviewed papers, eleven webpages and YouTube videos met the inclusion criteria. Reported interventions included: strengthening, orthoses, assistive equipment, education and pacing. Evidence of intervention effectiveness and evidence-based guidance on dosage were absent, with no consistency of outcome measures monitoring intervention effectiveness. Online platforms posted by health professionals predominantly provided advice for families without clinical detail of interventions. CONCLUSIONS: There is a consistent suite of interventions identified in both peer-reviewed literature and online platforms used by clinicians and families to manage hand impairment for children and adolescents with HDCT. Clear dosage parameters and outcome measures are needed in future intervention studies to determine the effectiveness of interventions and guide clinicians in how best to treat hand impairment. Increasing accountability and quality of online resources posted by health professionals for families is warranted to ensure dosage details and precautions are provided.

Construct Validity of the Both Hands Assessment Using Wrist-Worn Accelerometers.

AIM: The aim of this study was to evaluate the construct validity of the Both Hands Assessment (BoHA) using activity of the upper limbs as detected by accelerometry in children with bilateral cerebral palsy (CP). METHODS: Observational study of children with CP (n = 44, n = 27 boys, aged 9.1 ± 1.6 years; Manual Ability Classification Scale I: n = 15, II: n = 22, III: n = 7) completing a BoHA assessment while wearing a triaxial accelerometer on each wrist. BoHA Each-Hand sub-scores, BoHA percentage difference between hands, BoHA Units, mean activity for each hand, mean activity asymmetry index and total mean activity were calculated. Linear regressions were used to analyze associations between measures. RESULTS: There were significant, positive associations between BoHA Units and total mean activity (B = 0.86, 95%CI: 0.32, 1.40), BoHA Percentage difference between hands and mean activity asymmetry index (B = 0.95, 95%CI: 0.75,1.15), and BoHA Each-Hand sub-score and mean activity for the non-dominant hand (B = 1.71, 95%CI: 1.16, 2.28), but not the dominant hand (B = 0.50, 95%CI: -0.45, 1.45). CONCLUSIONS: This study provides further evidence for the construct validity of the BoHA as a measure of upper limb performance. Wearable wrist sensors such as accelerometers capture and quantify gross upper limb movement in children with CP but cannot measure fine finger movements captured by the BoHA. CLINICAL TRIALS REGISTRATION: Australian New Zealand Clinical Trials Registry (ACTRN12616001488493 and ACTRN12618000164291).

Investigation of grip strength, pain threshold, pain tolerance and function in smartphone users.

PURPOSE/AIM OF THE STUDY: Few studies have demonstrated the effects of smartphone use on grip strength and upper extremity function. The present study was purposed to compare smartphone users' grip/lateral pinch strength, pain threshold/tolerance and upper limb function. MATERIALS AND METHODS: A prospective cross-sectional study was conducted with 241 individuals. Participants were divided into three groups with the cut-off values of the Smartphone Addiction Scale (SAS). The Edinburgh Handedness Inventory (EHI) was used to determine the dominant side. Thumb pain threshold and tolerance were evaluated with the algometer. A hand dynamometer measured the grip and lateral pinch strength. Upper extremity functions were evaluated with the Shortened Disabilities of the Arm, Shoulder and Hand Questionnaire (Quick-DASH). RESULTS: Handgrip strength of the dominant/non-dominant extremities and Quick-DASH scores were higher in low-level smartphone users (p < 0.05). There was no significant difference between the groups on lateral pinch strength and pain threshold/tolerance (p > 0.05). Smartphone usage significantly affected dominant and non-dominant hand grip strength (Standardized ß1 = -0.15, ß2 = -0.15, p < 0.05). In addition, the smartphone use level negatively affected dominant lateral pinch strength (Standardized ß = -0.12, p = 0.05). On the other hand, smartphone use positively affected upper extremity function (Standardized ß = 0.17, p < 0.05). CONCLUSIONS: As smartphone addiction increases, standard handgrip strength and functionality decrease. Pain threshold/tolerance is not affected by smartphone use. Future studies should focus on fine motor skills to present a more comprehensive upper limb function evaluation.

Are the sensorimotor control capabilities of the hands the factors influencing hand function in people with schizophrenia?

BACKGROUND: Previous works reported people with schizophrenia experienced inferior hand functions which influence their daily participation and work efficiency. Sensorimotor capability is one of indispensable elements acting in a well-executed feed-forward and feedback control loop to contribute to hand performances. However, rare studies investigated contribution of sensorimotor ability to hand functions for people with schizophrenia. This study aimed to explore hand function in people with schizophrenia based on the perspective of the sensorimotor control capabilities of the hands. METHODS: Twenty-seven people at the chronic stage of schizophrenia were enrolled. The following assessment tools were used: the Purdue Pegboard Test (PPT) and the VALPAR Component Work Sample-8 (VCWS 8) system for hand function; the Self-Reported Graphic version of the Personal and Social Performance (SRG-PSP) scale for functionality; and the Semmes-Weinstein Monofilaments (SWM), the pinch-holding-up-activity (PHUA) test and the Manual Tactile Test (MTT) for the sensory and sensorimotor parameters. The Clinical Global Impression-Severity (CGI-S) scale and the Extrapyramidal Symptom Rating Scale (ESRS) were used to grade the severity of the illness and the side-effects of the drugs. Spearman's rank correlation coefficient was used to analyze associations among hand function, functionality, and sensorimotor capabilities. A multiple linear regression analysis was used to identify the determinants of hand function. RESULTS: The results indicated that both hand function and sensorimotor capability were worse in people with schizophrenia than in healthy people, with the exception of the sensory threshold measured with the SWM. Moreover, the sensorimotor abilities of the hands were associated with hand function. The results of the regression analysis showed that the MTT measure of stereognosis was a determinant of the PPT measure of the dominant hand function and of the performance on the VCWS 8, and that the ESRS and the MTT measure of barognosis were determinants of the performance on the assembly task of the PPT. CONCLUSIONS: The findings suggested that sensorimotor capabilities, especially stereognosis and barognosis, are crucial determinants of hand function in people with schizophrenia. The results also revealed that the side effects of drugs and the duration of the illness directly affect hand function. CLINICAL TRAIL REGISTRATION: ClinicalTrials.gov , identifier NCT04941677, 28/06/2021.

Restoration of intrinsic hand function by superficial radial nerve: an anatomical study.

BACKGROUND: The contralateral seventh cervical (cC7) nerve root transfer represents a cornerstone technique in treating total brachial plexus avulsion injury. Traditional cC7 procedures employ the entire ulnar nerve as a graft, which inevitably compromises its restorative capacity. OBJECTIVE: Our cadaveric study seeks to assess this innovative approach aimed at preserving the motor branch of the ulnar nerve (MBUN). This new method aims to enable future repair stages, using the superficial radial nerve (SRN) as a bridge connecting cC7 and MBUN. METHODS: We undertook a comprehensive dissection of ten adult cadavers, generously provided by the Department of Anatomy, Histology, and Embryology at Fudan University, China. It allowed us to evaluate the feasibility of our proposed technique. For this study, we harvested only the dorsal and superficial branches of the ulnar nerve, as well as the SRN, to establish connections between the cC7 nerve and recipient nerves (both the median nerve and MBUN). We meticulously dissected the SRN and the motor and sensory branches of the ulnar nerve. Measurements were made from the reverse point of the SRN to the wrist flexion crease and the coaptation point of the SRN and MBUN. Additionally, we traced the MBUN from distal to proximal ends, recording its maximum length. We also measured the diameters of the nerve branches and tallied the number of axons. RESULTS: Our modified approach proved technically viable in all examined limbs. The distances from the reverse point of the SRN to the wrist flexion crease were 8.24 ± 1.80 cm and to the coaptation point were 6.60 ± 1.75 cm. The maximum length of the MBUN was 7.62 ± 1.03 cm. The average axon diameters in the MBUN and the anterior and posterior branches of the SRN were 1.88 ± 0.42 mm、1.56 ± 0.38 mm、2.02 ± 0.41 mm,respectively. The corresponding mean numbers of axons were 1426.60 ± 331.39 and 721.50 ± 138.22, and 741.90 ± 171.34, respectively. CONCLUSION: The SRN demonstrated the potential to be transferred to the MBUN without necessitating a nerve graft. A potential advantage of this modification is preserving the MBUN's recovery potential.

The BE-UJI hand function activity set: a reduced set of activities for the evaluation of the healthy and pathological hand.

BACKGROUND: Hand kinematics during hand function tests based on the performance of activities of daily living (ADLs) can provide objective data to determine patients' functional loss. However, they are rarely used during clinical assessments because of their long duration. Starting with the 20 Sollerman Hand Function Test (SHFT) tasks, we propose identifying a reduced set of ADLs that provides similar kinematic information to the original full set in terms of synergies, ranges of motion and velocities. METHODS: We followed an iterative method with the kinematics of 16 hand joints while performing the 20 ADLs of the SHFT. For each subject, ADLs were ordered according to their influence on the synergies obtained by means of a principal component analysis, the minimum number of ADLs that represented the original kinematic synergies (maximum angle of 30° between synergies), and the maintained ranges of joint movements (85% of the original ones) were selected for each subject. The set of the most frequently selected ADLs was verified to be representative of the SHFT ADLs in terms of motion strategies, ranges of motion and joint velocities when considering healthy subjects and Hand Osteoarthritis patients. RESULTS: A set of 10 tasks, the BE-UJI activity set, was identified by ensuring a certain (minimum) similarity in synergy (maximum mean angle between synergies of 25.5°), functional joint ranges (maximum differences of 10°) and joint velocities (maximum differences of 15°/s). The obtained tasks were: pick up coins from purses, lift wooden cubes, pick up nuts and turn them, write with a pen, cut with a knife, lift a telephone, unscrew jar lids and pour water from a cup, a jar and a Pure-Pak. These activities guarantee using the seven commonest handgrips in ADLs. CONCLUSION: The BE-UJI activity set for the hand function assessment can be used to obtain quantitative data in clinics as an alternative to the SHFT. It reduces the test time and allows clinicians to obtain objective kinematic data of the motor strategies, ranges of motion and joint velocities used by patients.

Restoring natural upper limb movement through a wrist prosthetic module for partial hand amputees.

BACKGROUND: Most partial hand amputees experience limited wrist movement. The limited rotational wrist movement deteriorates natural upper limb system related to hand use and the usability of the prosthetic hand, which may cause secondary damage to the musculoskeletal system due to overuse of the upper limb affected by repetitive compensatory movement patterns. Nevertheless, partial hand prosthetics, in common, have only been proposed without rotational wrist movement because patients have various hand shapes, and a prosthetic hand should be attached to a narrow space. METHODS: We hypothesized that partial hand amputees, when using a prosthetic hand with a wrist rotation module, would achieve natural upper limb movement muscle synergy and motion analysis comparable to a control group. To validate the proposed prototype design with the wrist rotation module and verify our hypothesis, we compared a control group with partial hand amputees wearing hand prostheses, both with and without the wrist rotation module prototype. The study contained muscle synergy analysis through non-negative matrix factorization (NMF) using surface electromyography (sEMG) and motion analyses employing a motion capture system during the reach-to-grasp task. Additionally, we assessed the usability of the prototype design for partial hand amputees using the Jebsen-Taylor hand function test (JHFT). RESULTS: The results showed that the number of muscle synergies identified through NMF remained consistent at 3 for both the control group and amputees using a hand prosthesis with a wrist rotation module. In the motion analysis, a statistically significant difference was observed between the control group and the prosthetic hand without the wrist rotation module, indicating the presence of compensatory movements when utilizing a prosthetic hand lacking this module. Furthermore, among the amputees, the JHFT demonstrated a greater improvement in total score when using the prosthetic hand equipped with a wrist rotation module compared to the prosthetic hand without this module. CONCLUSION: In conclusion, integrating a wrist rotation module in prosthetic hand designs for partial hand amputees restores natural upper limb movement patterns, reduces compensatory movements, and prevent the secondary musculoskeletal. This highlights the importance of this module in enhancing overall functionality and quality of life.

Analysis of Results of Contralateral Hemi-C7 Root Used for Restoring Hand Function in Global Birth Brachial Plexus Palsy.

PURPOSE: To analyze the outcome of the use of contralateral hemi-C7 for the restoration of hand function in patients with birth brachial plexus global palsy. METHODS: From 2004 to 2017, 19 infants with Narakas types III and IV birth brachial plexus palsy underwent transfer of contralateral hemi-C7 (posterior division of the contralateral C7 root) to the lower trunk or medial cord on the affected side. All the patients were evaluated for shoulder function using the Gilbert and Mallet scores, elbow flexion using the modified Medical Research Council score for children, and hand function using the Raimondi score. After the surgery, the children were followed-up at 3-month intervals for the first year and 6-month intervals thereafter. Hand function achieving Raimondi scores of 3-5 was considered a useful outcome. RESULTS: The patients were followed-up for a mean duration of 88 months, with a minimum of 35 and a maximum of 192 months of follow-up. All patients attained a Gilbert score of ≥3, whereas 9 patients attained a score of ≥4. Similarly, all patients attained a minimum aggregate Mallet score of 15, and 9 patients attained a score of ≥20. All patients attained a modified Medical Research Council score of ≥3, used for assessing elbow flexion. Useful hand function was attained in 73% (14/19) of the cases (a Raimondi score of ≥3). There was no clinically recorded deficit on the donor side. CONCLUSIONS: Contralateral hemi-C7 transfer in infants with brachial plexus root avulsions helped regain useful hand function in 73% (14/19) of the children treated. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Toward Early and Objective Hand Osteoarthritis Detection by Using EMG during Grasps.

The early and objective detection of hand pathologies is a field that still requires more research. One of the main signs of hand osteoarthritis (HOA) is joint degeneration, which causes loss of strength, among other symptoms. HOA is usually diagnosed with imaging and radiography, but the disease is in an advanced stage when HOA is observable by these methods. Some authors suggest that muscle tissue changes seem to occur before joint degeneration. We propose recording muscular activity to look for indicators of these changes that might help in early diagnosis. Muscular activity is often measured using electromyography (EMG), which consists of recording electrical muscle activity. The aim of this study is to study whether different EMG characteristics (zero crossing, wavelength, mean absolute value, muscle activity) via collection of forearm and hand EMG signals are feasible alternatives to the existing methods of detecting HOA patients' hand function. We used surface EMG to measure the electrical activity of the dominant hand's forearm muscles with 22 healthy subjects and 20 HOA patients performing maximum force during six representative grasp types (the most commonly used in ADLs). The EMG characteristics were used to identify discriminant functions to detect HOA. The results show that forearm muscles are significantly affected by HOA in EMG terms, with very high success rates (between 93.3% and 100%) in the discriminant analyses, which suggest that EMG can be used as a preliminary step towards confirmation with current HOA diagnostic techniques. Digit flexors during cylindrical grasp, thumb muscles during oblique palmar grasp, and wrist extensors and radial deviators during the intermediate power-precision grasp are good candidates to help detect HOA.