Processing in the non-dominant hand during sleep: in terms of early, middle-early and late brain responses.

The aim was to investigate brain responses to non-painful tactile stimuli applied to the non-dominant hand during sleep. 21 healthy subjects participated in the study (11 female, mean age ± SD: 20.67 ± 1.91 years). A 40-channel polysomnography system and a pneumatic tactile stimulator unit were used. Stimuli were applied to the participants' non-dominant hand. Evoked potential components of the CZ electrode were examined in four sleep stages (N1, N2, N3, and REM). Repeated measures ANOVA was used in statistical analyses. Brain responses, categorized as early (P50, N100, and P200), mid-early (N300, P450, and N550), and late (P900 and Nlate), were detected all sleep stages. No notable variances were found in the amplitude and latency of early brain responses when analyzed across different sleep stages. Differences in both amplitude and latency were observed across different sleep stages for the N300, P450, P900, and Nlate response components. This study presents a pioneering exploration into the responses of the non-dominant hand throughout all sleep stages, encompassing eight distinct response components. This novel investigation contributes to the existing literature by shedding light on previously unexplored aspects. The observed early responses are identified as sensory, while middle to late responses align with cognitive processes within the realm of sleep research. Notably, N300, P450, P900, and Nlate components display variations across diverse sleep stages, marked by alterations in both amplitude and latency. These findings offer valuable insights into the dynamic nature of hand responses throughout the sleep continuum.

Regional brain activity and neural network changes in cognitive-motor dual-task interference: A functional near-infrared spectroscopy study.

Previous neuroimaging studies have reported dual-task interference (DTi) and deterioration of task performance in a cognitive-motor dual task (DT) compared to that in a single task (ST). Greater frontoparietal activity is a neural signature of DTi; nonetheless, the underlying mechanism of cortical network in DTi still remains unclear. This study aimed to investigate the regional brain activity and neural network changes during DTi induced by highly demanding cognitive-motor DT. Thirty-four right-handed healthy young adults performed the spiral-drawing task. They underwent a paced auditory serial addition test (PASAT) simultaneously or independently while their cortical activity was measured using functional near-infrared spectroscopy. Motor performance was determined using the balanced integration score (BIS), a balanced index of drawing speed and precision. The cognitive task of the PASAT was administered with two difficulty levels defined by 1 s (PASAT-1 s) and 2 s (PASAT-2 s) intervals, allowing for the serial addition of numbers. Cognitive performance was determined using the percentage of correct responses. These motor and cognitive performances were significantly reduced during DT, which combined a drawing and a cognitive task at either difficulty level, compared to those in the corresponding ST conditions. The DT conditions were also characterized by significantly increased activity in the right dorsolateral prefrontal cortex (DLPFC) compared to that in the ST conditions. Multivariate Granger causality (GC) analysis of cortical activity in the selected frontoparietal regions of interest further revealed selective top-down causal connectivity from the right DLPFC to the right inferior parietal cortex during DTs. Furthermore, changes in the frontoparietal GC connectivity strength between the PASAT-2 s DT and ST conditions significantly correlated negatively with changes in the percentage of correct responses. Therefore, DTi can occur even in cognitively proficient young adults, and the right DLPFC and frontoparietal network being crucial neural mechanisms underlying DTi. These findings provide new insights into DTi and its underlying neural mechanisms and have implications for the clinical utility of cognitive-motor DTs applied to clinical populations with cognitive decline, such as those with psychiatric and brain disorders.

Efficacy of head postural correction program on craniovertebral angle, scapular position, and dominant hand grip strength in forward head posture subjects: A randomized controlled trial.

OBJECTIVE: Forward head posture (FHP) is a common postural disorder that alters shoulder function. This study examined the efficacy of a corrective program involving postural correction exercises (PCEs), scapular stabilization exercises (SSEs), and kinesiotaping (KT) on improving craniovertebral angle (CVA), scapular position, and dominant hand grip strength (HGS) in individuals with FHP. METHODS: Sixty subjects (8 males and 52 females, 18-40 years old) were randomly allocated into four equal groups: Group A: received PCEs only, Group B: received PCEs and SSEs, Group C: received PCEs and KT, Group D: received PCEs, SSEs and KT. All subjects received treatment for 4 weeks (4 times/week) and postural advice. Outcome measures included cranio-vertebral angle (CVA), scapular position using Lateral Scapular Slide Test and dominant HGS using a CAMRY dynamometer that were assessed at baseline and 4 weeks post intervention. RESULTS: Comparing all groups post training revealed that there were statistically significant increases (p < 0.05) in all measured variables (CVA, scapular position and dominant HGS) in favor of group (D). CONCLUSION: Combination of PCEs, SSEs and KT interventions has achieved the best gains in terms of CVA, dominant HGS and regaining optimal scapular position in FHP subjects.

Sex differences in laterality of motor unit firing behavior of the first dorsal interosseous muscle in strength-matched healthy young males and females.

PURPOSE: The purpose of this study was to compare laterality in motor unit firing behavior between females and males. METHODS: Twenty-seven subjects (14 females) were recruited for this study. The participants performed ramp up and hold isometric index finger abduction at 10, 30, and 60% of their maximum voluntary contraction (MVC). High-density surface electromyography (HD-sEMG) signals were recorded in the first dorsal interosseous (FDI) muscle and decomposed into individual motor unit (MU) firing behavior using a convolution blind source separation method. RESULTS: In total, 769 MUs were detected (females, n = 318 and males, n = 451). Females had a significantly higher discharge rate than males at each relative torque level (10%: male dominant hand, 13.4 ± 2.7 pps vs. female dominant hand, 16.3 ± 3.4 pps; 30%: male dominant hand, 16.1 ± 3.9 pps vs. female dominant hand, 20.0 ± 5.0 pps; and 60%: male dominant hand, 19.3 ± 3.8 vs. female dominant hand, 25.3 ± 4.8 pps; p < 0.0001). The recruitment threshold was also significantly higher in females than in males at 30 and 60% MVC. Furthermore, males exhibited asymmetrical discharge rates at 30 and 60% MVC and recruitment thresholds at 30 and 60% MVC, whereas no asymmetry was observed in females. CONCLUSION: In the FDI muscle, compared to males, females exhibited different neuromuscular strategies with higher discharge rates and recruitment thresholds and no asymmetrical MU firing behavior. Notably, the findings that sex differences in neuromuscular activity also occur in healthy individuals provide important information for understanding the pathogenesis of various diseases.

Comparison of dominant- and non-dominant-hand cateract surgery outcomes by a single surgeon.

PURPOSE: To compare dominant and non-dominant hand phacoemulsification surgery outcomes. METHODS: This retrospective, single-center study included 300 patients who underwent phacoemulsification surgery by a single, right-handed surgeon. The patients were divided into two groups according to whether the surgeon used his dominant or non-dominant hand during surgery. Right eye operations were performed with the right hand, and left eye operations were performed with the left hand. Detailed ophthalmological examinations were performed on all patients preoperatively and postoperatively. Intraoperative phacoemulsification parameters, the presence of intraoperative and postoperative complications, postoperative refractive errors, visual acuity, and surgically induced astigmatism values were compared between the groups. RESULTS: There were 171 patients in the dominant hand phacoemulsification group and 129 patients in the non-dominant hand phacoemulsification group. The distributions of age, gender, systemic diseases, and lens opacification were similar between the groups (p>0.05, for all). No statistically significant difference was observed between the two groups in terms of total operation time, phaco power, ellips fx, or ultrasonic time (p>0.05, for all). There was also no significant difference in relation to intraoperative and postoperative complication distributions, postoperative third-month refractive errors, visual acuity, or surgically induced astigmatism values (p>0.05, for all). CONCLUSION: This study demonstrated that cataract surgery performed by a single surgeon can be effectively and safely performed using both hands on patients in a real operating theater environment. More objective results can be obtained with surgeries performed by a larger number of experienced surgeons.

Whole-hand and regional bone mineral density involvement in rheumatoid arthritis.

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by symmetric polyarthritis that can lead to joint deformity, disability, and osteoporosis. We aimed to evaluate whole hand and regional BMD in RA patients compared to controls. In addition, we evaluated the BMD of dominant versus non-dominant hands in healthy subjects. We included adult female and male RA patients and control subjects matched by age, sex, and BMI. BMD (g/cm2) was measured by DXA in lumbar spine (LS), whole hand, and three regions of interest: carpus, metacarpal bones, and phalanges. Results: 44 control subjects (49.5±11.8 y) and 60 with RA (52.7±12.7 y) were included. Significant lower BMD in RA patients was found in LS (-8.7%), dominant whole hand (-9.5%), carpus, metacarpal bones, and phalanges, and non-dominant whole hand (-8.7%), metacarpal bones, and phalanges compared to controls. A significant positive correlation was found between LS and whole-hand BMD (dominant r=.63, non-dominant r=.67). Finally, the whole hand, metacarpal bones, and carpus BMD measurements were significantly higher in the dominant hand compared to the non-dominant hand without differences in the phalangeal ROI. In conclusion, hand BMD was significantly lower in RA patients compared to control subjects and there was a significant correlation with LS BMD. We demonstrated that BMD measurements of the whole-hand, and different ROI (carpus, metacarpal bones, and phalanges) by DXA would be an easily reproducible technique to evaluate bone loss. In addition, the whole hand, metacarpal bones and carpus BMD measurements were significantly higher in the dominant hand compared to the non-dominant hand without differences in the phalanges.

Análisis de Variables Antropométricas y su Relación con la Fuerza Pinch / Analysis of the Anthropometric Variables and their Relationship with the Pinch Force

Resumen: La evaluación de la fuerza en la mano es utilizada en ámbitos de salud y laborales, está compuesta por la fuerza de agarre y la fuerza de pellizco o fuerza pinch (Palmar Pinch - PP y Key Pinch - KP). La fuerza pinch ha sido poco estudiada y relacionada con variables antropométricas. El objetivo del presente trabajo fue determinar la relación entre la fuerza PP y KP con el género, la dominancia, la edad y variables antropométricas. Haciendo uso de un dinamómetro Jamar y con la participación de 681 sujetos (48,9 % F y 51.1 % M) aparentemente sanos de la Ciudad de Bogotá (Colombia), quienes desempeñaban diferentes actividades ocupacionales, se encontró que las fuerzas PP y KP fueron significativamente más altas en los hombres que en las mujeres tanto en la mano no dominante (8.27 Kgf Vs 6.0 Kgf) como en la mano dominante (8.57 Kgf Vs 6.27 Kgf). Se propusieron modelos predictivos que definieron como variables principales la edad, espesor, circunferencia y circunferencia máxima de la mano. En el género femenino se estableció como variable primordial la edad, mientras que en el masculino en dos modelos se define la circunferencia de la mano y en otros dos la circunferencia máxima de la mano.

Abstract: The evaluation of the force in the hand is used in health and labor fields; it is composed of the grip force and the pinch force (Palmar Pinch - PP and Key Pinch - KP). The pinch force has not had significant amount of studies and connections with anthropometric variables. This work aimed to determine the relationship between the PP and KP strength with gender, dominance, age, and anthropometric variables. Using a Jamar dynamometer and with the participation of 681 subjects apparently healthy (48.9 % F and 51.1 % M) from the City of Bogotá (Colombia), who performed different occupational activities, it was found that the PP and KP forces were significantly higher in men than in women both in the non-dominant hand (8.27 Kgf Vs. 6.0 Kgf) and in the dominant hand (8.57 Kgf Vs 6.27 Kgf). The predictive models proposed in this study defined age, thickness, circumference, and maximum circumference of the hand as the main variables. In the female gender, age was established as the primary variable. At the same time, in the male, the circumference of the hand was defined in two models, and the maximum circumference of the hand in another two.

Whole-hand and regional bone mineral density involvement in rheumatoid arthritis / Compromiso de la densidad mineral ósea de la mano completa y regional en la artritis reumatoide

Rheumatoid arthritis (RA) is a chronic autoimmune disease characterized by symmetric polyarthritis that can lead to joint deformity, disability, and osteoporosis. We aimed to evaluate whole hand and regional BMD in RA patients compared to controls. In addition, we evaluated the BMD of dominant versus non-dominant hands in healthy subjects. We included adult female and male RA patients and control subjects matched by age, sex, and BMI. BMD (g/cm2) was measured by DXA in lumbar spine (LS), whole hand, and three regions of interest: carpus, metacarpal bones, and phalanges. Results: 44 control subjects (49.5±11.8 y) and 60 with RA (52.7±12.7 y) were included. Significant lower BMD in RA patients was found in LS (−8.7%), dominant whole hand (−9.5%), carpus, metacarpal bones, and phalanges, and non-dominant whole hand (−8.7%), metacarpal bones, and phalanges compared to controls. A significant positive correlation was found between LS and whole-hand BMD (dominant r=.63, non-dominant r=.67). Finally, the whole hand, metacarpal bones, and carpus BMD measurements were significantly higher in the dominant hand compared to the non-dominant hand without differences in the phalangeal ROI. In conclusion, hand BMD was significantly lower in RA patients compared to control subjects and there was a significant correlation with LS BMD. We demonstrated that BMD measurements of the whole-hand, and different ROI (carpus, metacarpal bones, and phalanges) by DXA would be an easily reproducible technique to evaluate bone loss. In addition, the whole hand, metacarpal bones and carpus BMD measurements were significantly higher in the dominant hand compared to the non-dominant hand without differences in the phalanges.(AU)

La artritis reumatoide (AR) es una enfermedad autoinmune crónica caracterizada por poliartritis simétrica que puede provocar deformidad e incapacidad articular y osteoporosis. Nuestro objetivo fue evaluar la DMO de manos completa y por regiones en los pacientes con AR en comparación con los controles. Se incluyeron pacientes adultos de ambos sexos con AR, y sujetos controles de edad, sexo e IMC similar. La DMO se midió por DXA en columna lumbar (CL), manos completas y 3 regiones de interés: carpo, metacarpianos y falanges. Resultados: se incluyeron 44 sujetos control (49,5±11,8 años) y 60 con AR (52,7±12,7 años). Se encontró una DMO significativamente más baja en los pacientes con AR en CL (−8,7%), mano completa dominante (−9,5%) y mano completa no dominante (−8,7%) en comparación con los sujetos controles. Se encontró una correlación positiva significativa entre la CL y la DMO de la mano completa (dominante, r=0,63; no dominante, r=0,67). Finalmente, la DMO de la mano completa, los huesos metacarpianos y el carpo fueron significativamente más altos en la mano dominante en comparación con la mano no dominante sin diferencias en la región de las falanges. En conclusión, la DMO de la mano fue significativamente menor en los pacientes con AR en comparación con los sujetos controles, y hubo una correlación significativa con la DMO de la CL. Demostramos que las mediciones de la DMO de toda la mano y diferentes ROI (carpo, huesos metacarpianos y falanges) por DXA serían una técnica fácilmente reproducible para evaluar la pérdida ósea. Además, la DMO de la mano completa, los huesos metacarpianos y el carpo fueron significativamente más altos en la mano dominante en comparación con la mano no dominante.(AU)

Influence of hand dominance, gender, and body mass index on hand grip strength.

Background: Hand grip strength (HGS) measurements serve as an objective measure of upper extremity function. Reliable hand strength evaluation is vital for assessing treatment effectiveness. Objectives: To determine the influence of hand dominance, gender, and body mass index (BMI) on HGS among university students in Ghana. Method: In our cross-sectional study of 304 participants, height, weight, and BMI were measured using a stadiometer and weighing scale. Hand grip strength was assessed with a dynamometer. We compared HGS in dominant and non-dominant hands for males and females using a paired t-test and analysed the correlation between grip strength and weight, height, and BMI using Pearson's correlation coefficient. Results: The mean HGS for right-hand dominant (RHD) male participants was 35.62 kg (± 7.36) for the right hand compared with 32.84 kg (± 7.36) for the left hand. For females RHD the mean HGS in the right hand was 24.60 kg (± 6.42) compared to 22.12 kg (± 5.37) in the left hand. The mean weight, height and BMI of participants were 62.86 kg (± 10.30), 1.67 m (± 0.09) and 22.9 kg/m2 (± 4.9), respectively. A significant relationship existed between HGS and height (r = 0.492; p < 0.01) as well as HGS and BMI (r = 0.290; p < 0.01). However, no notable connection was found between HGS and weight (r = 0.001; p = 0.982). Conclusion: Hand grip strength was significantly stronger in the dominant hand of both males and females. Clinical implications: Physiotherapists should test HGS objectively and quantitatively for use in disease evaluation, diagnosis, and therapy.

Hand Selection in Dribbling Phases: An Analysis of Non-Dominant Hand Usage and Dribble Change in Basketball.

This study investigates the influence of different dribbling phases on hand selection among basketball players across various categories. A total of 33 guard players, including 11 from high school, college, and NBA teams each, were observed. Video data analysis was utilized to determine the frequency of players using their dominant hands (DHs) and non-dominant hands (NDHs) during in-game dribbling phases. The dribbling phases were classified into three categories: First (the initiation of the dribble), Middle (during the dribble but not in First and Last), and Last (the completion of the dribble). Percentage, means, and standard deviations were computed for each category within the First, Middle, and Last measurements. A two-factor analysis of variance (ANOVA) was conducted, considering player category and dribbling phase as factors. The ANOVA revealed significant main effects of player category (p < 0.01) and dribbling phase (p < 0.01). Post hoc multiple comparisons using Holm's method indicated that, in the First phase, players exhibited a 6.5% higher preference for using their NDHs (43.4 ± 11.9%) compared to the Middle phase (36.9 ± 13.9%) (p < 0.05). Similarly, in the Last phase, players displayed a 5.3% greater inclination towards using their NDHs (42.2 ± 11.7%) compared to the Middle phase (p < 0.05). These findings provide quantitative evidence that the specific dribbling phase influences hand selection during gameplay. The implications of these results are significant for basketball coaches, as they can design targeted training programs and drills that simulate game scenarios and encourage NDH usage. By understanding the factors influencing hand choice, players can enhance their versatility and adaptability on the court. Furthermore, these findings contribute to player performance, skill development, and strategic decision making in dribbling phases.

A randomized controlled trial of changes in resting-state functional connectivity associated with short-term motor learning of chopstick use with the non-dominant hand.

INTRODUCTION: This study identified the offline brain networks associated with motor learning of non-dominant hand chopstick use within-session. METHODS: 40 healthy right-handed adults were randomly assigned to the practice and control groups (20 each). The performance, resting-state functional connectivity (RSFC), and their correlation were compared within and between groups. Both groups repeated 9 cycles of 30 s task and rest. During the task, the practice group performed the chopstick-use practice with their left hand, while the control group held chopsticks without acquiring any skills. During the rest, both groups fixated their gaze on a fixation point. The number of times candies were moved using chopsticks with the left hand in 30 s was used to evaluate the performance. RSFC was obtained by resting-state fMRI scanning and extracting Z-scores between the right primary motor cortex and all other brain regions. RESULTS: Both the groups improved in the post-task performance; the practice group improved more. The RSFC of the two networks increased in the practice group. One network was the RSFC between the right M1 and the right cerebellar Crus I, positively correlated with performance in the post-task. Another was the RSFC between the right M1 and the left cerebellar Crus II, positively correlated with skills in the amount of change pre- and post-task. CONCLUSION: Offline enhancement of RSFC in these networks was shown to contribute to early chopstick-use motor learning with the left hand. These results serve as a basis for future studies on compensatory networks in individuals with stroke.

Retrospective multicenter (TRON group) study of humeral shaft fragility fractures: Analysis of mortality rates and risk factors.

AIMS: This study aimed to show the mortality rate following humeral shaft fragility fractures (HSFF) in the elderly. The secondary aim was to examine the predictors associated with mortality in elderly patients who have sustained HSFF. METHODS: From 2011 to 2020, all elderly patients aged 65 years and older with HSFF managed at our nine hospitals were retrospectively identified from our TRON database. Patient demographics and surgical characteristics were extracted from medical records and radiographs, and multivariable Cox regression analysis was used to identify factors affecting mortality. RESULTS: In total, 153 patients who sustained HSFF were included. The mortality rate for HSFF in the elderly was 15.7% at 1 year and 24.6% at 2 years. Multivariable Cox regression analysis showed significant differences in survival for the following variables: older age (p < 0.001), underweight (p = 0.022), severely ill (p = 0.025), mobility limited to indoors (p = 0.003), dominant-side injury (p = 0.027), and nonoperative treatment (p = 0.013). CONCLUSION: The outcome following HSFF in the elderly population appears to be relatively grim. The prognosis of elderly patients with HSFF is closely related to their medical history. In the elderly patients with HSFF, operative treatment should be positively considered while taking into account their medical status.

Using immersive virtual reality to remotely examine performance differences between dominant and non-dominant hands.

Circle drawing may be a useful task to study upper-limb function in patient populations. However, previous studies rely on expensive and bulky robotics to measure performance. For clinics or hospitals with limited budgets and space, this may be unfeasible. Virtual reality (VR) provides a portable and low-cost tool with integrated motion capture. It offers potentially a more feasible medium by which to assess upper-limb motor function. Prior to use with patient populations, it is important to validate and test the capabilities of VR with healthy users. This study examined whether a VR-based circle drawing task, completed remotely using participant's own devices, could capture differences between movement kinematics of the dominant and non-dominant hands in healthy individuals. Participants (n = 47) traced the outline of a circle presented on their VR head-mounted displays with each hand, while the positions of the hand-held controllers were continuously recorded. Although there were no differences observed in the size or roundness of circles drawn with each hand, consistent with prior literature our results did show that the circles drawn with the dominant hand were completed faster than those with the non-dominant hand. This provides preliminary evidence that a VR-based circle drawing task may be a feasible method for detecting subtle differences in function in clinical populations. Supplementary Information: The online version contains supplementary material available at 10.1007/s10055-023-00794-z.

A smart tablet application to quantitatively assess the dominant hand dexterity.

BACKGROUND AND OBJECTIVE: The Nine-Hole Peg Test (NHPT) is the most used test to assess hand dexterity in clinical practice and is considered the gold standard but only evaluates the time needed to complete the task. The aim of this work is to describe a graphic test on a smart tablet to assess in a quantitative as well qualitative way the dominant hand dexterity and to validate it in a cohort of neurological subjects and healthy controls. METHODS: The task consists in asking the subject to connect with a graphic line the start and the end point of a pre-defined path, with two different widths, in the most precise and fastest way possible. The path is constituted by a 'meander' and a 'spiral' part. The subjects perform the task on a smart tablet with a capacitive pen four times. The three parameters of interest considered at each trial are the execution time, length path, and number of interactions with the border. The app automatically computes these three parameters and stores the completed test files. The results of the digital graphic test are compared to the NHPT results. Healthy and pathological subjects are compared to each other, and performances obtained in different repetitions are compared to assess the learning effect in each population. RESULTS: 53 subjects with a definitive diagnosis of neurodegenerative/genetic neurological disorders (34 men, mean age 59.1 ± 16.1) and 78 healthy controls (33 men, mean age 42.5 ± 16.3) were recruited. Among the pathological subjects, 31 also performed the NHPT. The graphic test clearly distinguish between the two populations for all parameters of interest. Moreover, compared to the gold standard NHPT, time has a moderate positive correlation (r = 0.57, p ≤ 0.001), whereas interactions and length have a strong positive correlation (r = 0.81, p ≤ 0.001) and (r = 0.69, p ≤ 0.001), respectively. CONCLUSIONS: The proposed digital test can measure in an accurate, quantitative and qualitative way dominant hand disability and can result more informative with respect to the gold standard NHPT. In homogeneous cohort of subjects (for example affected by multiple sclerosis or Parkinson disease), the digital test can be used as an outcome measure in clinical trials as well as a tool for monitoring disease progression at the dominant hand level.

Transcranial direct current stimulation to the left dorsolateral prefrontal cortex enhances early dexterity skills with the left non-dominant hand: a randomized controlled trial.

BACKGROUND: The left dorsolateral prefrontal cortex (DLPFC) is involved in early-phase manual dexterity skill acquisition when cognitive control processes, such as integration and complexity demands, are required. However, the effectiveness of left DLPFC transcranial direct current stimulation (tDCS) on early-phase motor learning and whether its effectiveness depends on the cognitive demand of the target task are unclear. This study aimed to investigate whether tDCS over the left DLPFC improves non-dominant hand dexterity performance and determine if its efficacy depends on the cognitive demand of the target task. METHODS: In this randomized, double-blind, sham-controlled trial, 70 healthy, right-handed, young adult participants were recruited. They were randomly allocated to the active tDCS (2 mA for 20 min) or sham groups and repeatedly performed the Purdue Pegboard Test (PPT) left-handed peg task and left-handed assembly task three times: pre-tDCS, during tDCS, and post tDCS. RESULTS: The final sample comprised 66 healthy young adults (mean age, 22.73 ± 1.57 years). There were significant interactions between group and time in both PPT tasks, indicating significantly higher performance of those in the active tDCS group than those in the sham group post tDCS (p < 0.001). Moreover, a greater benefit was observed in the left-handed assembly task performance than in the peg task performance (p < 0.001). No significant correlation between baseline performance and benefits from tDCS was observed in either task. CONCLUSIONS: These results demonstrated that prefrontal tDCS significantly improved early-phase manual dexterity skill acquisition, and its benefits were greater for the task with high cognitive demands. These findings contribute to a deeper understanding of the underlying neurophysiological mechanisms of the left DLPFC in the modulation of early-phase dexterity skill acquisition. TRIAL REGISTRATION: This study was registered in the University Hospital Medical Information Network Clinical Trial Registry in Japan (UMIN000046868), Registered February 8, 2022 https://center6.umin.ac.jp/cgi-open-bin/ctr_e/ctr_view.cgi?recptno=R000053467.

The Intercostal Nerves Transfer to the Radial Nerve Branch to the Long Head Triceps Muscle: Influencing Factor and Outcome of 55 Cases.

PURPOSE: The objective of this study was to report the functional outcomes and factors affecting the result of intercostal nerves transfer to the radial nerve branch to the long head triceps muscle for restoration of elbow extension in patients with total brachial plexus palsy or C5 to C7 palsy with the loss of triceps muscle function. METHODS: Fifty-five patients with total brachial plexus palsy or C5 to C7 palsy with no triceps muscle function had a reconstruction of elbow extension by transferring the third to fifth intercostal nerves to the radial nerve branch to the long head triceps muscle. The functional outcomes determined by the Medical Research Council grading were evaluated. Factors influencing the outcomes were determined using logistic regression analysis. RESULTS: At the follow-up of at least 2 years, 36 patients (65%) had antigravity motor function (Medical Research Council grade, ≥3). Multivariable logistic regression analysis showed that the body mass index, time to surgery, and injury of the dominant limb were associated with the outcome. CONCLUSIONS: The third to fifth intercostal nerves transfer to the radial nerve branch to the long head triceps muscle is an effective procedure to restore elbow extension. We would recommend using 3 intercostal nerves without grafts; in cases of nerve root avulsion in which there is no chance of spontaneous recovery, early surgery should be considered. TYPE OF STUDY/LEVEL OF EVIDENCE: Therapeutic IV.

Association between Facial Types and Handedness among Students of Faculty of Basic Medical Sciences Bayero University, Kano

Background: Generally, a person's dominant hand is a simple and precise determinant of his preference for hand use in fine manual tasks. The main tools used in forensics are derived from the relationships between anthropometric features with important physical and /or biological traits. Objective: This study was to determine the association between facial types and handedness among students of the Faculty of Basic Medical Sciences of Bayero University, Kano. Methodology: Cross-sectional study design with a consecutive sampling of 400 (180 males and 220 females) students (aged 18 and above) of the Faculty of Basic Medical Sciences Bayero University, Kano was carried out. Facial height (FH) and facial width (FW) were measured using established landmarks and the facial index (FI) was calculated from them. The dominant handedness of each participant was determined using the writing component of the Edinburgh Handedness Inventory. This procedure involved asking the participants to mention which of their hands was dominant. The participant was then asked to write a sentence regarding the activitieshe/she was carrying out at the point of recruitment to ascertain the claim made by the participants. The sentence was written separately using each hand. All the data obtained were analyzed using statistical software (SPSS version 20.0). Results: The study population was relatively young (21.76 ± 2.77 years). Right-handedness was the commonest hand dominance observed in both males (90.7%) and females (91.7%). The commonest types of face were the hypereuriproscopic 2 (0.5%), Euriproscopic 41 (10.3%), Mesoproscopic 78 (19.5%), Leptoproscopic 127 (31.8%) and Hyperleptoproscopic 152 (37%) facial types. The majority of the participants were right-handed and this was regardless of gender. The prediction of handedness based on facial types (ꭕ2 = 1.39, Df =3, P = 0.85) or facial index (P = 0.92, OR=0.99, CI = 0.82 ­ 1.19) was not statistically significant. Conclusion: The facial types identified among the study population were not associated with their handedness and thus it was not a good predictor of handedness

Comparative Study of the Distal Transverse Arch of the Hand Between the Dominant and Non-Dominant Hands and By Age and Sex / The Japanese Journal of Rehabilitation Medicine

Introduction：The range of motion (ROM) of the distal transverse arch of the hand has not been established and cleared sufficiently.Purpose：The aim of this study was to clarify the differences in the distal transverse arch of the hand in ROM between the dominant and non-dominant hands and by sex and age.Participants：We enrolled 118 healthy participants aged 20-69 years.Results：The average active and passive ROMs of the distal transverse arch of the hand were 135.4° ± 10.3°/168.9° ± 12.1° on the dominant side and 131.8° ± 9.8°/166.9° ± 13.2° on the non-dominant side. Active and passive ROMs were significantly larger on the dominant side than on the non-dominant side (p＜0.001, p＝0.009). The active or passive ROM of the distal transverse arch of the hand on either side did not differ significantly between men and women. However, the ROM of the ring finger component was significantly larger in women than in men on both sides (p＝0.02～0.003). The active and passive ROMs of the distal transverse arch in both hands were significantly smaller in participants aged over 60 years than in those aged up to 60 years (p＜0.05). Moreover, compared to participants in their 20s, participants in their 30s and 40s showed lower passive ROMs of the dominant hand and little finger component of the transversal arch in both hands (p＜0.05).Discussion：Our results suggested that handedness, sex, and age should be considered when managing the distal transverse arch of the hand.

Comparative Study of the Distal Transverse Arch of the Hand Between the Dominant and Non-Dominant Hands and By Age and Sex / The Japanese Journal of Rehabilitation Medicine

Introduction：The range of motion (ROM) of the distal transverse arch of the hand has not been established and cleared sufficiently.Purpose：The aim of this study was to clarify the differences in the distal transverse arch of the hand in ROM between the dominant and non-dominant hands and by sex and age.Participants：We enrolled 118 healthy participants aged 20-69 years.Results：The average active and passive ROMs of the distal transverse arch of the hand were 135.4° ± 10.3°/168.9° ± 12.1° on the dominant side and 131.8° ± 9.8°/166.9° ± 13.2° on the non-dominant side. Active and passive ROMs were significantly larger on the dominant side than on the non-dominant side (p＜0.001, p＝0.009). The active or passive ROM of the distal transverse arch of the hand on either side did not differ significantly between men and women. However, the ROM of the ring finger component was significantly larger in women than in men on both sides (p＝0.02～0.003). The active and passive ROMs of the distal transverse arch in both hands were significantly smaller in participants aged over 60 years than in those aged up to 60 years (p＜0.05). Moreover, compared to participants in their 20s, participants in their 30s and 40s showed lower passive ROMs of the dominant hand and little finger component of the transversal arch in both hands (p＜0.05).Discussion：Our results suggested that handedness, sex, and age should be considered when managing the distal transverse arch of the hand.

Immediate Effects of Fine-Motor Training on Coordination and Dexterity of the Non-Dominant Hand in Healthy Adults: A Randomized Controlled Trial.

Several studies have demonstrated the beneficial effects of mirror training; however, only a few studies in Eastern countries have investigated fine-motor exercises using chopsticks, which have numerous advantages. We aimed to compare changes in coordination and dexterity of the non-dominant hand in healthy adults after conducting fine-motor training with the dominant hand using a mirror. We divided 100 healthy adults (age: 20−40 years) into experimental and control groups (each n = 50). The experimental group placed the non-dominant hand in a mirror box and indirectly imitated the fine-motor exercises conducted with the dominant hand using chopsticks. The control group performed the task with the non-dominant hand using chopsticks. We conducted the Chopsticks Manipulation Test and the Purdue Pegboard Test to assess the pre- and post-intervention coordination and dexterity of the non-dominant hand. Both groups showed a significant post-intervention improvement in coordination and dexterity (p < 0.01). There was no significant between-group difference in the functional improvement of coordination and dexterity (p > 0.05). Fine-motor training using mirrors and chopsticks significantly improved coordination and dexterity of the non-dominant hand. This training could be used to improve activity in brain regions associated with the non-dominant hand in healthy adults.