Right-handed Research Articles

Preparatory movement state enhances premovement EEG representations for brain–computer interfaces

Objective. Motor-related brain–computer interface (BCI) have a broad range of applications, with the detection of premovement intentions being a prominent use case. However, the electroencephalography (EEG) features during the premovement phase are not distinctly evident and are susceptible to attentional influences. These limitations impede the enhancement of performance in motor-based BCI. The objective of this study is to establish a premovement BCI encoding paradigm that integrates the preparatory movement state and validates its feasibility in improving the detection of movement intentions. Methods. Two button tasks were designed to induce subjects into a preparation state for two movement intentions (left and right) based on visual guidance, in contrast to spontaneous premovement. The low frequency movement-related cortical potentials (MRCPs) and high frequency event-related desynchronization (ERD) EEG data of 14 subjects were recorded. Extracted features were fused and classified using task related common spatial patterns (CSP) and CSP algorithms. Differences between prepared premovement and spontaneous premovement were compared in terms of time domain, frequency domain, and classification accuracy. Results. In the time domain, MRCPs features reveal that prepared premovement induce lower amplitude and earlier latency on both contralateral and ipsilateral motor cortex compared to spontaneous premovement, with susceptibility to the dominant hand’s influence. Frequency domain ERD features indicate that prepared premovement induce lower ERD values bilaterally, and the ERD recovery speed after button press is the fastest. By using the fusion approach, the classification accuracy increased from 78.92% for spontaneous premovement to 83.59% for prepared premovement (p < 0.05). Along with the 4.67% improvement in classification accuracy, the standard deviation decreased by 0.95. Significance. The research findings confirm that incorporating a preparatory state into premovement enhances neural representations related to movement. This encoding enhancement paradigm effectively improves the performance of motor-based BCI. Additionally, this concept has the potential to broaden the range of decodable movement intentions and related information in motor-related BCI.

Parkinson's disease patients show delayed hemodynamic changes in primary motor cortex in fine motor tasks and decreased resting-state interhemispheric functional connectivity: a functional near-infrared spectroscopy study.

People with Parkinson's disease (PD) experience changes in fine motor skills, which is viewed as one of the hallmark signs of this disease. Due to its non-invasive nature and portability, functional near-infrared spectroscopy (fNIRS) is a promising tool for assessing changes related to fine motor skills. We aim to compare activation patterns in the primary motor cortex using fNIRS, comparing volunteers with PD and sex- and age-matched control participants during a fine motor task and walking. Moreover, inter and intrahemispheric functional connectivity (FC) was investigated during the resting state. We used fNIRS to measure the hemodynamic changes in the primary motor cortex elicited by a finger-tapping task in 20 PD patients and 20 controls matched for age, sex, education, and body mass index. In addition, a two-minute walking task was carried out. Resting-state FC was also assessed. Patients with PD showed delayed hypoactivation in the motor cortex during the fine motor task with the dominant hand and delayed hyperactivation with the non-dominant hand. The findings also revealed significant correlations among various measures of hemodynamic activity in the motor cortex using fNIRS and different cognitive and clinical variables. There were no significant differences between patients with PD and controls during the walking task. However, there were significant differences in interhemispheric connectivity between PD patients and control participants, with a statistically significant decrease in PD patients compared with control participants. Decreased interhemispheric FC and delayed activity in the primary motor cortex elicited by a fine motor task may one day serve as one of the many potential neuroimaging biomarkers for diagnosing PD.

Relationship between Hand grip strength and Hand function in patients with Stroke: A Cross-Sectional Study

BackgroundHands are vital and inevitable organs. It's essential to evaluate hand function post-stroke as it is a major source of impairment. Grip strength gives a guide to hand function as a measure of impairment. The modified Sphygmomanometer Test (MST) offers an intriguing alternative method for assessing hand grip strength as compared to using hand-held dynamometers. ObjectivesThe study aimed to investigate the correlation between hand grip strength and hand function in stroke patients. MethodsA cross-sectional research was carried out on a group of 45 stroke patients, ranging in age from 40 to 70 years. The assessment included the measurement of hand grip strength through the Modified Sphygmomanometer Test (MST), as well as the evaluation of hand function using the Box and Block Test (BBT) and the Jebsen Taylor Hand Function Test (JTHFT). Correlation analysis was performed using the Pearson correlation coefficient test. ResultsThe outcomes showed a strong to excellent between MST and BBT (r = 0.909, p = 0.000); and between MST and JTHFT Non Dominant Hand (JTHFTNDH, r = −0.669 and p = 0.000). However, there was a weak correlation between MST and JTHFT Dominant Hand, and this correlation was not statistically significant (r = −0.243 and p = 0.108). ConclusionThe findings indicated a relationship between hand grip strength and hand function among stroke patients. MST holds potential as a convenient, objective and cost-effective alternative in clinical settings for evaluating hand grip strength and predicting hand function.

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.

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. Sixty subjects (8 males and 52 females, 18-40years 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 4weeks (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 4weeks post intervention. 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). 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.

Phase angle as an indicator of body composition and physical performance in handball players

BackgroundPhase angle (PhA), obtained from the bioimpedance analysis, is widely used in clinical situations and in sports. This study evaluated the association between PhA with body composition and physical performance of handball athletes.Methods43 national-level players (22.19 ± 3.86 years) of both sexes were evaluated regarding anthropometry, body composition, squat (SJ) and countermovement (CMJ) jumps, handgrip strength, and cardiorespiratory fitness.ResultsWe verified a correlation between PhA of the whole body and fat-free mass (r = 0.511), body mass index (r = 0.307), and body fat % (r = -0.303). There was a positive correlation between PhA of the whole body and SJ (r = 0.376), CMJ (r = 0.419), and handgrip for the dominant hand (r = 0.448). Moreover, PhA of the upper limbs was more strongly correlated with handgrip for the dominant (r = 0.630) and non-dominant hand (r = 0.575) compared to PhA of the whole body considering both sexes. Similarly, segmental PhA had a stronger significant correlation with SJ (r = 0.402) and handgrip for the dominant hand (r = 0.482) in males, as well as CMJ (r = 0.602) in females, compared to PhA of the whole body.ConclusionPhA of the whole body was positively related to fat-free mass, body mass index, body fat %, and lower- and upper-limbs strength in handball athletes. Segmental PhA might be used as a tool for estimating lower and upper limbs performance considering the sex, in preference to the PhA of the whole body.

Beyond words: an investigation of fine motor skills and the verbal communication spectrum in autism.

This study investigated the associations between fine motorskills and expressive verbal abilities in a group of 97 autistic participants (age 8-17, mean=12.41) and 46 typically developing youth (age 8-17, mean=12.48). Participants completed assessments of motor and verbal communication skills, including finger tapping speed, grooved pegboard, grip strength, visual-motor integration tasks, and measures of speech and communication skills. ASD group performance on motor tests was compared to controls. Non-parametric tests were used to analyze group differences and correlations between motor and verbal communication skills. Based on prior research, we hypothesized that individuals on the autism spectrum would exhibit deficits in fine motor speed, dexterity, pencil motor control, but not manual motor strength. Additionally, we expected that impaired fine motor skills would be linked to poorer performance on standardized measures of verbal abilities. The results indicated that 80% of autistic participants demonstrated an impairment on at least one measure of motor skills, and as a group, they exhibited significantly poorer fine motor performance compared to the non-ASD group in dominant hand finger tapping speed, bilateral fine motor dexterity measured via the grooved pegboard task, and pencil motor coordination and visual-motor integration measured on the Beery-Buktenica Developmental Test of Visual-Motor Integration-Sixth Edition. Moreover, impaired fine motor skills were associated with poorer performance on standardized clinical measures of verbal abilities, including articulation errors, receptive and expressive language and vocabulary, rapid naming, oromotor sequencing, and parent reported functional communication skills and social communication symptoms. Overall,our findings suggest there is a high prevalence of fine motor impairments in ASD, and these impairments were associated with a range of verbal abilities. Further research is warranted to better understand the underlying mechanisms of these associations and develop targeted interventions to address both fine motor and verbal impairments in ASD.

Visuotactile integration in individuals with fibromyalgia.

Our brain constantly integrates afferent information, such as visual and tactile information, to perceive the world around us. According to the maximum-likelihood estimation (MLE) model, imprecise information will be weighted less than precise, making the multisensory percept as precise as possible. Individuals with fibromyalgia (FM), a chronic pain syndrome, show alterations in the integration of tactile information. This could lead to a decrease in their weight in a multisensory percept or a general disruption of multisensory integration, making it less beneficial. To assess multisensory integration, 15 participants with FM and 18 pain-free controls performed a temporal-order judgment task in which they received pairs of sequential visual, tactile (unisensory conditions), or visuotactile (multisensory condition) stimulations on the index and the thumb of the non-dominant hand and had to determine which finger was stimulated first. The task enabled us to measure the precision and accuracy of the percept in each condition. Results indicate an increase in precision in the visuotactile condition compared to the unimodal conditions in controls only, although we found no intergroup differences. The observed visuotactile precision was correlated to the precision predicted by the MLE model in both groups, suggesting an optimal integration. Finally, the weights of the sensory information were not different between the groups; however, in the group with FM, higher pain intensity was associated with smaller tactile weight. This study shows no alterations of the visuotactile integration in individuals with FM, though pain may influence tactile weight in these participants.

Left-handedness in otolaryngology, who is right?

This study aimed to ascertain the prevalence of left-handedness (LH) among otolaryngology-head and neck surgery (ORLHN) practitioners, investigate dexterity's impact on LH trainees, and identify common patterns in their training to improve the training experience. A web-based survey was distributed anonymously via email to members of the Saudi Otorhinolaryngology Society. The survey targeted ORLHN attending consultants, board-certified registrars, and current residents. It consisted of three sections: the first focused on the experience of attending consultants in training LH individuals, the second investigated common maneuvers employed by rhinologists, and the third explored the experiences and impacts reported by LH trainees. The study included 174 participants, and found a 13.2% LH prevalence among them. Rhinologists showed disparities, with 50% advising trainees to stand on the left side of the bed and use their left hand for the scope, whereas the other half asked otherwise. Additionally, 94.4% of the participants had not encountered any courses specifically tailored for LH trainees. Among LH trainees, 57% and 41% reported difficulties in learning and performing side-specific procedures such as functional endoscopic sinus surgery and endoscopic septoplasty, respectively, often attempting to switch to their nondominant hand, and feeling disadvantaged due to their laterality. Left-handedness presents challenges for both LH trainees and their trainers in surgical specialties, particularly in ORLHN, in which specific positioning and instruments are crucial to gain access to the desired surgical field. Despite these challenges, there is insufficient support for LH individuals. We recommend encouraging LH trainees to openly disclose and discuss their left-handedness, provide them with mentors, establish standardized operating room setups and techniques, supply appropriate instruments, and demonstrate flexibility in accommodating their needs. Level 5.

Erosive Progression by High-Resolution Peripheral Quantitative Computed Tomography and Conventional Radiography in Rheumatoid Arthritis.

To investigate the diagnostic accuracy of high-resolution peripheral quantitative computed tomography (HR-pQCT) to assess erosive progression during one year compared to conventional radiography (CR) in rheumatoid arthritis (RA). This prospective study included 359 patients with RA (disease duration ≥ 5 years) between March 2018 and October 2020. HR-pQCT and CR were obtained at inclusion and after one year. Erosive assessment was performed at two metacarpophalangeal joints of the dominant hand using HR-pQCT and progression was defined as an increase in erosion number ≥ 1 or an increase in erosive volume > least significant change. CR of hands, wrists, and feet were evaluated using Sharp/van der Heijde scores and erosive progression was defined as a 1.1-point increase in erosion score according to the smallest detectable change. In paired analyses (n = 310), erosive progression was identified in 30 patients using CR and in 40 patients using HR-pQCT. In the 40 patients with erosive progression on HR-pQCT, progression was not identified by CR in 33 patients. Adding HR-pQCT to CR doubled the proportion of patients identified with progression from 30 (10%) to 63 (20%) patients. Using CR as the reference, the sensitivity (% (95% CI)) of HR-pQCT for identifying erosive progression was 23.3 (9.9-42.3) and the specificity was 88.2 (83.8-91.7). A substantial proportion of patients with erosive progression are overlooked using CR only to monitor erosive progression. Adding high-resolution peripheral CT to CR doubles the proportion of patients, who may benefit from individualised therapy targeting erosive progression in RA.

Italian Canyoning Guides: Physiological Profile and Cardiometabolic Demand during Rope Activities.

Canyoning activities require physical effort, highlighting the importance of maintaining a proper physical fitness. Canyoning guides emerge as key figures, not only to ensure safety during the experience but also to handle unforeseen situations promptly. This study aims to assess the physiological profile of canyoning guides and the cardiorespiratory demands experienced during rope activities by means of oxygen uptake and heart rate measurements. Seventeen canyoning guides (42.6 y ± 10.78; BMI of 24.0 kg/m2 ± 2.95) carried out coordinative and conditional tests. The participants showed good values in strength tests (27.3 cm ± 5.97 and 23.3 rep ± 8.06 in SJ and PUp tests, respectively), while the flexibility of males and females was below and well above the average, respectively. A noteworthy result was observed in the reaction test, in which a better performance was recorded with the non-dominant hand (168.1 ms vs. 202.0 ms). All subjects exhibited a low aerobic capacity by means of an RD test (10.6 ua ± 6.62). During rope activities and emergency/support simulations, metabolic and cardiovascular data indicated that a moderate/high effort was exerted, confirmed by an oxidative stress analysis. In conclusion, this study demonstrated how canyoning guides face significant physical requirements, but their physiological profile regarding aerobic power was not appropriate. Therefore, these findings could offer valuable insights into the development of specific training to ensure an appropriate aerobic fitness to perform canyoning safely.

The Association Between Grip Strength, Upper Body Power, and Limb Dominance in a Military Population.

Military service members rely on upper body strength and power to accomplish tasks such as carrying heavy weapons and gear, rappelling, combat grappling, and marksmanship. Early identification of the factors that lead to reduced upper body strength and power would enable leadership to predict and mitigate aspects that decrease military operational readiness and increase injury risk. The purpose of this study was to investigate the relationship between grip strength and upper body power in U.S. Infantry Marines. We hypothesized that dominant arm grip strength would show a strong positive correlation with upper body power and that the dominant arm would be more powerful than the non-dominant arm. A total of 120 U.S. Marines completed 3 maximum effort isometric grip strength trials with their dominant hand and 3 maximum effort ballistic pushups on a ForceDecks force plate system. Force plate data were used to estimate pushup height and peak power. Maximum grip strength, pushup height, and peak power across the 3 trials were used for analysis. Pearson's correlation was used to test for associations between peak power, pushup height, and grip strength. Paired t-tests were used to test for differences in peak power between the dominant and non-dominant arms. A very weak correlation was found between grip strength and upper body power, but there was no relationship between grip strength and pushup height. Additionally, there were no significant differences in upper body power between the dominant and non-dominant arms. The results of this study suggest that grip strength is not predictive of upper body power and cannot be used as a stand-alone measure of physical readiness in a military unit. These findings do not, however, degrade the potential of both measures to predict and inform health status and physical readiness. Future prospective research should be conducted to determine if either of these measures can be used as indicators of performance and/or injury susceptibility and if limb dominance plays a role in injury incidence within the upper extremity.

Impact of Handedness on Driver’s Situation Awareness When Driving under Unfamiliar Traffic Regulations

Situation awareness (SA) describes an individual’s understanding of their surroundings and actions in the near future based on the individual’s comprehension and understanding of the surrounding inputs. SA measurements can be applied to improve system performance or human effectiveness in many fields of study, including driving. However, in some scenarios drivers might need to drive in unfamiliar traffic regulations (UFTRs), where the traffic rules and vehicle configurations are a bit different from what the drivers are used to under familiar traffic regulations. Such driving conditions require drivers to adapt their attention, knowledge, and reactions to safely reach the destination. This ability is influenced by the degree of handedness. In such tasks, mixed-/left-handed people show better performance than strong right-handed people. This paper aims to explore the influence of the degree of handedness on SA when driving under UFTRs. We analyzed the SA of two groups of drivers: strong right-handed drivers and mixed-/left-handed drivers. Both groups were not familiar with driving in keep-left traffic regulations. Using a driving simulator, all participants drove in a simulated keep-left traffic system. The participants’ SA was measured using a subjective assessment, named the Participant Situation Awareness Questionnaire PSAQ, and performance-based assessment. The results of the study indicate that mixed-/left-handed participants had significantly higher SA than strong right-handed participants when measured by performance-based assessment. Also, in the subjective assessment, mixed-/left-handed participants had significantly higher PSAQ performance scores than strong right-handed participants. The findings of this study suggest that advanced driver assistance systems (ADAS), which show improvement in road safety, should adapt the system functionality based on the driver’s degree of handedness when driving under UFTRs.

How we perceive the width of grasped objects: Insights into the central processes that govern proprioceptive judgements.

Low-level proprioceptive judgements involve a single frame of reference, whereas high-level proprioceptive judgements are made across different frames of reference. The present study systematically compared low-level (grasp grasp) and high-level (vision grasp, grasp vision) proprioceptive tasks, and quantified the consistency of grasp vision and possible reciprocal nature of related high-level proprioceptive tasks. Experiment 1 (n = 30) compared performance across vision grasp, a grasp vision and a grasp grasp tasks. Experiment 2 (n = 30) compared performance on the grasp vision task between hands and over time. Participants were accurate (mean absolute error 0.27 cm [0.20 to 0.34]; mean [95% CI]) and precise ( = 0.95 [0.93 to 0.96]) for grasp grasp judgements, with a strong correlation between outcomes (r = -0.85 [-0.93 to -0.70]). Accuracy and precision decreased in the two high-level tasks ( = 0.86 and 0.89; mean absolute error = 1.34 and 1.41 cm), with most participants overestimating perceived width for the vision grasp task and underestimating it for grasp vision task. There was minimal correlation between accuracy and precision for these two tasks. Converging evidence indicated performance was largely reciprocal (inverse) between the vision grasp and grasp vision tasks. Performance on the grasp vision task was consistent between dominant and non-dominant hands, and across repeated sessions a day or week apart. Overall, there are fundamental differences between low- and high-level proprioceptive judgements that reflect fundamental differences in the cortical processes that underpin these perceptions. Moreover, the central transformations that govern high-level proprioceptive judgements of grasp are personalised, stable and reciprocal for reciprocaltasks. KEY POINTS: Low-level proprioceptive judgements involve a single frame of reference (e.g. indicating the width of a grasped object by selecting from a series of objects of different width), whereas high-level proprioceptive judgements are made across different frames of reference (e.g. indicating the width of a grasped object by selecting from a series of visible lines of different length). We highlight fundamental differences in the precision and accuracy of low- and high-level proprioceptive judgements. We provide converging evidence that the neural transformations between frames of reference that govern high-level proprioceptive judgements of grasp are personalised, stable and reciprocal for reciprocal tasks. This stability is likely key to precise judgements and accurate predictions in high-level proprioception.

Side of chute does not affect the sensitivity of Tritrichomonas foetus sample collection in bulls when using dominant hand for collection

Tritrichomonas foetus, a sexually transmitted disease in cattle, continues to plague the cattle industry despite years of control programs. One reason for this continued prevalence through­out the U.S. and the world is that accurate diagnosis is compli­cated in the fact that retrieval of organisms for diagnosis and subsequent testing may be compromised by multiple factors in­cluding, but not limited to, how samples are collected. A commonly used sampling technique for diagnosing T. foetus in bulls is scraping of the preputial and penile mucosa with ei­ther an artificial insemination pipette or specially designed T. foetus testing device such as the Pizzle Stick Trich Testing De­vice (Lane Manufacturing Denver, CO). Parker et al. noted that right-hand dominant practitioners were more commonly suc­cessful in retrieving T. foetus in known positive bulls when col­lecting from the right side of the bull compared to the left; how­ever, the opposite was not investigated for left-hand dominant practitioners and only cultures were used to declare whether a sample was positive or not. The objective of this study was to determine if using current RT-qPCR testing if there is a differ­ence in rate of positive tests pending side of chute and use of dominant hand for testing.

Impact of long-term white matter hyperintensity changes on mobility and dexterity.

White matter hyperintensities (WMH), a common feature of cerebral small vessel disease, are related to worse clinical outcomes after stroke. We assessed the impact of white matter hyperintensity changes over 1 year after minor stroke on change in mobility and dexterity, including differences between the dominant and non-dominant hands and objective in-person assessment versus patient-reported experience. We recruited participants with lacunar or minor cortical ischaemic stroke, performed medical and cognitive assessments and brain MRI at presentation and at 1 year. At both time points, we used the timed-up and go test and the 9-hole peg test to assess mobility and dexterity. At 1 year, participants completed the Stroke Impact Scale. We ran two linear mixed models to assess change in timed-up and go and 9-hole peg test, adjusted for age, sex, stroke severity (National Institutes of Health Stroke Scale), dependency (modified Rankin Score), vascular risk factor score, white matter hyperintensity volume (as % intracranial volume) and additionally for 9-hole peg test: Montreal cognitive assessment, hand (dominant/non-dominant), National Adult Reading Test (premorbid IQ), index lesion side. We performed ordinal logistic regression, corrected for age and sex, to assess relations between timed-up and go and Stroke Impact Scale mobility, and 9-hole peg test and Stroke Impact Scale hand function. We included 229 participants, mean age 65.9 (standard deviation = 11.13); 66% male. 215/229 attended 1-year follow-up. Over 1 year, timed-up and go time increased with aging (standardized β [standardized 95% Confidence Interval]: 0.124[0.011, 0.238]), increasing National Institutes of Health Stroke Scale (0.106[0.032, 0.180]), increasing modified Rankin Score (0.152[0.073, 0.231]) and increasing white matter hyperintensity volume (0.176[0.061, 0.291]). Men were faster than women (-0.306[0.011, 0.238]). Over 1 year, slower 9-hole peg test was related to use of non-dominant hand (0.290[0.155, 0.424]), aging (0.102[0.012, 0.192]), male sex (0.182[0.008, 0.356]), increasing National Institutes of Health Stroke Scale (0.160 [0.094, 0.226]), increasing modified Rankin Score (0.100[0.032, 0.169]), decreasing Montreal cognitive assessment score (-0.090[-0.167, -0.014]) and increasing white matter hyperintensity volume (0.104[0.015, 0.193]). One year post-stroke, Stroke Impact Scale mobility worsened per second increase on timed-up and go, odds ratio 0.67 [95% confidence interval 0.60, 0.75]. Stroke Impact Scale hand function worsened per second increase on the 9-hole peg test for the dominant hand (odds ratio 0.79 [0.71, 0.86]) and for the non-dominant hand (odds ratio 0.88 [0.83, 0.93]). Decline in mobility and dexterity is associated with white matter hyperintensity volume increase, independently of stroke severity. Mobility and dexterity declined more gradually for stable and regressing white matter hyperintensity volume. Dominant and non-dominant hands might be affected differently. In-person measures of dexterity and mobility are associated with self-reported experience 1-year post-stroke.

Age-related differences in finger interdependence during complex hand movements.

The well-known decrease in finger dexterity during healthy aging leads to a significant reduction in quality of life. Still, the exact patterns of altered finger kinematics of older adults in daily life are fairly unexplored. Finger interdependence is the unintentional comovement of fingers that are not intended to move, and it is known to vary across the lifespan. Nevertheless, the magnitude and direction of age-related differences in finger interdependence are ambiguous across studies and tasks and have not been explored in the context of daily life finger movements. We investigated five different free and daily-life-inspired finger movements of the right, dominant hand as well as a sequential finger tapping task of the thumb against the other fingers, in 17 younger (22-37 yr) and 17 older (62-80 yr) adults using an exoskeleton data glove for data recording. Using inferential statistics, we found that the unintentional comovement of fingers generally decreases with age in all performed daily-life-inspired movements. Finger tapping, however, showed a trend towards higher finger interdependence for older compared with younger adults. Using machine learning, we predicted the age group of a person from finger interdependence features of single movement trials significantly better than chance level for the daily-life-inspired movements, but not for finger tapping. Taken together, we show that for specific tasks, decreased finger interdependence (i.e., less comovement) could potentially act as a marker of human aging that specifically characterizes older adults' complex finger movements in daily life.NEW & NOTEWORTHY Kinematic finger movement data were analyzed with regard to age-related differences. Extensive analyses of complex and daily-life-inspired movements reveal that the direction of age effects is not uniform but task-dependent: Although older adults generally show more finger interdependence than younger adults in a simple finger tapping task, this effect is reversed for daily-life-inspired movement tasks. For these tasks, finger interdependence indices offer potential new markers to predict the age group of an individual using machine learning approaches.

Implicit visuospatial sequence representations are accessible in both the practice and the transfer hand

A serial reaction time task was used to test whether the representations of a probabilistic second-order sequence structure are (i) stored in an effector-dependent, effector-independent intrinsic or effector-independent visuospatial code and (ii) are inter-manually accessible. Participants were trained either with the dominant or non-dominant hand. Tests were performed with both hands in the practice sequence, a random sequence, and a mirror sequence. Learning did not differ significantly between left and right-hand practice, suggesting symmetric intermanual transfer from the dominant to the non-dominant hand and vice versa. In the posttest, RTs were shorter for the practice sequence than for the random sequence, and longest for the mirror sequence. Participants were unable to freely generate or recognize the practice sequence, indicating implicit knowledge of the probabilistic sequence structure. Because sequence-specific learning did not differ significantly between hands, we conclude that representations of the probabilistic sequence structure are stored in an effector-independent visuospatial code.

Hand Motion Analysis Using Accelerometer-Based Sensors and Sheep's Head Model for Basic Training in Functional Endoscopic Sinus Surgery.

Motion analysis, the study of movement patterns to evaluate performance, plays a crucial role in surgical training. It provides objective data that canbe usedto assess and improve trainee's precision, efficiency, and overall surgical technique. The primary aim of this study is to employ accelerometer-based sensors placed on the wrist to analyze hand motions during endoscopic sinus surgery training using the sheep's head. By capturing detailed movement data, the study seeks to quantify the motion characteristics that distinguish different levels of surgical expertise. This approach seeks to quantify motion characteristics indicative of surgical expertise and enhance the objectivity and effectiveness of surgical training feedback mechanisms. Twenty-four participantswere dividedinto three groups based on their experience with endoscopic endonasal surgery. Each participantwas tasked with performingspecified procedures on an individual sheep's head, concentrating on exploring both nasal passages. A single Bluetooth Accelerometer WitMotion sensorwas mountedon the dorsal surface of each hand.Thisfacilitates the evaluation of efficiency parameters such as time, path length, and acceleration during the training procedures. Accelerometer data were collected and imported in CSV format (comma-separated values) for each group of surgeons-senior, specialist, and resident-mean values and standard deviationswere computed. The Shapiro-Wilk Test assessed the normality of the distribution. The Kruskal-Wallis test was employed to compare procedural time, acceleration, and path length differences across the three surgeon experience levels. For the procedural time, statistical significance appears in all surgical steps (p<0.001), with thebiggestdifference in the septoplasty group in favor of the senior group. A clear difference can be observed between the resulting acceleration of the dominant hands (instrument hand) and the non-dominant hand (endoscopic hand) and between the study groups. The difference between groups reaches statistical significance with a p-value <0.001. A statistically significant difference canbe seenbetween the paths covered by each hand of every participant (p<0.001). Also, senior doctors covered significantly less movement with both hands than the specialists and the resident doctors (p<0.001). The data showa clearlearning curve from resident to senior,with residents taking more time and using more hand movementsto complete the same tasks. Specialists are in the intermediate phase, showing signs of honing their technique towards efficiency. This comprehensive data set can help tailor training programs to focus onbothefficiency (quicker procedures) and economy of motion (reduced path length and acceleration), especially in more complex procedures where the difference in performance ismore pronounced.

Flow-Through Procedure in Sequela After Complex Injuries of the Hand With Fingers’ Amputation

PurposeComplex injuries of the hand with finger amputation can result in important functional impairment. If the amputated fingers cannot be replanted, the developed sequelae should be further evaluated. Sometimes, in the presence of a few remaining local vascular resources, the use of the flow-through technique can help in solving the problem. MethodsThis study retrospectively reviews 4 cases who underwent single or multiple fingers reconstruction with toe transfers by using true flow-through or flow-through conduit flaps. A thorough description of the two methods is done, and the quality of the regained functionality of the hand is presented. ResultsAll the patients were males, aged between 21 and 45 (median age 31.75). One of them injured the left dominant hand, and the other three their right dominant hand. The median time between the accident and reconstructive surgery was 14.5 months (range, 3 months-36 months). All the initial lesions were work-related trauma. One patient had severe sequela after forearm compartment syndrome and amputation of the thumb and fifth finger; one patient had a metacarpal hand, one patient had amputation of two fingers (2nd and 4th); and one patient had three fingers amputated (2nd, 3rd, and 4th). In the first patient, a true flow-through flap and a second toe transfer was done, and in the other three patients multiple toe transfers by using the flow-through conduit technique were used. A good functionality of the reconstructed hand was obtained in all the patients. ConclusionsToe transfer remains one of the best methods in the reconstruction of hands with missing fingers. The use of both true flow-through flap and flow-through conduit methods are very useful, especially in cases with few vascular resources.

Deep burn surgery of the whole dorsum of the hand: Composite skin grafting over acellular dermal matrix versus thick split-thickness skin grafting.

Preservation and restoration of hand function after burn injuries are challenging yet imperative. This study aimed to assess the curative effect of a composite skin graft over an acellular dermal matrix (ADM) and a thick split-thickness skin graft (STSG) for treating deep burns on the hand. Patients who met the inclusion criteria at the First Affiliated Hospital of Wenzhou Medical University between September 2011 and January 2020 were retrospectively identified from the operative register. We investigated patient characteristics, time from operation to the start of active motion exercise, take rates of skin graft 7 days post-surgery, donor site recovery, complications and days to complete healing. Patients were followed up for 12 months to evaluate scar quality using the Vancouver Scar Scale (VSS) and hand function through total active motion (TAM) and the Jebsen-Taylor Hand Function Test (JTHFT). A total of 38 patients (52 hands) who received thin STSG on top of the ADM or thick STSG were included. The location of the donor sites was significantly different between Group A (thick STSG) and Group B (thin STSG + ADM) (p = 0.03). There were no statistical differences in age, gender, underlying disease, cause of burn, burn area, dominant hand, patients with two hands operated on and time from burn to surgery between the two groups (p > 0.05). The time from operation to the start of active motion exercise, take rates of skin graft 7 days post-surgery and days to complete healing were not significantly different between Group A and Group B (p > 0.05). The rate of donor sites requiring skin grafting was lower in Group B than in Group A (22.2% vs. 100%, p < 0.001). There were no statistically significant differences in complications between the groups (p = 0.12). Moreover, 12 months postoperatively, the pliability subscore in the VSS was significantly lower in Group A than in Group B (p = 0.01). However, there were no statistically significant differences in vascularity (p = 0.42), pigmentation (p = 0.31) and height subscores (p = 0.13). The TAM and JTHFT results revealed no statistically significant differences between the two groups (p = 0.22 and 0.06, respectively). The ADM combined with thin STSG is a valuable approach for treating deep and extensive hand burns with low donor site morbidity. It has a good appearance and function in patients with hand burns, especially in patients with limited donor sites.