Hand Actions Research Articles

Automated Gesture Recognition Using Zebra Optimization Algorithm with Deep Learning Model for Visually Challenged People

Gesture recognition for visually challenged people plays a vital role in improving their convenience and interaction with digital gadgets and environments. It includes improvement of systems that permit them to relate with digital devices by using hand actions or gestures. To improve user-friendliness, these systems select in-built and effortlessly learnable gestures, often integrating wearable devices prepared with sensors for precise detection. Incorporating auditory or haptic feedback devices offers real-time cues about achievement of familiar gestures. Machine learning (ML) and deep learning (DL) methods are useful tools for accurate gesture detection, with customization choices to accommodate individual preferences. In this view, this article concentrates on design and development of Automated Gesture Recognition using Zebra Optimization Algorithm with Deep Learning (AGR-ZOADL) model for Visually Challenged People. The AGR-ZOADL technique aims to recognize the gestures to aid visually challenged people. In the AGR-ZOADL technique, the primary level of data pre-processing is involved by median filtering (MF). Besides, the AGR-ZOADL technique applies NASNet model to learn complex features from the preprocessed data. To enhance performance of NASNet technique, ZOA based hyperparameter procedure performed. For gesture recognition process, stacked long short term memory (SLSTM) model is applied. The performance validation of AGR-ZOADL technique carried out using a benchmark dataset. The experimental values stated that AGR-ZOADL methodology extents significant performance over other present approaches

Therapy effect on hand function after home use of a wearable assistive soft-robotic glove supporting grip strength.

Soft-robotic gloves with an assist-as-needed control have the ability to assist daily activities where needed, while stimulating active and highly functional movements within the user's possibilities. Employment of hand activities with glove support might act as training for unsupported hand function. To evaluate the therapeutic effect of a grip-supporting soft-robotic glove as an assistive device at home during daily activities. This multicentre intervention trial consisted of 3 pre-assessments (averaged if steady state = PRE), one post-assessment (POST), and one follow-up assessment (FU). Participants with chronic hand function limitations were included. Participants used the Carbonhand glove during six weeks in their home environment on their most affected hand. They were free to choose which activities to use the glove with and for how long. The primary outcome measure was grip strength, secondary outcome measures were pinch strength, hand function and glove use time. 63 patients with limitations in hand function resulting from various disorders were included. Significant improvements (difference PRE-POST) were found for grip strength (+1.9 kg, CI 0.8 to 3.1; p = 0.002) and hand function, as measured by Jebson-Taylor Hand Function Test (-7.7 s, CI -13.4 to -1.9; p = 0.002) and Action Research Arm Test (+1.0 point, IQR 2.0; p≤0.001). Improvements persisted at FU. Pinch strength improved slightly in all fingers over six-week glove use, however these differences didn't achieve significance. Participants used the soft-robotic glove for a total average of 33.0 hours (SD 35.3), equivalent to 330 min/week (SD 354) or 47 min/day (SD 51). No serious adverse events occurred. The present findings showed that six weeks use of a grip-supporting soft-robotic glove as an assistive device at home resulted in a therapeutic effect on unsupported grip strength and hand function. The glove use time also showed that this wearable, lightweight glove was able to assist participants with the performance of daily tasks for prolonged periods.

Multisensory Integration in Body Representation.

To be aware of and to move one's body, the brain must maintain a coherent representation of the body. While the body and the brain are connected by dense ascending and descending sensory and motor pathways, representation of the body is not hardwired. This is demonstrated by the well-known rubber hand illusion in which a visible fake hand is erroneously felt as one's own hand when it is stroked in synchrony with the viewer's unseen actual hand. Thus, body representation in the brain is not mere maps of tactile and proprioceptive inputs, but a construct resulting from the interpretation and integration of inputs across sensory modalities.

Performance during object retrieval tasks in young children with and without Down syndrome: A pilot study

AbstractObject retrieval skills requiring means‐end exploration are an area of relative weakness in young children with Down syndrome (DS). The current pilot study examined the object retrieval skills of a small sample of young children with DS for tasks with varying level of complexity. Thirteen children with DS (31.55 ± 4.14 months) and 13 mental age‐matched typically developing (TD) children (17.31 ± 1.64 months) completed three tasks involving retrieving a toy from a transparent box (Task 1), an opaque box (Task 2) and a transparent box hidden inside an opaque box (Task 3). Both DS and TD group performed similarly for the simpler Task 1, but for Tasks 2 and 3, the DS group had a lower success rate, less frequent use of complex asymmetric hand actions and/or longer execution times compared to the TD group. Future studies should examine the developmental trends and specificity of means‐end exploratory behaviours in children with DS.

A New Fusion Feature Selection Model (FFSM) based Feature Extraction System for Hand Gesture Recognition

The research presented here proposes a unique approach for exact feature extraction that makes use of the Fusion Feature Selection Model (FFSM). The method encompasses various stages to preprocess and extract crucial features from first-person hand action (FHPA) images. Preprocessing involves video-to-frame conversion, RGB to grayscale conversion, an improved median filter, and Gaussian blur-based image smoothing. Segmentation is achieved using the Improved SwinNet to identify meaningful regions within the images. Feature extraction employs the Gabor Line Derivative (GLD) method, Active Shape Model (ASM), and Histogram of Oriented Gradients (HOG) to capture texture, edge, and shape information, respectively. Extensive experimental evaluations demonstrate the effectiveness of our proposed approach, achieving remarkable performance in accurate feature extraction tasks.

Age-related differences in the interhemispheric asymmetry of local cortical responses to abstract and concrete verbs in children: a magnetic mismatch negativity study

BACKGROUND: The development of brain neural networks that support lexico-semantic processing in children remains a poorly understood topic in neuroscience. Meanwhile, investigations in adults have provided ample evidence regarding the brain circuits underpinning the processing of abstract and concrete semantics. These studies have shown that interhemispheric asymmetry in neural responses across modal and amodal cortical areas might be an important marker that helps in distinguishing these two types of semantics, with more left-lateralized activity patterns for abstract than concrete word comprehension. However, little is known about such distinctions in children; thus, addressing this gap was the goal of this study. AIM: This study aimed to investigate age-related differences in the lateralization of neural response patterns associated with the processing of abstract and concrete semantics in children. METHODS: This study employed magnetoencephalography and a mismatch negativity (MMN) paradigm in a group of 41 healthy children aged 5–13 years. The participants were passively exposed to the auditory series of abstract and concrete Russian verbs presented outside the focus of attention. Spatiotemporal patterns of the dynamics of neuromagnetic sources activity were reconstructed using minimum-norm estimate within predefined regions of interest: primary auditory cortex, primary motor cortex, and inferior frontal gyrus of both hemispheres. The magnitudes of MMN responses were further compared statistically between the two hemispheres within two age groups: younger (aged 5–9 years) and older (aged 10–13 years) children. RESULTS: Regionally specific differences were found in the lateralization of event-related MMN responses to concrete compared with abstract words in motor and inferior frontal cortical areas (paired permutation tests, p 0.05). Moreover, in the younger group (aged 5–9 years), responses to the abstract and pseudoword stimulus were left-lateralized, and this effect was most pronounced in the inferior frontal regions (45 and 47 Brodmann fields) of the left hemisphere. In the older group (aged 10–13 years), no pronounced left-lateralized response was observed in these areas. However, for the concrete hand action verb stimulus, different patterns of the interhemispheric asymmetry of the hand motor area responses were observed: the response in the younger group was right-lateralized, whereas in the older group, the response was bilateral. CONCLUSION: The present area- and hemisphere-specific dynamics of neuromagnetic responses in the motor cortex and Broca’s area might correlate with the age-related changes in neurocognitive strategies for the comprehension of abstract and concrete language.

A Real-Time Subway Driver Action Sensoring and Detection Based on Lightweight ShuffleNetV2 Network

The driving operations of the subway system are of great significance in ensuring the safety of trains. There are several hand actions defined in the driving instructions that the driver must strictly execute while operating the train. The actions directly indicate whether equipment is normally operating. Therefore, it is important to automatically sense the region of the driver and detect the actions of the driver from surveillance cameras to determine whether they are carrying out the corresponding actions correctly or not. In this paper, a lightweight two-stage model for subway driver action sensoring and detection is proposed, consisting of a driver detection network to sense the region of the driver and an action recognition network to recognize the category of an action. The driver detection network adopts the pretrained MobileNetV2-SSDLite. The action recognition network employs an improved ShuffleNetV2, which incorporates a spatial enhanced module (SEM), improved shuffle units (ISUs), and shuffle attention modules (SAMs). SEM is used to enhance the feature maps after convolutional downsampling. ISU introduces a new branch to expand the receptive field of the network. SAM enables the model to focus on important channels and key spatial locations. Experimental results show that the proposed model outperforms 3D MobileNetV1, 3D MobileNetV3, SlowFast, SlowOnly, and SE-STAD models. Furthermore, a subway driver action sensoring and detection system based on a surveillance camera is built, which is composed of a video-reading module, main operation module, and result-displaying module. The system can perform action sensoring and detection from surveillance cameras directly. According to the runtime analysis, the system meets the requirements for real-time detection.

No Evidence for Cross-Modal fMRI Adaptation in Macaque Parieto-Premotor Mirror Neuron Regions.

To probe the presence of mirror neurons in the human brain, cross-modal fMRI adaptation has been suggested as a suitable technique. The rationale behind this suggestion is that this technique allows making more accurate inferences about neural response properties underlying fMRI voxel activations, beyond merely showing shared voxels that are active during both action observation and execution. However, the validity of using cross-modal fMRI adaptation to demonstrate the presence of mirror neurons in parietal and premotor brain regions has been questioned given the inconsistent and weak results obtained in human studies. A better understanding of cross-modal fMRI adaptation effects in the macaque brain is required as the rationale for using this approach is based on several assumptions related to macaque mirror neuron response properties that still need validation. Here, we conducted a cross-modal fMRI adaptation study in macaque monkeys, using the same action execution and action observation tasks that successfully yielded mirror neuron region cross-modal action decoding in a previous monkey MVPA study. We scanned two male rhesus monkeys while they first executed a sequence of either reach-and-grasp or reach-and-touch hand actions and then observed a video of a human actor performing these motor acts. Both whole-brain and region-of-interest analyses failed to demonstrate cross-modal fMRI adaptation effects in parietal and premotor mirror neuron regions. Our results, in line with previous findings in non-human primates, show that cross-modal motor-to-visual fMRI adaptation is not easily detected in monkey brain regions known to house mirror neurons. Thus, our results advocate caution in using cross-modal fMRI adaptation as a method to infer whether mirror neurons can be found in the primate brain.

The parietal architecture binding cognition to sensorimotor integration: a multimodal causal study.

Despite human's praxis abilities are unique among primates, comparative observations suggest that these cognitive motor skills could have emerged from exploitation and adaptation of phylogenetically older building blocks, namely the parieto-frontal networks subserving prehension and manipulation. Within this framework, investigating to which extent praxis and prehension-manipulation overlap and diverge within parieto-frontal circuits could help in understanding how human cognition shapes hand actions. This issue has never been investigated by combining lesion mapping and direct electrophysiological approaches in neurosurgical patients. To this purpose, 79 right-handed left-brain tumour patient candidates for awake neurosurgery were selected based on inclusion criteria. First, a lesion mapping was performed in the early postoperative phase to localize the regions associated with an impairment in praxis (imitation of meaningless and meaningful intransitive gestures) and visuo-guided prehension (reaching-to-grasping) abilities. Then, lesion results were anatomically matched with intraoperatively identified cortical and white matter regions, whose direct electrical stimulation impaired the Hand Manipulation Task. The lesion mapping analysis showed that prehension and praxis impairments occurring in the early postoperative phase were associated with specific parietal sectors. Dorso-mesial parietal resections, including the superior parietal lobe and precuneus, affected prehension performance, while resections involving rostral intraparietal and inferior parietal areas affected praxis abilities (covariate clusters, 5000 permutations, cluster-level family-wise error correction P < 0.05). The dorsal bank of the rostral intraparietal sulcus was associated with both prehension and praxis (overlap of non-covariate clusters). Within praxis results, while resection involving inferior parietal areas affected mainly the imitation of meaningful gestures, resection involving intraparietal areas affected both meaningless and meaningful gesture imitation. In parallel, the intraoperative electrical stimulation of the rostral intraparietal and the adjacent inferior parietal lobe with their surrounding white matter during the hand manipulation task evoked different motor impairments, i.e. the arrest and clumsy patterns, respectively. When integrating lesion mapping and intraoperative stimulation results, it emerges that imitation of praxis gestures first depends on the integrity of parietal areas within the dorso-ventral stream. Among these areas, the rostral intraparietal and the inferior parietal area play distinct roles in praxis and sensorimotor process controlling manipulation. Due to its visuo-motor 'attitude', the rostral intraparietal sulcus, putative human homologue of monkey anterior intraparietal, might enable the visuo-motor conversion of the observed gesture (direct pathway). Moreover, its functional interaction with the adjacent, phylogenetic more recent, inferior parietal areas might contribute to integrate the semantic-conceptual knowledge (indirect pathway) within the sensorimotor workflow, contributing to the cognitive upgrade of hand actions.

Bimanual Asymmetric Coordination in a Three-Dimensional Zooming Task Based on Leap Motion: Implications for Upper Limb Rehabilitation

This paper explores the practicability of bimanual asymmetric interaction and the factors affecting it when manipulating virtual three-dimensional objects through Leap, a novel hand motion capture device. This research has the potential to aid in the rehabilitation of people with upper limb function impairments. The participants were asked to enlarge a virtual three-dimensional box device to a predefined specified scale. Three influencing factors were addressed, i.e., task difficulty, task allocation and interactive mode. The results indicate that all factors have significant effects on movement time. However, analysis of variance tests shows that there are significant effects on the error rate and spatial patterns due to task difficulty and interactive mode, while no significant effects are found for task allocation. Additionally, task allocation is observed to have significant effects on the time of each hand from zooming phase onset to peak velocity. The action of the nondominant hand is coarser than that of the dominant hand. Interestingly, the velocities of both hands synchronized as the task difficulty level increased, even though the limbs moved at quite different speeds in the initial stage. This research provides insights into how one hand coordinates with the other in terms of the temporal aspects of movement kinematics and thus can help in designing rehabilitative devices that interact with the healthy hand.

Meaning in hand: Investigating shared mechanisms of motor imagery and sensorimotor simulation in language processing

There is substantial evidence to support grounded theories of semantic representation, however the mechanisms of simulation in most theories are underspecified. In the present study, we used an individual differences approach to test whether motor imagery may share some mechanisms with sensorimotor simulations engaged during semantic processing. We quantified individual differences in motor imagery ability via implicit imagery tasks and explicit imagery questionnaires and tested their relationship to sensorimotor effects in syntactic classification tasks. In Experiment 1 (N = 185) we tested relationships between motor imagery and semantic processing of body-object interaction meaning (BOI; the degree to which you can interact with a word's referent) and foot/leg action meaning. We observed two interactions between imagery ability measured on the Florida Praxis Imagery Questionnaire (FPIQ) and BOI effects in semantic processing (response time and accuracy). In both interactions poorer imagery ability was associated with null BOI effects, whereas better imagery was associated with BOI effects. We also observed faster and more accurate responses to verbs associated with more foot/leg action meaning than verbs with less foot/leg action meaning, but this foot/leg action effect did not significantly interact with individual differences in motor imagery. In Experiment 2 (N = 195) we tested whether the interactions observed in Experiment 1 were dependent on the object-directed nature of the actions, or whether similar effects would be observed for hand actions not associated with objects. We also expanded our investigation beyond hand and foot imagery to consider whole body imagery. We observed an interaction between performance on a hand laterality judgement task (HLJT; assessing hand motor imagery) and sensorimotor effects in semantic processing of verbs associated with hand/arm action meaning. Participants with the fastest responses on the most difficult trials of the HLJT showed no significant difference in their response times to words with high and low hand/arm action meaning. We also observed faster and more accurate responses to high relative to low embodiment verbs, but this sensorimotor effect did not interact with individual differences in motor imagery. The results suggest specific (and not general) associations, in that some, but not all forms of hand and object-directed motor imagery are related to sensorimotor effects in language processing of hand/arm action verbs and nouns describing objects that are easy to interact with. As such, hand and object-directed motor imagery may share mechanisms with sensorimotor simulation during semantic processing.

Effect of loading speed on gap resistance and tensile strength of flexor tendon repair under cyclic loading test

Postoperative digit motion is important for the functional recovery of injured tendons. To date, it is unknown whether the loading speed impacts the biomechanical properties of a repaired tendon. This study investigated the effect of loading speed on the gap resistance and tensile strength of tendon repairs. One hundred porcine flexor tendons were repaired with two core sutures, 4-strand modified Kessler and double Q, and cyclically loaded at the speeds of 10, 40, 80, 160, and 320 mm/min. The number of tendons that formed an initial or 2 mm gap at the repair site during cyclic loading, stiffness at the 1st and 20th loading cycles, gap size between tendon ends when cyclic loading ended, and the ultimate strength were recorded. Under the lowest loading speed, the tendons repaired with the 4-strand modified Kessler suture developed significantly larger gaps and smaller stiffness than those with a greater loading speed. The loading speed did not affect the maximum strength of both tendon repairs. The findings suggest that very slow motion promotes gap formation of tendon repair with inferior gap resistance. The rate corresponds to regular hand action or the tendon core suture possessing a strong gap resistance increases the safety margin during early active finger movement. Our findings help to guide the exercise regimens after tendon surgery.

Mechanisms and neuroanatomy of response selection in tool and non-tool action tasks: Evidence from left-hemisphere stroke

The ability to select between potential actions is central to the complex process of tool use. After left hemisphere stroke, individuals with limb apraxia make more hand action errors when gesturing the use of tools with conflicting hand actions for grasping-to-move and use (e.g., screwdriver) relative to tools that are grasped-to-move and used with the same hand action (e.g., hammer). Prior research indicates that this grasp-use interference effect is driven by abnormalities in the competitive action selection process. The goal of this project was to determine whether common mechanisms and neural substrates support the competitive selection of task-appropriate responses in both tool and non-tool domains. If so, the grasp-use interference effect in a tool use gesturing task should be correlated with response interference effects in the classic Eriksen flanker and Simon tasks, and at least partly overlapping neural regions should subserve the 3 tasks. Sixty-four left hemisphere stroke survivors (33 with apraxia) participated in the tool- and non-tool interference tasks and underwent T1 anatomical MRI. There were robust grasp-use interference effects (grasp-use conflict test) and response interference effects (Eriksen flanker and Simon tasks), but these effects were not correlated. Lesion-symptom mapping analyses showed that lesions to the left inferior parietal lobule, ventral premotor cortex, and insula were associated with grasp-use interference. Lesions to the left inferior parietal lobule, postcentral gyrus, insula, caudate, and putamen were associated with response interference in the Eriksen flanker task. Lesions to the left caudate and putamen were also associated with response interference in the Simon task. Our results suggest that the selection of hand posture for tool use is mediated by distinct cognitive mechanisms and partly distinct neuroanatomic substrates from those mapping a stimulus to an appropriate motor response in non-tool domains.

Fast & scrupulous: Gesture-based alarms improve accuracy and reaction times under various mental workload levels. An ERSP study

In high-risk environments, fast and accurate responses to warning systems are essential to efficiently handle emergency situations. The aim of the present study was twofold: 1) investigating whether hand action videos (i.e., gesture alarms) trigger faster and more accurate responses than text alarm messages (i.e., written alarms), especially when mental workload (MWL) is high; and 2) investigating the brain activity in response to both types of alarms as a function of MWL. Regardless of MWL, participants (N = 28) were found to be both faster and more accurate when responding to gesture alarms than to written alarms. Brain electrophysiological results suggest that this greater efficiency might be due to a facilitation of the action execution, reflected by the decrease in mu and beta power observed around the response time window observed at C3 and C4 electrodes. These results suggest that gesture alarms may improve operators’ performances in emergency situations.

Surveillance of hand hygiene practices in hospitals, its evaluation, and audit

Abstract Background: Healthcare-associated infections (HAIs) continue to pose a significant challenge within most intensive care units. The most straightforward and impactful approach to mitigate these HAIs remains proper hand hygiene. Consequently, evaluating documented hand hygiene routines and conducting direct observations are vital in identifying deficiencies. Thus, this enables the formulation of focused approaches to reduce HAIs. Study objectives: (a) To evaluate the hand hygiene practices among healthcare workers and (b) to analyze the factors contributing to non-compliance. Materials and Methods: The research was conducted at the Mayo Institute of Medical Sciences, Intensive Care Unit, Barabanki, Uttar Pradesh, India. This endeavor adopted an observational approach, involving 50 healthcare workers (HCWs) for direct observation and an additional 50 for the evaluation of documented hand hygiene practices. Data collection relied upon the utilization of questionnaires and observation instruments. Results: The investigation brought to light a contrast between the perspectives of healthcare workers and their actual hand hygiene practices. The collective adherence rate stood at 67.08% (with the observation study encompassing 75 HCWs and 111 instances where hand hygiene should have been carried out, out of which only 76 were performed). Notably, physiotherapists exhibited a notably higher compliance rate at 78%, whereas nurses and residents demonstrated a compliance rate of 68%. In contrast, technicians and unit helpers displayed a lower adherence rate of 60%. Regarding reported hand hygiene compliance among HCWs, the figures exceeded 90% (derived from a questionnaire administered to 50 HCWs, some of whom may or may not have been part of the observation study). Nurses reported an impressive 98% compliance, technicians reported 81%, and other personnel reported rates ranging between 90% and 95%. Conclusion: The researcher undertook two distinct investigations involving direct observation and the other based on reported data. The findings from the observational study indicated a collective hand hygiene compliance rate of 67.08%, whereas the reported study yielded a compliance rate exceeding 90% among HCWs.

The Urgency of Environmental Management From the Al Quran Perspective

Al-Qur'an is a holy book that does not only discuss religious issues but all dimensions of life including environmental issues. The environmental damage around us needs serious attention. One of the environmental damage causes is the lack of practice of religious values. Therefore, the role of religion in providing solutions to environmental problems is very much needed. Based on this, it is very important to do research with the title “The Urgency of Environmental Management from the Al Qu’ran Perspective”. The research method is descriptive qualitative by explaining the concept of environmental management from the perspective of the Qur'an. The collection of data needed for this research is secondary data using Library Research (Library Studies). The approach in this study uses the approach of the science of interpretation (tafsir madhu'iy) and the science of geography because it is related to the study of the Qur'an and the environment. The result of this study indicates that the environmental elements specifically and in detail are mentioned in the Qur’an. Environmental problems that often occur in our lives are related to these elements, such as al-ardh (earth), as-sama (atmosphere), al-mâ (water), anhâr (river), jabâl/jibâl (mountain), etc. The Qur'an also mentions mujmal (generally) environmental damage as a result of the actions of human hands. The damage occurred through the human hand, so it is through human hands to fix it for the sake of realizing sustainable environmental development.

The Impact of Handwashing Education through Animation Videos on Knowledge and Attitudes towards Handwashing among UMY Students during the COVID-19 Pandemic

In this study, the primary objective was to assess the impact of teaching about hand washing and video animation on the knowledge and attitudes of UMY students regarding hand washing during the Covid-19 pandemic. A one-group pre-posttest design was used, involving 63 student respondents selected through simple random sampling. Data was collected using a questionnaire, and the findings revealed a significant increase in both knowledge (p = 0.031) and attitudes (p = 0.040) towards hand washing. The study emphasizes the importance of educating students about hand washing practices, as it is expected to benefit them in their future roles in healthcare institutions, contributing to improved infection prevention and control measures. It is worth noting that this study focused solely on knowledge and attitudes towards hand washing and did not assess actual hand washing compliance.

The Impact of Handwashing Education through Animation Videos on Knowledge and Attitudes towards Handwashing among UMY Students during the COVID-19 Pandemic

In this study, the primary objective was to assess the impact of teaching about hand washing and video animation on the knowledge and attitudes of UMY students regarding hand washing during the Covid-19 pandemic. A one-group pre-posttest design was used, involving 63 student respondents selected through simple random sampling. Data was collected using a questionnaire, and the findings revealed a significant increase in both knowledge (p = 0.031) and attitudes (p = 0.040) towards hand washing. The study emphasizes the importance of educating students about hand washing practices, as it is expected to benefit them in their future roles in healthcare institutions, contributing to improved infection prevention and control measures. It is worth noting that this study focused solely on knowledge and attitudes towards hand washing and did not assess actual hand washing compliance.

Comparative study of preoperative sagittal alignment between patients with multisegment cervical ossification of the posterior longitudinal ligament and cervical spondylotic myelopathy

BACKGROUND CONTEXTPreoperative sagittal alignment is of great significance in the development of spinal deformities, degenerative diseases, preoperative planning, postoperative clinical evaluation, and functional recovery. However, few reports have focused on the difference in preoperative sagittal alignment between patients with ossification of the posterior longitudinal ligament (OPLL) and patients with cervical spondylotic myelopathy (CSM). PURPOSETo compare preoperative sagittal alignment between patients with multisegment cervical OPLL and multilevel CSM. STUDY DESIGNRetrospective study. PATIENT SAMPLEA total of 243 patients were included in this study. OUTCOME MEASURESThe outcome measures were the Japanese Orthopaedic Association (JOA) score, visual analog scale (VAS) score, number of hand actions in 10 seconds, hand-grip strength, C2 to C7 Cobb angle, C2 to C5 Cobb angle, C5 to C7 Cobb angle, C2 to C7 sagittal vertical axis, C7 slope, T1 slope, K-line, K-line tilt, and range of motion (ROM). METHODSThe outcome measures were calculated in the OPLL group and CSM group and the data were analyzed using the unpaired t-test, χ² test, and one-way analysis of variance. RESULTSA total of 243 patients (136 men, 107 women; mean age, 59.1±10.6 years) underwent surgical treatment from September 2013 to December 2021. In total, 123 patients were diagnosed with multisegment cervical OPLL, including continuous type (n=39), segmental type (n=38), and mixed type (n=46). The remaining 120 patients had multisegment CSM. The disease course in the OPLL group was significantly shorter than that in the CSM group (p<.05). Among the above preoperative measurements, the JOA score, number of hand actions in 10 seconds, hand-grip strength, and VAS score were not significantly different between the two groups (p>.05). The C2 to C7 Cobb angle was significantly larger in the OPLL than CSM group (17.7°±9.2° and 14.9°±9.3°, respectively; p< .05), as was the C5 to C7 Cobb angle (10.0°±6.3° and 7.5°±6.1°, respectively; p<.05). The ROM was significantly smaller in the OPLL than CSM group (33.1°±8.1° and 40.1°±10.9°, respectively; p<.001). Within the OPLL group, the ROM was significantly smaller in the continuous type than in the segmental type (p<.05). CONCLUSIONPatients with multisegment cervical OPLL have greater lordotic preoperative sagittal alignment and smaller preoperative ROM than patients with CSM.

Field measurement of hand forces of palm oil harvesters and evaluating the risk of work-related musculoskeletal disorders (WMSDs) through biomechanical analysis

Hand force data is critical in evaluating work-related musculoskeletal disorders (WMSDs). Nevertheless, earlier studies on oil palm workers relied on estimated or laboratory measurements, which may not accurately reflect the actual hand forces. This study is the first report on the field measurement of hand forces for palm oil harvesters using a chisel and sickle to harvest low and tall palm trees, respectively. The dynamic hand forces and ground reaction forces were measured using instrumented harvesting tools and force plates, while wearable motion (IMU) and electromyography (EMG) sensors were incorporated for quantifying postural angles and muscle activations, respectively. Additionally, the spinal loadings, continuous Rapid Entire Body Assessment (REBA) scores, and subjective pain scores were determined to evaluate the risk of WMSDs. A total of 10 harvesters were recruited to perform the palm pruning tasks using a chisel and sickle. Resultantly, the sickle and chisel recorded a maximum cutting force of 1601.23 ± 424.26 N and 420.80 ± 96.00 N, respectively. All pruning tasks were found to be highly risky to harvesters, with a peak REBA score of 12. Likewise, all investigated muscles were activated for over 40% MVC, thus inducing moderate pain in the muscles. The peak L5-S1 compression forces for all tasks exceeded the safety threshold (>3400 N), but the values were not significantly different. The shear force of the L5-S1 was extreme in pruning with a sickle (1446.10 ± 411.00 N) compared to using a chisel. In conclusion, palm harvesters were at a high risk of developing WMSDs following poor postures, high physical exertion and muscle activity, and excessive spinal loads.