Time-independent relationship between digits closure velocity and hand transport acceleration during reach-to-grasp movements.

Prehension movements in primates have been extensively studied for decades, and hand transport and hand grip adjustment are usually considered as the main components of any object reach-to-grasp action. Evident temporal patterns were found for the velocity of the hand during the transport phase and for the digits kinematics during pre-shaping and enclosing phases. However, such kinematics were always analysed separately in regard to time, and never studied in terms of dependence one from another. Nevertheless, if a reliable one-to-one relationship is proven, it would allow reconstructing the digit velocity (and position) simply by knowing the hand acceleration during reaching motions towards the target object, ceasing the usual dependence seen in literature from time of movement and distance from the target. In this study, the aim was precisely to analyse reach-to-grasp motions to explore if such relationship exists and how it can be formulated. Offline and real-time results not only seem to suggest the existence of a time-independent, one-to-one relationship between hand transport and hand grip adjustment, but also that such relationship is quite resilient to the different intrinsic and extrinsic properties of the target objects such as size, shape and position.

["Zero heavy restraint" objective]. / Objectif "zéro contention forte".

When caring for a patient with an intellectual disability, restraint is often an ambush. At the Institut Jérôme Lejeune, the nursing team has put in place a series of measures designed to help both patient and caregiver, whether in managing the pain induced by care or the apprehension it provokes. After a year's implementation, the number of heavy restraints has fallen significantly.

A novel tool for characterising upper limb function in progressive multiple sclerosis through kinematic assessment.

INTRODUCTION: Current upper limb assessment methods in MS rely on measuring duration in tasks like the nine-hole peg test (9HPT). Kinematic techniques may provide a more useful measure of functional change in clinical and research practice. The aim of this study was to assess upper limb function prospectively in people with progressive MS using a kinematic 3D motion capture system and compare with current measures. METHODS: 42 people with progressive MS (PwPMS) and 15 healthy controls reached-and-grasped different objects whilst recorded by a kinematic assessment system. 9HPT, Expanded Disability Status Scale (EDSS), and patient reported outcome measures (PROs) were collected. All measures were taken at baseline for PwPMS and controls, and again at six months for PwPMS. RESULTS: Relative to controls, PwPMS had significantly longer reaction (0.11 s, p < 0.05) and reach (0.25 s, p < 0.05) times. PwPMS took longer to pick-up (0.34 s, p < 0.05), move (0.14 s, p < 0.05), and place (0.18 s, p < 0.05) objects. PwPMS had lower peak velocities when reaching (7.4 cm/s, p < 0.05) and moving (7.3 cm/s, p < 0.05) objects. Kinematic assessment demonstrated consistent differences between PwPMS with mild and severe upper limb dysfunction as defined by PROs, which were not captured by 9HPT or EDSS in this group. PwPMS demonstrated altered grip apertures profiles, as measured by their ability to complete individual parts of the reach and grasp task, between the baseline and follow-up timepoints. CONCLUSIONS: We have created and tested a novel upper limb function assessment tool which has detected changes and characteristics in hand function, not currently captured by the EDSS and 9HPT.

Postural control during gait termination and prehension.

BACKGROUND: Challenges to postural stability emerge in the transition from locomotion to a standing posture as during gait termination, often accompanied by another task (e.g., opening a door), which may complicate control. However, less is known about postural control during terminating gait while engaged in a secondary manual task. RESEARCH QUESTION: What are the changes in postural control when terminating gait with and without a prehension task? METHODS: In a cross-sectional design, 15 healthy young adults (M=8, F=7; 27±2 years; 69±13 kg; 171±8 cm) underwent both a single task gait termination (GTO) and dual task (gait termination plus reaching; GTR). Postural Time-to-Contact (TtC) was measured using Center of Pressure (CoP) and the sternum position in anterior-posterior (AP) and medial-lateral (ML) directions over two different phases: preparatory phase and stabilization phase. Five successful trials were recorded to obtain a mean TtC. For statistical analysis of TtC, a two-tailed paired t-test was used (p =.05) as normality was satisfied. RESULTS: For the preparatory phase, there were no differences for the CoP, but TtC of the sternum position in AP was shorter in GTR than GTO (p =.001). Meanwhile, for the stabilization phase, TtCs of both the CoP and sternum position were longer in GTR in both AP and ML directions (p's <.001). SIGNIFICANCE: We suggest that for the preparatory phase, the shorter TtC of the sternum position with intact TtC of the CoP in GTR indicates that healthy young individuals are flexible, in that they smoothly integrate CoP control with the upper body demands required to also perform the prehension task. Meanwhile, for the stabilization phase, the longer TtC in dual termination and prehension task indicates that the perturbation imposed by the prehension movement did not result in reduced stabilization when returning to an upright posture.

Effect of the habitat and tusks on trunk grasping techniques in African savannah elephants.

Among tetrapods, grasping is an essential function involved in many vital behaviours. The selective pressures that led to this function were widely investigated in species with prehensile hands and feet. Previous studies namely highlighted a strong effect of item properties but also of the species habitat on manual grasping behaviour. African savannah elephants (Loxodonta africana) are known to display various prehensile abilities and use their trunk in a large diversity of habitats. Composed of muscles and without a rigid structure, the trunk is a muscular hydrostat with great freedom of movement. This multitasking organ is particularly recruited for grasping food items while foraging. Yet, the diet of African savannah elephants varies widely between groups living in different habitats. Moreover, they have tusks alongside the trunk which can assist in grasping behaviours, and their tusk morphologies are known to vary considerably between groups. Therefore, in this study, we investigate the food grasping techniques used by the trunk of two elephant groups that live in different habitats: an arid study site in Etosha National Park in Namibia, and an area with consistent water presence in Kruger National Park in South Africa. We characterised the tusks profiles and compared the grasping techniques and their frequencies of use for different foods. Our results show differences in food-grasping techniques between the two groups. These differences are related to the food item property and tusk profile discrepancies highlighted between the two groups. We suggest that habitat heterogeneity, particularly aridity gaps, may induce these differences. This may reveal an optimisation of grasping types depending on habitat, food size and accessibility, as well as tusk profiles.

Back to the water: Tongue morphology associated to contrasting lifestyles in two Andean frogs of the genus Telmatobius.

The evolution of the tongue in tetrapods is associated with feeding in the terrestrial environment. This study analyzes the tongue morphology of two closely related frog species, Telmatobius oxycephalus and T. rubigo, which exhibit contrasting feeding mechanisms. Telmatobius oxycephalus, a semi-aquatic species, relies on its tongue to capture terrestrial prey whereas T. rubigo, a secondarily aquatic species, uses suction feeding not involving the tongue. Through anatomical, histological and scanning electron microscopy analyses, we revealed remarkable differences in tongue morphology between these species. Telmatobius oxycephalus exhibits a well-developed tongue whose dorsal epithelium has numerous and slender filiform papillae. The epithelial cells of the papillae are protruded and have a complex array of microridges. In contrast, T. rubigo possesses a reduced tongue with flat and less numerous filiform papillae. The epithelial cells are completely flat and lack microridges. These findings highlight the remarkable adaptability of lingual morphology in Telmatobius to respond to the contrasting ecological niches and prey capture mechanisms. This study sheds light on the relationship between tongue shape and the different functional demands, contributing to our understanding of the evolution of prey capture mechanisms in amphibians.

Kinematic Assessment of Fine Motor Skills in Children: Comparison of a Kinematic Approach and a Standardized Test.

Deficits in fine motor skills have been reported in some children with neurodevelopmental disorders such as amblyopia or strabismus. Therefore, monitoring the development of motor skills and any potential improvement due to therapy is an important clinical goal. The aim of this study was to test the feasibility of performing a kinematic assessment within an optometric setting using inexpensive, portable, off-the-shelf equipment. The study also assessed whether kinematic data could enhance the information provided by a routine motor function screening test (the Movement Assessment Battery for Children, MABC). Using the MABC-2, upper limb dexterity was measured in a cohort of 47 typically developing children (7-15 years old), and the Leap motion capture system was used to record hand kinematics while children performed a bead-threading task. Two children with a history of amblyopia were also tested to explore the utility of a kinematic assessment in a clinical population. For the typically developing children, visual acuity and stereoacuity were within the normal range; however, the average standardized MABC-2 scores were lower than published norms. Comparing MABC-2 and kinematic measures in the two children with amblyopia revealed that both assessments provide convergent results and revealed deficits in fine motor control. In conclusion, kinematic assessment can augment standardized tests of fine motor skills in an optometric setting and may be useful for measuring visuomotor function and monitoring treatment outcomes in children with binocular vision anomalies.

Effect of binocular visual cue availability on fruit and insect grasping performance in two cheirogaleids: Implications for primate origins hypotheses.

Forward-facing eyes with parallel optic axes, which provide a wide field of binocular vision and precise depth perception, are among the diagnostic features of crown primates; however, the adaptive significance of this feature remains contentious. Two of the most prominent primate-origins hypotheses propose that either foraging for fruit or nocturnal predation on insects created selective pressures that led to the evolution of diagnostic primate traits, including a wide binocular field. To determine whether either of these hypotheses provides a viable explanation for the evolution of primates' derived eye orientation, the importance of binocular depth cues for the two tasks invoked by these hypotheses was evaluated experimentally in Microcebus murinus and Cheirogaleus medius, cheirogaleids' considered reasonable living analogs of the earliest euprimates. Performance in grasping insects and fruit was evaluated when the animals made use of their full binocular visual field and when their binocular visual field was restricted using a helmet-mounted blinder. Restriction of the binocular field had no effect on fruit grasping performance; however, restriction of the binocular field resulted in a significant deficit in insect predation performance. Differences in behavioral variables also suggest that insect predation is a more visually demanding task than fruit foraging. These results support the role of insect predation, but not fruit foraging, in contributing to the selective pressures that led to the evolution of parallel optic axes and a wide binocular field in crown primates.

Postural Stability When Grasping an Object While Standing: Younger and Older Adults (Fallers and Non-Fallers).

We investigated postural stability through the margin of stability (MoS) while reaching and grasping an object with increasing difficulty levels in younger, fallers and non-fallers. Forty-five individuals distributed into three groups participated in this study: younger adults (YA), non-fallers (OA), and fallers (FOA). They stood upright and reached and grasped a dowel. Six conditions combining the stability of the dowel's base and obstacles close to the dowel were manipulated to characterize different difficulty levels. We computed the MoS in both anterior-posterior (AP) and medial-lateral (ML) directions in the interval between reaching onset and dowel contact. From the MoS time series, we analyzed the minimum and maximum, including the time of occurrence of these events. The MoS was smaller for OA than for YA in both directions. In the ML direction, the minimum MoS was smaller for FOA than for YA. The minimum MoS took place earlier for FOA than YA in the AP direction. FOA and OA exhibited similar behavior with reduced MoS, suggesting impaired postural control during reaching-to-grasping in a standing posture. FOA used a more cautious strategy by reverting the MoS earlier than YA, allowing them to increase their MoS before YA when preparing to grasp the dowel.

The Functional Dexterity Test in Adult Populations: An Exploration of a Simplified Test Protocol and Parameters Guided by Statistical Outcomes.

BACKGROUND: The Functional Dexterity Test (FDT) is a standardized assessment used to quantify dexterity, in-hand manipulation, related to function. Recommendations to modify the scoring have been proposed to eliminate penalties, adapt the test protocol, and change the outcome parameter. A new psychometrically sound scoring system has been used in the pediatric population; however, research in the adult population requires exploration. PURPOSE: The purpose of this study was to test if alterations in test administration, outcome recording, and outcome parameters show predictive validity for measured outcomes for age, ethnicity, and self-identified gender. The new method of administering the FDT eliminates penalties for improper performance and uses a score of speed derived from the timed score. It was theorized that eliminating assessment of reported errors in quality of movement in the quantitative scoring may improve the test validity. STUDY DESIGN: Clinical Measurement. METHODS: The FDT was administered to 148 healthy adults aged between 18 and 78 years. No penalties were included in the quantitative scoring. Age, self-identified gender, ethnicity, and self-reported hand dominance were recorded. Time to complete the test was measured in seconds per usual protocol. The result was recorded as time and calculated as speed. Linear regression was performed to predict FDT speed from age, hand dominance, and self-identified gender. RESULTS: The three predictors (age, hand dominance, and gender) associated with a linear decline in dexterity were significant (p ≤0.02). Dexterity showed a linear decline with age, and participants showed faster speeds with the dominant hand. Gender was a significant predictor of speed, with males having faster speeds by an average of 0.047 pegs per second (p = 0.01). CONCLUSIONS: Scores using a simplified administration and speed as an outcome showed moderate predictive validity with age, gender, and the dominant hand used in this adult population. Future research exploring relationships with activities of daily living is needed.

Influence of Single-Digit Exclusions on Grip Strength in Healthy Male Adults.

Grip strength (GS) of the human hand is vital to deal with objects of various sizes and shapes in daily life. The strength deteriorates if one or more digits of the hand are amputated. The main aim of this study was to determine the influence of single-digit exclusions on the GS. Healthy adults (n = 102, male) with an age range of 20 to 70 years (mean ± SD, 31.92 ± 13.14 years) participated in the study. The movements of unused digits were restrained using splints to avoid digit enslaving effects. T (Thumb), (I) Index, M (Middle), R (Ring), L (Little) digits were chosen for exclusion based on the digit configurations. The digit configurations were IMRL, MRLT, IMRT IRLT and, IMLT with exclusions T, I, L, M, and, R respectively. The results of two-way ANOVA with repeated measures showed no significant interaction (p = 0.923) between hand dominance and digit configurations. But statistical significance (p = 0.000) was observed in digit configurations and hand dominance individually. The results of posthoc analysis using Bonferroni corrected pairwise comparisons showed no statistical significance (p = 0.004) between IRLT and IMLT of both hands since the corrected p-value was 0.003. The outcomes of the F-test showed no statistical significance (p > 0.05) between the digit configurations IMRLT, IMRL; IMRL, MRLT; MRLT, IMRT; IRLT, IMLT individually within dominant (D) and non-dominant (ND) hands. When the F-test was performed using the same digit configurations between both hands, statistical significance was not observed in all the configurations except IMLT (p < 0.05). The results of the Pearson correlation of GS were observed to be very strong between the same digit configurations of D and ND hands.

La force de préhension (FP) de la main humaine est essentielle pour manipuler des objets de diverses dimensions et de diverses formes au quotidien. La force se détériore si au moins l'un des doigts de la main est amputé. Le principal objectif de la présente étude consistait à déterminer l'influence de l'exclusion d'un doigt sur la FP. Des hommes adultes en bonne santé (n=102) de 20 à 70 ans (moyenne ± ÉT, 31,92 ± 13,14 ans) ont participé à l'étude. Les mouvements de leurs doigts non utilisés ont été restreints à l'aide d'une attelle afin d'éviter les effets d'asservissement. L'exclusion du T (pouce), de l'I (index), du M (majeur), du R (annulaire) et du L (auriculaire) a été privilégiée en fonction des configurations des doigts, qui s'établissaient comme suit : IMRL, MRLT, IMRT IRLT et IMLT, et qui excluaient le T, l'I, le L, le M et le R, respectivement. Les résultats de l'analyse de variance bidirectionnelle avec reprise des mesures n'ont révélé aucune interaction significative (p=0,923) entre la dominance de la main et les configurations des doigts. Toutefois, les chercheurs ont constaté une signification statistique (p=0,000) de ces configurations avec la dominance individuelle des mains. Les résultats de l'analyse post hoc au moyen des comparaisons par paires corrigées n'ont révélé aucune signification statistique (p=0,004) entre les IRLT et les IMLT des deux mains, puisque la valeur p corrigée était de 0,003. Les résultats du test de Fischer n'ont établi aucune signification statistique (p>0,05) entre chaque configuration des doigts IMRLT, IMRL; IMRL, MRLT; MRLT, IMRT; IRLT, IMLT de la main dominante et non dominante. Lorsque les chercheurs avaient recours au test de Fischer avec les mêmes configurations des doigts sur les deux mains, ils n'ont pas observé de signification statistique, sauf la configuration IMLT (p<0,05). Les chercheurs ont remarqué des résultats très solides de la corrélation de Pearson au test de FP entre les mêmes configurations de doigts de la main dominante et non dominante.

Increased Risk of Falling in Older Adults When Coordinating Obstacle Avoidance and Grasping.

This study aimed to investigate the kinematic changes in obstacle avoidance and prehension tasks performed simultaneously by older adults with a history of falls at different levels of task difficulty. Twenty-six older adults were divided into faller and nonfaller groups. The experimental protocol was divided into two different tasks: walking with obstacle avoidance and walking with obstacle avoidance combined with a reach-to-grasp task. Two types of sensors (Kinect v2 and Leap Motion Controller, respectively) were used to analyze gait and grasp. Fallers presented kinematic changes associated with the grasping task during obstacle avoidance, such as a decrease in the velocity of the center of mass and the step length, an increase in the step width, a decrease in toe-obstacle horizontal distance, and an increase in vertical foot clearance distance, and an increase in movement time in the grasping task compared with nonfallers. To cope with the obstacle avoidance demands of both walking and grasping, fallers turned to a specific sequencing strategy. While slowing down, they attended first to the grasping task and then to crossing the obstacle on the floor.

How the timing of visual feedback influences goal-directed arm movements: delays and presentation rates.

Visual feedback normally helps guide movements to their goal. When moving one's hand, such guidance has to deal with a sensorimotor delay of about 100 ms. When moving a cursor, it also has to deal with a delay of tens of milliseconds that arises between the hand moving the mouse and the cursor moving on the screen. Moreover, the cursor is presented at a certain rate, so only positions corresponding with the position of the mouse at certain moments are presented. How does the additional delay and the rate at which cursor positions are updated influence how well the cursor can be guided to the goal? We asked participants to move a cursor to consecutive targets as quickly as they could. They did so for various additional delays and presentation rates. It took longer for the mouse to reach the target when the additional delay was longer. It also took longer when a lower presentation rate was achieved by not presenting the cursor all the time. The fraction of the time during which the cursor was present was more important than the rate at which the cursor's position was updated. We conclude that the way human arm movements are guided benefits from continuous access to recent visual feedback.

How prism adaptation reveals the distinct use of size and positions in grasping.

The size of an object equals the distance between the positions of its opposite edges. However, human sensory processing for perceiving positions differs from that for perceiving size. Which of these two information sources is used to control grip aperture? In this paper, we answer this question by prism adaptation of single-digit movements of the index finger and thumb. We previously showed that it is possible to adapt the index finger and thumb in opposite directions and that this adaptation induces an aftereffect in grip aperture in grasping. This finding suggests that grasping is based on the perceived positions of the contact points. However, it might be compatible with grasping being controlled based on size provided that the opposing prism adaptation leads to changes in visually perceived size or proprioception of hand opening. In that case, one would predict a similar aftereffect in manually indicating the perceived size. In contrast, if grasping is controlled based on information about the positions of the edges, the aftereffect in grasping is due to altered position information, so one would predict no aftereffect in manually indicating the perceived size. Our present experiment shows that there was no aftereffect in manually indicating perceived size. We conclude that grip aperture during grasping is based on perceived positions rather than on perceived size.

Influence of pre-grazing herbage mass on bite mass, eating behaviour, and dairy cow performance on pasture.

Knowledge about individual daily herbage dry matter (DM) intake (DMI) helps identifying efficient dairy cows and adapting supplementation better to herbage intake and nutrient requirements of grazing dairy cows. With the aid of behavioural characteristics, raw data recorded with the RumiWatch (RW) system and processed with the RW converter 0.7.3.31 (C31), estimation of herbage DMI may be possible. First, C31, which allows differentiation of prehension bites and mastication chews, was validated through direct observation of behavioural characteristics and compared to the previous RW converter 0.7.3.11 (C11). Further, the influence of a low and high pre-grazing herbage mass (HM), with the same target herbage allowance (HA), on bite mass, DMI, number of prehension bites, and milk production was investigated. In total, 24 lactating Holstein cows were pairwise allotted to one of two HM treatments. The cows received a new pasture paddock twice per day with a daily target HA of 22 kg DM per cow/day. On average, low HM (LHM) and high HM (HHM) paddocks had an HM of 589 and 2288 kg DM/ha, respectively, above 6.7 click units (1 CU = 0.5 cm). Overall, LHM cows produced 2.7 kg/day more milk and 2.5 kg/day more energy-corrected milk, had the same herbage DMI and a similar prehension bite mass. The averaged bite mass per week was 0.49 g DM/bite (LHM) or 0.47 g DM/bite (HHM), respectively. A longer eating time (617 vs. 559 min/day) and a shorter rumination time (297 vs. 365 min/day) were observed for the LHM cows compared with the HHM cows. The validation of the RW showed similar results for C11 and C31 apart from prehension bites, where C31 showed a mean absolute deviation of 12.4%. Pre-grazing HM had no effect on relevant behavioural characteristics for prospective intake estimation, namely, bite mass and number of prehension bites.

Hierarchical and synergistic organization of control variables during the multi-digit grasp of a free and an externally fixed object.

In the referent control theory, grip force emerges by designating the referent aperture (Ra) as a threshold position inside the object. This study quantified Ra and investigated whether the synergistic control of digit referent coordinate (RC) and apparent stiffness (k) depend on the external mechanical constraints on the hand-held object. Subjects held a motorized handle capable of adjusting the grip width and performed static multi-digit prehension tasks in which the handle was free and externally fixed in different conditions. The RC and k of individual digits were reconstructed from the changes in digit normal forces and the positions as the grip width was modulated. RCs of the thumb and virtual finger were used to calculate the width and midpoint of Ra, and synergy indices quantifying the task-specific covariation in the space of the digit normal forces and {RC, k} variables were computed. We found that the k and width of the Ra were larger when holding a free handle than the fixed handle. The higher stiffness in the free condition could be a strategy to ensure grip stability. The midpoint of Ra was skewed toward the virtual finger, reflecting different magnitudes of k for the two digits. Further, the normal forces and control variables {RC, k} displayed synergistic covariation for stabilization of the total grasping force. Finally, the synergies were weaker when the handle was externally fixed, demonstrating the dependence of synergies on external constraints. These results add to the current literature by demonstrating that grasp control involves modulation of digit apparent stiffness in addition to the referent coordinate and by identifying the synergistic organization of the control variables during static grasp.

Incompatibility Influences Cursor Placement When Pointing to Images of Cups.

OBJECTIVE: As images are used within graphical user interfaces to signify menu selection, it is important to understand how image properties can influence cursor placement online. BACKGROUND: Objects have multiple dimensions that create potential ambiguity and Stroop-like confusions for the operator if a previously habitual response conflicts with the required response. METHODS: To examine the impact of compatibility and other contextual factors, 41 participants used a computer Mouse or touch screen to place the cursor upon images of full or empty cups that varied in size, and direction of handle. RESULTS: Cursor placements took longer using the Mouse than touch screen. Although participants were placing the cursor on images, the size of the cup, whether it was empty or full, and the handle orientation interacted in their effects upon response duration and cursor placement. The effects of cup size reversed for empty cups or those with incompatible handles. CONCLUSION: Context can influence cursor placement. Perceived spillability influenced precision requirements, and the cup handle can serve as target or a flanking distractor. APPLICATION: Image content can influence screen hotspots. As performance can change with cup spillability, this bodes well for attempts to detect intent from cursor trajectories.

Expectation of volitional arm movement has prolonged effects on the grip force exerted on a pinched object.

Humans closely coordinate the grip force exerted on a hand-held object with changes in the load arising from the object's dynamics. Recent work suggests the grip force is responsive to the predictability of the load forces as well. The well-known grip-force-load-force coupling is intermittent when the load arising from volitional movements fluctuates predictably, whereas grip force increases when loads are unpredictable. Here, we studied the influence of expected but uncertain volitional movements on the digit forces during a static grasp. Young, healthy participants used a pinch grasp to hold an instrumented object and track visual targets by moving the object. We quantified the mean grip force, the temporal decline in grip force (slacking), and the coupling between the pressing digit forces that yield the grip force during static prehension with no expectation of movement, and during the static phase of a choice reaction time task, when the participant expected to move the object after a variable duration. Simply expecting to move the object led to sustained (for at least 5 s) higher magnitude and lower slacking in the grip force, and weaker coupling between the pressing digit forces. These effects were modulated by the direction of the expected movement and the object's mass. The changes helped to maintain the safety margin for the current grasp and likely facilitated the transition from static to dynamic object manipulation. Influence of expected actions on the current grasp may have implications for manual dexterity and its well-known loss with age.

Dynamical Synergies of Multidigit Hand Prehension.

Hand prehension requires highly coordinated control of contact forces. The high-dimensional sensorimotor system of the human hand operates at ease, but poses several challenges when replicated in artificial hands. This paper investigates how the dynamical synergies, coordinated spatiotemporal patterns of contact forces, contribute to the hand grasp, and whether they could potentially capture the force primitives in a low-dimensional space. Ten right-handed subjects were recruited to grasp and hold mass-varied objects. The contact forces during this multidigit prehension were recorded using an instrumented grip glove. The dynamical synergies were derived using principal component analysis (PCA). The contact force patterns during the grasps were reconstructed using the first few synergies. The significance of the dynamical synergies, the influence of load forces and task configurations on the synergies were explained. This study also discussed the contribution of biomechanical constraints on the first few synergies and the current challenges and possible applications of the dynamical synergies in the design and control of exoskeletons. The integration of the dynamical synergies into exoskeletons will be realized in the near future.

The Value of 'Cow Signs' in the Assessment of the Quality of Nutrition on Dairy Farms.

The aim of this review is to provide dairy farm advisors, consultants, nutritionists, practitioners, and their dairy farmer clients with an additional toolkit that can be used in the assessment of the quality of their dairy cattle nutrition. Cow signs are behavioral, physiological, and management parameters that can be observed and measured. They are detected by examining and observing the cattle. Other physiological parameters such as fecal scoring, rumen fill, and body condition scoring are also included in 'cow signs'. The assessment should be both qualitative and quantitative; for example, is the cattle individual lame and what is the severity of lameness. The 'diagnosis' of a problem should be based on establishing a farm profile of 'cow signs' and other relevant information. Information gathered through assessment of cow signs should be used as an advisory tool to assist and improve decision making. Cow signs can be used as part of an investigation and or farm audit.