Manual (a)symmetries in grasp posture planning: a short review

Seegelke C, Hughes CML, Schack T. Manual (a)symmetries in grasp posture planning: a short review. Frontiers in Psychology. 2014;5:1480.Many activities of daily living require that we physically interact with one or more objects. Object manipulation provides an intriguing domain in which the presence and extent of manual asymmetries can be studied on a motor planning and a motor execution level. In this literature review we present a state of the art for manual asymmetries at the level of motor planning during object manipulation. First, we introduce pioneering work on grasp posture planning. We then sketch the studies investigating the impact of future task demands during unimanual and bimanual object manipulation tasks in healthy adult populations. In sum, in contrast to motor execution, there is little evidence for hand-based performance differences in grasp posture planning. We discuss potential reasons for the lack of manual asymmetries in motor planning and outline potential avenues of future research

Simulating My Own or Others Action Plans? – Motor Representations, Not Visual Representations Are Recalled in Motor Memory

Seegelke C, Hughes CML, Schack T. Simulating My Own or Others Action Plans? – Motor Representations, Not Visual Representations Are Recalled in Motor Memory. PLoS ONE. 2013;8(12): e84662.Action plans are not generated from scratch for each movement, but features of recently generated plans are recalled for subsequent movements. This study investigated whether the observation of an action is sufficient to trigger plan recall processes. Participant dyads performed an object manipulation task in which one participant transported a plunger from an outer platform to a center platform of different heights (first move). Subsequently, either the same (intra-individual task condition) or the other participant (inter-individual task condition) returned the plunger to the outer platform (return moves). Grasp heights were inversely related to center target height and similar irrespective of direction (first vs. return move) and task condition (intra- vs. inter-individual). Moreover, participants' return move grasp heights were highly correlated with their own, but not with their partners' first move grasp heights. Our findings provide evidence that a simulated action plan resembles a plan of how the observer would execute that action (based on a motor representation) rather than a plan of the actually observed action (based on a visual representation)

The detection and prediction of surgical site infections using multi-modal sensors and machine learning: Results in an animal model

IntroductionSurgical Site Infection (SSI) is a common healthcare-associated infection that imposes a considerable clinical and economic burden on healthcare systems. Advances in wearable sensors and digital technologies have unlocked the potential for the early detection and diagnosis of SSI, which can help reduce this healthcare burden and lower SSI-associated mortality rates.MethodsIn this study, we evaluated the ability of a multi-modal bio-signal system to predict current and developing superficial incisional infection in a porcine model infected with Methicillin Susceptible Staphylococcus Aureus (MSSA) using a bagged, stacked, and balanced ensemble logistic regression machine learning model.ResultsResults demonstrated that the expression levels of individual biomarkers (i.e., peri-wound tissue oxygen saturation, temperature, and bioimpedance) differed between non-infected and infected wounds across the study period, with cross-correlation analysis indicating that a change in bio-signal expression occurred 24 to 31 hours before this change was reflected by clinical wound scoring methods employed by trained veterinarians. Moreover, the multi-modal ensemble model indicated acceptable discriminability to detect the presence of a current superficial incisional SSI (AUC = 0.77), to predict an SSI 24 hours in advance of veterinarian-based SSI diagnosis (AUC = 0.80), and to predict an SSI 48 hours in advance of veterinarian-based SSI diagnosis (AUC = 0.74).DiscussionIn sum, the results of the current study indicate that non-invasive multi-modal sensor and signal analysis systems have the potential to detect and predict superficial incisional SSIs in porcine subjects under experimental conditions

Self-Paced Reaching after Stroke: A Quantitative Assessment of Longitudinal and Directional Sensitivity Using the H-Man Planar Robot for Upper Limb Neurorehabilitation

Hussain A, Budhota A, Hughes CML, et al. Self-Paced Reaching after Stroke: A Quantitative Assessment of Longitudinal and Directional Sensitivity Using the H-Man Planar Robot for Upper Limb Neurorehabilitation. Frontiers in Neuroscience. 2016;10:477

The effects of physical object coupling on interlimb coordination

Recent research (Hughes, Haddad, Franz, Zelaznik, & Ryu, under review) has demonstrated that when the hands manipulate two objects that are physically coupled they exhibit greater spatiotemporal independence. On the basis of these results it was proposed that if the actions of the individual hands can be conceptualized as subparts of a larger action (or task) then the tendency toward spatiotemporal synchronization could be reduced. Thus, the present experiments were designed to explore interlimb coordination during the manipulation of physically coupled objects. In the first paper, participants were assigned to either a control or transfer group. Participants in the control group performed the task when the objects were separate (no-spring group) or when the objects were connected by a spring (spring group). Participants in the transfer group either performed the task when the objects were separate, and then when the objects were connected by a spring (no-spring-first group), or in the reverse order (spring-first-group). The task required participants to grasp and place two objects on a target board to either identical or different object end-orientations. Regardless of the order in which the tasks were performed, the hands were less coupled when manipulating objects that were connected compared to objects that were not connected. Thus, the spatiotemporal trajectories of the individual hands appeared to be less constrained when the objects were physically connected. This result supported the interpretation that the manner in which the manipulated objects were perceived can modulate the constraints that underlie bimanual coordination. This perceptual interpretation was directly tested in the second paper by manipulating the manner in which the objects were coupled. Participant’s manipulated objects that were not connected, connected with a telescopic rod, or connected with a band or spring in which stiffness constants varied based on the type of physical connection. There were three main findings: (1) interlimb coupling was similar between the no-stiffness and rod groups (2) interlimb coupling changed as a function of the stiffness of the connecting material, and (3) although the right hand moved toward the target in a straighter fashion when the objects were physically independent, this was reversed when the objects were connected. In this context, the non-dominant left hand performed the task in a straighter fashion than the dominant right hand. That is, the left-hand adopted a stabilizing role while the dominant right hand adopted a more manipulative role. Thus, there was no support for the perceptual interpretation forwarded in the first paper. Instead, it is proposed that the tactics employed by the central nervous system (CNS) changes in response to different behavioral contexts as well as physical demands

Interlimb coupling during cooperative bimanual actions when objects are physically connected

Hughes CML, Zelaznik HN, Haddad JM, Gipson AD. Interlimb coupling during cooperative bimanual actions when objects are physically connected. Journal of Sport & Exercise Psychology. 2010:79

Upper extremity proprioception in healthy aging and stroke populations, and the effects of therapist- and robot-based rehabilitation therapies on proprioceptive function

The world’s population is aging, with the number of people ages 65 or older expected to surpass 1.5 billion people, or 16% of the global total. As people age, there are notable declines in proprioception due to changes in the central and peripheral nervous systems. Moreover, the risk of stroke increases with age, with approximately two-thirds of stroke-related hospitalizations occurring in people over the age of 65. In this literature review, we first summarize behavioral studies investigating proprioceptive deficits in normally aging older adults and stroke patients, and discuss the differences in proprioceptive function between these populations. We then provide a state of the art review the literature regarding therapist- and robot-based rehabilitation of the upper extremity proprioceptive dysfunction in stroke populations and discuss avenues of future research.NMRC (Natl Medical Research Council, S’pore)Published versio

Scatter plot comparing return move slopes of a given participant with first move slopes of the same participant (panel A) and with first move slopes of their partner (panel B) during the inter-individual task condition.

<p>Scatter plot comparing return move slopes of a given participant with first move slopes of the same participant (panel A) and with first move slopes of their partner (panel B) during the inter-individual task condition.</p

Experimental setup.

<p>The participants shown here have given written informed consent, as outlined in the PLOS consent form, to publication of their photographs.</p