Age-Related Decline in Anticipatory Motor Planning and Its Relation to Cognitive and Motor Skill Proficiency

Anticipatory motor planning abilities mature as children grow older, develop throughout childhood and are likely to be stable till the late sixties. In the seventh decade of life, motor planning performance dramatically declines, with anticipatory motor planning abilities falling to levels of those exhibited by children. At present, the processes enabling successful anticipatory motor planning in general, as do the cognitive processes mediating these age-related changes, remain elusive. Thus, the aim of the present study was (a) to identify cognitive and motor functions that are most affected by normal aging and (b) to elucidate key (cognitive and motor) factors that are critical for successful motor planning performance in young (n = 40, mean age = 23.1 ± 2.6 years) and older adults (n = 37, mean age = 73.5 ± 7.1 years). Results indicate that normal aging is associated with a marked decline in all aspects of cognitive and motor functioning tested. However, age-related declines were more apparent for fine motor dexterity, processing speed and cognitive flexibility. Furthermore, up to 64% of the variance in motor planning performance across age groups could be explained by the cognitive functions processing speed, response planning and cognitive flexibility. It can be postulated that anticipatory motor planning abilities are strongly influenced by cognitive control processes, which seem to be key mechanisms to compensate for age-related decline. These findings support the general therapeutic and preventive value of cognitive-motor training programs to reduce adverse effects associated with high age

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 complexity of the relationship between neuropsychological deficits and impairment in everyday tasks after stroke

Background and purpose: A large body of research reports that stroke patients are debilitated in terms of daily independence after dismissal from the hospital unit. Patients struggle with the use of daily objects or performing complex actions. Differences between individual deficits of patients are often associated with the site of the brain damage. However, clinical studies suggest that patients exhibit varied constellations of action-associated difficulties and neuropsychological deficits. There is a lack of conclusive evidence indicating how different neuropsychological symptoms link to the impaired ability to perform activities of daily living (ADL). Materials and methods: To further address this matter, in this study we compared the behavior of patients with left brain damage (LBD) and right brain damage (RBD) following stroke in two naturalistic task scenarios (tea making and document filing),and compared the committed action errors to the neuropsychological screening results. Results: We observed mild to severe impairments in both the LBD and RBD groups amounting to 37-55% of failure rate in attainment of action goal. Interestingly, the performance on both tasks was not correlated to each other, suggesting that the tasks involved a different set of higher cognitive functions. Despite similar behavioral manifestations, in the LBD group poor task performance was related to deficits in praxis performance and unilateral tactile and visual extinction. The presence of aphasia did not correlate with task performance, except for a link between low scores in Aachen aphasia test scales and misestimation error in the tea making task. In the RBD group, difficulties with performance were primarily linked to deficit in praxis and unilateral visual extinction. Conclusions: Despite similar behavior, the underlying mechanisms of the deficits after stroke might be different (in patients with LBD and RBD) and reveal complex interlinks of cognitive networks involved in the ability to carry on everyday tasks

Use of Biological Motion based Cues and Ecological Sounds in the Neurorehabilitation of Apraxia

Technological progress in the area of informatics and human interface platforms create a window of opportunities for the neurorehablitation of patients with motor impairments. The CogWatch project (www.cogwatch.eu) aims to create an intelligent assistance system to improve motor planning and execution in patients with apraxia during their daily activities. Due to the brain damage caused by cardiovascular incident these patients suffer from impairments in the ability to use tools, and to sequence actions during daily tasks (such as making breakfast). Based on the common coding theory (Hommel et al., 2001) and mirror neuron primate research (Rizzolatti et al., 2001) we aim to explore use of cues, which incorporate aspects of biological motion from healthy adults performing everyday tasks requiring tool use and ecological sounds linked to the action goal. We hypothesize that patients with apraxia will benefit from supplementary sensory information relevant to the task, which will reinforce the selection of the appropriate motor plan. Findings from this study determine the type of sensory guidance in the CogWatch interface. Rationale for the experimental design is presented and the relevant literature is discussed

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 influence of action possibility and end-state comfort on motor imagery of manual action sequences

Seegelke C, Hughes C. The influence of action possibility and end-state comfort on motor imagery of manual action sequences. Brain and Cognition. 2015;101:12-16.It has been proposed that the preparation of goal-direct actions involves internal movement simulation, or motor imagery. Evidence suggests that motor imagery is critically involved in the prediction of action consequences and contributes heavily to movement planning processes. The present study examined whether the sensitivity towards end-state comfort and the possibility/impossibility to perform an action sequence are considered during motor imagery. Participants performed a mental rotation task in which two images were simultaneously presented. The image on the left depicted the start posture of a right hand when grasping a bar, while the right image depicted the hand posture at the end of the action sequence. The right image displayed the bar in a vertical orientation with the hand in a comfortable (thumb-up) or in an uncomfortable (thumb-down) posture, while the bar in the left image was rotated in picture plane in steps of 450. Crucially, the two images formed either a physically possible or physically impossible to perform action sequence. Results revealed strikingly different response time patterns for the two action sequence conditions. In general, response times increased almost monotonically with increasing angular disparity for the possible to perform action sequences. However, slight deviations from this monotonicity were apparent when the sequences contained an uncomfortable as opposed to a comfortable final posture. In contrast, for the impossible sequences, response times did not follow a typical mental rotation function, but instead were uniformly very slow. These findings suggest that both biomechanical constraints (i.e., end-state comfort) and the awareness of the possibility/impossibility to perform an action sequence are considered during motor imagery. We conclude that motor representations contain information about the spatiotemporal movement organization and the possibility of performing an action, which are crucially involved in anticipation and planning of action sequences. (C) 2015 Elsevier Inc. All rights reserved

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

Perturbations in Action Goal Influence Bimanual Grasp Posture Planning

Hughes C, Seegelke C. Perturbations in Action Goal Influence Bimanual Grasp Posture Planning. Journal Of Motor Behavior. 2013;45(6):473-478.The authors examined the effects of perturbations in action goal on bimanual grasp posture planning. Sixteen participants simultaneously reached for 2 cylinders and placed either the left or the right end of the cylinders into targets. As soon as the participants began their reaching movements, a secondary stimulus was triggered, which indicated whether the intended action goal for the left or right hand had changed. Overall, the tendency for a single hand to select end-state comfort compliant grasp postures was higher for the nonperturbed condition compared to both the perturbed left and perturbed right conditions. Furthermore, participants were more likely to plan their movements to ensure end-state comfort for both hands during nonperturbed trials, than perturbed trials, especially object end-orientation conditions that required the adoption of at least one underhand grasp posture to satisfy bimanual end-state comfort. Results indicated that when the action goal of a single object was perturbed, participants attempted to reduce the cognitive costs associated with grasp posture replanning by maintaining the original grasp posture plan, and tolerating grasp postures that result in less controllable final postures