G. Macrì

Characterization of age-related modifications of upper limb motor control strategies in a new dynamic environment

BackgroundIn the past, several research groups have shown that when a velocity dependent force field is applied during upper limb movements subjects are able to deal with this external perturbation after some training. This adaptation is achieved by creating a new internal model which is included in the normal unperturbed motor commands to achieve good performance. The efficiency of this motor control mechanism can be compromised by pathological disorders or by muscular-skeletal modifications such as the ones due to the natural aging process. In this respect, the present study aimed at identifying the age-related modifications of upper limb motor control strategies during adaptation and de-adaptation processes in velocity dependent force fields.MethodsEight young and eight elderly healthy subjects were included in the experiment. Subjects were instructed to perform pointing movements in the horizontal plane both in a null field and in a velocity dependent force field. The evolution of smoothness and hand path were used to characterize the performance of the subjects. Furthermore, the ability of modulating the interactive torque has been used as a paradigm to explain the observed discoordinated patterns during the adaptation process.ResultsThe evolution of the kinematics during the experiments highlights important behavioural differences between the two groups during the adaptation and de-adaptation processes. In young subjects the improvement of movement smoothness was in accordance with the expected learning trend related to the consolidation of the internal model. On the contrary, elders did not show a coherent learning process. The kinetic analysis pointed out the presence of different strategies for the compensation of the external perturbation: older people required an increased involvement of the shoulder with a different modulation of joint torque components during the evolution of the experiments.ConclusionThe results obtained with the present study seem to confirm the presence of different adaptation mechanisms in young and senior subjects. The strategy adopted by young subjects was to first minimize hand path errors with a secondary process that is consistent with the optimization of the effort. Elderly subjects instead, seemed to shift the importance of the two processes involved in the control loop slowing the mechanism optimizing kinematic performance and enabling more the dynamic adaptation mechanism.

Microfabricated Instruments for Fetal Cardiac Surgery: Experiments on Haptic Tissue Recognition

This paper describes the performance of a microfabricated gripper, equipped with semiconductor strain gauges as force sensors, and teleoperated via a PHANTOM haptic interface. The main objective is to demonstrate that the force sensed by the gripper, when rendered to the user by means of a haptic interface, can provide a feeling of tissue stiffness that allows the user to successfully discriminate among different tissue types during the most delicate operations of minimally invasive surgery, such as in fetal cardiac surgery. Experiments aimed to prove the usefulness of this approach have been carried out: the system allowed unskilled operators to qualitatively discriminate pieces of pulmonary valve and endocardium (excited from fetal lamb). Haptic response models were created from the measured data and additional experiments were carried out off-line on a PHANTOM interface. User trials on the simulated tissue demonstrate the excellent discrimination capability of the system.

Biorobotics for longevity

The main aim of this paper is to illustrate the potentials that the use of robotic and mechatronic technologies (in combination with advanced biomechanical models) can offer to help elderly people identifying and slowing down the effects of the age-related modifications of the neuro-musculo-skeletal systems and therefore increasing their possibility of staying at home reducing the hospitalization time. In particular, a three phases approach is proposed in this paper: (i) the use of robotic and mechatronic systems to analyse the age-related modifications of the motor control strategies (in particular for falling risk) in clinics or research laboratories; (ii) the use of wearable systems to assess motor performance in a unstructured environment (e.g., the house of the people); (iii) the use of technological aids to help elderly people to live autonomously in their domestic environment. The results illustrated in this manuscript seems to confirm that this approach can provide interesting and useful tools to increase the quality of life of elderly people.

Microfabricated instrument for haptic tissue recognition in fetal cardiac surgery

To keep a minimal level of invasiveness, some of the most delicate interventions of minimally invasive surgery, such as fetal cardiac surgeries, have to be carried out without direct vision, which makes tissue recognition extremely difficult. In this paper we investigate whether the haptic sense can be used instead. We describe a micro-fabricated gripper, equipped with semiconductor strain gauges as force sensors, and teleoperated via a haptic interface. We demonstrate that the force sensed by the gripper and rendered to the user through the haptic interface can provide a feeling of tissue stiffness that allows the user to successfully discriminate among two different tissue types. Experiments show that the system allowed unskilled operators to qualitatively discriminate tiny tissue samples excited from the heart of a fetal lamb. Haptic response models were created from the strain gauges response during grasping and additional experiments were carried out off-line on the haptic interface, to avoid tissue decay. User trials on the simulated tissues demonstrate that discrimination is possible with high statistical significance

Teaching with Minirobots: The Local Educational Laboratory on Robotics

In this paper, we are going to present and discuss a few activities related to the application of minirobots in school education. The activities have been carried out in the framework of the Local Educational Laboratory on Robotics (LELR), which has been developed by Scuola Superiore Sant’Anna (SSSA) in collaboration with local Municipalities (i.e. Valdera Union) and a network of primary and secondary schools (i.e. Costellazione Network) in the Valdera area of Tuscany, Italy. The LELR is part of SSSA efforts to actively participate in the scientific and technological education of young generations, starting from school age. The laboratory is based on the deployment of robotics, in its several manifestations. in teaching activities. Drawing on preliminary activities and experiences, the paper will report on and discuss a few projects about teaching with minirobots in primary and secondary schools education, pointing out the relevance of promoting an interdisciplinary approach to minirobots educational activities – namely not limited to scientific and technological subjects – as well as developing a critical attitude towards scientific and technological progress in students.

Evaluation of the KOBIAN and HABIAN Emotion Expression Humanoid Robots with European Elderly People

Our world is getting older and older (OECD 2009), and therefore there is considerable expectation for more widespread home, medical, and nursing care services to assist not self-sufficient elderly people, both from the physical and psychological points of view. In this context, robots are expected to perform human tasks such as operating equipment designed for humans in dangerous environments, providing personal assistance, social care, cognitive therapy, entertainment, and education (Kozima, Nakagawa et al. 2007). These robots should be capable of a smooth and natural adaptation and interaction with their human partners as well as with the environment. They should also be able to communicate naturally with humans, especially in home and personal assistance applications for elderly and/or handicapped persons. Moreover, these devices should be safe and, more in general, should never have a negative effect on their human partners, neither physical nor emotional.

Analysis of age-related modifications of lower limb motor control strategies by using a wearable biomechatronic system

The main aim of this work was to identify an experimental method for the quantitative assessment of the motor performance of elderly people, during motor tasks requiring also different cognitive efforts. Specifically, a dual task approach was used to investigate age-related deficits in the ability to walk or climb stairs, and to concurrently perform various categories of cognitive tasks. A wearable biomechatronic system was used to measure the kinematics of the lower limb, during the task execution. Parameters derived from gait analysis were used for the quantitative assessment of examined subjects motor performances. Preliminary results showed that the proposed method can provide accurate and reliable measurements, which could be useful to deep inside the comprehension of the age-related deficits of lower limb motor control strategies.

Adaptation in velocity dependent force fields: a comparison between young and elderly subjects

The aim of this study was to investigate whether and how learning process is affected in elderly subjects while they carry out pointing tasks in different force fields generated by a planar robot. In particular, the evolution of movement smoothness during the trials has been used to characterize the learning process. The results indicate that elderly people can deal with novel dynamics showing a predictable aftereffect as young subjects. However, the evolution of the smoothness of their movements was not in accordance with the standard learning process shown by the young group. These results could be partly related to the decay of basic response speed and decision making, all phenomena related to ageing.