COMPUTER HAPTICS FOR NEUROMOTOR REHABILITATION

Over 15 years. Did this proposal  get written up into a protocol? Or is incompentency again showing up in the stroke medical world?

COMPUTER HAPTICS FOR NEUROMOTOR REHABILITATION

XVIII IMEKO WORLD CONGRESS 

 Metrology for a Sustainable Development September, 17 – 22, 2006, 

Rio de Janeiro, Brazil

 Maura Casadio 1 , 

Alessandro Noriaki Ide 2,
 Pietro G. Morasso 3 , 

Vittorio Sanguineti 4

 

1  University of Genova, DIST, Neurolab, Genova, Italy, maura.casadio@dist.unige.it
2 University of Genova, DIST, Neurolab, Genova, Italy, noriaki@dist.unige.it
3  University of Genova, DIST, Neurolab, Genova, Italy, sangui@dist.unige.it
4  University of Genova, DIST, Neurolab, Genova, Italy, morasso@dist.unige.it 

 

 Abstract:
The paper proposes an approach for linking the analysis of the neural control of movement and motor learning with robot therapy in neuromotor rehabilitation. A new haptic workstation is described and a pilot study of robot therapy with hemiplegic patients is presented.
Keywords:
 computer haptics, neural control of movement, motor learning, robot therapy, neuromotor rehabilitation.
1. INTRODUCTION
The experimental investigation of the mechanical impedance of the hand [1,2,3] has made evident the strong anisotropic nature of the musculo-skeletal system and this is, at the same time, a cause of computational complexity for the neural control of movement and a source of sensorimotor affordances in the Gibsonian sense. Also the analysis of the interaction forces points in the same direction. On the other hand, this is in strong contrast with the substantial isotropy of the spatio-temporal structure of the reaching movements, described by Morasso [4]. A stiffness control hypothesis, as a general mechanism of compensation of self-generated disturbances and other elements of anisotropy, has been falsified by the measurements of the physiological levels of muscle stiffness, which appear to be too low to be an effective compensation mechanism. In this context we should consider the emergence of the concept of
internal model
, i.e. the idea that the brain is able to develop, over the years, a representation of its own dynamics and dynamic interaction with the external world. However, this is a difficult process to study in an experimentally controllable way because it occurs spontaneously in a variety of contexts and over a long time. Therefore, the next logical step [5] was to use the same type of technology (haptic robots) also for generating artificial dynamic environments, completely unfamiliar to the subjects: in this way, it is possible to study in a systematic, controllable way, the modality of acquisition and consolidation of internal models of control. A number of recent investigation in primates and humans have provided evidence that the primary motor area as well as other frontal, parietal, and subcortical areas are involved in motor learning [6,7]. The high-level functions that underlie acquisition of motor skills require the integration of these various and distributed cortical areas.

An important mechanism for such large-scale integration might be the transient formation of dynamic connections among cooperating cortical areas. It is quite plausible that occurrence of such functional neuronal aggregations are associated with the synchronization of neuronal activity in different frequency bands. This may be regarded as a self-organization process that allows the appropriate selection and assembly of neural networks that evolve into adaptive control system. This kind of knowledge is the necessary substrate for addressing neurorehabilitation topics, whose goal is to  promote and speed up functional recovery processes, based on the exploitation of the intrinsic neural plasticity. Even in the adult age, the cerebral cortex retains its plasticity, that is the capability to reorganize itself in the case of brain lesions. The underlying physiological mechanisms are still scarcely understood but there is ground to assume that they are  potentially capable of inducing a functional modulation of  pre-existing and active neural pathways as well as calling into operation neuronal circuits, which in the intact brain are maintained in a state of functional inhibition. The rehabilitation process of patients affected by alteration of the voluntary control of the upper/lower limb as a consequence of lesions in the central nervous system requires a phase of evaluation of the brain damage and the related disability. The functional evaluation is particularly important in rehabilitation, for the purpose of structuring and organizing the treatment and follow-up of the patients in the short, medium, and long terms. For this reason, a number of clinical evaluation scales have been defined for characterizing to which extent the patients are indeed able to carry out a certain number of activities of the daily life. Such scales have well known limitations due to their semi-qualitative nature: crude sensitivity, floor and ceiling effects and, in particular, the large margin of subjective judgment. On the other hand, these limitations are common to a number of areas, which require a clinical evaluation on the  basis of measurements and procedures of analysis of the modifications in the status and behaviour of the patients. The need for a quantitative evaluation of motor abilities has contributed to the diffusion of instrumental techniques into contexts such as gait and posture analysis. Less research efforts have been devoted to evaluate the functionality of the upper limb and this work is a contribution in this direction.