Simone Pittaccio

Primary sensory and motor cortex activities during voluntary and passive ankle mobilization by the SHADE orthosis

This study investigates cortical involvement during ankle passive mobilization in healthy subjects, and is part of a pilot study on stroke patient rehabilitation. Magnetoencephalographic signals from the primary sensorimotor areas devoted to the lower limb were collected together with simultaneous electromyographic activities from tibialis anterior (TA). This was done bilaterally, on seven healthy subjects (aged 29 ± 7), during rest, left and right passive ankle dorsiflexion (imparted through the SHADE orthosis, O‐PM, or neuromuscular electrical stimulation, NMES‐PM), and during active isometric contraction (IC‐AM). The effects of focussing attention on ankle passive movements were considered. Primary sensory (FSS1) and motor (FSM1) area activities were discriminated by the Functional Source Separation algorithm. Only contralateral FSS1 was recruited by common peroneal nerve stimulation and only contralateral FSM1 displayed coherence with TA muscular activity. FSM1 showed higher power of gamma rhythms (33–90 Hz) than FSS1. Both sources displayed higher beta (14–32 Hz) and gamma powers in the left than in the right hemisphere. Both sources displayed a bilateral reduction of beta power during IC‐AM with respect to rest. Only FSS1 beta band power reduced during O‐PM. No beta band modulation was observed of either source during NMES‐PM. Mutual FSS1‐FSM1 coherence in gamma2 band (61–90 Hz) showed a slight trend towards an increase when focussing attention during O‐PM. Somatosensory and motor counterparts of lower limb cortical representations were discriminated in both hemispheres. SHADE was effective in generating repeatable dorsiflexion and inducing primary sensory involvement similarly to voluntary movement. Hum Brain Mapp, 2010.

Passive ankle dorsiflexion by an automated device and the reactivity of the motor cortical network

Gait impairment is an important consequence of neurological disease. Passive mobilization of the affected lower limbs is often prescribed in order to safeguard tissue properties and prevent circulatory sequelae during paresis. However, passive movement could play a role also in stimulating cortical areas of the brain devoted to the control of the lower limb, so that deafferentation and learned non-use can be contrasted. The purpose of the present work is to investigate cortical involvement during active and passive movements of the ankle joint, in an attempt to gain deeper insight in the similarities between these two conditions. A wearable device to mobilize the ankle joint was implemented utilizing rotary shape memory alloy actuators. The technical characteristics of this actuator make it very compatible with the tight limitations on electromagnetic noise imposed by diagnostic instrumentation. Eleven healthy volunteers took part in the pre-clinical phase of the study. According to the protocol, brain activity was recorded by 165-channel magnetoencephalography (MEG) under three different conditions: rest, active dorsiflexion of the ankle and passive mobilization of the same joint. The acquired data were processed to obtain cortical ERD/ERS (Event Related Desynchronization/ Synchronization) maps, which were then compared. The results of this analysis show that there are similar patterns of activity between active and passive movement, particularly in β band, in the contralateral primary sensorimotor, dorsal premotor and supplementary motor areas. This result, albeit obtained from healthy subjects, might suggest that passive motion provides somatosensory afferences that, to some extent, are processed in a similar manner as for voluntary control. Should this evidence be confirmed by further experiments on neurological patients, it could support the prescription of passive exercise as a surrogate of active workout, at least, so long as patients are paretic.

Design and implementation of a portable amagnetic shape memory rotary actuator

Actuators based on standard technologies often do not comply with environmental constraints on electromagnetic noise. Even though shape memory actuators are not ferromagnetic, activation by Joule’s effect poses a question about magnetic compatibility. This article presents a new concept design of a rotary actuator based on a double coil of NiTi wire, which permits to abate dramatically the electromagnetic fields generated. A particular implementation of the idea was devised as a case study to investigate feasibility. The desired torque and stroke were 83 N cm and 40°, respectively, and mechanical tests confirmed that a maximal stroke of 38° can be achieved for resisting torques ranging from 33 to 122 N cm. The built prototype proved appropriate to respond to the needs of a neuroscience study requiring mobilization of the ankle. So, this device was tested during measurement of brain activity in healthy subjects with both magnetoencephalography and functional magnetic resonance imaging, that is, diagnostic equipment with very demanding constraints on electromagnetic noise. Neither magnetoencephalography signals nor the functional magnetic resonance imaging images were affected by any electromagnetic noise or artifacts, allowing for further analysis and extraction of neurological features. Besides the discussed uses, this type of actuator could find an application in several fields, such as biomedical, robotic, aerospace, or automotive.

Shape Memory Actuators for Medical Rehabilitation and Neuroscience

Actuators based on shape memory alloys (SMA) proved to be particularly advantageous with respect to other actuation technologies when they are embedded in applications requiring strict compliance to a set of compatibility (e.g. mechanical, biological, weight, ...) and environmental constraints. Most noteworthy are the uses in miniaturised components, lightweight systems, sensing-actuating systems (e.g. actuators interacting with changing environmental variables), low-noise or low-impact appliances (e.g. actuators with reduced interaction with the environment) and self-sensing controllable devices. With particular regard to these preferred applications, SMA can also play a role in solving specific actuation problems in the fields of Medical Rehabilitation and Neuroscience. The main characteristics expected of SMA actuators for these fields are light weight and portability; self-adjustment to evolving needs; applicability of actuation in shielded environments (with bioimaging and diagnostic devices: magnetic resonance imaging (MRI, fMRI), magnetoencephalography (MEG), and the like).

Can passive mobilization provide clinically-relevant brain stimulation? A pilot eeg and nirs study on healthy subjects

Lower limb rehabilitation is a fundamental part of post-acute care in neurological disease. Early commencement of active workout is often prevented by paresis, thus physical treatment may be delayed until patients regain some voluntary command of their muscles. Passive mobilization of the affected joints is mostly delivered in order to safeguard tissue properties and shun circulatory problems. The present paper investigates the potential role of early passive motion in stimulating cortical areas of the brain devoted to the control of the lower limb. An electro-mechanical mobilizer for the ankle joint (Toe-Up!) was implemented utilizing specially-designed shape-memory-alloy-based actuators. This device was constructed to be usable by bedridden subjects. Besides, the slowness and gentleness of the imparted motion, make it suitable for patients in a very early stage of their recovery. The mobilizer underwent technical checks to confirm reliability and passed the required safety tests for electric biomedical devices. Four healthy volunteers took part in the pre-clinical phase of the study. The protocol consisted in measuring of brain activity by EEG and NIRS in four different conditions: rest, active dorsiflexion of the ankle, passive mobilization of the ankle, and assisted motion of the same joint. The acquired data were processed to obtain maps of cortical activation, which were then compared. The measurements collected so far show that there is a similar pattern of activity between active and passive/assisted particularly in the contralateral premotor areas. This result, albeit based on very few observations, might suggest that passive motion provides somatosensory afferences that are processed in a similar manner as for voluntary control. Should this evidence be confirmed by further trials on healthy individuals and neurological patients, it could form a basis for a clinical use of early passive exercise in supporting central functional recovery.

Applications of Shape Memory Alloys for Neurology and Neuromuscular Rehabilitation

Shape memory alloys (SMAs) are a very promising class of metallic materials that display interesting nonlinear properties, such as pseudoelasticity (PE), shape memory effect (SME) and damping capacity, due to high mechanical hysteresis and internal friction. Our group has applied SMA in the field of neuromuscular rehabilitation, designing some new devices based on the mentioned SMA properties: in particular, a new type of orthosis for spastic limb repositioning, which allows residual voluntary movement of the impaired limb and has no predetermined final target position, but follows and supports muscular elongation in a dynamic and compliant way. Considering patients in the sub-acute phase after a neurological lesion, and possibly bedridden, the paper presents a mobiliser for the ankle joint, which is designed exploiting the SME to provide passive exercise to the paretic lower limb. Two different SMA-based applications in the field of neuroscience are then presented, a guide and a limb mobiliser specially designed to be compatible with diagnostic instrumentations that impose rigid constraints in terms of electromagnetic compatibility and noise distortion. Finally, the paper discusses possible uses of these materials in the treatment of movement disorders, such as dystonia or hyperkinesia, where their dynamic characteristics can be advantageous.

Quantitative EEG and Virtual Reality to Support Post-stroke Rehabilitation at Home

Post-stroke rehabilitation has an enormous impact on health services worldwide because of the high prevalence of stroke, in continuous growth due to the progressive population aging. Systems for neuro-motor rehabilitation at home can help reduce the economic burden of long lasting treatment in chronic post-stroke patients; however the efficacy of these systems in providing a correct and effective rehabilitation should be established. From this point of view, coupling home rehabilitation systems with quantitative EEG methodologies for objectively characterizing patients’ cerebral activity could be useful for the clinician to optimize the rehabilitation protocol and assess its efficacy. Moreover, the use of virtual/augmented reality technologies could assist the patients during unsupervised rehabilitation by providing an empathic feedback to improve their adherence to the treatment. These two aspects were studied and implemented in RIPRENDO@home, a multidisciplinary project, aimed to develop an integrated technological platform oriented to home neurorehabilitation for stroke patients.

WO02 Cortical correlate of passive mobilisation of the ankle joint by means of the SHADE orthosis

WO02 Cortical correlate of passive mobilisation of the ankle joint by means of the SHADE orthosis Simone Pittaccio 1, Filippo Zappasodi 2, Stefano Viscuso 1, Francesca Mastrolilli 3 , Matilde Ercolani 3, Francesco Passarelli 3 , Franco Molteni 4, Paolo Maria Rossini 5, Franca Tecchio 6 1CNR-IENI, Unità di Lecco, Italy; 2CNR-ISTC, Unità MEG, Ospedale Fatebenefratelli, Isola Tiberina, Rome, Italy; 3AFaR, Ospedale Fatebenefratelli, Isola Tiberina, Rome, Italy; 4Ospedale Valduce, Clinica Villa Beretta, Costamasnaga, Italy; 5Dept. of Neurology, ‘Campus Bio-Medico’ University, Rome, Italy; 6IRCCS San Raffaele, Tosinvest Sanità, Cassino, Italy

A magnetically quasi-transparent tool for ankle passive mobilization in investigations on cortical involvement using MEG

Passive mobilization of the paretic limbs is commonly part of standard care in the first stages after stroke, but at this moment it is not clear whether this can positively impact brain reorganization and functional recovery. Applying passive mobilization during MEG measurements poses the question of finding a way to provide repeatable cycles of movement without interfering too much with the biosignal acquisition. This paper presents SHADE, an active orthosis that promotes ankle dorsiflexion and fulfils these requirements by using shape memory alloy wire actuators. These alloys are very deformable at room temperature but can recover large deformations and generate considerable forces when heated above a characteristic temperature. Heating is provided by Joule’s effect, cooling by natural convection. Since current is provided by a dc-generator, only limited and easily removable magnetic noise is produced. SHADE was tested in a MEG shielded room to evaluate both orthosis performance and sensorimotor cortical involvement during passive mobilization induced in 7 healthy subjects (30.3±6.9y/o). The measurements could be cleaned from any noise produced by SHADE and suitably analyzed to describe the activation patterns of primary sensorimotor areas devoted to the ankle control. The cerebral involvement in these regions during the use of SHADE was significantly different from rest. This suggests that passive stimulation with SHADE could have clinical implications and possibly a role in the recovery of active functionality in stroke patients.

Two single cases treated by a new pseudoelastic upper-limb orthosis for secondary dystonia of the young

The study proposes a new treatment for dystonia based on a dynamic wearable orthosis equipped with metallic materials of non-linear mechanical characteristics. Two boys with upper-limb dystonia were enrolled, as well as six healthy children. Fully-customised devices were made for the patients. They used the orthosis for one month and their performances were evaluated before and after the treatment. The assessment was done with clinical scales (Modified Ashworth Score, Melbourne Upper Limb Assessment, PedsQL), interviews and optoelectronic kinematic analysis. Normal kinematics was obtained from the healthy group for comparison. Kinematic analysis showed modifications in motor patterns for both patients, with increases in the ranges of motion of initially stiff segments, improvements in posture, emergence of multi-joint strategies. Clinical scales did not always show similar trends in the two cases. The changes in control strategies could be linked to the force field dynamically applied by the device and appear to be learnable. This interpretation will be further tested with larger groups and longer treatments.