Design and custom fabrication of specialized orthoses for the upper-limb stabilization in childhood dyskinesia.

BACKGROUND: Childhood dyskinesia (CD) is a complex movement disorder with components of dystonic and hyperkinetic nature, characterized by involuntary, sometimes stereotypical postures and gestures that are often impossible to control and hinder the execution of willful motion. The standard orthoses for the treatment of neurological diseases, including CD, are generally poorly differentiated for functional characteristics. The application of similar devices for movement disorders is far less generalized because of the very different symptoms, including the incapacity to control rather than initiate movement. OBJECTIVES: This article aims to describe an innovative method to fabricate personalized orthoses for the elbow-wrist joints in CD, taking into account anatomical and functional diversities. It also proposes functional elements to implement the required dynamic postural control. METHODS: Wearable custom-made upper-limb orthoses have been fabricated and preliminarily tested on five patients with CD. Optoelectronic stereophotogrammetry was used as an innovative tool for all-in-one-frame acquisition of limb geometry. A new process for the functional personalization of the orthoses has been developed using shape memory alloys. CONCLUSIONS: The innovative method presented, encompassing data acquisition, virtual design, fabrication, and assembling, overcomes the problems due to the involuntary movements of the patients, which cannot be avoided during the fitting operations, providing comfortable and useful orthoses with minimal nuisance for the patients. Initial tests show that the orthoses were well tolerated by all the subjects; the promising comments of caregivers, together with improvements, were observed by the clinicians using specific clinical scales.

Application of upper-limb dynamic pseudoelastic splinting in the treatment of stroke chronic patient: a pilot assessment.

PURPOSE: The chronic sequelae of stroke are often a strong limitation to patient's quality of life. New non-invasive elective treatments are required to support postural and functional improvements long after the primary insult. This study is an uncontrolled pilot evaluation of pseudoelastic orthotics for post-stroke upper-limb rehabilitation. MATERIALS AND METHODS: Six chronic hemiplegic patients (3.8 ± 1.7 years since stroke) were evaluated with clinical scales, covering the ICF domains of body functions and structures (Modified Ashworth Score [MAS], Medical Research Council Scale for Muscle Strength, Fugl-Meyer [FM], Motricity Index [MI]), activities (Wolf Motor Function Test [WMF], Motor Activity Log [MAL]) and participation (quality of life questionnaires); sensors applied to the orthosis were used to assess changes in the articular and functional domains over a month's treatment. RESULTS: Significant gains were achieved in elbow spasticity (MAS, p = .020), upper-limb motor function (FM, p = .005), reaching task (p = .035), and gait (p = .00046) speed. Most patients improved in functional tasks (WMF), but this did not reflect in daily-life activities as measured with MAL. Some patients reported an improved quality of life, especially the quality of sleep. CONCLUSIONS: Pseudoelastic orthoses could be a comfortable and useful adjunct in the long-term management of stroke. Broader trials will have to confirm these preliminary observations.Implications for rehabilitationUse of new materials in neuromuscular rehabilitation.Customised and adjustable therapeutic action obtained with dynamic personalised orthoses.Non-invasive interventions could be of help for patients with chronic disability.

Why orthotic devices could be of help in the management of Movement Disorders in the young.

BACKGROUND: Movement Disorders (MD) are a class of disease that impair the daily activities of patients, conditioning their sensorimotor, cognitive and behavioural capabilities. Nowadays, the general management of patients with MD is based on rehabilitation, pharmacological treatments, surgery, and traditional splints. Although some attempts have been made to devise specific orthoses for the rehabilitation of patients affected by MD, especially the younger ones, those devices have received limited attention. MAIN BODY: This paper will principally discuss the case of upper limb rehabilitation in Childhood Dyskinesia (CD), a complex motor disease that affects paediatric patients. Through a critical review of the present solutions and a discussion about the neurophysiological characteristics of the disease, the study will lead to the formulation of desirable features of a possible new upper-limb orthosis. CONCLUSIONS: Design principles will be derived to provide specialised orthoses for the dynamic control of posture and the stabilisation of voluntary movements: those include using biomechanical actions and enhanced proprioception to support the sensorimotor rehabilitation of the children affected by CD. A similar approach could be advantageously applied in other MD-related conditions, especially with hyperkinetic and/or hypertonic traits.

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.

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.

Pilot study of the cortical correlates and clinical effects of passive ankle mobilisation in children with upper motorneuron lesions.

Upper motoreuron lesions (UML) affects people of all ages and conditions and is a major cause of disability in the young. Whereas active exercise is recognised as paramount to restore the lost motor functions, passive mobilisation of the affected limbs is regarded as a means to safeguard muscular tissue properties during a period of disuse and lack of voluntary control, which often characterises the acute and sub-acute phases. The purpose of the present work is to study the cortical reactivity in UML patients who are treated for two weeks with a robotic passive ankle mobiliser, and the clinical effects of this treatment. The rationale is that, if passive mobilisation can affect positively the functional reorganisation at a cortical level, it could be proposed as a suitable tool to maintain afferentation and guide central nervous remapping, thus bridging the period of time when active exercise is impossible due to acute paresis. Preliminary results on 7 patients (aged 15.35±4.36) showed that this therapy is very well tolerated and suggest that its application could specifically improve ankle PROM and plantarflexor muscle length. EEG data showed improved desynchronisation in at least one frequency band in 3 patients of the study, thus confirming the effects of passive mobilisation on the cortical re-organisation of some patients having UML.

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.

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 ß 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.

Implementation, testing and pilot clinical evaluation of superelastic splints that decrease joint stiffness.

The present work aims at demonstrating that a customised choice of shape memory alloy (SMA) composition, thermo-mechanical treatment and shaping can lead to effective rehabilitation devices applicable to sub-acute and chronic spastic paresis in paediatric patients. SMA pseudoelasticity is regarded as a means to implement a corrective action on posture without hindering residual voluntary or reflex mobility of the affected limb. Specific hinges containing NiTi or NiTiNb elements were designed and constructed to transfer pseudoelastic recovery force to fitted splints for the elbow or the ankle joint. The devices were mechanically tested and showed complete stability after 20-100 cycles, and unchanged characteristics after 1000 full-range deflections. Repositioning splints equipped with patient-specific pseudoelastic hinges were prescribed to 25 individuals (aged 7.75 ± 5.40 years) with mild to severe spastic tetraparesis. Clinical and instrumental evaluations were carried out during crossover trials with traditional and pseudoelastic splints. The sequence of treatment steps was randomized for each subject. The results show that, compared to fixed-angle braces, pseudoelastic devices decrease passive joint stiffness while providing the same control on limb posture. Dynamic pseudoelastic braces are therefore an innovative treatment for spastic paresis, which may reduce joint stiffness.

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 (FS(S1)) and motor (FS(M1)) area activities were discriminated by the Functional Source Separation algorithm. Only contralateral FS(S1) was recruited by common peroneal nerve stimulation and only contralateral FS(M1) displayed coherence with TA muscular activity. FS(M1) showed higher power of gamma rhythms (33-90 Hz) than FS(S1). 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 FS(S1) beta band power reduced during O-PM. No beta band modulation was observed of either source during NMES-PM. Mutual FS(S1)-FS(M1) 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.

Pilot studies suggesting new applications of NiTi in dynamic orthoses for the ankle joint.

NiTi is a metal alloy with unconventional functional characteristics: Shape memory and pseudoelasticity. Its use in the field of rehabilitation is very innovative. This work presents applications in lower limb orthotics. Three different devices were assembled and tested: An equinus gait dynamic splint, a compliant ankle positioning brace, and a dual-mode haptic/active exerciser for the dorsiflexors. Results are derived from technical and preclinical trials. The gait splint improves several walking parameters even better than a traditional flexible ankle-foot orthoses (AFO). In particular, it supports mid-stance and propulsion biomechanics and affects physiological activation of tibialis anterior during swing much less than posterior leaf AFO. The haptic/active exerciser, able to provide dorsiflexion through a suitable articular range, could be controlled on the basis of minimal surface electromyographic (sEMG) signals, suggesting its use as an aid for early active workouts as soon as patients start to recover voluntary control of tibialis anterior. Further evidence must be sought in future to confirm for the ankle joint the promising results obtained in repositioning applications in prior upper limb studies. The work done so far on the tested prototypes is encouraging: Material characteristics and dimensioning will be optimized so that customized NiTi devices can be prescribed to best meet individual patients' requirements.

On the use of computational models for the quantitative assessment of surgery in congenital heart disease.

The surgical repair of congenital heart disease often involves significant modifications to the circulatory tree. Resections, reconstructions, graft insertions and the deployment of implants and biomedical devices have an impact on local and systemic haemodynamics, which may be difficult to foresee or to assess quantitatively by clinical investigation alone. Mathematical models can be employed to visualise, estimate or predict events and physical quantities that are difficult to observe or measure, and can be successfully applied to the study of the pre- and post-operative physiology of cardiovascular malformations. This paper analyses the potentialities of computation fluid dynamics in this respect, outlining the method, its requirements and its limitations. Examples are given of lumped parameter models, axi-symmetric models, three-dimensional models, fluid-structure interaction simulations and multiscale computing applied to total cavo-pulmonary connection, aortic coarctation and aortic arch reconstruction.

Computational fluid dynamic study of flow optimization in realistic models of the total cavopulmonary connections.

OBJECTIVES AND BACKGROUND: In the Fontan circulation, pulmonary and systemic vascular resistances are in series. The influence of various inferior vena cava to pulmonary artery connections in this unique circulatory arrangement was evaluated using computation fluid dynamics methods. METHODS: Realistic three-dimensional models of total cavopulmonary connections were created from angiographic measurements to include the hepatic vein, superior vena cava, and branches of the pulmonary arteries. Steady-state finite volume analyses were performed using identical in vivo boundary conditions. Computational solutions calculated the percent hydraulic power dissipation and left-to-right pulmonary arterial flow distribution. RESULTS: Simulations of the lateral tunnel, intra-atrial tube, extracardiac conduit with left and right pulmonary artery anastomosis demonstrated extracardiac conduit with left pulmonary artery anastomosis having the lowest energy loss. Varying the extracardiac conduit from 10 to 30 mm resulted in the least energy dissipation at 20 mm. Serial dilation of the lateral tunnel pathway showed a small incremental worsening of energy loss. CONCLUSIONS: Maximizing energy conservation in a low-energy flow domain, such as the Fontan circulation, can be significant to its fluid dynamic performance. Although computational modeling cannot predict postoperative failure or functional outcome, this study confirms the importance of local geometry of the surgically created pathway in the total cavopulmonary connection.