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Applications of shape memory alloys for neurology and neuromuscular rehabilitation.

Pittaccio S, Garavaglia L, Ceriotti C, Passaretti F - J Funct Biomater (2015)

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: National Research Council of Italy, Institute for Energetics and Interphases (CNR-IENI), C.so Promessi Sposi, 29-23900 Lecco, Italy. s.pittaccio@ieni.cnr.it.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus

(a) The Toe-Up! device for passive ankle mobilization of bedridden patients; (b) the shape memory alloy (SMA) actuator used to generate ankle dorsiflexion.
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jfb-06-00328-f001: (a) The Toe-Up! device for passive ankle mobilization of bedridden patients; (b) the shape memory alloy (SMA) actuator used to generate ankle dorsiflexion.

Mentions: The Toe-Up! device is shown in (Figure 1). It includes a leg rest for the patient’s shank; the foot is strapped to a moving plate that rotates up and down under the combined action of a shape-memory actuator and two pseudoelastic bias springs: the actuator, activated in a cyclic manner by an electronic controller, produces a nominal dorsiflexion of 30°, while the bias springs reset the position in plantarflexion. The actuator is composed of a quadruple arrangement of 0.25-mm NiTi wires. Those wires are electrically connected in series two-by-two, but produce a total force of four (max. 30 N) by pulling in parallel. The particular wire coiling is designed in such a manner that magnetic fields produced by the flowing electric current tend to be cancelled out by antiparallel fields. The actuator is powered from the mains via a transformer/rectifier (56 Vdc) lodged within the device case. Therapy with Toe-Up! was prescribed to seven pediatric patients affected by spastic tetraparesis as a consequence of UML (TBI, traumatic brain injury; AVM, arteriovenous malformation; anoxia). The study protocol comprised two 30-min sessions of passive mobilization a day for 14 days and clinical evaluation pre- and post-treatment. In addition, EEG was recorded from the patients during passive mobilization by Toe-Up! and active movement, to evaluate if any differences in brain cortical (re)activity would arise over the time of treatment. The data collected are currently being analyzed. It can already be anticipated that the device was very well received by the patients and their families and often resulted in an added motivation to work out. The working life of the SMA wire in the actuator depended on the conditions of the patient (particularly on the level of hypertone, which directly affects the intensity of mechanical stress), but it always exceeded at least two weeks. The actuator was always able to produce dorsi-plantarflexion, and no problems were reported about its functioning or safety. Results of preliminary trials at EEG acquisition and analysis, which were carried out on a few healthy subjects, have been published in [22].


Applications of shape memory alloys for neurology and neuromuscular rehabilitation.

Pittaccio S, Garavaglia L, Ceriotti C, Passaretti F - J Funct Biomater (2015)

(a) The Toe-Up! device for passive ankle mobilization of bedridden patients; (b) the shape memory alloy (SMA) actuator used to generate ankle dorsiflexion.
© Copyright Policy
Related In: Results  -  Collection

License
Show All Figures
getmorefigures.php?uid=PMC4493515&req=5

jfb-06-00328-f001: (a) The Toe-Up! device for passive ankle mobilization of bedridden patients; (b) the shape memory alloy (SMA) actuator used to generate ankle dorsiflexion.
Mentions: The Toe-Up! device is shown in (Figure 1). It includes a leg rest for the patient’s shank; the foot is strapped to a moving plate that rotates up and down under the combined action of a shape-memory actuator and two pseudoelastic bias springs: the actuator, activated in a cyclic manner by an electronic controller, produces a nominal dorsiflexion of 30°, while the bias springs reset the position in plantarflexion. The actuator is composed of a quadruple arrangement of 0.25-mm NiTi wires. Those wires are electrically connected in series two-by-two, but produce a total force of four (max. 30 N) by pulling in parallel. The particular wire coiling is designed in such a manner that magnetic fields produced by the flowing electric current tend to be cancelled out by antiparallel fields. The actuator is powered from the mains via a transformer/rectifier (56 Vdc) lodged within the device case. Therapy with Toe-Up! was prescribed to seven pediatric patients affected by spastic tetraparesis as a consequence of UML (TBI, traumatic brain injury; AVM, arteriovenous malformation; anoxia). The study protocol comprised two 30-min sessions of passive mobilization a day for 14 days and clinical evaluation pre- and post-treatment. In addition, EEG was recorded from the patients during passive mobilization by Toe-Up! and active movement, to evaluate if any differences in brain cortical (re)activity would arise over the time of treatment. The data collected are currently being analyzed. It can already be anticipated that the device was very well received by the patients and their families and often resulted in an added motivation to work out. The working life of the SMA wire in the actuator depended on the conditions of the patient (particularly on the level of hypertone, which directly affects the intensity of mechanical stress), but it always exceeded at least two weeks. The actuator was always able to produce dorsi-plantarflexion, and no problems were reported about its functioning or safety. Results of preliminary trials at EEG acquisition and analysis, which were carried out on a few healthy subjects, have been published in [22].

Bottom Line: 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.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.

View Article: PubMed Central - PubMed

Affiliation: National Research Council of Italy, Institute for Energetics and Interphases (CNR-IENI), C.so Promessi Sposi, 29-23900 Lecco, Italy. s.pittaccio@ieni.cnr.it.

ABSTRACT
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.

No MeSH data available.


Related in: MedlinePlus