Brain activity during stepping: A novel MRI-compatible device

Hollnagel, Christoph; Brügger, Mike; Vallery, Heike; Wolf, Peter; Dietz, Volker; Kollias, Spyros; Riener, Robert

doi:10.1016/j.jneumeth.2011.07.022

Cited by 56 publications

(71 citation statements)

References 28 publications

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“…Robotic devices have been used for the mobilisation of body parts also in the field of Neuroscience [10][11][12][13][14][15]. Machines to manage the motion of the effectors (muscles) can in fact be used to support the measurement and visualisation of the interconnections between the activities of peripheral segments and the brain structures involved in their control.…”

Section: Biomedical Backgroundmentioning

confidence: 99%

“…Increasing interest has being expressed during the last few years [10][11][12][13][14][15] to the effect of finding specialised tools that can be compatible with the instrumentation used to conduct Neuroscience experiments, e.g. magnetic resonance imaging (MRI, fMRI), magnetoencephalography (MEG), electroencephalography (EEG), near-infrared spettroscopy (NIRS).…”

Section: Neurosciencementioning

confidence: 99%

See 1 more Smart Citation

Shape Memory Actuators for Medical Rehabilitation and Neuroscience

Pittaccio¹,

Viscuso²

2012

Smart Actuation and Sensing Systems - Recent Advances and Future Challenges

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Section: Biomedical Backgroundmentioning

confidence: 99%

Section: Neurosciencementioning

confidence: 99%

Shape Memory Actuators for Medical Rehabilitation and Neuroscience

Pittaccio¹,

Viscuso²

2012

Smart Actuation and Sensing Systems - Recent Advances and Future Challenges

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“…Finally, Discussion and Conclusion section provides an overall evaluation of the proposed approaches. (Newton et al 2008) No actuation Non-magnetic -Ankle, knee and hip 6-axis load cell torque measurements (Mehta et al 2009) No actuation -Optical encoder Pedaling speed measurements (Sergi et al 2011) No actuation -Optical encoders Post rehabilitation efficacy prediction (Menon et al 2014) Particle-jamming via --Mechanical modulation pneumatic actuation of device stiffness (Khanicheh et al 2008) ERF actuation Aluminum Optical encoders Mechanical modulation strain gage of device damping (Hara et al 2009) Electrostatic motors Non-magnetic Synchronous drive 2-Dof motion & force force sensor rendering joystick (Hollnagel et al 2011) Pneumatic actuation Resistive Optical encoder, Analysis of strain gauges foil potentiometer stepping patterns Hydraulic actuation Fiber optic Shielded optical Analysis of force sensors encoders reaching movements (Yu et al 2008) Pneumatic The first category belongs to devices with no actuation (Hidler et al 2006;Newton et al 2008;Mehta et al 2009). The purpose of these devices is to measure the interaction forces or movement patterns of patients during, just before, or just after the MRI process.…”

Section: Introductionmentioning

confidence: 99%

MRI-VisAct: a Bowden-cable-driven MRI-compatible series viscoelastic actuator

Şentürk

Patoğlu

2017

Transactions of the Institute of Measurement and Control

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Presence of the strong magnetic fields in the Magnetic Resonance Imaging (MRI) environment limits the integration of robotic rehabilitation systems to the MRI process. The tendency to improve imaging quality by the amplification of magnetic field strength further tightens the bidirectional compatibility constraints on MRI compatible rehabilitation devices. We present the design, control, and characterization of MRI-VisAct-a low-cost, Bowden cable-actuated rotary series viscoelastic actuator that fulfills the bidirectional compatibility requirements to the maximum extend. Components of MRI-VisAct that are placed in the magnet room are built using nonconductive, diamagnetic MRI compatible materials, while ferromagnetic/paramagnetic components are placed in the control room, located outside the MRI room. Power and data transmission are achieved through Bowden-cables and fiber optics, respectively. This arrangement ensures that neuroimaging artifacts are minimized, while safety hazards are eliminated, and the device performance is not affected by the magnetic field. MRIVisAct works under closed-loop torque control enabled through series viscoelastic actuation. MRI-VisAct is fully customizable; it can serve as the building block of higher degrees of freedom MRI compatible robotic devices.

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“…Therefore, the gait movement needs to be simplified, but still should take into account the real displacements in the most relevant joints and the natural ground reaction forces during real gait foot loading [8,18]. Foot loading is important to activate the relevant brain and spinal cord neuronal circuits underlying stepping movements [6,7], however, it also increases the required actuators' force range.…”

Section: Introductionmentioning

confidence: 99%

“…In this work, we present an iterative learning controller (ILC) [2] and a performance-based adaptive control [10] to improve the usability of our magnetic resonance compatible stepper (MARCOS) with pneumatic actuation [18].…”

Section: Introductionmentioning

confidence: 99%

Non-linear adaptive controllers for an over-actuated pneumatic MR-compatible stepper

Hollnagel

Schädler

López

et al. 2013

Med Biol Eng Comput

Self Cite

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Pneumatics is one of the few actuation principles that can be used in an MR environment, since it can produce high forces without affecting imaging quality. However, pneumatic control is challenging, due to the air high compliance and cylinders non-linearities. Furthermore, the system's properties may change for each subject. Here, we present novel control strategies that adapt to the subject's individual anatomy and needs while performing accurate periodic gait-like movements with an MRI compatible pneumatically driven robot. In subject-passive mode, an iterative learning controller (ILC) was implemented to reduce the system's periodic disturbances. To allow the subjects to intend the task by themselves, a zeroforce controller minimized the interaction forces between subject and robot. To assist patients who may be too weak, an assist-as-needed controller that adapts the assistance based on online measurement of the subject's performance was designed. The controllers were experimentally tested. The ILC successfully learned to reduce the variability and tracking errors. The zero-force controller allowed subjects to step in a transparent environment. The assist-as-needed controller adapted the assistance based on individual needs, while still challenged the subjects to perform the task. The presented controllers can provide accurate pneumatic control in MR environments to allow assessments of brain activation.

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Brain activity during stepping: A novel MRI-compatible device

Cited by 56 publications

References 28 publications

Shape Memory Actuators for Medical Rehabilitation and Neuroscience

Shape Memory Actuators for Medical Rehabilitation and Neuroscience

MRI-VisAct: a Bowden-cable-driven MRI-compatible series viscoelastic actuator

Non-linear adaptive controllers for an over-actuated pneumatic MR-compatible stepper

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