Neuromodulation : journal of the International Neuromodulation Society
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Objective. This study assessed 3-Tesla magnetic resonance imaging (MRI) issues for a programmable infusion pump and associated catheters. Methods. A programmable infusion pump and associated catheters (MedStream Programmable Infusion Pump, 40 mL; SureStream TI Coil-Reinforced Intraspinal Catheter; SureStream TI Connector; and SureStream Silicone Catheter; Codman and Shurtleff Inc., a Johnson & Johnson Company, Raynham, MA, USA) underwent evaluation for magnetic field interactions (deflection angle and torque), heating (transmit/receive body radiofrequency coil; whole-body averaged specific absorption rate, 3 W/kg for 15 min), functional changes (before and after MRI using eight different MRI conditions), and artifacts (T1-weighted spin-echo and gradient-echo pulse sequences) at 3-Tesla. Results. The programmable infusion pump and associated catheters exhibited minor magnetic field interactions. ⋯ Artifacts were relatively large for the pump and minor for the catheter. Conclusions. The programmable infusion pump and catheters will not pose increased risk to a patient examined using 3-Tesla MRI as long as specific safety guidelines are followed, which includes interrogation of the pump post-MRI to ensure proper settings. Artifacts for the programmable infusion pump may impact the diagnostic use of MRI if the area of interest is in the same area or near the device.
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Objectives. This paper describes an experimental investigation of variable frequency stimulation patterns as a means of increasing torque production and, hence, performance in cycling induced by functional electrical stimulation. Materials and Methods. Experiments were conducted on six able-bodied subjects stimulating both quadriceps during isokinetic trials. Constant-frequency trains (CFT) with 50-msec interpulse intervals and four catchlike-inducing trains (CIT) were tested. ⋯ Conclusions. The use of CITs improves the functional electrical stimulation cycling performance compared with CFT stimulation. This application might have a relevant clinical importance for individuals with stroke where the residual sensation is still present and thus the maximization of the performance without an excessive increase of the stimulation intensity is advisable. Therefore, exercise intensity can be increased yielding a better muscle strength and endurance that may be beneficially for later gait training in individuals with stroke.
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The aim of this study was to perform a preliminary evaluation of a new method for therapeutic exercise of grasping in patients with upper limb disability. The new method combines active voluntary exercise augmented with electrical stimulation and controlled by using force feedback. The feedback has two functions: automatic control of the intensity of electrical stimulation by minimizing the tracking error, and biofeedback to the patient on the computer screen. ⋯ Results in healthy subjects were used for reference and for stimulation controller evaluation. The therapy in incomplete tetraplegic subjects of 45-min daily session delivered during four weeks. The results of pilot study show that augmentation of voluntary grip force control with presented system is possible.
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Objectives. Motor cortex stimulation has been used as a treatment for intractable pain. However, the mechanisms underlying its effects remain unclear. In this study, neuroplasticity induced by chronic sensorimotor cortex stimulation was investigated experimentally on the basis of c-Fos expression. ⋯ We examined the neural activation in response to chronic stimulation using c-Fos immunopositivity. Results. The results are as follows: 1) c-Fos was significantly expressed immediately after the stimulation compared with that in the control; 2) c-Fos expression became extensive over the various regions with an increase in stimulation duration; and 3) after two months of stimulation, c-Fos was expressed not only on the stimulation side, but also within the contralateral cerebral hemisphere. Conclusions. Changes in c-Fos expression induced by long-term stimulation indicate the existence of a time-dependent neural plasticity.
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Objective. Classically, a decerebrated animal by mesencephalic lesioning is considered the paradigm for experimental study of spasticity that accompanies cerebral palsy, but, the model does not actually correspond with anatomical and pathologic realities. Therefore, a new and novel animal model is needed. Our objective was to create a more adapted animal model to be used in neuromodulation and functional electrical stimulation research. ⋯ Conclusions. This animal model presents anatomic similarities to lesions currently present in cerebral palsy and related diseases. The model also shows electrophysiologic differences that signal chronic brain damage. Therefore, this method is useful in research when spastic syndromes produced by upper motor lesions need to be modeled.