Biomedical subjects

Maurizio Ferrarin

Publications and source records attributed to Maurizio Ferrarin.

5 recordsLinked to original sources

PubMed2005

Head control: volitional aspects of rehabilitation training in patients with multiple sclerosis compared with healthy subjects.

OBJECTIVE: To investigate the role of voluntary mechanisms and motor learning in head stability and the impact of longitudinal biofeedback training in head control. DESIGN: Crossover trial and single-subject research design. SETTING: Neurorehabilitation research institute. PARTICIPANTS: Head stability during treadmill gait was measured in healthy subjects and patients with multiple sclerosis (MS). INTERVENTION: The experimental condition in which subjects walked on the treadmill was compared with that in which the head was voluntarily stabilized. In another experimental condition, augmented feedback of head displacement was provided by means of a laser mounted on the head that projected a laser beam on a screen. The motor learning was investigated with biofeedback training sessions. Positional feedback was represented by the laser beam, with subjects having to stabilize the beam while walking on the treadmill. MAIN OUTCOME MEASURE: Head angular oscillation in the sagittal and frontal planes. RESULTS: Results showed that on verbal request, healthy subjects and patients further stabilized the head during gait, especially in the sagittal plane. Short-term feedback of head displacement was no better than self-stabilization at improving head control. Conversely, the motor learning was evident in the rehabilitation protocol: after 10 to 15 training sessions, patients with MS showed a clinically relevant decrease of head angular oscillations. CONCLUSIONS: Voluntary mechanisms play a role in head stabilization during gait. Augmented biofeedback of head displacement may be effective in reducing head oscillations.

Adaptation, Physiological↗

PubMed2002

Quantitative analysis of gait in Parkinson's disease: a pilot study on the effects of bilateral sub-thalamic stimulation.

Four patients with Parkinson's disease who had a Subthalamic Nucleus (STN) stimulator implanted and four age-matched controls underwent gait analysis using a three-dimensional system. STN stimulation substantially improved most of the key variables in the patients, without producing inefficient compensatory movements of the trunk. A reduction of ankle power production during push off was the most persistent abnormality seen when the patients were stimulated. We also found a reduction of trunk lateral bending and torsion when the patients were not stimulated when compared with controls.

Biomechanical Phenomena↗

PubMed2002

Coding of far and near space during walking in neglect patients.

Previous studies have shown that far space can be remapped as near when reached by a stick that artificially prolongs the participants' personal space. In the present study, the authors asked whether a similar remapping occurs when far space is reached not by using a tool but by locomotion. Neglect patients showed more severe neglect in far than in near space in bisection tasks executed from different distances either by pointing to a target line with a projection light pen or by walking across the line. A kinematic study of the walking performance of one of those neglect patients showed that, contrary to the prediction of remapping during locomotion, the walking trajectories were rectilinear. The authors interpreted these results as evidence that in their patients-at least for short, linear trajectories-no remapping of space took place during locomotion. The location of far objects was coded at the beginning of the movement, and the error in the bisection computation was generated within the 1st representation that was activated.

Adolescent↗

PubMedDate not supplied

Functional electrical stimulation reinforced tenodesis effect controlled by myoelectric activity from wrist extensors.

We demonstrated a method for enhancing the tenodesis grip in individuals with sustained tetraplegia at the 6th cervical vertebra neurological level. Subjects used the myoelectric activity from wrist extensor muscles to directly control the electrical stimulation of the extrinsic finger and thumb flexors (flexor pollicis longus and flexor digitorum superficialis/ profondus) with the use of a specially designed system, Myoelectrically Controlled Functional Electrical Stimulation (MeCFES). We screened 20 medical records and selected 9 subjects. Of the nine subjects, five showed a positive response to the surface stimulation and could test the system; the other four failed to achieve functional finger flexion because of skin sensitivity or inadequate movement. We evaluated hand function, with and without the MeCFES system, using tests involving three everyday objects: manipulating a videocassette with the key grip, drinking from a bottle with the palmar grasp, and writing with a pen using the tripod grip. Without the system, none of the five subjects could complete all three tasks; but, when assisted with MeCFES, all subjects completed all the tasks. The system proved simple and intuitively easy to use, and no training was needed for subjects to obtain immediate functionality. We will need further research to evaluate the usefulness of the system in activities of daily living.

Adolescent↗

PubMedDate not supplied

Functional electrical stimulation controlled by artificial neural networks: pilot experiments with simple movements are promising for rehabilitation applications.

This study falls within the ambit of research on functional electrical stimulation for the design of rehabilitation training for spinal cord injured patients. In this context, a crucial issue is the control of the stimulation parameters in order to optimize the patterns of muscle activation and to increase the duration of the exercises. An adaptive control system (NEURADAPT) based on artificial neural networks (ANNs) was developed to control the knee joint in accordance with desired trajectories by stimulating quadriceps muscles. This strategy includes an inverse neural model of the stimulated limb in the feedforward line and a neural network trained on-line in the feedback loop. NEURADAPT was compared with a linear closed-loop proportional integrative derivative (PID) controller and with a model-based neural controller (NEUROPID). Experiments on two subjects (one healthy and one paraplegic) show the good performance of NEURADAPT, which is able to reduce the time lag introduced by the PID controller. In addition, control systems based on ANN techniques do not require complicated calibration procedures at the beginning of each experimental session. After the initial learning phase, the ANN, thanks to its generalization capacity, is able to cope with a certain range of variability of skeletal muscle properties.

Adult↗