Abnormal sensorimotor control, but intact force field adaptation, in multiple sclerosis subjects with no clinical disability

• Published in: Multiple sclerosis Vol. 14; no. 3; pp. 330 - 342
• Main Authors: Casadio, Maura, Sanguineti, Vittorio, Morasso, Pietro, Solaro, Claudio
• Format: Journal Article
• Language: English
• Published: London, England SAGE Publications 01.04.2008; Arnold; Sage Publications Ltd
• Subjects: Adaptation, Physiological - physiology; Adult; Biological and medical sciences; Degenerative and inherited degenerative diseases of the nervous system. Leukodystrophies. Prion diseases; Disability Evaluation; Female; Hand - physiology; Humans; Male; Medical sciences; Middle Aged; Models, Biological; Motor Neurons - physiology; Movement - physiology; Multiple sclerosis and variants. Guillain barré syndrome and other inflammatory polyneuropathies. Leukoencephalitis; Multiple Sclerosis, Relapsing-Remitting - physiopathology; Multiple Sclerosis, Relapsing-Remitting - rehabilitation; Neurology; Neurons, Afferent - physiology; Physical Therapy Modalities - instrumentation; Predictive Value of Tests; Robotics; robot therapy; motor adaptation; motor control; multiple sclerosis; Human; Nervous system diseases; Multiple sclerosis; Force; Motor control; Inflammatory disease; Disability; Treatment; Central nervous system disease; Degenerative disease; Robot; Adaptation
• ISSN: 1352-4585; 1477-0970
• DOI: 10.1177/1352458507085068

In MS subjects with no clinical disability, we assessed sensorimotor organization and their ability to adapt to an unfamiliar dynamical environment. Eleven MS subjects performed reaching movements while a robot generated a speed-dependent force field. Control and adaptation performance were compared with that of an equal number of control subjects. During a familiarization phase, when the robot generated no forces, the movements of MS subjects were more curved, displayed greater and more variable directional errors and a longer deceleration phase. During the force field phase, both MS and control subjects gradually learned to predict the robot-generated forces. The rates of adaptation were similar, but MS subjects showed a greater variability in responding to the force field. These results suggest that MS subjects have a preserved capability of learning to predict the effects of the forces, but make greater errors when actually using such predictions to generate movements. Inaccurate motor commands are then compensated later in the movement through an extra amount of sensory-based corrections. This indicates that early in the disease MS subjects have intact adaptive capabilities, but impaired movement execution. Multiple Sclerosis 2008; 14: 330—342. http://msj.sagepub.com