Investigation of the adaptation to artificial damping in cerebellar ataxia using the myohaptic technology

We investigated fast pointing and fast reversal single-joint movements performed under artificial damping conditions applied with the myohaptic technology. Healthy subjects were able to scale the intensity of the agonist and antagonist electromyographic (EMG) activities when damping was added during both types of movements. Cerebellar patients were able to scale the magnitude of the agonist and antagonist EMG activities during pointing movements. For reversal movements, patients could scale the intensity of the initial agonist EMG activity but were unable to modulate the intensities of the second set of EMG discharges associated with the return to the initial position. Patients were able to adopt the appropriate motor strategy for the first phase of reversal movements, but they were unable to implement the suitable sequential strategy for the superimposition of motor plans during artificial damping. The myohaptic technology is the first to allow the detection of deficits in the implementation of sequential motor coding under the mechanical condition of artificial damping. © 2009 Springer-Verlag.SCOPUS: cp.p