The role of proprioceptive reflexes in movement disorders of patients with Parkinson's disease.
1999 - 99 / 2003
In Delft a one Degree-of-Freedom (translational) robotic manipulator has been developed to impose force perturbations on the hand with a varying frequency content. By using advanced closed-loop identification algorithms using force, position and EMG recordings, intrinsic properties and proprioceptive reflex gains have been estimated. Patients with Parkinson's disease and dystonia are hypothesised to have, amongst others, a disturbed motion control resulting from excessive proprioceptive feedback gains. The goal of this project is to evaluate and quantify the impaired proprioceptive reflex gains (PRG) in patients with Parkinson's disease and dystonia, monitor changes of impaired PRG in relation to disease progression, to detect at which site of the proprioceptive feedback loop the neurological disorders have their effect, and to evaluate the effect of medication. The new methodology of measuring feedback gains will be applied to patients with PD and dystonia. It is anticipated that patients with tremors will show very high feedback gains, whereas even higher feedback gains will lead to tonic muscle contractions. In the latter case, adding environmental impedance by the robotic manipulator will result in a stable system again, in which the feedback gains can be recorded. A broad group of patients with severe and less severe symptoms will be measured, in order to assess the accuracy and sensitivity of the method. A small group of patients will be monitored for a period of three years, in order to determine the progression of the disease. In a double-blind placebo controlled experimental trial, the effect of medication will be investigated. The location of the disease and the response to medication is different between the patients with PD and dystonia. This offers the opportunity to investigate the role of Central Nervous System on the feedback gains. It is estimated that there are about 15000 patients with PD and about 8000 patients with dystonia in the Netherlands. Quantification of the proprioceptive feedback gains will provide a valuable, objective measure to determine the severity and progression of the disease, and accelerate the search for new medication. Cheaper versions of the robotic manipulator can be developed in order to provide an effective clinical tool to quantitatively assess the severity of the disease.
Comment: This project is in collaboration with the Dept. of Neurology, Leiden University Medical Centre (Dr. J.J. van Hilten).