Optimization of symptomatic therapy in Parkinson's disease.

A third-order nonlinear mathematical model of the dose-effect relationship of levodopa, one of the most common drugs used for the symptomatic therapy of Parkinson's disease, is derived with the aid of a visual tracking based method which allows the measurement of some Parkinsonian symptoms quantitatively and objectively. The parameters of this model are identified for each subject separately due to the large interpatient variability in response to treatment. The model is then used to optimize the dosage regimen for each patient individually (according to the clinical particularities and needs of each patient) with respect to an objective function which includes the symptoms dynamically and the total amount of levodopa which is to be administered. Encouraging clinical results of this control engineering approach to therapy optimization are presented. The advantages and drawbacks of this approach are discussed and further research directions are indicated.