<qa>  What is the best population for assessing a disease-modifying effect without dopaminergic3. Treatment-naïve, i.e. the best population for assessing a disease-modifying effect without the interaction of dopaminergic treatment no dopaminergic agonists, L-dopa, anticholinergics, monoamine oxidase B inhibitors e.g. rasagiline or deep brain stimulation. 