Two examples to illustrate opposite results following drug regimen change. In situation 1, a change in drug regimen decreased dyskinesia amplitude which then led to increased signal-to-noise ratio (SNR) (dark grey lines), and consequently increased motor repertoire. In situation 2, the same change in drug regimen also led to a reduction of dyskinesia amplitude. However, there is resurgence of typical motor symptoms associated with PD, thus increasing the noise, which will induce a decrease of overall SNR, hence a reduction in the motor repertoire (light grey lines). Here, the patient did not benefit from the reduction of dyskinesia, as his/her motor repertoire worsened. These examples illustrate the challenges faced by clinicians when managing dyskinesia. PD, Parkinson's disease.