This study is looking at how safe and effective a treatment called *peroneal transcutaneous neuromodulation (eTNM®)* is for people with Parkinson's Disease (PD) and Essential Tremor (ET). The treatment uses a device called **URIS I™** at home to help with movement issues. In a previous short study, 24 people used the device for 6 weeks and found it safe and easy to use. Now, this study will last 24 months to see if these benefits continue over a longer time. **Key Points:** - **Duration**: The study will last for 24 months and participants will use the device at home. - **Safety**: No bad side effects were seen in the earlier study. - **Eligibility**: Participants must have completed a previous related study and be stable on other medications they might be taking. People cannot join if they have other medical devices, certain health conditions, or are pregnant. This study is important to see if this home-based treatment can help people with PD and ET over a long time.