Sometimes doctors have trouble telling if a person's shaking, or tremor, is from Parkinson's disease or essential tremor. Parkinson's disease is a disorder that affects movement, often including tremors. Essential tremor is a different condition that also causes shaking but is not due to Parkinson's. This study aims to use machine learning (a type of computer program that learns from data) to help doctors make a better diagnosis. The study will include 110 patients who already know if they have Parkinson's or essential tremor. They will take two tests: a tapping test and drawing an Archimedean spiral (a type of spiral shape), to gather data for the machine learning program.

• The study is suitable for those who can actively participate and have a confirmed diagnosis.
• Patients need to sign a consent form to join the study.
• People taking certain medicines or with very severe tremors may not be eligible.