You will have a neurological exam, which will include a series of questions and tasks (such as walking, talking, and touching your nose). The interview will take about 20 minutes to complete. Additionally, the study doctor will test your reflexes by tapping your arms, knees, and the bottom of your feet with a rubber triangle-shaped end of a special instrument that looks like a little hammer. The study doctor will also test your ability to sense light touch and pinprick, and will check your eyes with a special light source (ophthalmoscope). You will be asked questions about your physical, social/family, emotional, and functional well-being, as well as additional concerns you may have regarding numbness, tingling, discomforts, and difficulties you may be having. The interview will take about 10 minutes to complete.