Doctors frequently check for early signs of brain conditions like Alzheimer's and Parkinson's by looking at irregularities in your drawings, but it's an imperfect art based largely on the doctor's opinion. All too often, the only concrete signs show up by the time you've already been ravaged by the disease. MIT researchers might have a more effective way to catch these conditions early on, though. By using custom tracking software to monitor the output from a digital pen, they can more accurately predict the onset of brain conditions based not only on what you draw, but how you draw. Healthy people spend a bit more time thinking than scribbling; those with memory issues (such as Alzheimer's sufferers) spend a lot more time in thought, while Parkinson's patients tend to struggle with the drawing process.