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(THE CONVERSATION) For many, hearing the word “Parkinson’s” conjures an image of tremors. But Parkinson’s disease, brought about by loss of nerve and other brain cells, is actually an incredibly complex movement disorder that can cause symptoms as wide-ranging as smell loss, thinking issues, depression and swallowing problems. More than 1.5 million people in the U.S. have the illness, and millions more loved ones and caregivers are affected by it, too.

Thanks to medical advances an...