Nonmotor Manifestations of Parkinson’s Disease

The idea that Parkinson’s disease involves more than its classic motor symptoms (tremor, slowness, shuffling, etc.) is not new. Even James Parkinson recognized this in his seminal publication describing this disease in 1817. However, it is only in the last 25 years or so that neurologists have taken a serious, in-depth look at the nonmotor manifestations of Parkinson’s disease. What they have found has evolved into a rich field of study that has both permitted a greater understanding, and revealed greater levels of complexity, of Parkinson’s disease than previously known. ...

A New Definition of Parkinson’s Disease

Although the issue has not gained many headlines, a great deal of energy is being expended by movement disorders neurologists to develop a new way of thinking about Parkinson’s disease. This effort has been prompted by two major trends: a growing recognition that traditional definitions are inadequate, and an assortment of new scientific discoveries that compel us to broaden our understanding of what exactly constitutes Parkinson’s disease.

To neurologists, the classic definition of Parkinson’s disease in patients consists of a combination of clinical (i.e., ...