ABSTRACT
Parkinson’s disease (PD) is a complex and heterogeneous disorder with no clearly dened demarcation between “early,” “moderate,” or “advanced” PD. The management issues encountered in these stages clearly overlap, yet become increasingly more complex as the disease progresses. An arbitrary, but convenient, marker of advanced PD could well be the point at which postural reŸexes become impaired such that assisted ambulation may be required (i.e., Hoehn and Yahr stage IV) (Hoehn and Yahr, 1967). However, there are other motor and a variety of nonmotor features that constitute signs of advanced PD, some beginning early in the disease and others developing later, but each having a signicant impact on the patient’s quality of life. Some patients evolve to a point of dependency in less than a decade; others can maintain independence for several decades (Selikhova et al., 2009).
