RT Book, Section A1 Yacoubian, Talene A. A1 Standaert, David G. A2 Watts, Ray L. A2 Standaert, David G. A2 Obeso, Jose A. SR Print(0) ID 55793891 T1 Chapter 14. Neuroprotective Therapies for Parkinson's Disease T2 Movement Disorders, 3e YR 2012 FD 2012 PB The McGraw-Hill Companies PP New York, NY SN 978-0-07-161312-5 LK accessphysiotherapy.mhmedical.com/content.aspx?aid=55793891 RD 2024/03/28 AB Parkinson's disease (PD) is a relentlessly progressive disorder. The symptoms are usually mild at onset, most frequently a resting tremor of a hand, but worsen steadily over years to cause severe disability in most cases. Indeed, much evidence suggests that the onset of the neurodegenerative process precedes the appearance of clinical symptoms by as much as a decade, and that the neurodegenerative process is well established by the time the disease is clinically apparent.