ROCHESTER, N.Y., Jan. 29 A University of Rochester study says the number of Parkinson's disease cases will double over the next generation in the world's largest nations.The bulk of the growth in Parkinson's disease in the next 25 years will not be in the United States and Europe but in other places, namely China, where Parkinson's may not be viewed as a major public health problem, said University of Rochester neurologist Dr. Ray Dorsey. Moreover, this growth will occur in societies where there is very limited infrastructure in place to diagnose individuals, much less address their medical needs or the societal impact.The researchers examined the projected population growth in France, Spain, Germany, the United Kingdom and Italy and the 10 most populous nations worldwide: China, India, Indonesia, the United States, Brazil, Pakistan, Bangladesh, Nigeria, Japan and Russia.Parkinson's disease is a degenerative disorder of the central nervous system that impairs motor skills and walking. Despite the fact that the disease is treatable with a combination of medications, therapy and exercise, many individuals in the developing world do not receive appropriate care, according to the study published in the journal Neurology.Copyright 2007 by UPI