4348
BACKGROUND : Posteroventral medial pallidotomy sometimes produces striking improvement in patients with advanced Parkinson ' s disease , but the studies to date have involved small numbers of patients and short - term follow - up .
 Disease: Parkinson ' s disease
Please list all entity words in the text that fit the category.Output format is "type1: word1; type2: word2". 
Option: Disease, Chemical 
Text: {0} 
Answer:
 Disease: Parkinson ' s disease