title: Levodopa challenge test and (123) I-metaiodobenzylguanidine scintigraphy for diagnosing Parkinson's disease.
abstract: OBJECTIVE
  To explore the possibility of a generally applicable tool for the immediate diagnosis of Parkinson's disease (PD) in its early stage, we compared the sensitivity and specificity of an acute levodopa challenge test with that of (123) I-metaiodobenzylguanidine (MIBG) myocardial scintigraphy.
  
  
  METHODS
  A consecutive series of 45 patients with extrapyramidal symptoms were recruited to the acute levodopa challenge and evaluated for improvement by use of the Unified Parkinson's Disease Rating Scale motor scores. Of these patients, 32 of them were also examined by MIBG scintigraphy. The patients were followed up for at least 24 months, and 22 patients were diagnosed as having clinically definite PD.
  
  
  RESULTS
  The sensitivity and specificity of the acute levodopa challenge test to predict clinical diagnosis of PD were 81.8% and 81.8%, respectively, which were better than those obtained by MIBG scintigraphy (62.5% and 62.5%). In both early- and middle-stages of PD, the test gave better sensitivity than MIBG scintigraphy.
  
  
  CONCLUSIONS
  Considering that the well-established and frequently referred clinical diagnostic criteria require longitudinal observation for at least 24 months, the acute levodopa challenge test can be used as an immediate diagnostic tool for PD with sensitivity and specificity comparable to those of MIBG.
authors: Department of Neurology, Kansai Medical University, Moriguchi, Osaka, Japan.
authors: S
authors: S
authors: Asayama
authors: R
authors: R
authors: Wate
authors: S
authors: S
authors: Kaneko
authors: T
authors: T
authors: Asayama
authors: M
authors: M
authors: Oki
authors: A
authors: A
authors: Tsuge
authors: M
authors: M
authors: Nagashima
authors: J
authors: J
authors: Morita
authors: S
authors: S
authors: Nakamura
authors: M
authors: M
authors: Nakamura
authors: M
authors: M
authors: Nishii
authors: K
authors: K
authors: Fujita
authors: A
authors: A
authors: Saito
authors: S
authors: S
authors: Nakano
authors: H
authors: H
authors: Ito
authors: H
authors: H
authors: Kusaka
mesh_terms: D019797:3-Iodobenzylguanidine; D000368:Aged; D000369:Aged, 80 and over; D000978:Antiparkinson Agents / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D007980:Levodopa / Q000627:therapeutic use*; D008297:Male; D008875:Middle Aged; D010300:Parkinson Disease / Q000175:diagnosis* / Q000188:drug therapy*; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals; D012680:Sensitivity and Specificity; D013997:Time Factors
chemical_list: D000978:Antiparkinson Agents; D019275:Radiopharmaceuticals; D019797:3-Iodobenzylguanidine; D007980:Levodopa
keywords: Levodopa; Parkinson's disease; metaiodobenzylguanidine (MIBG) scintigraphy