title: Stimulation of growth-hormone release with clonidine does not distinguish individual cases of idiopathic Parkinson's disease from those with striatonigral degeneration.
abstract: Multiple System Atrophy (MSA) and idiopathic Parkinson's disease (PD) can be difficult to distinguish. There is an ongoing debate about the diagnostic value of the growth-hormone response to clonidine (CGH-test) in PD and MSA. We investigated whether the CGH-test can identify individual patients in the early stages of PD (n = 21) and Striatonigral Degeneration (SND, n = 11), a particular variety of MSA. Patients were diagnosed on the basis of clinical criteria and IBZM-SPECT. Clonidine induced a greater total serum growth-hormone production in PD than in SND (p = 0.01). However, taking the difference in prevalence of PD and SND into account, and because of the low likelihood ratios of the test, an increase of GH after clonidine increases the pre-test probability for PD by about only 5 %, while an absent response of GH also increases the pre-test probability for SND by about 5 %. We conclude that the CGH-test discriminates between groups of patients with PD and SND, but has little practical diagnostic value for identifying individual patients.
authors.affiliation: Dept. of Neurology, University Medical Center, PO Box 9101, 6500 HB Nijmegen, The Netherlands.
authors.forename: E
authors.initials: E
authors.lastname: Strijks
authors.forename: M
authors.initials: M
authors.lastname: van't Hof
authors.forename: F
authors.initials: F
authors.lastname: Sweep
authors.forename: J W
authors.initials: JW
authors.lastname: Lenders
authors.forename: W J
authors.initials: WJ
authors.lastname: Oyen
authors.forename: M W I M
authors.initials: MW
authors.lastname: Horstink
mesh_terms: D000368:Aged; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003000:Clonidine; D003937:Diagnosis, Differential; D013006:Growth Hormone / Q000097:blood / Q000378:metabolism*; D006801:Humans; D008875:Middle Aged; D010300:Parkinson Disease / Q000097:blood / Q000175:diagnosis*; D018709:Statistics, Nonparametric; D020955:Striatonigral Degeneration / Q000097:blood / Q000175:diagnosis*
chemical_list: D013006:Growth Hormone; D003000:Clonidine