title: Monosymptomatic resting tremor and Parkinson's disease: a multitracer positron emission tomographic study.
abstract: We sought to elucidate the relationship between monosymptomatic resting tremor (mRT) and Parkinson's disease (PD). We studied eight mRT patients (mean Hoehn and Yahr [H&Y], 1.1 +/- 0.4), eight patients with PD (mean H&Y, 1.5 +/- 0.8), who showed all three classic parkinsonian symptoms, and seven age-matched healthy subjects. Subjects underwent cerebral magnetic resonance imaging (MRI) and multitracer positron emission tomography (PET) with 6-[(18)F]fluoro-L-dopa (F-dopa), [(18)F]fluorodeoxyglucose (FDG), and [(11)C]raclopride (RACLO). PD and mRT patients did not show significant differences in F-dopa-, RACLO-, or FDG-PET scans. In F-dopa- and RACLO-PET, significant differences between the pooled patient data and control subjects were found for the following regions: anterior and posterior putamen ipsilateral and contralateral to the more affected body side, and ipsilateral and contralateral putaminal gradients of the K(i) values. Furthermore, we found a difference for the normalized glucose values of the whole cerebellum between the control group (0.94 +/- 0.06) and PD patients (1.01 +/- 0.04; P < 0.05) but not for the mRT group (0.97 +/- 0.03). Our findings indicate that monosymptomatic resting tremor represents a phenotype of Parkinson's disease, with a nearly identical striatal dopaminergic deficit and postsynaptic D2-receptor upregulation in both patient groups. We suggest that the cerebellar metabolic hyperactivity in PD is closer related to akinesia and rigidity rather than to tremor.
authors.affiliation: Klinik für Neurologie der Universität zu Köln, Köln, Germany.
authors.forename: Mehran
authors.initials: M
authors.lastname: Ghaemi
authors.forename: Jan
authors.initials: J
authors.lastname: Raethjen
authors.forename: Rüdiger
authors.initials: R
authors.lastname: Hilker
authors.forename: Jobst
authors.initials: J
authors.lastname: Rudolf
authors.forename: Jan
authors.initials: J
authors.lastname: Sobesky
authors.forename: Günther
authors.initials: G
authors.lastname: Deuschl
authors.forename: Wolf-Dieter
authors.initials: WD
authors.lastname: Heiss
mesh_terms: D000328:Adult; D000368:Aged; D001921:Brain / Q000000981:diagnostic imaging* / Q000503:physiopathology; D002531:Cerebellum / Q000000981:diagnostic imaging / Q000503:physiopathology; D004295:Dihydroxyphenylalanine / Q000031:analogs & derivatives*; D004292:Dominance, Cerebral / Q000502:physiology; D004734:Energy Metabolism / Q000502:physiology; D005260:Female; D019788:Fluorodeoxyglucose F18; D006801:Humans; D008279:Magnetic Resonance Imaging; D008297:Male; D008875:Middle Aged; D009460:Neurologic Examination; D010300:Parkinson Disease / Q000000981:diagnostic imaging* / Q000503:physiopathology; D011699:Putamen / Q000000981:diagnostic imaging / Q000503:physiopathology; D020891:Raclopride; D017448:Receptors, Dopamine D2 / Q000502:physiology; D012016:Reference Values; D014055:Tomography, Emission-Computed / Q000379:methods*; D014202:Tremor / Q000000981:diagnostic imaging* / Q000503:physiopathology; D015854:Up-Regulation / Q000502:physiology
chemical_list: D017448:Receptors, Dopamine D2; D019788:Fluorodeoxyglucose F18; C043437:fluorodopa F 18; D020891:Raclopride; D004295:Dihydroxyphenylalanine