Funding agencies: This project was supported by the University Hospital of Grenoble and the France Parkinson Association.
Levodopa does not change cerebral vasoreactivity in Parkinson's disease
Article first published online: 12 DEC 2012
Copyright © 2012 Movement Disorders Society
Volume 28, Issue 4, pages 469–475, April 2013
How to Cite
Krainik, A., Maillet, A., Fleury, V., Sahin, M., Troprès, I., Lamalle, L., Thobois, S., Fraix, V., Villien, M., Warnking, J., Pollak, P., Pinto, S. and Krack, P. (2013), Levodopa does not change cerebral vasoreactivity in Parkinson's disease. Mov. Disord., 28: 469–475. doi: 10.1002/mds.25267
Relevant conflicts of interest/financial disclosures: Nothing to report.
Full financial disclosures and author roles may be found in the online version of this article.
- Issue published online: 8 APR 2013
- Article first published online: 12 DEC 2012
- Manuscript Accepted: 30 SEP 2012
- Manuscript Revised: 27 SEP 2012
- Manuscript Received: 3 AUG 2012
- Parkinson's disease;
- cerebral vasoreactivity;
- carbon dioxide;
- BOLD fMRI
The aim of this work was to study cerebral vasoreactivity to hypercapnia in Parkinson's disease (PD) before and after levodopa administration. The prospective study was conducted in 20 patients presenting with PD, using 3T blood oxygenation level-dependent (BOLD) functional MRI (fMRI) covering the whole brain. The hypercapnic stimulus was block-designed using carbogen inhalation, a gas mixture of 7% CO2 and 93% O2, before (OFF) and 60 minutes after administration of a suprathreshold (120%) therapeutic L-dopa dose (ON). Ten age-matched controls were enrolled for between-group comparisons. Analyses were conducted with a random effects model and corrected for multiple comparisons. No adverse reaction to the hypercapnic stimulus was reported. However, 10 patients and 2 controls were excluded because of incomplete protocol realization, inappropriate hypercapnic stimulus, or excessive movements, leaving 10 patients and 8 controls for further analyses. The hypercapnic stimulus increased whole-brain BOLD signal of 1.48% ± 0.06% (mean ± standard error) in controls, 1.59% ± 0.05% in patients OFF, and 1.62% ± 0.09% in patients ON. Regions of interest analyses showed a signal increase in gray matter of 2.60% ± 0.16% in controls, 2.89% ± 0.21% in patients OFF, and 2.87% ± 0.12% in patients ON. No global or regional significant difference was detected, when comparing patients OFF and ON L-dopa, or between patients and controls. Contrary to Alzheimer's disease, the vasoreactivity to hypercapnia was normal in PD before and after L-dopa administration, compared to controls. This negative result is an important finding, especially for neuroscientists using fMRI to investigate motricity and cognition, discarding a significant confounding effect. © 2012 Movement Disorder Society