Is Cerebral Blood Flow Altered in Parkinson's Disease? A Systematic Review and Meta-analysis
Hamidreza Ghodsi1, Amin Saberi2, Sriya Avadhanam3, Melanie Pitzer1, Katherine Longadner1
1Parkinson and Other Movement Disorders Center, University of California San Diego, 2Institute of Neurosciences and Medicine (INM-7), Research Centre Jülich, 3Tufts University School of Medicine
Objective:
To meta-analytically determine how resting-state cerebral blood flow (CBF) changes in Parkinson's disease (PD) compared to healthy controls (HC).
Background:
PD manifests with non-motor symptoms (e.g., autonomic failure and dementia). Autonomic failure disrupts cerebral autoregulation, a critical mechanism that maintains physiological CBF despite fluctuations in systemic blood pressure. Alterations in CBF may be associated with cognitive impairment. However, the reported findings in the literature on brain regions that exhibit CBF alterations in PD are inconsistent, highlighting the need for a quantitative synthesis of these findings.
Design/Methods:

We systematically searched PubMed and ISI Web of Science for studies comparing resting-state CBF in persons with PD and HC using modalities including arterial spin labeling (ASL)-MRI, SPECT, and PET. We performed activation likelihood estimation (ALE) meta-analysis to identify the convergence of reported CBF abnormalities in PD tested against randomly distributed foci, corrected for multiple comparisons using family-wise error correction at the cluster level (cFWE). Then, we performed behavioral decoding of the resulting convergent clusters based on the NeuroSynth database.

Results:

Out of 1,847 records initially screened, 530 articles were selected for full-text review. Of these, 30 studies met the eligibility criteria and were included. We identified two convergent clusters with reduced CBF in PD compared to HC. The first cluster, located in the left middle frontal gyrus (Montreal Neurological Institute (MNI): -32, 8, 56; 392 mm³), is associated with cognitive functions such as working memory and reasoning. The second cluster, found in the cuneus, precuneus, and posterior cingulate cortex (MNI: -2, -68, 16; 984 mm³), is linked to sleep and mood functions.

Conclusions:

Compared to HC, persons with PD had lower resting CBF in the left middle frontal gyrus and precuneus/poster cingulate cortex, which are associated with higher-level neuropsychiatric functions such as working memory, sleep regulation, and mood, which are clinically relevant non-motor manifestations of PD.

10.1212/WNL.0000000000212535
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