Functional brain changes in Parkinson's disease: a whole brain ALE study

Resting-state functional magnetic resonance imaging (rs-fMRI) was widely used as an effective tool in the diagnosis of neurodegenerative diseases. However, prior rs-fMRI studies reported inconsistent results for comparison between Parkinson's disease (PD) and healthy controls (HC).

We searched studies published before December 2021 in databases (PubMed, Web of Science, and Google Scholar). An activation likelihood estimation (ALE) meta-analysis was made for functional changes in PD.

The study finally included 25 studies (including 973 PD patients and 766 HC). PD patients showed reduced amplitude of low frequency fluctuations (ALFF) in the left superior temporal gyrus (STG), the left superior frontal gyrus (SFG), the left medial frontal gyrus (MFG), the left precuneus (PCUN), and the right lentiform nucleus, compared to HC. PD patients showed increased ALFF in the right SFG, the left superior parietal lobule (SPL), the left STG, the right fusiform gyrus, the left inferior temporal gyrus (ITG), and the right parahippocampal gyrus (PHG), compared to HC. PD patients showed reduced regional homogeneity (ReHo) in the right declive, the right MFG, the left culmen, and the left thalamus, compared to HC. PD patients showed increased ReHo in the right SFG, compared to HC. Additionally, PD patients showed reduced functional connectivity (FC) in the right posterior cingulate (PCG), compared to HC.

The present ALE analysis has confirmed functional deficits in motor-, emotion-, and cognition-related regions in PD. Deficits in these regions in rs-fMRI studies could play a role in early diagnosis of PD.