Abnormal Spontaneous Brain Activity in Left-Onset Parkinson Disease: A Resting-State Functional MRI Study

Abstract

Objective: Motor asymmetry is characteristic in Parkinson disease (PD). This phenomenon is originated from uneven degeneration of bilateral substantia nigra. However, this asymmetry may not restrict to substantia nigra or striatum. We aimed to determine the effect of asymmetry on spontaneous brain activity across the whole brain. Methods: We consecutively recruited 71 patients with PD, as well as 35 healthy controls, and collected relevant demographic, clinical, and neuropsychological information. The PD patients were divided into two groups according to the side of motor symptom onset. All the participants underwent resting-state functional magnetic resonance imaging, and spontaneous brain activity was assessed using amplitude of low-frequency fluctuation (ALFF). The associations between areas showing significant group differences and various clinical and neuropsychological measures were analyzed. Results: Finally, the data of 30 PD patients with left-onset (LPD), 27 PD patients with right-onset (RPD), and 32 healthy controls were obtained. The three groups had similar age and gender ratios. Our results demonstrated that LPD patients had increased ALFF in the left inferior temporal gyrus and decreased ALFF in bilateral thalamus and cerebellum anterior lobes than the control group. The value of ALFF of the left inferior temporal gyrus was correlated with motor function, and ALFF value of the thalamus was associated with cognition. Comparisons between LPD and RPD patients and between RPD patients and the controls did not yield significant difference. Conclusions: The present study provides new insights into the distinct characteristics of spontaneous brain activity in LPD, which may be associated with motor and cognitive function.

Motor Symptom Lateralization Influences Cortico-Striatal Functional Connectivity in Parkinson's Disease

“…They found several abnormalities of gray matter volume also in the right hemisphere in LPD patients, but they did not identify any significant difference between the two PD groups or between the controls and the RPD patients (52). Two additional MRI studies using structural and functional imaging techniques also showed more impairments in LPD patients than in RPD patients (41,53). Our findings are consistent with the above studies; LPD patients may have more severe neurodegeneration or less compensation than RPD patients.…”

“…This phenomenon is not uncommon. Some previous studies using structural imaging and fMRI techniques failed to identify significant differences in the direct comparison between LPD and RPD patients, although these two groups showed different patterns of abnormalities compared with the controls (41,52,53,55). In the present study, both PD groups had an average disease duration of more than 6 years and an average Hoehn-Yahr stage higher than 2.…”

Altered Spontaneous Neural Activity and Functional Connectivity in Parkinson’s Disease With Subthalamic Microlesion

“…Functional data was preprocessed using the rs-fMRI data processing assistant (DPABI_V4.3, Beijing, China) 1 base on the MATLAB 2013b 2 platform. The preprocessing steps are consistent with previous literature (Xue et al, 2019;Li K. et al, 2020;Sun et al, 2020;Wang et al, 2020). The specific steps are described below.…”

Disrupted dynamic pattern of regional neural activity in early-stage cognitively normal Parkinson's disease

“…As a conventional fMRI-derived method, amplitude of low-frequency fluctuation (ALFF) serves as a quantifiable index by calculating low-frequency (0.01-0.08 Hz) BOLD fluctuations (10). Although most previous studies utilized ALFF to characterize regional neural activity in PD, the aberrant brain regions in their results were inconsistent (11)(12)(13). This issue is mainly ascribed to clinical heterogeneity, medication effects, or differences in inclusion criteria.…”