Alterations of Regional Homogeneity in the Mild and Moderate Stages of Parkinson’s Disease

Abstract

Objectives: This study aimed to investigate alterations in regional homogeneity (ReHo) in early Parkinson’s disease (PD) at different Hoehn and Yahr (HY) stages and to demonstrate the relationships between altered brain regions and clinical scale scores.Methods: We recruited 75 PD patients, including 43 with mild PD (PD-mild; HY stage: 1.0–1.5) and 32 with moderate PD (PD-moderate; HY stage: 2.0–2.5). We also recruited 37 age- and sex-matched healthy subjects as healthy controls (HC). All subjects underwent neuropsychological assessments and a 3.0 Tesla magnetic resonance scanning. Regional homogeneity of blood oxygen level-dependent (BOLD) signals was used to characterize regional cerebral function. Correlative relationships between mean ReHo values and clinical data were then explored.Results: Compared to the HC group, the PD-mild group exhibited increased ReHo values in the right cerebellum, while the PD-moderate group exhibited increased ReHo values in the bilateral cerebellum, and decreased ReHo values in the right superior temporal gyrus, the right Rolandic operculum, the right postcentral gyrus, and the right precentral gyrus. Reho value of right Pre/Postcentral was negatively correlated with HY stage. Compared to the PD-moderate group, the PD-mild group showed reduced ReHo values in the right superior orbital gyrus and the right rectus, in which the ReHo value was negatively correlated with cognition.Conclusion: The right superior orbital gyrus and right rectus may serve as a differential indicator for mild and moderate PD. Subjects with moderate PD had a greater scope for ReHo alterations in the cortex and compensation in the cerebellum than those with mild PD. PD at HY stages of 2.0–2.5 may already be classified as Braak stages 5 and 6 in terms of pathology. Our study revealed the different patterns of brain function in a resting state in PD at different HY stages and may help to elucidate the neural function and early diagnosis of patients with PD.

Abnormal intra- and inter-network functional connectivity of brain networks in early-onset Parkinson’s disease and late-onset Parkinson’s disease

“…Functional connectivity changes in some brain networks may not be apparent at this time. In a previous study, we investigated different patterns of altered brain activity in PD at different stages of the disease, and found that the higher the grade, the more extensive the involvement of the brain (Li et al, 2021). Thirdly, our study is a cross-sectional study.…”

Behavioral, neural and ultrastructural alterations in a graded-dose 6-OHDA mouse model of early-stage Parkinson’s disease

“…The key component of PD pathogenesis is a degeneration of DAergic neurons of the SNc, resulting in the deafferentation of the striatum (7,47). The onset of cellular neurodegenerative mechanisms underlying PD precedes the appearance of the disease symptoms by multiple years (14,46,48): estimations date the initial presymptomatic phase 5 to 30 years prior to the clinical manifestation (6). Motor symptoms first appear in patients after the degeneration of 50-60% of DAergic neurons and 70-80% dopamine depletion in the striatum (22,(44)(45)(46).…”

“…Accordingly, most of the classic literature based on animal experiments -monkey and rodent models -and human studies reflect late, chronic, dopamine-depleted states when compensatory mechanisms are already in place in most related neural network functions (2,11,12). In the past decades, however, early stages of the disease have received increasing focus (13)(14)(15).…”

Drooling disrupts the brain functional connectivity network in Parkinson's disease

“…PD patients have been reported to have structural or functional changes in the Rolandic operculum (ROL) 42,43 . In early PD, reduced ReHo values in the ROL are most likely connected to swallowing and speech disorders 44 . In patients with amyotrophic lateral sclerosis, gray matter atrophy in the ROL is associated with movement disorders or tonic contractions of the perioral muscles, which could induce swallowing dysfunction or dysarthria 45 .…”