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.
Highlights
Parkinson’s disease (PD) was first described by James Parkinson in 1817 (Hurwitz, 2017) and is the second most common neurodegenerative disease after Alzheimer’s disease (Khan et al, 2019)
Correlation analysis revealed a positive correlation between the following clinical parameters in the PD groups: Mini-Mental State Exam (MMSE) scores with years of education (r = 0.621, p < 0.001); disease duration with UPDRS scores (r = 0.396, p < 0.001) and UPDRS-III scores (r = 0.382, p = 0.001); HAMD scores with UPDRS scores (r = 0.579, p < 0.001) and UPDRS-III scores (r = 0.444, p < 0.001); Hoehn and Yahr (HY) stages with disease duration (r = 0.323, p = 0.005), UPDRS scores (r = 0.576, p < 0.001), UPDRS-III scores (r = 0.609, p < 0.001), and HAMD scores (r = 0.295, p = 0.010)
Our current findings suggest that the HC, PD-mild, and PD-moderate, groups exhibited different regional homogeneity analysis (ReHo) alterations in the bilateral cerebellum, right superior orbital gyrus, right rectus, right superior temporal gyrus, right Rolandic operculum, right postcentral gyrus, and right precentral gyrus
Summary
Parkinson’s disease (PD) was first described by James Parkinson in 1817 (Hurwitz, 2017) and is the second most common neurodegenerative disease after Alzheimer’s disease (Khan et al, 2019). The core pathology of PD is considered to involve the deposition of Lewy bodies and the destruction of dopamine neurons in the substantia nigra pars compacta of the midbrain, leading to disruption of the basal ganglia and the initiation of motor symptoms (Rai et al, 2016, 2017, 2019; Singh et al, 2020b). When motor symptoms appear, the loss of dopaminergic neurons in the substantia nigra has already reached at least 60% (Hornykiewicz, 2006), corresponding to Braak stage 3 or 4. At Braak stages 1 or 2, patients with PD often have only motor symptoms with no typical characteristics on conventional imaging. These patients tend to be diagnosed with other neurological diseases, such as depression, anxiety disorders, Alzheimer’s disease, and sleep disorders. Identifying PD patients at an early stage is critical for the clinical management and treatment of this disease
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