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BACKGROUND: Tremor-dominant (TD) and postural instability/gait difficulty (PIGD) are common subtypes of Parkinson's disease, each with distinct clinical manifestations and prognoses. The neural mechanisms underlying these subtypes remain unclear. This study aimed to investigate the altered connectivity of the frontal cortex and supplementary motor area (SMA) in different types of Parkinson's disease. METHODS: Data of 173 participants, including 41 TD patients, 65 PIGD patients, and 67 healthy controls, were retrospectively analyzed. All subjects underwent resting-state functional magnetic resonance imaging (rs-fMRI) and clinical assessments. Differences in amplitude of low frequency fluctuation (ALFF), voxel-wise functional connectivity (FC), and functional network connectivity (FNC) among the three groups were compared, followed by partial correlation analysis. RESULTS: Compared to healthy controls, the left dorsolateral superior frontal gyrus (DLSFG) ALFF was significantly increased in both PIGD and TD patients. The FC between the left DLSFG and the left SMA, as well as between the left paracentral lobule and the right DLSFG, was significantly decreased. Similarly, the FNC between the visual network and the auditory network was reduced. Compared to TD patients, PIGD patients showed a significantly higher ALFF in the left DLSFG and a notably reduced FC between the left DLSFG and left SMA. Additionally, the FC of the left DLSFG-SMA was inversely correlated with the PIGD score exclusively in PIGD patients. The FNC of the visual-auditory network was inversely associated with the tremor score only in TD patients. CONCLUSION: Decreases in the left DLSFG-SMA connectivity may be a key feature of the PIGD subtype, while reduced VN-AUD connectivity may characterize the TD subtype.
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Background: Repetitive transcranial magnetic stimulation (rTMS) is an effective noninvasive neuromodulation technique for Parkinson's disease (PD). However, the efficacy of rTMS varies widely between individuals. This study aimed to investigate the factors related to the response to rTMS in PD patients. Methods: We retrospectively analyzed the response of 70 idiopathic PD patients who underwent rTMS for 14 consecutive days targeting the supplementary motor area (SMA) in either an open-label trail (n = 31) or a randomized, double-blind, placebo-controlled trial (RCT) (n = 39). The motor symptoms of PD patients were assessed by the United Parkinson's Disease Rating Scale Part III (UPDRSIII). Based on previous studies, the UPDRSIII were divided into six symptom clusters: axial dysfunction, resting tremor, rigidity, bradykinesia affecting right and left extremities, and postural tremor. Subsequently, the efficacy of rTMS to different motor symptom clusters and clinical predictors were analyzed in these two trails. Results: After 14 days of treatment, only the total UPDRSIII scores and rigidity scores improved in both the open-label trial and the RCT. The results of multiple linear regression analysis indicated that baseline rigidity scores (ß = 0.37, p = 0.047) and RMT (ß = 0.30, P = 0.02) positively predicted the improvement of UPDRSIII. The baseline rigidity score (ß = 0.55, P < 0.0001) was identified as an independent factor to predict the improvement of rigidity. Conclusion: This study demonstrated significant improvements in total UPDRSIII scores and rigidity after 14-day treatment, with baseline rigidity scores and RMT identified as predictors of treatment response, underscoring the need for individualized therapy.
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Introduction: The Chinese Smell Identification Test (CSIT) was developed specifically for Chinese populations. This work investigated the utility of this test in detecting Parkinson's disease (PD). Olfactory dysfunction is a common non-motor symptom of PD. There are different opinions on the efficacy of drugs for anosmia in PD.Objective: To investigate the olfactory function of Chinese PD patients, verify the effectiveness of the CSIT, and further detect the effects of dopaminergic drugs on anosmia.Methods: In total, 149 PD patients were recruited from the First Affiliated Hospital of Anhui Medical University and 149 healthy comparison participants (HCP) were recruited from the Institute of Psychology of the Chinese Academy of Sciences. The CSIT was used for olfactory function testing in all participants.Results: CSIT scores were significantly lower in the PD group than in the HCP group (t(296) = -12.797, P < 0.001, d = 1.48). Receiver operating characteristic curve analysis showed that the optimal threshold value for the olfactory recognition test was 22.5, which had a sensitivity and specificity of 71.1% and 89.3%, respectively, for the detection of Parkinson's disease. Sex showed a significant influence on CSIT score (t = -3.552, P = 0.001), with males being more likely to develop olfactory dysfunction. We found CSIT scores of the non-medication group and the group with medication were lower than those of the HCP group, and the difference was statistically significant (t(82) = -7.116, P < 0.0167, d = 1.59; t(82) = -4.907, P < 0.0167, d = 1.10). CSIT scores of the group with medication were significantly higher than those of the non-medication group (t(41) = -3.067, P < 0.0167, d = 0.41).Conclusions: In China, the CSIT is recommended to improve the sensitivity of PD detection. The olfactory function of PD patients was improved after treatment with dopaminergic drugs.