Striatal and Extrastriatal Monoaminergic Disruption in Progressive Supranuclear Palsy.

BACKGROUND: As a biomarker targeting vesicular monoamine transporter 2 (VMAT2), 18F-9-fluoropropyldihydrotetrabenazine (18F-FP-DTBZ) positron emission tomography (PET) is highly accurate in diagnosing Parkinson's disease (PD) and assessing its severity. However, evidence is insufficient in patients with progressive supranuclear palsy (PSP). OBJECTIVE: We evaluated the striatal and extrastriatal monoaminergic disruption of PSP and differences in patterns between patients with PSP, PD, and healthy controls (HCs) using 18F-FP-DTBZ PET, as well as its correlations with the clinical characteristics of PSP. METHODS: We recruited 58 patients with PSP, 23 age- and duration-matched patients with PD, as well as 17 HCs. Patients were scanned using 18F-FP-DTBZ PET/computed tomography, and images were spatially normalized and analyzed based on the volume of interest. RESULTS: VMAT2 binding differed significantly in the striatum and substantia nigra among the groups (P < 0.001). A more severe disruption in the caudate was noted in the PSP group (P < 0.001) than in the PD group. However, no differences were found in the nucleus accumbens, hippocampus, amygdala, or raphe between the PD and PSP groups. Within the PSP group, striatal VMAT2 binding was significantly associated with the fall/postural stability subscore of the PSP Rating Scale, especially in the putamen. Furthermore, VMAT2 binding was correlated with Mini-Mental State Examination or Montreal Cognitive Assessment in the hippocampus. CONCLUSIONS: Caudate disruptions showed prominent differences among the groups. VAMT2 binding in the striatum and hippocampus reflects the severity of fall/postural stability and cognition, respectively. © 2024 International Parkinson and Movement Disorder Society.

Reorganization of intrinsic functional connectivity in early-stage Parkinson's disease patients with probable REM sleep behavior disorder.

REM sleep behavior disorder (RBD) symptoms in Parkinson's disease (PD) suggest both a clinically and pathologically malignant subtype. However, whether RBD symptoms are associated with alterations in the organization of whole-brain intrinsic functional networks in PD, especially at early disease stages, remains unclear. Here we use resting-state functional MRI, coupled with graph-theoretical approaches and network-based statistics analyses, and validated with large-scale network analyses, to characterize functional brain networks and their relationship with clinical measures in early PD patients with probable RBD (PD+pRBD), early PD patients without probable RBD (PD-pRBD) and healthy controls. Thirty-six PD+pRBD, 57 PD-pRBD and 71 healthy controls were included in the final analyses. The PD+pRBD group demonstrated decreased global efficiency (t = -2.036, P = 0.0432) compared to PD-pRBD, and decreased network efficiency, as well as comprehensively disrupted nodal efficiency and whole-brain networks (all eight networks, but especially in the sensorimotor, default mode and visual networks) compared to healthy controls. The PD-pRBD group showed decreased nodal degree in right ventral frontal cortex and more affected edges in the frontoparietal and ventral attention networks compared to healthy controls. Furthermore, the assortativity coefficient was negatively correlated with Montreal cognitive assessment scores in the PD+pRBD group (r = -0.365, P = 0.026, d = 0.154). The observation of altered whole-brain functional networks and its correlation with cognitive function in PD+pRBD suggest reorganization of the intrinsic functional connectivity to maintain the brain function in the early stage of the disease. Future longitudinal studies following these alterations along disease progression are warranted.

18F-FP-DTBZ PET/CT detectable associations between monoaminergic depletion in the putamen with rigidity and the pallidus with tremor in Parkinson's disease.

INTRODUCTION: The motor subtypes of Parkinson's disease (PD) are widely accepted and implemented. However, the motor subtypes have been thought to represent different stages of PD recently because some patients experience tremor-dominant (TD) conversion to the non-tremor-dominant subtype, such as postural instability-gait difficulty (PIGD). In this study, we explore the monoaminergic denervation features of the striatal and extra-striatal areas in patients with different subtypes of PD with 18F-9-fluoropropyl-(+)-dihydrotetrabenazine (18F-FP-DTBZ) PET/CT. METHODS: Sixty-five patients diagnosed with PD were included and classified as TD (n = 25) and PIGD (n = 40). We evaluated the difference of monoaminergic features of each subregion of brain between motor subtypes of PD, as well as associations between these features and Parkinsonian motor symptoms. RESULTS: The striatal standardized uptake value ratios (SUVR) showed that dopaminergic disruption of patients with PIGD was more symmetrical in the posterior ventral putamen (p < 0.001) and more severe in the ipsilateral posterior dorsal putamen (p < 0.001 corrected) compared with that of patients with TD. The severity of PIGD scores was associated with striatal dopaminergic depletion, while tremor was associated with monoaminergic changes in extra-striatal areas, including pallidus, thalamus, and raphe nuclie. CONCLUSION: These results indicate that patients with different motor subtypes may have different underlying mechanisms of PD pathogenesis. Therefore, accurate diagnosis of PD subtypes can aid prognosis evaluation and treatment decision-making.

Detection of Motor Dysfunction With Wearable Sensors in Patients With Idiopathic Rapid Eye Movement Disorder.

Patients with idiopathic rapid eye movement sleep behavior disorder (iRBD) are at high risk for conversion to synucleinopathy and Parkinson disease (PD). This can potentially be monitored by measuring gait characteristics of iRBD patients, although quantitative data are scarce and previous studies have reported inconsistent findings. This study investigated subclinical gait changes in polysomnography-proven iRBD patients compared to healthy controls (HCs) during 3 different walking conditions using wearable motor sensors in order to determine whether gait changes can be detected in iRBD patients that could reflect early symptoms of movement disorder. A total 31 iRBD patients and 20 HCs were asked to walk in a 10-m corridor at their usual pace, their fastest pace, and a normal pace while performing an arithmetic operation (dual-task condition) for 1 min each while using a wearable gait analysis system. General gait measurements including stride length, stride velocity, stride time, gait length asymmetry, and gait variability did not differ between iRBD patients and HCs; however, the patients showed decreases in range of motion (P = 0.004) and peak angular velocity of the trunk (P = 0.001) that were significant in all 3 walking conditions. iRBD patients also had a longer step time before turning compared to HCs (P = 0.035), and the difference between groups remained significant after adjusting for age, sex, and height. The decreased trunk motion while walking and increased step time before turning observed in iRBD may be early manifestations of body rigidity and freezing of gait and are possible prodromal symptoms of PD.

Repetitive transcranial magnetic stimulation improves Parkinson's freezing of gait via normalizing brain connectivity.

Robust, effective treatments for Parkinson's freezing of gait remain elusive. Our previous study revealed beneficial effects of high-frequency rTMS over the supplementary motor area. The present study aims to explore the neural mechanisms of rTMS treatments utilizing novel exploratory multivariate approaches. We first conducted a resting-state functional MRI study with a group of 40 Parkinson's disease patients with freezing of gait, 31 without freezing of gait, and 30 normal controls. A subset of 30 patients with freezing of gait (verum group: N = 20; sham group: N = 10) who participated the aforementioned rTMS study underwent another scan after the treatments. Using the baseline scans, the imaging biomarkers for freezing of gait and Parkinson's disease were developed by contrasting the connectivity profiles of patients with freezing of gait to those without freezing of gait and normal controls, respectively. These two biomarkers were then interrogated to assess the rTMS effects on connectivity patterns. Results showed that the freezing of gait biomarker was negatively correlated with Freezing of Gait Questionnaire score (r = -0.6723, p < 0.0001); while the Parkinson's disease biomarker was negatively correlated with MDS-UPDRS motor score (r = -0.7281, p < 0.0001). After the rTMS treatment, both the freezing of gait biomarker (0.326 ± 0.125 vs. 0.486 ± 0.193, p = 0.0071) and Parkinson's disease biomarker (0.313 ± 0.126 vs. 0.379 ± 0.155, p = 0.0378) were significantly improved in the verum group; whereas no significant biomarker changes were found in the sham group. Our findings indicate that high-frequency rTMS over the supplementary motor area confers the beneficial effect jointly through normalizing abnormal brain functional connectivity patterns specifically associated with freezing of gait, in addition to normalizing overall disrupted connectivity patterns seen in Parkinson's disease.

Primary familial brain calcifications linked with a novel SLC20A2 gene mutation in a Chinese family.

It has been recently reported that mutations in SLC20A2 gene are a major cause of primary familial brain calcifications, a rare neurodegenerative disorder characterized by symmetrical and bilateral intracranial calcification. We conducted a pedigree study by performing next Generation Sequencing in a Chinese family with three generations. Three members in this family developed Parkinsonism in their sixth decade, also, the proband presented with schizophrenia for 40 years. Next Generation Sequencing identified a novel nonsense heterozygous substitution c.1158C > A (p.Thr 386*) of SLC20A2 gene, introducing a stop codon in exon 10. The mutation was present in symptomatic and asymptomatic individuals with intracranial calcification, but absent in the individual without calcification, suggesting the mutation segregates with brain calcification. mRNA expression was decreased by 35% in the proband. We are the first to demonstrate a novel c.1158C > A mutation of SLC20A2 gene in a Chinese family with primary familial brain calcifications.

[Relationship between computed tomography perfusion imaging and prognosis in hyperacute cerebral infarction].

OBJECTIVE: To explore the diagnostic valves of computed tomography perfusion imaging (CTP) in hyperacute cerebral infarction patients and examine the correlation of time period from symptom onset to examination and CTP parameters. METHODS: Non-enhancement CT and CTP were performed on 75 patients with acute cerebral infarction of internal carotid system within 8 hours of symptom onset at our department from January 2006 to May 2008. National Institute of Health Stroke Scale score (NIHSS), Barthel index (BI) and modified Rankin scale (mRS) were assessed at the same day, days 14 and 90 after stroke onset respectively for neurological function impairment, activity of daily living and extent of disability in prognosis. RESULTS: (1) All CTP parameters in ischemic region had no correlation with time period from symptom onset to examination (P > 0.05). No significant differences were found between the patients with > 3 hours and < 3 hours after stroke onset in terms of the above parameters; (2) the areas of CBF (cerebral blood flow) on ischemic region significantly correlated with NIHSS at the day of symptom onset (r = 0.391, P < 0.001), Day 14 (r = 0.564, P < 0.001) and Day 90 (r = 0.549, P < 0.001) after symptom onset. CBV (cerebral blood volume) and TTP (time-to-peak) on ischemic region significantly correlated with the evaluation indices of predicting clinical outcomes at the day of symptom onset, Days 14 and 90 (P < 0.01). CBF, CBV, rCBF (regional CBF) and rCBV (regional CBV) correlated only with some of the clinical outcome scores. CONCLUSION: Time period after symptom onset can not reflect the ischemic extent and volume of cerebral infarction. But CTP may evaluate the severity and prognosis of acute cerebral infarction patients. The area of abnormal perfusion is the most sensitive parameter.

Polymorphism of HD and UCHL-1 genes in Huntington's disease.

This study analyzed the association between the polymorphism of the Huntington's disease (HD) and ubiquitin carboxyl-terminal hydrolase L1 (UCHL-1) genes and the age of HD onset. We examined the size of trinucleotide CAG repeats in the HD gene of 53 individuals from families with a history of HD, six unrelated HD patients, and 51 healthy controls. Polymerase chain reaction and restriction fragment length polymorphism was performed to examine UCHL-1 S18Y polymorphism prevalence in this group. We identified five HD patients in the families and four pre-clinical HD patients in their high-risk offspring. The differences in S18Y allele prevalence between families and healthy controls were not statistically significant. The SY genotype was identified most frequently (prevalence >50%). The YY genotype was not identified in non-related HD patients, and the SS genotype had a higher prevalence than the SY genotype. The S allele was identified more frequently than the Y allele, and the difference with healthy controls was significant. Multiple linear regression analysis revealed that UCHL-1 S18Y polymorphism accounted for 15.6% of variance in the age of disease onset among 11 patients. The number of CAG repeats accounted for 71.4% of the variance. The size of CAG repeats in the HD gene is an important factor affecting the age at disease onset, but is not the only factor. UCHL-1 S18Y polymorphism is a modifier of HD with a modest regulatory role in the age at disease onset, suggesting that UCHL-1 may be involved in HD pathogenesis.