Fluorescence-tagged salivary small extracellular vesicles as a nanotool in early diagnosis of Parkinson's disease.

BACKGROUND: Parkinson's disease is generally asymptomatic at earlier stages. At an early stage, there is an extensive progression in the neuropathological hallmarks, although, at this stage, diagnosis is not possible with currently available diagnostic methods. Therefore, the pressing need is for susceptibility risk biomarkers that can aid in better diagnosis and therapeutics as well can objectively serve to measure the endpoint of disease progression. The role of small extracellular vesicles (sEV) in the progression of neurodegenerative diseases could be potent in playing a revolutionary role in biomarker discovery. METHODS: In our study, the salivary sEV were efficiently isolated by chemical precipitation combined with ultrafiltration from subjects (PD = 70, healthy controls = 26, and prodromal PD = 08), followed by antibody-based validation with CD63, CD9, GAPDH, Flotillin-1, and L1CAM. Morphological characterization of the isolated sEV through transmission electron microscopy. The quantification of sEV was achieved by fluorescence (lipid-binding dye-labeled) nanoparticle tracking analysis and antibody-based (CD63 Alexa fluor 488 tagged sEV) nanoparticle tracking analysis. The total alpha-synuclein (α-synTotal) in salivary sEVs cargo was quantified by ELISA. The disease severity staging confirmation for n = 18 clinically diagnosed Parkinson's disease patients was done by 99mTc-TRODAT-single-photon emission computed tomography. RESULTS: We observed a significant increase in total sEVs concentration in PD patients than in the healthy control (HC), where fluorescence lipid-binding dye-tagged sEV were observed to be higher in PD (p = 0.0001) than in the HC using NTA with a sensitivity of 94.34%. In the prodromal PD cases, the fluorescence lipid-binding dye-tagged sEV concentration was found to be higher (p = 0.008) than in HC. This result was validated through anti-CD63 tagged sEV (p = 0.0006) with similar sensitivity of 94.12%. We further validated our findings with the ELISA based on α-synTotal concentration in sEV, where it was observed to be higher in PD (p = 0.004) with a sensitivity of 88.24%. The caudate binding ratios in 99mTc-TRODAT-SPECT represent a positive correlation with sEV concentration (r = 0.8117 with p = 0.0112). CONCLUSIONS: In this study, for the first time, we have found that the fluorescence-tagged sEV has the potential to screen the progression of disease with clinically acceptable sensitivity and can be a potent early detection method for PD.

Validation of the Rainbow Model of Integrated Care Measurement Tool in Parkinson's Disease.

BACKGROUND: Integrated care is essential for improving the management and health outcomes for people with Parkinson's disease (PD); reliable and objective measures of care integration are few. OBJECTIVE: The aim of this study was to test the psychometric properties of the Rainbow Model of Integrated Care Measurement Tool (RMIC-MT, provider version) for healthcare professionals involved in PD care. METHODS: A cross-sectional survey was administered online to an international network representing 95 neurology centers across 41 countries and 588 healthcare providers. Exploratory factor analysis with principal axis extraction method was used to assess construct validity. Confirmatory factor analysis was used to evaluate model fit of the RMIC-MT provider version. Cronbach's alpha was used to assess the internal consistency reliability. RESULTS: Overall, 371 care providers (62% response rate) participated in this study. No item had psychometric sensitivity problems. Nine factors (professional coordination, cultural competence, triple aims outcome, system coordination, clinical coordination, technical competence, community-centeredness, person-centeredness, and organizational coordination) with 42 items were determined by exploratory factor analysis. Cronbach's alpha ranged from 0.76 (clinical coordination) to 0.94 (system coordination) and showed significant correlation among all items in the scale (>0.4), indicating good internal consistency reliability. The confirmatory factor analysis model passed most goodness-of-fit tests, thereby confirming the factor structure of nine categories with a total of 40 items. CONCLUSIONS: The results provide evidence for the construct validity and other psychometric properties of the provider version of the RMIC-MT to measure integrated care in PD. © 2023 The Authors. Movement Disorders published by Wiley Periodicals LLC on behalf of International Parkinson and Movement Disorder Society.

Mesenchymal Stem Cell Therapy in the Treatment of Neurodegenerative Cerebellar Ataxias: a Systematic Review and Meta-analysis.

The objective of this study is to synthesise the findings of clinical studies in order to derive evidence for use of the mesenchymal stem cell (MSC) therapy in the treatment of neurodegenerative cerebellar ataxias. In order to find relevant studies for the systematic review, we searched through Medline (1985 to July 2020), PubMed and Clinical trial register. We included both single-arm and comparative studies in which MSCs were given as intervention in neurodegenerative ataxia patients at any time after the diagnosis. We used Joanna Briggs Institute (JBI) quality scale to evaluate the methodological qualities of the included studies. Our literature search obtained 81 publications. Three articles comprising a total of 47 patients were included in the meta-analysis. None of them were randomised controlled trials (RCTs). Pooled analysis noted that there was a decrease in the Berg Balance Scale (BBS)/Scale for the Assessment and Rating of Ataxia (SARA) score from pre to post assessment; however, the difference was statistically not significant (standardised mean difference (SMD) - 0.20; 95% CI - 0.78 to 0.38). No significant side effects were reported in any of the studies. We did not observe any statistically significant difference in the pooled mean difference in the International Cooperative Ataxia Rating Scale (ICARS) score between pre and post assessment in patients with ataxia after receiving the stem cells (SMD 0.36, 95% CI - 0.08 to 0.81). Our systematic review and meta-analysis concluded that MSC cell therapy appeared safe but provided insufficient evidence to support the use of MSCs to treat patients with neurodegenerative cerebellar ataxia at present. No l RCTs was available in the literature to test efficacy; therefore, well-designed RCTs are needed to ascertain the effectiveness of MSCs in patients with neurodegenerative cerebellar ataxias.

Is disease a threat to identity? A systematic review of parkinson's disease and personal identity.

Introduction: Parkinson's disease (PD) is a neurological condition that impacts the physical and psychological functioning of the patients. The physical and cognitive changes come with social stigma and threats to roles previously associated with their identities. Objectives: The current paper attempts to study the influence of the disease on the personal identity of the patients. Methods: A systematic review was done on PD and personal identity following the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020 guidelines. The Consolidated Criteria for Reporting Qualitative Research checklist was used to assess the quality of the papers. The selected papers were synthesized to understand the relationship between PD and personal identity. Results: The emerging themes were: (1) dissociation of old personal identity: (1.1) Influence of physical symptoms, (1.2) influence of society and stigma, and (1.3) threats to roles associated with identity and (2) changing family dynamics. A Model of Personal, Family, and Disease Dynamics was also developed based on clinical first-hand experience with the patients and the review. Conclusion: The personal identity of the PD patients shifts drastically as a result of their physical and psychosocial experiences. This also results in changed family dynamics, with the patient feeling sidelined due to loss of control and responsibilities in the family.

Device-Assisted and Neuromodulatory Therapies for Parkinson's Disease: A Network Meta-Analysis.

BACKGROUND: Device-assisted and neuromodulatory therapies are the standard of care for Parkinson's disease (PD) with disabling motor complications. We aimed to compare and rank the currently available advanced therapies for PD on patient relevant outcomes. METHODS: We searched various databases for randomized controlled trials that studied subthalamic nucleus deep brain stimulation (STN-DBS), globus pallidus interna (GPi) DBS, pallidotomy, subthalamotomy, continuous subcutaneous apomorphine infusion (CSAI), or intrajejunal levodopa infusion (IJLI), in patients with PD and motor complications. Primary outcome was the quality of life (QOL) at 6 months. Secondary outcomes included Unified Parkinson's Disease Rating Scale III and II, ON time, OFF time, levodopa equivalent daily doses, and adverse events (AE). Data were pooled using a Bayesian network meta-analysis, summarized as mean difference (MD) with 95% credibility intervals (CrI) and visualized in forest plots/league tables. Surface under the cumulative ranking curve plots determined the ranking probability. RESULTS: We identified 6745 citations and included 26 trials. STN-DBS (MD, -8.0; 95% CrI, -11, -5.8), GPi-DBS (MD, -7.1; 95% CrI, -11, -2.9), and IJLI (MD, -7.0; 95% CrI, -12, -1.8) led to better QOL than medical therapy alone, without significant differences among them. STN-DBS had the highest probability of being ranked the best treatment for QOL (79.6%), followed by IJLI (63.5%) and GPi-DBS (62.8%). CONCLUSIONS: In advanced PD, STN-DBS alleviates more patient and clinician relevant outcomes, followed by GPi-DBS and IJLI. In resource limited settings, unilateral pallidotomy may improve motor symptoms and activities of daily living, although overall QOL may not be improved. © 2022 International Parkinson and Movement Disorder Society.

Underrepresented Populations in Parkinson's Genetics Research: Current Landscape and Future Directions.

BACKGROUND: Human genetics research lacks diversity; over 80% of genome-wide association studies have been conducted on individuals of European ancestry. In addition to limiting insights regarding disease mechanisms, disproportionate representation can create disparities preventing equitable implementation of personalized medicine. OBJECTIVE: This systematic review provides an overview of research involving Parkinson's disease (PD) genetics in underrepresented populations (URP) and sets a baseline to measure the future impact of current efforts in those populations. METHODS: We searched PubMed and EMBASE until October 2021 using search strings for "PD," "genetics," the main "URP," and and the countries in Latin America, Caribbean, Africa, Asia, and Oceania (excluding Australia and New Zealand). Inclusion criteria were original studies, written in English, reporting genetic results on PD from non-European populations. Two levels of independent reviewers identified and extracted information. RESULTS: We observed imbalances in PD genetic studies among URPs. Asian participants from Greater China were described in the majority of the articles published (57%), but other populations were less well studied; for example, Blacks were represented in just 4.0% of the publications. Also, although idiopathic PD was more studied than monogenic forms of the disease, most studies analyzed a limited number of genetic variants. We identified just nine studies using a genome-wide approach published up to 2021, including URPs. CONCLUSION: This review provides insight into the significant lack of population diversity in PD research highlighting the immediate need for better representation. The Global Parkinson's Genetics Program (GP2) and similar initiatives aim to impact research in URPs, and the early metrics presented here can be used to measure progress in the field of PD genetics in the future. © 2022 International Parkinson and Movement Disorder Society.

Spectrum of Movement Disorders of Late-Onset Niemann-Pick Disease Type C.

Niemann-Pick disease type C (NPC), is a rare lysosomal storage disorder, which has a variable presentation based on the age of onset. We describe five adult/adolescent-onset NPC cases presenting with a range of movement disorders along with vertical supranuclear gaze palsy as part of the clinical presentation. A diagnostic delay of 4-17 years from the symptom onset was found in this case series. A high index of clinical suspicion in adult/adolescent patients presenting with vertical supranuclear gaze palsy along with various movement disorder phenomenology can help in the early diagnosis of NPC.

Bilateral pallidotomy for acquired or heredodegenerative generalized dystonia in children.

OBJECTIVE: Dystonias are relatively rare disorders characterized by sustained or intermittent muscle contractions causing abnormal movements or postures. Generalized dystonia is a therapeutic challenge because medications are unable to control dystonia adequately in most patients. These patients may be candidates for surgical therapy. The commonly used surgical procedures in these patients are pallidotomy and deep brain stimulation. Limited studies are available on the role of pallidotomy in children with acquired/heredodegenerative generalized dystonia. The objective of this study was to describe the authors' experience with bilateral pallidotomy in this group of patients. METHODS: The authors retrospectively reviewed all pediatric patients (less than 18 years of age) with acquired/heredodegenerative generalized dystonia who underwent bilateral simultaneous pallidotomy at their center between January 2014 and January 2021. Burke-Fahn-Marsden Dystonia Rating Scale (BFMDRS) scores before and after surgery were recorded. Complications arising after the procedure were recorded as well. RESULTS: Ten patients (8 male and 2 female) with a mean (range) age of 11.1 (5-17) years were included in this study. The mean duration between disease onset and surgical intervention was 3.9 years. Two patients presented in status dystonicus. The mean ± SD (range) preoperative BFMDRS score of the patients without status dystonicus (n = 8) was 80 ± 18.9 (59.5-108). The mean ± SD BFMDRS score at the time of discharge from the hospital after surgery was 58.8 ± 37.9. Three patients had more than 20% change in BFMDRS score at the time of discharge from the hospital. The mean improvement was 25.5% at the end of 1 year. Of 5 surviving patients in the non-status dystonicus group, 3 patients had more than 40% change in BFMDRS score while the other 2 patients developed recurrence at the last follow-up (4.5 years). Status dystonicus abated after bilateral pallidotomy in both patients. Permanent bulbar complications were seen in 2 patients. CONCLUSIONS: Bilateral pallidotomy may result in clinically significant improvement in children with acquired/heredodegenerative generalized dystonia, although the benefits should be closely weighed against the risk of irreversible bulbar dysfunction. It is a viable option for children in resource-limited settings.

A Scientometric Analysis of the 100 Most Cited Articles on Pallidotomy.

BACKGROUND: Pallidotomy is the oldest stereotactically performed neurosurgical procedure for movement disorders. Consequently, there is a wealth of literature available on the topic. OBJECTIVES: The aim of this analysis was to identify the top-cited articles on pallidotomy in order to discern the origins, spread, the current trends, and the future directions of this surgical procedure. METHODS: We performed a search of the Web of Science database on 19 October 2020 using the keyword "pallidotomy." The top-100 cited articles found were arranged in descending order on the basis of citation count (CC) and citation per year (CY). Relevant conclusions were derived. RESULTS: The 100 top-cited articles were published between 1961 and 2017, in 24 journals. The average CC and CY were 118.1 (range - 856-46) and 5.326 (range - 29.52-2.09), respectively. The 3 most prolific authors were Lang AE (Neurologist - Toronto), Lozano AM (Neurosurgeon - Toronto), and Vitek JL (Neurologist - Atlanta). The Journal of Neurosurgery published the highest number of top-cited articles [Neurology. 1960;10:61-9]. The maximum articles were from the USA. University of Toronto and Emory University were the most productive institutions. CONCLUSIONS: Pallidotomy has gone through several ebbs and flows. Unilateral pallidotomy is currently recommended for the treatment of motor symptoms of Parkinson's disease and dystonia. The need for further research and improved technology to make the technique safer and prove its efficacy is highlighted, especially keeping in mind a large number of populations to which the prohibitively expensive deep brain stimulation is unavailable.

Use of Twitter in Neurology: Boon or Bane?

Twitter is a free, open access social media platform that is widely used in medicine by physicians, scientists, and patients. It provides an opportunity for advocacy, education, and collaboration. However, it is likely not utilized to its full advantage by many disciplines in medicine, and pitfalls exist in its use. In particular, there has not been a review of Twitter use and its applications in the field of neurology. This review seeks to provide an understanding of the current use of Twitter in the field of neurology to assist neurologists in engaging with this potentially powerful application to support their work.

Educating Caregivers to Reduce Complications and Improve Outcomes of Stroke Patients (ECCOS) - A Cluster-Randomized Trial.

OBJECTIVES: Stroke constitutes a significant public health problem in developing countries. Caregivers provide an important support system for patient care but usually lack knowledge and skill to attend their stroke patients. We assessed whether a caregiver-directed educational intervention would reduce hospital-acquired complications and improve stroke patients' outcomes. MATERIALS AND METHODS: We randomly assigned two Neurology inpatient wards to receive either standard care or an educational intervention. The coprimary outcomes included incidence of hospital-acquired complications and in-hospital mortality. Secondary outcomes included the modified Rankin Scale and mortality at three months. RESULTS: Among 164 patients recruited, 82 received intervention, and standard care each. The mean (Standard deviation) Glasgow coma scale of patients was 11.01 (3.4), and National Institute of Health Stroke Scale was 19.17 (8.54). The incidence of complications (72 in the intervention versus 81 in the control group; p=0.56) was not different. Ten patients (12.2%) in the intervention group and 16 (19.5%) in the control group (p=0.20) died in-hospital. Twenty patients (27.8%) in the intervention and twelve (18.2%) in the control group attained modified Rankin Scale 0-2 at three months (p=0.12). The mortality at three months (20 [24.4%] in the intervention versus 25 [30.5%] in the control group) was not different (p=0.38). The intervention group had fewer complications (42 versus 68 in the control group; p=0.01) during the initial ten days of hospital stay, but adjusted analysis revealed no difference. CONCLUSION: A structured educational intervention did not reduce the incidence of hospital-acquired complications, mortality, or morbidity. However, there was a trend towards fewer complications in the initial days of hospital stay. Extended hospital stay, caregiver fatigue, and dilution of the intervention over time might be reasons for the apparent lack of effect. CLINICAL TRIAL REGISTRATION-URL: http://www.ctri.nic.in. Unique identifier: CTRI/2018/11/016312.

Integrated Care in Parkinson's Disease: A Systematic Review and Meta-Analysis.

BACKGROUND: Quality of life in Parkinson's disease (PD) is affected by motor and nonmotor symptoms, necessitating an integrated care approach. Existing care models vary considerably in numerous domains. The objectives of this study were to perform a systematic review and meta-analysis of PD integrated care models and develop recommendations for a representative model. METHODS: We conducted a systematic review of published integrated care models and a meta-analysis of randomized, controlled trials examining integrated care versus standard care. The primary outcome was health-related quality of life using a validated PD scale. We evaluated levels of care integration using the Rainbow Model of Integrated Care. RESULTS: Forty-eight publications were identified, including 8 randomized, controlled trials with health-related quality of life data (n = 1,149 total PD patients). Qualitative evaluation of individual care model integration guided by the Rainbow Model of Integrated Care revealed frequent clinical and professional integration, but infrequent organizational and population-based integration elements. Meta-analysis of randomized, controlled trials revealed significant heterogeneity (I2 = 90%, P < 0.0001). Subgroup analysis including only outpatient care models (n = 5) indicated homogeneity of effects (I2 = 0%, P = 0.52) and improved health-related quality of life favoring integrated care, with a small effect size (standardized mean difference [SMD], -0.17; 95% CI, -0.31 to -0.03; P = 0.02). CONCLUSIONS: Outpatient integrated PD care models may improve patient-reported health-related quality of life compared with standard care; however, because of variable methodological approaches and a high risk of bias related to inherent difficulties in study design (eg, blinding of participants and interventionists), generalizability of these results are difficult to establish. The Rainbow Model of Integrated Care is a promising method of evaluating elements and levels of integration from individual patient care to population health in a PD context. © 2020 The Authors. Movement Disorders published by Wiley Periodicals, LLC. on behalf of International Parkinson and Movement Disorder Society.

Understanding the role of genetic variability in LRRK2 in Indian population.

BACKGROUND: Genetic variability in LRRK2 has been unequivocally established as a major risk factor for familial and sporadic forms of PD in ethnically diverse populations. OBJECTIVES: To resolve the role of LRRK2 in the Indian population. METHODS: We performed targeted resequencing of the LRRK2 locus in 288 cases and 298 controls and resolved the haplotypic structure of LRRK2 in a combined cohort of 800 cases and 402 controls in the Indian population. We assessed the frequency of novel missense variants in the white and East Asian population by leveraging exome sequencing and densely genotype data, respectively. We did computational modeling and biochemical approach to infer the potential role of novel variants impacting the LRRK2 protein function. Finally, we assessed the phosphorylation activity of identified novel coding variants in the LRRK2 gene. RESULTS: We identified four novel missense variants with frequency ranging from 0.0008% to 0.002% specific for the Indian population, encompassing armadillo and kinase domains of the LRRK2 protein. A common genetic variability within LRRK2 may contribute to increased risk, but it was nonsignificant after correcting for multiple testing, because of small cohort size. The computational modeling showed destabilizing effect on the LRRK2 function. In comparison to the wild-type, the kinase domain variant showed 4-fold increase in the kinase activity. CONCLUSIONS: Our study, for the first time, identified novel missense variants for LRRK2, specific for the Indian population, and showed that a novel missense variant in the kinase domain modifies kinase activity in vitro. © 2018 International Parkinson and Movement Disorder Society.

Interictal cerebral and systemic endothelial dysfunction in patients with migraine: a case-control study.

BACKGROUND: Although systemic endothelial function is unimpaired in migraine, it is unknown whether cerebral endothelial function impairment exists in migraineurs. MATERIALS AND METHODS: We conducted a prospective study to assess endothelial function in migraineurs (n=45) and healthy volunteers (n=44). Cerebral endothelial function was assessed by Breath Holding Index (BHI) on transcranial Doppler in bilateral middle cerebral artery (MCA at 30-60 mm), posterior cerebral artery (PCA at 60-80 mm) and basilar artery (BA at 80-120 mm) using bilateral monitoring probes fixed on headband. Brachial artery flow-mediated dilation (FMD) was used as measure of systemic endothelial function. RESULTS: There was no difference in baseline mean velocities of MCA, PCA, BA among migraineurs and controls. Mean BHI was significantly lower in PCA (p<0.001) and BA (p<0.001) in patients with migraine with no difference in MCA (p=0.909, 0.450). Cerebral endothelial dysfunction (BHI<1.15) was present in 62.2% of migraineurs in the right PCA (p<0.001), 57.8% in left PCA (p<0.001) and 77.8% in BA (BHI <0.83, p<0.001). There was no difference in BHI among migraineurs without and with aura (n=15). Cerebral and systemic endothelial function had no correlation in migraineurs. Increasing BMI was identified as a predictor of impaired BHI in the BA in migraineurs (p=0.020). Age, sex, presence of aura, lateralisation of headache, headache frequency, time to last attack and impaired FMD were not associated with impaired PCA and BA BHI in migraineurs. CONCLUSIONS: Migraineurs may have isolated cerebral endothelial dysfunction restricted to the posterior circulation in the absence of systemic endothelial dysfunction.

Bridging the gap between statistical significance and clinical relevance: A systematic review of minimum clinically important difference (MCID) thresholds of scales reported in movement disorders research.

Background: Minimum clinically important difference (MCID) is the smallest change in an outcome measure that is considered clinically meaningful. Using validated MCID thresholds for outcomes powers trials adequately to detect meaningful treatment effects, aids in their interpretation and guides development of new outcome measures. Objectives: To provide a comprehensive summary of MCID thresholds of various symptom severity scales reported in movement disorder. Methods: We conducted systematic review of the literature and included studies of one or more movement disorders, and reporting MCID scales. Results: 2763 reports were screened. Final review included 32 studies. Risk of bias (RoB) assessment showed most studies were of good quality. Most commonly evaluated scale was Unified Parkinson's Disease Rating Scale (UPDRS) (11 out of 32). Four studies assessing MDS-UPDRS had assessed its different sub-parts, reporting a change of 2.64,3.05,3.25 and 0.9 points to detect clinically meaningful improvement and 2.45,2.51,4.63 and 0.8 points to detect clinically meaningful worsening, for the Part I, II, III and IV, respectively. For Parts II + III, I + II + III and I + II + III + IV, MCID thresholds reported for clinically meaningful improvement were 5.73, 4.9, 6.7 and 7.1 points respectively; while those for clinically meaningful worsening were 4.7, 4.2, 5.2 and 6.3 points, respectively. MCID thresholds reported for other scales included Abnormal Involuntary Movement Scale (AIMS), Toronto Western Spasmodic Torticollis Rating Scale (TWSRS), and Burke-Fahn-Marsden Dystonia Scale (BFMD). Conclusion: This review summarizes all the MCID thresholds currently reported in Movement disorders research and provides a comprehensive resource for future trials, highlighting the need for standardized and validated MCID scales in movement disorder research.

Gray Matter Atrophy in a 6-OHDA-induced Model of Parkinson's Disease.

INTRODUCTION: Magnetic resonance imaging (MRI) based brain morphometric changes in unilateral 6-hydroxydopamine (6-OHDA) induced Parkinson's disease (PD) model can be elucidated using voxel-based morphometry (VBM), study of alterations in gray matter volume and Machine Learning (ML) based analyses. METHODS: We investigated gray matter atrophy in 6-OHDA induced PD model as compared to sham control using statistical and ML based analysis. VBM and atlas-based volumetric analysis was carried out at regional level. Support vector machine (SVM)-based algorithms wherein features (volume) extracted from (a) each of the 150 brain regions (b) statistically significant features (only) and (c) volumes of each cluster identified after application of VBM (VBM_Vol) were used for training the decision model. The lesion of the 6-OHDA model was validated by estimating the net contralateral rotational behaviour by the injection of apomorphine drug and motor impairment was assessed by rotarod and open field test. RESULTS AND DISCUSSION: In PD, gray matter volume (GMV) atrophy was noted in bilateral cortical and subcortical brain regions, especially in the internal capsule, substantia nigra, midbrain, primary motor cortex and basal ganglia-thalamocortical circuits in comparison with sham control. Behavioural results revealed an impairment in motor performance. SVM analysis showed 100% classification accuracy, sensitivity and specificity at both 3 and 7 weeks using VBM_Vol. CONCLUSION: Unilateral 6-OHDA induced GMV changes in both hemispheres at 7th week may be associated with progression of the disease in the PD model. SVM based approaches provide an increased classification accuracy to elucidate GMV atrophy.