The contribution of white matter lesions to Parkinson's disease motor and gait symptoms: a critical review of the literature

Is white matter hyperintensity burden associated with cognitive and motor impairment in patients with parkinson's disease? A systematic review and meta-analysis

White matter damage quantified as white matter hyperintensities (WMH) may aggravate cognitive and motor impairments, but whether and how WMH burden impacts these problems in Parkinson's disease (PD) is not fully understood. This study aimed to examine the association between WMH and cognitive and motor performance in PD through a systematic review and meta-analysis. We compared the WMH burden across the cognitive spectrum (cognitively normal, mild cognitive impairment, dementia) in PD including controls. Motor signs were compared in PD with low/negative and high/positive WMH burden. We compared baseline WMH burden of PD who did and did not convert to MCI or dementia. MEDLINE and EMBASE databases were used to conduct the literature search resulting in 50 studies included for data extraction. Increased WMH burden was found in individuals with PD compared with individuals without PD (i.e. control) and across the cognitive spectrum in PD (i.e. PD, PD-MCI, PDD). Individuals with PD with high/positive WMH burden had worse global cognition, executive function, and attention. Similarly, PD with high/positive WMH presented worse motor signs compared with individuals presenting low/negative WMH burden. Only three longitudinal studies were retrieved from our search and they showed that PD who converted to MCI or dementia, did not have significantly higher WMH burden at baseline, although no data was provided on WMH burden changes during the follow up. We conclude, based on cross-sectional studies, that WMH burden appears to increase with PD worse cognitive and motor status in PD.

Regional white matter hyperintensity volume in Parkinson's disease and associations with the motor signs

OBJECTIVE

To determine whether white matter hyperintensity (WMH) volumes in specific regions are associated with Parkinson's disease (PD) compared to non-PD controls, and to assess their impact on motor signs through cross-sectional and longitudinal analyses.

METHODS

A total of 50 PD participants and 47 age- and gender-matched controls were enrolled. All PD participants were followed up for at least 2 years. To detect regions of greater WMH in the PD, the WMH volume of each region was compared with the corresponding region in the control group. Linear regression and linear mixed effects models were respectively used for cross-sectional and longitudinal analyses of the impact of increases in WMH volume on motor signs.

RESULTS

The PD group had greater WMH volume in the occipital region compared with the control group. Cross-sectional analyses only detected a significant correlation between occipital WMH volume and motor function in PD. Occipital WMH volume positively correlated with the severity of tremor, and gait and posture impairments, in the PD group. During the follow-up period, the participants' motor signs progressed and the WMH volumes remained stable, no longitudinal association was detected between them. The baseline occipital WMH volume cannot predict the progression of signs after adjustment for baseline disease duration and the presence of vascular risk factors.

INTERPRETATION

PD participants in this study were characterized by greater WMH at the occipital region, and greater occipital WMH volume had cross-sectional associations with worse motor signs, while its longitudinal impact on motor signs progression was limited.

Cognitive Deficits in Parkinson's Disease Are Associated with Neuronal Dysfunction and Not White Matter Lesions

Background

Cognitive deficits considerably contribute to the patient's burden in Parkinson's disease (PD). While cognitive decline is linked to neuronal dysfunction, the additional role of white matter lesions (WML) is discussed controversially.

Objective

To investigate the influence of WML, in comparison to neuronal dysfunction, on cognitive deficits in PD.

Methods

We prospectively recruited patients with PD who underwent neuropsychological assessment using the Mattis Dementia Rating Scale 2 (DRS-2) or Parkinson Neuropsychometric Dementia Assessment (PANDA) and both MRI and PET with [¹⁸F]fluorodeoxyglucose (FDG). WML-load and PD cognition-related covariance pattern (PDCP) as a measure of neuronal dysfunction were read out. Relationship between cognitive performance and rank-transformed WML was analyzed with linear regression, controlling for the patients' age. PDCP subject scores were investigated likewise and in a second step adjusting for age and WML load.

Results

Inclusion criteria were met by 76 patients with a mean (± SD) age of 63.5 ± 9.0 years and disease duration of 10.7 ± 5.4 years. Neuropsychological testing revealed front executive and parietal deficits and a median DRS-2 score of 137 (range 119-144)/144 and PANDA score of 22 (range 3-30)/30. No association between WML and cognition was observed, whereas PDCP subject scores showed a trend-level negative correlation with the DRS-2 (P = 0.060) as well as a negative correlation with PANDA (P = 0.049) which persisted also after additional correction for WML (P = 0.039).

Conclusion

The present study indicates that microangiopathic WML do not have a relevant impact on neurocognitive performance in PD whereas neuronal dysfunction does.

White matter hyperintensity burden predicts cognitive but not motor decline in Parkinson's disease: results from the Ontario Neurodegenerative Diseases Research Initiative

BACKGROUND AND PURPOSE

The pathophysiology of Parkinson's disease (PD) negatively affects brain network connectivity, and in the presence of brain white matter hyperintensities (WMHs) cognitive and motor impairments seem to be aggravated. However, the role of WMHs in predicting accelerating symptom worsening remains controversial. The objective was to investigate whether location and segmental brain WMH burden at baseline predict cognitive and motor declines in PD after 2 years.

METHODS

Ninety-eight older adults followed longitudinally from Ontario Neurodegenerative Diseases Research Initiative with PD of 3-8 years in duration were included. Percentages of WMH volumes at baseline were calculated by location (deep and periventricular) and by brain region (frontal, temporal, parietal, occipital lobes and basal ganglia + thalamus). Cognitive and motor changes were assessed from baseline to 2-year follow-up. Specifically, global cognition, attention, executive function, memory, visuospatial abilities and language were assessed as were motor symptoms evaluated using the Movement Disorder Society Unified Parkinson's Disease Rating Scale Part III, spatial-temporal gait variables, Freezing of Gait Questionnaire and Activities Specific Balance Confidence Scale.

RESULTS

Regression analysis adjusted for potential confounders showed that total and periventricular WMHs at baseline predicted decline in global cognition (p < 0.05). Also, total WMH burden predicted the decline of executive function (p < 0.05). Occipital WMH volumes also predicted decline in global cognition, visuomotor attention and visuospatial memory declines (p < 0.05). WMH volumes at baseline did not predict motor decline.

CONCLUSION

White matter hyperintensity burden at baseline predicted cognitive but not motor decline in early to mid-stage PD. The motor decline observed after 2 years in these older adults with PD is probably related to the primary neurodegenerative process than comorbid white matter pathology.

Clinical and MRI features of gait and balance disorders in neurodegenerative diseases

Gait and balance disorders are common signs in several neurodegenerative diseases such as Parkinson's disease, atypical parkinsonism, idiopathic normal pressure hydrocephalus, cerebrovascular disease, dementing disorders and multiple sclerosis. According to each condition, patients present with different gait and balance alterations depending on the structural and functional brain changes through the disease course. In this review, we will summarize the main clinical characteristics of gait and balance disorders in the major neurodegenerative conditions, providing an overview of the significant structural and functional MRI brain alterations underlying these deficits. We also will discuss the role of neurorehabilitation strategies in promoting brain plasticity and gait/balance improvements in these patients.

Radiological identification of the globus pallidus motor subregion in Parkinson's disease

OBJECTIVE

Globus pallidus (GP) lesioning improves motor symptoms of Parkinson's disease (PD) and is occasionally associated with nonmotor side effects. Although these variable clinical effects were shown to be site-specific within the GP, the motor and nonmotor subregions have not been distinguished radiologically in patients with PD. The GP was recently found to have a distinct radiological signature on diffusion MRI (dMRI), potentially related to its unique cellular content and organization (or tissue architecture). In this study, the authors hypothesize that the magnitude of water diffusivity, a surrogate for tissue architecture, will radiologically distinguish motor from nonmotor GP subregions in patients with PD. They also hypothesize that the therapeutic focused ultrasound pallidotomy lesions will preferentially overlap the motor subregion.

METHODS

Diffusion MRI from healthy subjects (n = 45, test-retest S1200 cohort) and PD patients (n = 33) was parcellated based on the magnitude of water diffusivity in the GP, as measured orientation distribution function (ODF). A clustering algorithm was used to identify GP parcels with distinct ODF magnitude. The individual parcels were used as seeds for tractography to distinguish motor from nonmotor subregions. The locations of focused ultrasound lesions relative to the GP parcels were also analyzed in 11 patients with PD.

RESULTS

Radiologically, three distinct parcels were identified within the GP in healthy controls and PD patients: posterior, central, and anterior. The posterior and central parcels comprised the motor subregion and the anterior parcel was classified as a nonmotor subregion based on their tractography connections. The focused ultrasound lesions preferentially overlapped with the motor subregion (posterior more than central). The hotspots for motor improvement were localized in the posterior GP parcel.

CONCLUSIONS

Using a data-driven approach of ODF-based parcellation, the authors radiologically distinguished GP motor subregions in patients with PD. This method can aid stereotactic targeting in patients with PD undergoing surgical treatments, especially focused ultrasound ablation.

Correlation Between Lacunae and the Wearing-off Phenomenon in Parkinson's Disease

PURPOSE

Lacunae are imaging biomarkers of cerebral small vessel disease (CSVD) and are correlated with the degree of gait instability in Parkinson's disease (PD). The wearing-off phenomenon (WO) occurs more frequently in PD patients as disease progresses. The present study aimed to investigate the overall impact of the quantity and location of lacunae on the WO in PD.

PATIENTS AND METHODS

This retrospective, single-center study included 315 consecutive eligible patients with PD from Beijing Tiantan Hospital from May 2016 to August 2018. We collected data on demographics and clinical features, assessed lacunae and examined the presence of the WO. The association between lacunae and the WO was assessed using a binary logistic regression model.

RESULTS

The number of lacunae was significantly associated with the WO in patients with PD according to a model adjusted for age at onset, disease duration, Hoehn-Yahr (H-Y) staging, Movement Disorder Society-Unified Parkinson's Disease Rating Scale part III (MDS-UPDRS III) total score and levodopa equivalent daily dosage (LEED) (P=0.037, OR 1.156, 95% CI 1.009, 1.325) and to a model further adjusted for other CSVD imaging biomarkers (P=0.046, OR 1.172, 95% CI 1.003, 1.369). Following additional adjustment for other potential confounders, the association remained significant (P=0.043, OR 1.195, 95% CI 1.005, 1.421). Lacunae in subcortical areas (P=0.004, OR 0.498, 95% CI 0.308, 0.803) and basal ganglia (P=0.046, OR 1.616, 95% CI 1.009, 2.587), especially in the caudate nuclei (P=0.023, OR 1.104, 95% CI 0.185, 0.881), were significantly associated with the WO in PD patients.

CONCLUSION

Our finding highlights the significant association between lacune and the WO, and lacunae may be an independent contributor to the WO in PD patients. Promoting neurovascular health may prevent the progression of the WO in PD patients.

Parkinsonism and cerebrovascular disease

The relationship between cerebrovascular disease and parkinsonism is commonly seen in everyday clinical practice but remains ill-defined and under-recognised with little guidance for the practising neurologist. We attempt to define this association and to illustrate key clinical, radiological and pathological features of the syndrome of Vascular Parkinsonism (VaP). VaP is a major cause of morbidity in the elderly associated with falls, hip fractures and cognitive impairment. Although acute parkinsonism is reported in the context of an acute cerebrovascular event, the vast majority of VaP presents as an insidious syndrome usually in the context of vascular risk factors and radiological evidence of small vessel disease. There may be an anatomic impact on basal ganglia neuronal networks, however the effect of small vessel disease (SVD) on these pathways is not clear. There are now established reporting standards for radiological features of SVD on MRI. White matter hyperintensities and lacunes have been thought to be the representative radiological features of SVD but other features such as the perivascular space are gaining more importance, especially in context of the glymphatic system. It is important to consider VaP in the differential diagnosis of Parkinson disease (PD) and in these situations, neuroimaging may offer diagnostic benefit especially in those patients with atypical presentations or refractoriness to levodopa. Proactive management of vascular risk factors, monitoring of bone density and an exercise program may offer easily attainable therapeutic targets in PD and VaP. Levodopa therapy should be considered in patients with VaP, however the dose and effect may be different from use in PD. This article is part of the Special Issue "Parkinsonism across the spectrum of movement disorders and beyond" edited by Joseph Jankovic, Daniel D. Truong and Matteo Bologna.

Emerging role of white matter lesions in cerebrovascular disease

White matter lesions have been implicated in the setting of stroke, dementia, intracerebral haemorrhage, several other cerebrovascular conditions, migraine, various neuroimmunological diseases like multiple sclerosis, disorders of metabolism, mitochondrial diseases and others. While much is understood vis a vis neuroimmunological conditions, our knowledge of the pathophysiology of these lesions, and their role in, and implications to, management of cerebrovascular diseases or stroke, especially in the elderly, are limited. Several clinical assessment tools are available for delineating white matter lesions in clinical practice. However, their incorporation into clinical decision-making and specifically prognosis and management of patients is suboptimal for use in standards of care. This article sought to provide an overview of the current knowledge and recent advances on pathophysiology, as well as clinical and radiological assessment, of white matter lesions with a focus on its development, progression and clinical implications in cerebrovascular diseases. Key indications for clinical practice and recommendations on future areas of research are also discussed. Finally, a conceptual proposal on putative mechanisms underlying pathogenesis of white matter lesions in cerebrovascular disease has been presented. Understanding of pathophysiology of white matter lesions and how they mediate outcomes is important to develop therapeutic strategies.

Altered structural and functional connectivity in CSF1R-related leukoencephalopathy

CSF1R-related leukoencephalopathy is a rare white-matter encephalopathy characterized by motor and neuropsychiatric symptoms due to colony-stimulating factor 1 receptor (CSF1R) gene mutation. Few studies have investigated the intrinsic brain alternations of patients with CSF1R-related leukoencephalopathy. We aim to evaluate the structural and functional changes in those patients. Seven patients with CSF1R-related leukoencephalopathy and 15 age-matched healthy controls (HCs) underwent multimodal magnetic resonance imaging (MRI), including high-resolution T1-weighted imaging, T2-weighted fluid attenuated inversion recovery imaging, diffusion-weighted imaging, diffusion kurtosis imaging (DKI) and resting-state functional MRI. First, to detect structural alterations, the gray matter volumes were compared using voxel-based morphometry analyses. Second, DKI parametric maps were used to evaluate the white matter (WM) connectivity changes. Finally, we constructed a seed-based resting-state functional connectivity matrix based on 90 regions of interest and examined the functional network changes of CSF1R-related leukoencephalopathy. Unlike the HCs, patients with CSF1R-related leukoencephalopathy predominantly had morphological atrophy in the bilateral thalamus and left hippocampus. In addition, the abnormal diffusivity was mainly distributed in the splenium of the corpus callosum, periventricular regions, centrum semiovale, subcortical U-fibers and midline cortex structures. Moreover, the patients had significantly reduced functional connectivity between the bilateral caudate nucleus and their contralateral hippocampus. Therefore, in addition to hyperintensity on the T2-weighted images, CSF1R-related leukoencephalopathy also showed abnormal structural and functional alterations, including subcortical atrophy and reduced functional connectivity, as well as altered diffuse parameters in the WM and subcortical regions. These findings expand our understanding of the potential pathophysiologic mechanism behind this hereditary disease.

Clinical correlates of white matter lesions in Parkinson's disease using automated multi-modal segmentation measures

BACKGROUND

Age-related white matter lesions (WML) are common, impact neuronal connectivity, and affect motor function and cognition. In addition to pathological nigrostriatal losses, WML are also common co-morbidities in Parkinson's disease (PD) that affect postural stability and gait. Automated brain volume measures are increasingly incorporated into the clinical reporting workflow to facilitate precision in medicine. Recently, multi-modal segmentation algorithms have been developed to overcome challenges with WML quantification based on single-modality input.

OBJECTIVE

We evaluated WML volumes and their distribution in a case-control cohort of PD patients to predict the domain-specific clinical severity using a fully automated multi-modal segmentation algorithm.

METHODS

Fifty-five subjects comprising of twenty PD patients and thirty-five age- and gender-matched control subjects underwent standardized motor/gait and cognitive assessments and brain MRI. Spatially differentiated WML obtained using automated segmentation algorithms on multi-modal MPRAGE and FLAIR images were used to predict domain-specific clinical severity. Preliminary statistical analysis focused on describing the relationship between WML and clinical scores, and the distribution of WML by brain regions. Subsequent stepwise regressions were performed to predict each clinical score using WML volumes in different brain regions, while controlling for age.

RESULTS

WML volume strongly correlates with both motor and cognitive dysfunctions in PD patients (p < 0.05), with differential impact in the frontal lobe and periventricular regions on cognitive domains (p < 0.01) and severity of motor deficits (p < 0.01), respectively.

CONCLUSION

Automated multi-modal segmentation algorithms may facilitate precision medicine through regional WML load quantification, which show potential as imaging biomarkers for predicting domain-specific disease severity in PD.

Microstructural Connectivity is More Related to Cognition than Conventional MRI in Parkinson's Disease

BACKGROUND

The different effects of white matter hyperintensity (WMH) severity and WMH-associated microstructural connectivity on cognition in the early stages of Parkinson's disease (PD) have not been investigated.

OBJECTIVE

To investigate the differential effect of WMH severity and WMH-associated microstructural connectivity on cognition in early stages of PD.

METHODS

A total of 136 de novo PD patients were enrolled and divided into groups based on total WMH visual rating scores as follows: mild, moderate, and severe. Microstructural connectivity was measured using graph theoretical analysis according to WMH severity. Additionally, correlation coefficients between WMH-associated microstructural connectivity or WMH scores and cognitive performance were assessed.

RESULTS

Patients with severe WMHs demonstrated poorer performance in language function than those with moderate WMHs, and in frontal/executive and visual memory function than those with mild WMHs. Areas of microstructural connectivity were more extensive in patients with severe WMHs compared to those with mild and moderate WMHs, involving frontal and parieto-temporal regions. WMH-associated right fronto-temporo-parietal microstructural disintegration was correlated with cognitive dysfunction in attention, frontal/executive, and memory domains, whereas there was no correlation between WMH scores and any cognitive domains.

CONCLUSION

These data suggest that disruption of microstructural networks by WMHs, rather than WMH burden itself, contributed more to cognitive impairment in PD.

White Matter Hyperintensities, Dopamine Loss, and Motor Deficits in De Novo Parkinson's Disease

BACKGROUND

White matter hyperintensities, prevalent in patients with Parkinson's disease (PD), significantly affect parkinsonian motor symptoms. The objective of this study was to investigate the relationship between white matter hyperintensities and nigrostriatal dopamine depletion and their interaction or mediating effects on motor symptoms in patients with drug-naive early-stage PD.

METHODS

This cross-sectional study enrolled 501 patients with de novo PD who initially underwent [¹⁸ F] N-(3-fluoropropyl)-2β-carbonethoxy-3β-(4-iodophenyl) nortropane positron emission tomography and brain magnetic resonance imaging scans between April 2009 and September 2015 in a tertiary-care university hospital. We quantified dopamine transporter availability in each striatal subregion and assessed the severity of periventricular and lobar white matter hyperintensities using the Scheltens scale. The relationship between white matter hyperintensities, dopamine transporter availability in the posterior putamen, and Unified Parkinson's Disease Rating Scale (UPDRS) motor scores was assessed using multivariate linear regression and mediation analyses.

RESULTS

Periventricular and frontal white matter hyperintensities were generally associated with dopamine transporter availability in striatal subregions after adjusting for age at symptom onset, sex, disease duration, and vascular risk factors. There was an interaction effect between periventricular white matter hyperintensities and dopamine transporter availability in the posterior putamen for the axial motor score. The effect of white matter hyperintensities on UPDRS total score and bradykinesia subscore was indirectly mediated by dopamine transporter availability in the posterior putamen, whereas the axial sub-score was directly affected by white matter hyperintensities.

CONCLUSIONS

This study suggests that the detrimental effect of white matter hyperintensities on parkinsonian motor symptoms is more relevant and independent for axial motor impairments in the status of mildly decreased striatal dopamine transporter availability. © 2021 International Parkinson and Movement Disorder Society.

The pattern of FP-CIT PET in pure white matter hyperintensities-related vascular parkinsonism

OBJECTIVES

To determine whether vascular parkinsonism (VaP) patients with visually normal dopamine transporter (DAT) scans have presynaptic dopaminergic depletion.

METHODS

We enrolled 23 VaP patients who had parkinsonism, relevant diffuse subcortical white matter hyperintensities (WMH), and visually normal DAT scans, 23 Parkinson's disease (PD) patients, and 31 control subjects. By quantitatively analyzing ¹⁸F-N-(3-fluoropropyl)-2β-carbon ethoxy-3β-(4-iodophenyl) nortropane (¹⁸F-FP-CIT) positron emission tomography, we compared the pattern of striatal DAT availability among groups. The discriminatory power of striatal DAT availability to differentiate VaP patients from control subjects or PD patients was assessed using receiver operating characteristics (ROC) analyses. Additionally, correlation analysis was performed to determine whether WMH severity or Unified Parkinson Disease Rating Scale Part III (UPDRS-III) score is related to presynaptic dopaminergic depletion in VaP.

RESULTS

VaP patients exhibited decreased DAT availability in all striatal subregions, including posterior putamen, compared to control subjects. VaP patients and control subjects had similar patterns of anteroposterior and ventrodorsal DAT gradients in caudate and putamen level, but VaP patients exhibited significantly different patterns at putamen level, relative to PD patients. The severity of periventricular WMH was significantly correlated with all substriatal DAT availability in VaP, but not with UPDRS-III scores. The ROC analysis showed that DAT availability in caudate and posterior putamen had a fair discriminatory power when differentiating VaP patients from control subjects.

CONCLUSIONS

This study demonstrates that VaP patients with WMH exhibited diffusely decreased DAT availability without any specific regional gradients of DAT patterns distinct from either control subjects or PD patients.

Brain White-Matter Degeneration Due to Aging and Parkinson Disease as Revealed by Double Diffusion Encoding

Microstructure imaging by means of multidimensional diffusion encoding is increasingly applied in clinical research, with expectations that it yields a parameter that better correlates with clinical disability than current methods based on single diffusion encoding. Under the assumption that diffusion within a voxel can be well described by a collection of diffusion tensors, several parameters of this diffusion tensor distribution can be derived, including mean size, variance of sizes, orientational dispersion, and microscopic anisotropy. The information provided by multidimensional diffusion encoding also enables us to decompose the sources of the conventional fractional anisotropy and mean kurtosis. In this study, we explored the utility of the diffusion tensor distribution approach for characterizing white-matter degeneration in aging and in Parkinson disease by using double diffusion encoding. Data from 23 healthy older subjects and 27 patients with Parkinson disease were analyzed. Advanced age was associated with greater mean size and size variances, as well as smaller microscopic anisotropy. By analyzing the parameters underlying diffusion kurtosis, we found that the reductions of kurtosis in aging and Parkinson disease reported in the literature are likely driven by the reduction in microscopic anisotropy. Furthermore, microscopic anisotropy correlated with the severity of motor impairment in the patients with Parkinson disease. The present results support the use of multidimensional diffusion encoding in clinical studies and are encouraging for its future clinical implementation.

Therapy of Parkinson's Disease Subtypes

Early descriptions of subtypes of Parkinson's disease (PD) are dominated by the approach of predetermined groups. Experts defined, from clinical observation, groups based on clinical or demographic features that appeared to divide PD into clinically distinct subsets. Common bases on which to define subtypes have been motor phenotype (tremor dominant vs akinetic-rigid or postural instability gait disorder types), age, nonmotor dominant symptoms, and genetic forms. Recently, data-driven approaches have been used to define PD subtypes, taking an unbiased statistical approach to the identification of PD subgroups. The vast majority of data-driven subtyping has been done based on clinical features. Biomarker-based subtyping is an emerging but still quite undeveloped field. Not all of the subtyping methods have established therapeutic implications. This may not be surprising given that they were born largely from clinical observations of phenotype and not in observations regarding treatment response or biological hypotheses. The next frontier for subtypes research as it applies to personalized medicine in PD is the development of genotype-specific therapies. Therapies for GBA-PD and LRRK2-PD are already under development. This review discusses each of the major subtyping systems/methods in terms of its applicability to therapy in PD, and the opportunities and challenges designing clinical trials to develop the evidence base for personalized medicine based on subtypes.

White Matter Hyperintensities Related to Parkinson's Disease Executive Function

BACKGROUND

People with Parkinson's disease (PD) can develop multidomain cognitive impairments; however, it is unclear whether different pathologies underlie domain-specific cognitive dysfunction.

OBJECTIVES

We investigated the contribution of vascular copathology severity and location, as measured by MRI white matter hyperintensities (WMHs), to domain-specific cognitive impairment in PD.

METHODS

We studied 85 PD (66.6 ± 9.2 years) and 18 control (65.9 ± 6.6) participants. Using the Fazekas scale for rating the severity of WMH, we subdivided PD into 14 PD-WMH+ and 71 PD-WMH-. Participants underwent global, executive, visuospatial, episodic memory, and language testing. We performed nonparametric permutation testing to create WMH probability maps based on PD-WMH group and cognitive test performance.

RESULTS

The PD-WMH+ group showed worse global and executive cognitive performance than the PD-WMH- group. On individual tests, the PD-WMH+ group showed worse Montreal Cognitive Assessment (MoCA), Stroop, Symbol Digit Modalities Test (SDMT), and Digit Span scores. WMH probability maps showed that in the PD-WMH+ group, worse Stroop was associated with lesions centered around the corticospinal tract (CST), forceps major, inferior-fronto-occipital fasciculus, and superior longitudinal fasciculus; worse SDMT with lesions around the CST, forceps major, and posterior corona radiata; worse Digit Span with lesions around the posterior corona radiata; and worse MoCA with lesions around the CST.

CONCLUSIONS

We found that WMH severity was associated with PD executive dysfunction, including worse attention, working memory, and processing speed. Disruption of key white matter tracts in proximity to vascular lesions could contribute to these specific cognitive impairments. Early treatment of vascular disease might mitigate some executive dysfunction in a subset of patients with PD.

Parkinson's Disease, NOTCH3 Genetic Variants, and White Matter Hyperintensities

BACKGROUND

White matter hyperintensities (WMH) on magnetic resonance imaging may influence clinical presentation in patients with Parkinson's disease (PD), although their significance and pathophysiological origins remain unresolved. Studies examining WMH have identified pathogenic variants in NOTCH3 as an underlying cause of inherited forms of cerebral small vessel disease.

METHODS

We examined NOTCH3 variants, WMH volumes, and clinical correlates in 139 PD patients in the Ontario Neurodegenerative Disease Research Initiative cohort.

RESULTS

We identified 13 PD patients (~9%) with rare (<1% of general population), nonsynonymous NOTCH3 variants. Bayesian linear modeling demonstrated a doubling of WMH between variant negative and positive patients (3.1 vs. 6.9 mL), with large effect sizes for periventricular WMH (d = 0.8) and lacunes (d = 1.2). Negative correlations were observed between WMH and global cognition (r = -0.2).

CONCLUSION

The NOTCH3 rare variants in PD may significantly contribute to increased WMH burden, which in turn may negatively influence cognition. © 2020 International Parkinson and Movement Disorder Society.

Effect of small vessel disease burden and lacunes on gait/posture impairment in Parkinson's disease

INTRODUCTION

The comorbidity of cerebral small vessel disease (CSVD) may worsen gait impairment of Parkinson's disease (PD). However, the evidence remains scarce and controversial, and the mechanism of their potential interaction remains largely unknown. The present study aimed to investigate the overall impact of quantity and location of CSVD on gait/posture function in PD.

METHODS

This cross-sectional study included 315 consecutive eligible patients with PD from Beijing Tiantan Hospital from May 2016 to August 2018. Associations of gait/posture subscores with the burden score of CSVD and four CSVD imaging markers were assessed using multivariate linear regression models.

RESULTS

Burden of CSVD was significantly associated with more severe gait/posture impairment in PD in the unadjusted model (β = 0.521, P = 0.011, 95% CI 0.118-0.923) and in the model adjusted for age, hypertension, ischemic stroke, low-density lipoprotein level, cholesterol level, and cognitive statues (β = 0.448, P = 0.047, 95% CI 0.006-0.891). The presence of lacunes, but not other CSVD markers, was significantly associated with higher gait/posture subscores after the adjustment (β = 0.492, P = 0.041, 95% CI 0.021-0.964), and the number of lacunes in the basal ganglia significantly correlated with the gait/posture subscores in patients with PD (P = 0.012, Spearman r = 0.161).

CONCLUSIONS

CSVD and lacunes in the basal ganglia may independently contribute to gait/posture dysfunction in PD. Promoting neurovascular health may preserve some gait/posture function of PD.

Gender-specific effect of urate on white matter integrity in Parkinson's disease

OBJECTIVES

To investigate the potential protective influence of serum uric acid (UA) level on white matter (WM) microstructural changes in de novo Parkinson's disease (PD).

METHODS

We enrolled a total of 184 patients with drug-naïve de novo PD and 59 age and gender-matched controls that underwent diffusion tensor imaging (DTI). Based on the distribution, serum UA levels were stratified into tertiles in PD patients by gender. Using tract-based spatial statistics (TBSS) analysis, fractional anisotropy (FA), mean diffusivity (MD), axial diffusivity (AD), and radial diffusivity (RD) were used to compare WM integrity between the groups.

RESULTS

Interaction analysis showed that interaction effect on FA values between gender and UA levels in PD was significant in widespread WM areas, including frontal-parieto-temporal, corpus callosum, bilateral internal and external capsule, and thalamic regions. Multiple regression analysis revealed that FA values had a significantly positive correlation with UA levels across widespread WM areas in male patients. However, there was no significant correlation between DTI measures and UA levels in female patients. In a group comparison in male patients, PD with the lowest UA level (PD-L-UA) group showed significantly lower FA and higher MD and RD values in frontal-parieto-temporal WM regions than PD with the highest UA level (PD-H-UA) group. However, female patients did not show significant difference of DTI measures between PD-L-UA and PD-H-UA groups.

CONCLUSIONS

The present study demonstrated that the serum UA levels may have the potentially gender-specific close relationship with WM integrity in the early stage of PD.

White matter hyperintensities and risk of levodopa-induced dyskinesia in Parkinson's disease

Objective

To investigate whether the burden of white matter hyperintensities (WMHs) is associated with the risk of developing levodopa‐induced dyskinesia (LID) in Parkinson’s disease (PD).

Methods

According to the Clinical Research Center for Dementia of South Korea WMH visual rating scale, 336 patients with drug‐naïve early stage PD (follow‐up >3 years) were divided into two groups of PD with minimal WMHs (PD‐WMH–; n = 227) and moderate‐to‐severe WMHs (PD‐WMH+; n = 109). The Cox regression model was used to estimate the hazard ratio for the development of LID in the PD‐WMH + group compared with the PD‐WMH– group, while adjusting for age at PD onset, sex, striatal dopamine depletion, and PD medication dose. Additionally, we assessed the effects of WMH burden rated by the Scheltens scale and regional WMH distribution on the development of LID.

Results

Patients in the PD‐WMH + group were older and had more severe parkinsonian motor signs despite comparable striatal dopamine transporter availability than those in the PD‐WMH– group. Patients in the PD‐WMH + group had a higher risk of developing LID (hazard ratio, 2.66; P < 0.001) than those in the PD‐WMH– group after adjustment for other confounding factors. A greater WMH burden was associated with earlier occurrence of LID (hazard ratio, 1.04; P = 0.001), although the effects of WMHs on LID development did not exhibit region‐specific patterns.

Interpretation

The present study demonstrates that the burden of WMHs is associated with occurrence of LID in patients with PD, suggesting comorbid WMHs as a risk factor for LID.

White matter hyperintensities as a predictor of freezing of gait in Parkinson's disease

INTRODUCTION

To investigate the effect of white matter hyperintensities (WMH) on long-term motor outcomes in Parkinson's disease (PD).

METHODS

We retrospectively reviewed medical records of 268 patients with de novo PD (follow-up > 3 years). According to the Clinical Research Center for Dementia of South Korea (CREDOS) WMH visual rating scale scores, the patients were divided into two groups: a PD group with minimal WMH (PD-WMH-; n = 198) and a PD group with moderate to severe WMH (PD-WMH+; n = 70). We compared longitudinal increases in doses of dopaminergic medications between the two groups using a mixed model. We also assessed the effects of WMH on the development of freezing of gait (FOG).

RESULTS

Patients in the PD-WMH + group were older than those in the PD-WMH- group, and had more severe motor deficits and more severely decreased striatal dopamine transporter availability. The PD-WMH + group required higher doses of dopaminergic medications for symptom control, compared to the PD-WMH- group, over the follow-up period. After adjusting for age, sex, striatal dopamine transporter availability, and levodopa-equivalent dose, the PD-WMH + group showed a higher risk of developing FOG (HR, 3.29; 95% CI, 1.79-6.05; p < 0.001) than the PD-WMH- group.

CONCLUSION

This study demonstrates that WMH burden negatively affects the longitudinal requirement of dopaminergic medication and the development of FOG. These findings suggest that baseline WMH severity or volume may be a useful prognostic marker of motor outcomes in PD.

Dyskinesia and FAB score predict future falling in Parkinson's disease

A growing body of research highlights the importance of cognition for prediction of falls in Parkinson's disease (PD). However, a previously proposed prediction model for future near falls and falls in PD, which includes history of near falls, tandem gait, and retropulsion, was developed without considering cognitive impairment. Therefore, by using a sample of 64 individuals with relatively mild PD and not excluding those with impaired cognition we aimed to externally validate the previously proposed model as well as to explore the value of additional predictors that also consider cognitive impairment. Since this validation study failed to support the proposed model in a PD sample including individuals with impaired global cognition, extended analyses generated a new model including dyskinesia (item 32 of Unified PD Rating Scale) and frontal lobe impairment (Frontal Assessment Battery-FAB) as significant independent predictors for future near falls and falls in PD. The discriminant ability of this new model was acceptable (AUC, 0. 80; 95% CI 0.68-0.91). Replacing the continuous FAB scores by a dichotomized version of FAB with a cut-off score ≤14 yielded slightly lower but still acceptable discriminant ability (AUC, 0. 79; 95% CI 0.68-0.91). Further studies are needed to test our new model and the proposed cut-off score of FAB in additional samples. Taken together, our observations suggest potentially important additions to the evidence base for clinical fall prediction in PD with concomitant cognitive impairment.

Association of homocysteine, folate, and white matter hyperintensities in Parkinson's patients with different motor phenotypes

OBJECTIVE

To investigate the association of homocysteine (Hcy), folate, and white matter hyperintensities in Parkinson's disease (PD) with different motor phenotypes.

METHODS

Of the PD patients, 176 were included. Based on the Unified Parkinson's Disease Rating Scale, the PD patients were classified into postural instability gait disorder (PIGD) and non-PIGD phenotypes. According to the Fazekas score, patients were divided into the none/mild white matter hyperintensity (WMH) group and the moderate/severe WMH group. The relationship of Hcy, folate, and white matter hyperintensities (WMHs), and the motor phenotype of PD were analyzed.

RESULTS

PD-PIGD patients had higher proportion of moderate/severe WMHs, Hcy levels, and lower folate levels than PD-non-PIGD patients (p all ≤ 0.001). In the subgroup analysis, patients with both PD-PIGD and moderate/severe WMHs had the highest Hcy and lowest folate levels compared with others. Binary logistic regression analysis showed that age, folate, and Hcy were independent risk factors for WMHs. In an a priori-determined stratified analysis, after adjustment for confounding factors, the odds ratio of WMHs was 8.01 (95% CI 2.700-23.767, p trend = 0.001) in the patients with Hcy levels in the highest quintile compared with the lowest quintile and 16.81 (95% CI 4.74-59.65, p trend < 0.001) in the patients with folate levels in the lowest quintile compared with the highest quintile.

CONCLUSIONS

Our data showed a close association between WMHs and Hcy, folate especially in PD-PIGD patients. It can be speculated that higher Hcy and lower folate probably played important roles in the development of WMHs and motor heterogeneity in PD.

The effect of small vessel disease on motor and cognitive function in Parkinson's disease

OBJECTIVES

Small vessel disease (SVD) has been associated with motor and cognitive impairments in neurodegenerative diseases. We investigated SVD markers using brain magnetic resonance imaging (MRI) and the global SVD score in Parkinson's disease (PD).

PATIENTS AND METHODS

Seventy-one patients with PD were assessed for vascular risk factors, motor severity, and motor phenotype. Global cognition was evaluated using the Mini-Mental State Examination (MMSE) and Montreal Cognitive Assessment (MoCA). Based on the MoCA score, we categorized cases into normal (>23) or cognitively impaired (≤23). We calculated the total SVD score (range, 0-4) based on white matter hyper intensities (WMHs), lacunae, cerebral microbleeds (MBs), and enlarged perivascular spaces (PVSs). In addition, we evaluated global brain atrophy.

RESULTS

There were no significant associations with total SVD score and vascular risk factors, PD severity, and motor phenotype. Increasing age and reduced MMSE and MoCA scores were associated with increased SVD burden. Logistic regression analyses demonstrated that periventricular WMH (PVH), PVS in the basal ganglia (BG-PVS), and atrophy were predictors of cognitive impairment in PD.

CONCLUSION

The contribution of SVD may be important in elderly patients with PD. Impaired cognition due to SVD-related brain changes was associated with BG-PVS and PVH. These measures suggest that PD with PVS can provide novel insights into SVD.

The association of cognitive reserve with motor and cognitive functions for different stages of Parkinson's disease

INTRODUCTION

The cognitive reserve (CR) theory has been proposed to account for the mismatch between the degree of neuropathological changes and clinical outcome in dementias. Recently, it has also been applied to Parkinson's disease (PD) with promising results, but mostly just focusing on separate proxy measures of CR, such as education, working and leisure time activities, instead of adopting a more comprehensive approach. Using the Cognitive Reserve Index questionnaire (CRIq), this study examined the association of CR with motor functions and cognition in patients with medium-low (1-9 years) and medium-high (>9 years) PD duration.

METHODS

Fifty patients with PD underwent a neurological and a neuropsychological assessment, comprised of: Unified Parkinson's Disease Rating Scale- section III, Mini-Mental State Examination, Clock-Drawing Test, Rey auditory verbal learning test (immediate and delayed recall trials), Digit Span Forward, Corsi Span Forward, Frontal Assessment Battery, Raven's Colored Progressive Matrices, WAIS similarities subtest, Phonemic Fluency, Semantic Fluency and CRIq.

RESULTS

PD patients with a higher CRIq score showed a reduced motor impairment and a better global cognitive performance when compared to PD patients with a lower CRIq score, with an advantage especially observed on executive functions and short-term memory. The CR effect was even enhanced in the case of longer disease duration, as observed when considering the overall neuropsychological tests performance and non-verbal abstract reasoning in particular. The results obtained when considering education, as a single proxy measure of CR, provided no additional findings, nor did they reveal all the effects yielded by the adoption of the CRI score.

CONCLUSION

Our results support the beneficial role of CR against motor and cognitive dysfunctions in PD and suggest that its protective role may be mostly manifested at the later stages of the disease. A theoretical framework able to explain the different impact of CR on Alzheimer Disease and PD is discussed. Finally, our results stressed the importance of using a comprehensive measure of CR instead of focusing on just one of its proxies.

Modifiable vascular risk factors, white matter disease and cognition in early Parkinson's disease

BACKGROUND AND PURPOSE

Dementia in Parkinson's disease (PD) is common and disabling. Identification of modifiable risk factors for it is essential. Vascular risk factors (VRFs) may be associated with cognitive decline in early PD. Biomarkers that serve as surrogates of the long-term effect of VRFs on PD are needed. To that end, we aimed to quantitate white matter hyperintensities (WMH) in early PD, measure associations with VRFs and examine relationships between WMH and longitudinal cognition.

METHODS

Participants in the Parkinson's Progression Markers Initiative study (141 patients with PD, 63 healthy controls) with adequate baseline structural brain magnetic resonance imaging data were included. Hypertension and diabetes history, and body mass index were combined to create a vascular risk score. WMH were quantitated via automated methods. Cognition was assessed annually with a comprehensive test battery.

RESULTS

In the PD group, vascular risk score was associated with WMH for total brain (β = 0.210; P = 0.021), total white matter (β = 0.214; P = 0.013), frontal (β = 0.220; P = 0.002) and temporal (β = 0.212; P = 0.002) regions. Annual rate of change in global cognition was greater in those with higher vascular risk score (β = -0.040; P = 0.007) and greater WMH (β = -0.029; P = 0.049). Higher temporal WMH burden was associated with great decline over time in verbal memory (β = -0.034; P = 0.031).

CONCLUSIONS

In early PD, modifiable VRFs are associated with WMH on brain magnetic resonance imaging. Temporal WMH burden predicts decline in verbal memory. WMH may serve as a surrogate marker for the effect of VRFs on cognitive abilities in PD.

Quantitative Analysis of Relationship Between Hypokinetic Dysarthria and the Freezing of Gait in Parkinson's Disease

Hypokinetic dysarthria (HD) and freezing of gait (FOG) are both axial symptoms that occur in patients with Parkinson's disease (PD). It is assumed they have some common pathophysiological mechanisms and therefore that speech disorders in PD can predict FOG deficits within the horizon of some years. The aim of this study is to employ a complex quantitative analysis of the phonation, articulation and prosody in PD patients in order to identify the relationship between HD and FOG, and establish a mathematical model that would predict FOG deficits using acoustic analysis at baseline. We enrolled 75 PD patients who were assessed by 6 clinical scales including the Freezing of Gait Questionnaire (FOG-Q). We subsequently extracted 19 acoustic measures quantifying speech disorders in the fields of phonation, articulation and prosody. To identify the relationship between HD and FOG, we performed a partial correlation analysis. Finally, based on the selected acoustic measures, we trained regression models to predict the change in FOG during a 2-year follow-up. We identified significant correlations between FOG-Q scores and the acoustic measures based on formant frequencies (quantifying the movement of the tongue and jaw) and speech rate. Using the regression models, we were able to predict a change in particular FOG-Q scores with an error of between 7.4 and 17.0 %. This study is suggesting that FOG in patients with PD is mainly linked to improper articulation, a disturbed speech rate and to intelligibility. We have also proved that the acoustic analysis of HD at the baseline can be used as a predictor of the FOG deficit during 2 years of follow-up. This knowledge enables researchers to introduce new cognitive systems that predict gait difficulties in PD patients.

Association between White Matter Lesions and Non-Motor Symptoms in Parkinson Disease

Background: There are only few studies exploring the relationship between white matter lesions (WMLs) and non-motor symptoms in Parkinson disease (PD). This study aimed to investigate the association between WMLs and the severity of non-motor symptoms in PD. Methods: The severity of motor dysfunction, cognitive impairment, and non-motor symptoms was assessed by various scales in 105 PD patients. We used a visual semiquantitative rating scale and divided the subjects into four groups: no, mild, moderate, and severe WMLs. We compared the means of all scores between the four groups and analyzed the association between the severity of WMLs and the specific domain of non-motor symptoms. Results: The non-motor symptoms as assessed by the Non-Motor Symptoms Scale, Parkinson’s Disease Questionnaire (PDQ-39), Parkinson’s Disease Sleep Scale, Beck Depression Inventory (BDI), Beck Anxiety Inventory (BAI), Neuropsychiatric Inventory (NPI), and Parkinson Fatigue Scale (PFS) were significantly worse in the patients with moderate and severe WMLs than in those without WMLs. Compared with the no WML group, the scores for motor dysfunction were significantly higher in the mild, moderate, and severe WML groups. The scores for cognitive dysfunction were significantly higher in the patients with severe WMLs than in those without WMLs. The severity of WMLs showed linear associations with PFS, BDI, BAI, NPI, and PDQ-39 scores. The severity of WMLs also correlated linearly with scores for motor and cognitive dysfunction. Conclusions: Among the non-motor symptoms, fatigue, depression, anxiety, and quality of life were significantly affected by WMLs in PD. Confirmation of the possible role of WMLs in non-motor symptoms associated with PD in a prospective manner may be crucial not only for understanding non-motor symptoms but also for the development of treatment strategies.

Exploring the relationship between motor impairment, vascular burden and cognition in Parkinson's disease

OBJECTIVE

To determine frequency and type of cognitive disorders in cross-sectional analysis of a Parkinson's disease (PD) cohort, and explore its relations to motor symptoms, modifiable vascular risk factors and white matter lesions (WML) volume.

METHODS

In a group of 133 PD patients, mild cognitive impairment (PD-MCI) and dementia (PDD) were diagnosed according to Movement Disorders Society Task Force criteria (level 2 for PD-MCI). Detailed motor measurements were applied, including rigidity, axial, bradykinesia, tremor and postural instability gait disorders (PIGD) scores. Vascular risk was estimated by the Framingham General Cardiovascular Disease risk scoring algorithm and WML volume was measured for whole brain and frontal lobe.

RESULTS

Sixty-one (46.9%) patients fulfilled criteria for PD-MCI, and 23 (17.7%) for PDD. Non-amnestic multiple domain MCI was most frequent (52% of PD-MCI patients). Motor scores were significantly higher in cognitively impaired patients, but only axial score discriminated between MCI and dementia. High vascular risk was related to impaired cognition, bradykinesia, axial, PIGD and freezing of gait (FOG) score, while whole brain WML volume was associated with PDD, FOG and attention deficits. Furthermore, high vascular risk was identified as a potential predictor of both MCI and dementia in PD. Additionally, age and bradykinesia score were independently associated with PD-MCI and age, axial score and whole brain WML volume with PDD.

CONCLUSION

Cognitive disorders in PD are associated with more severe, predominantly axial motor deficits and increased, but partly modifiable vascular burden, thus opening a possibility for development of preventive strategies in PD.

White matter alterations in Parkinson's disease with normal cognition precede grey matter atrophy

INTRODUCTION

While progressive MRI brain changes characterize advanced Parkinson's disease (PD), little has been discovered about structural alterations in the earliest phase of the disease, i.e. in patients with motor symptoms and with normal cognition. Our study aimed to detect grey matter (GM) and white matter (WM) changes in PD patients without cognitive impairment.

METHODS

Twenty PD patients and twenty-one healthy controls (HC) were tested for attention, executive function, working memory, and visuospatial and language domains. High-resolution T1-weighted and 60 directional diffusion-weighted 3T MRI images were acquired. The cortical, deep GM and WM volumes and density, as well as the diffusion properties of WM, were calculated. Analyses were repeated on data flipped to the side of the disease origin.

RESULTS

PD patients did not show any significant differences from HC in cognitive functioning or in brain volumes. Decreased GM intensity was found in the left superior parietal lobe in the right (p<0.02) and left (p<0.01) flipped data. The analysis of original, un-flipped data demonstrated elevated axial diffusivity (p<0.01) in the superior and anterior corona radiata, internal capsule, and external capsule in the left hemisphere of PD relative to HC, while higher mean and radial diffusivity were discovered in the right (p<0.02 and p<0.03, respectively) and left (p<0.02 and p<0.02, respectively) in the fronto-temporal WM utilizing flipped data.

CONCLUSIONS

PD patients without cognitive impairment and GM atrophy demonstrated widespread alterations of WM microstructure. Thus, WM impairment in PD might be a sensitive sign preceding the neuronal loss in associated GM regions.

White Matter Changes-Related Gait and Executive Function Deficits: Associations with Age and Parkinson's Disease

Background: White matter changes (WMC) are a common finding among older adults and patients with Parkinson's disease (PD), and have been associated with, e.g., gait deficits and executive dysfunction. How the factors age and PD influence WMC-related deficits is, to our best knowledge, not investigated to date. We hypothesized that advanced age and presence of PD leads to WMC-related symptoms while practicing tasks with a low complexity level, and low age and absence of PD leads to WMC-related symptoms while practicing tasks with a high complexity level.

Methods: Hundred and thirty-eight participants [65 young persons without PD (50–69 years, yPn), 22 young PD patients (50–69 years, yPD), 36 old persons without PD (70–89 years, oPn) and 15 old PD patients (70–89 years, oPD)] were included. Presence and severity of WMC were determined with the modified Fazekas score. Velocity of walking under single and dual tasking conditions and the Trail Making Test (TMT) were used as gait and executive function parameters. Correlations between presence and severity of WMC, and gait and executive function parameters were tested in yPn, yPD, oPn, and oPD using Spearman's rank correlation, and significance between groups was evaluated with Fisher's z-transformed correlation coefficient.

Results: yPn and yPD, as well as oPn and oPD did not differ regarding demographic and clinical parameters. Severity of WMC was not significantly different between groups. yPn and yPD displayed significant correlations of WMC with executive function parameters at low levels of task complexity, oPn at intermediate, and oPD at high complexity levels.

Conclusion: This study argues for a relevant association of age and PD-related brain pathology with WMC-related gait and executive function deficits.

Aging of cerebral white matter

White matter (WM) occupies a large volume of the human cerebrum and is mainly composed of myelinated axons and myelin-producing glial cells. The myelinated axons within WM are the structural foundation for efficient neurotransmission between cortical and subcortical areas. Similar to neuron-enriched gray matter areas, WM undergoes a series of changes during the process of aging. WM malfunction can induce serious neurobehavioral and cognitive impairments. Thus, age-related changes in WM may contribute to the functional decline observed in the elderly. In addition, aged WM becomes more susceptible to neurological disorders, such as stroke, traumatic brain injury (TBI), and neurodegeneration. In this review, we summarize the structural and functional alterations of WM in natural aging and speculate on the underlying mechanisms. We also discuss how age-related WM changes influence the progression of various brain disorders, including ischemic and hemorrhagic stroke, TBI, Alzheimer's disease, and Parkinson's disease. Although the physiology of WM is still poorly understood relative to gray matter, WM is a rational therapeutic target for a number of neurological and psychiatric conditions.

Statins are underused in recent-onset Parkinson's disease with increased vascular risk: findings from the UK Tracking Parkinson's and Oxford Parkinson's Disease Centre (OPDC) discovery cohorts

BACKGROUND

Cardiovascular disease (CVD) influences phenotypic variation in Parkinson's disease (PD), and is usually an indication for statin therapy. It is less clear whether cardiovascular risk factors influence PD phenotype, and if statins are prescribed appropriately.

OBJECTIVES

To quantify vascular risk and statin use in recent-onset PD, and examine the relationship between vascular risk, PD severity and phenotype.

METHODS

Cardiovascular risk was quantified using the QRISK2 calculator (high ≥20%, medium ≥10 and <20%, low risk <10%). Motor severity and phenotype were assessed using the Movement Disorder Society Unified PD Rating Scale (UPDRS) and cognition by the Montreal cognitive assessment.

RESULTS

In 2909 individuals with recent-onset PD, the mean age was 67.5 years (SD 9.3), 63.5% were men and the mean disease duration was 1.3 years (SD 0.9). 33.8% of cases had high vascular risk, 28.7% medium risk, and 22.3% low risk, while 15.2% of cases had established CVD. Increasing vascular risk and CVD were associated with older age (p<0.001), worse motor score (p<0.001), more cognitive impairment (p<0.001) and worse motor phenotype (p=0.021). Statins were prescribed in 37.2% with high vascular risk, 15.1% with medium vascular risk and 6.5% with low vascular risk, which compared with statin usage in 75.3% of those with CVD.

CONCLUSIONS

Over 60% of recent-onset PD patients have high or medium cardiovascular risk (meriting statin usage), which is associated with a worse motor and cognitive phenotype. Statins are underused in these patients, compared with those with vascular disease, which is a missed opportunity for preventive treatment.

TRIAL REGISTRATION NUMBER

GN11NE062, NCT02881099.

Vascular disease and vascular risk factors in relation to motor features and cognition in early Parkinson's disease

OBJECTIVE

The purpose of this study was to examine the relationship between vascular disease (and vascular risk factors), cognition and motor phenotype in Parkinson's disease (PD).

METHODS

Recently diagnosed PD cases were enrolled in a multicenter prospective observational longitudinal cohort study. Montreal cognitive assessment (normal >23, mild cognitive impairment 22 to 23 or lower but without functional impairment, and dementia 21 or less with functional impairment) and Movement Disorder Society Unified PD Rating Scale part 3 (UPDRS 3) scores were analyzed in relation to a history of vascular events and risk factors.

RESULTS

In 1759 PD cases, mean age 67.5 (standard deviation 9.3) years, mean disease duration 1.3 (standard deviation 0.9) years, 65.2% were men, 4.7% had a history of prior stroke or transient ischemic attack, and 12.5% had cardiac disease (angina, myocardial infarction, heart failure). In cases without a history of vascular disease, hypertension was recorded in 30.4%, high cholesterol 27.3%, obesity 20.7%, diabetes 7.2%, and cigarette smoking in 4.6%. Patients with prior stroke or transient ischemic attack were more likely to have cognitive impairment (42% vs 25%) and postural instability gait difficulty (53.5% vs 39.5%), but these findings were not significant after adjustment for age, sex, and disease duration (P = .075). The presence of more than 2 vascular risks was associated with worse UPDRS 3 motor scores (beta coefficient 4.05, 95% confidence interval 1.48, 6.61, p = .002) and with cognitive impairment (ordinal odds ratio 2.24, 95% confidence interval 1.34, 3.74, p = .002). In 842 patients (47.8%) with structural brain imaging, white matter leukoaraiosis, but not lacunar or territorial infarction, was associated with impaired cognition (p = .006) and postural instability gait difficulty (p = .010).

CONCLUSION

Vascular comorbidity is significantly associated with cognitive and gait impairment in patients with early PD, which may have prognostic and treatment implications. © 2016 The Authors. Movement Disorders published by Wiley Periodicals, Inc. on behalf of International Parkinson and Movement Disorder Society.