Inverse Relationship Between Cerebrovascular Lesions and Severity of Lewy Body Pathology in Patients With Lewy Body Diseases

Clinical Predictors of Postmortem Amyloid and Nonamyloid Cerebral Small Vessel Disease in Middle-Aged to Older Adults

Background and Objectives

Sporadic cerebral small vessel disease (CSVD) is a class of important pathologic processes known to affect the aging brain and to contribute to cognitive impairment. We aimed to identify clinical risk factors associated with postmortem CSVD in middle-aged to older adults.

Methods

We developed and tested risk models for their predictive accuracy of a pathologic diagnosis of nonamyloid CSVD and cerebral amyloid angiopathy (CAA) in a retrospective sample of 160 autopsied cases from the Edinburgh Brain Bank. Individuals aged 40 years and older covering the spectrum of healthy aging and common forms of dementia (i.e., highly-prevalent etiologies such as Alzheimer disease (AD), vascular cognitive impairment (VCI), and mixed dementia) were included. We performed binomial logistic regression models using sample splitting and cross-validation methods. Demographics, lifestyle habits, traditional vascular risk factors, chronic medical conditions, APOE4, and cognitive status were assessed as potential predictors.

Results

Forty percent of our sample had a clinical diagnosis of dementia (AD = 33, VCI = 26 and mixed = 5) while others were cognitively healthy (n = 96). The mean age at death was 73.8 (SD 14.1) years, and 40% were female. The presence of none-to-mild vs moderate-to-severe nonamyloid CSVD was predicted by our model with good accuracy (area under the curve [AUC] = 0.84, sensitivity [SEN] = 72%, specificity [SPE] = 95%), with the most significant clinical predictors being age, history of cerebrovascular events, and cognitive impairment. The presence of CAA pathology was also predicted with high accuracy (AUC = 0.86, SEN = 93%, SPE = 79%). Significant predictors included alcohol intake, history of cerebrovascular events, and cognitive impairment. In a subset of atypical dementias (n = 24), our models provided poor predictive performance for both nonamyloid CSVD (AUC = 0.50) and CAA (AUC = 0.43).

Discussion

CSVD pathology can be predicted with high accuracy based on clinical factors in patients within the spectrum of AD, VCI, and normal aging. Whether this prediction can be enhanced by the addition of fluid and neuroimaging biomarkers warrants additional study. Improving our understanding of clinical determinants of vascular brain health may lead to novel strategies in the prevention and treatment of vascular etiologies contributing to cognitive decline.

Classification of Evidence

This study provides Class II evidence that selected clinical factors accurately distinguish between middle-aged to older adults with and without cerebrovascular small vessel disease (amyloid and nonamyloid) pathology.

Lewy body pathology modifies risk factors for cerebral amyloid angiopathy when comorbid with Alzheimer's disease pathology

INTRODUCTION

Cerebral amyloid angiopathy (CAA) often accompanies dementia-associated pathologies and is important in the context of anti-amyloid monoclonal therapies and risk of hemorrhage.

METHODS

We conducted a retrospective neuropathology-confirmed study of 2384 participants in the National Alzheimer Coordinating Center cohort (Alzheimer's disease [AD], n = 1175; Lewy body pathology [LBP], n = 316; and mixed AD and LBP [AD-LBP], n = 893). We used logistic regression to evaluate age, sex, education, APOE ε4, neuritic plaques, and neurofibrillary tangles (NFTs) in CAA risk.

RESULTS

APOE ε4 increased CAA risk in all three groups, while younger age and higher NFT stages increased risk in AD and AD-LBP. In AD-LBP, male sex and lower education were additional risk factors. The odds of APOE ε4 carrier homozygosity related to CAA was higher in LBP (25.69) and AD-LBP (9.50) than AD (3.17).

DISCUSSION

AD and LBPs modify risk factors for CAA and should be considered in reviewing the risk of CAA.

HIGHLIGHTS

Lewy body pathology modifies risk factors for cerebral amyloid angiopathy (CAA) when present along with Alzheimer's disease (AD) neuropathology. In the context of anti-amyloid monoclonal therapies and their associated risks for hemorrhage, the risk of underlying CAA in mixed dementia with Lewy body pathology needs to be considered.

Sex differences in brain atrophy in dementia with Lewy bodies

INTRODUCTION

Sex influences neurodegeneration, but it has been poorly investigated in dementia with Lewy bodies (DLB). We investigated sex differences in brain atrophy in DLB using magnetic resonance imaging (MRI).

METHODS

We included 436 patients from the European-DLB consortium and the Mayo Clinic. Sex differences and sex-by-age interactions were assessed through visual atrophy rating scales (n = 327; 73 ± 8 years, 62% males) and automated estimations of regional gray matter volume and cortical thickness (n = 165; 69 ± 9 years, 72% males).

RESULTS

We found a higher likelihood of frontal atrophy and smaller volumes in six cortical regions in males and thinner olfactory cortices in females. There were significant sex-by-age interactions in volume (six regions) and cortical thickness (seven regions) across the entire cortex.

DISCUSSION

We demonstrate that males have more widespread cortical atrophy at younger ages, but differences tend to disappear with increasing age, with males and females converging around the age of 75.

HIGHLIGHTS

Male DLB patients had higher odds for frontal atrophy on radiological visual rating scales. Male DLB patients displayed a widespread pattern of cortical gray matter alterations on automated methods. Sex differences in gray matter measures in DLB tended to disappear with increasing age.

New insight on the possible role of statins in Vascular Parkinsonism: A need for presumptive therapy

Vascular Parkinsonism (VP) is clinical term represents a progressive ischemic changes and subcortical lacunar infarct leading to Parkinsonism mainly in the lower limbs so called lower body Parkinsonism. The VP neuropathology is differed from that of PD neuropathology which rarely associated with basal ganglion lesions. Dopamine transporters are normal in VP but are highly reduced in PD, and dopaminergic agonists had no effective role on VP. The neuropathological mechanisms of VP are related to vascular injury which induces the interruption of the neural connection between basal ganglion and cerebral cortex. Hyperlipidemia and other cardiometabolic risk factors augment VP risk and the related neuropathology. Targeting of these cardiometabolic disorders by lipid-lowering statins may be effective in the management of VP. Therefore, this mini-review aims to clarify the possible role of statins in the management of VP. Statins have neuroprotective effects against different neurodegenerative diseases by anti-inflammatory, antioxidant and antithrombotic effects with enhancement of endothelial function. In conclusion, statins can prevent and treat VP by inhibiting inflammatory and oxidative stress disorders, mitigating of white matter hyperintensities and improving of neuronal signaling pathways. Additional preclinical, clinical trials and prospective studies are warranted in this regard.

Stroke in Parkinson's disease: a review of epidemiological studies and potential pathophysiological mechanisms

Parkinson's disease (PD) is the fastest growing neurological disorder and one of the leading neurological causes of disability worldwide following stroke. An overall aging global population, as well as general changes in lifestyle associated with mass industrialization in the last century, may be linked to both increased incidence rates of PD and an increase in cumulative cardiovascular risk. Recent epidemiological studies show an increased risk of stroke, post-stroke complications, and subclinical ischemic insults in PD. PD patients have a host of characteristics that might contribute to increasing the risk of developing ischemic stroke including motor impairment, dysautonomia, and sleep disorders. This increases the urgency to study the interplay between PD and other neurological disorders, and their combined effect on mortality, morbidity, and quality of life. In this review, we provide a comprehensive overview of the studied etiological factors and pathological processes involved in PD, specifically with regard to their relationship to stroke. We hope that this review offers an insight into the relationship between PD and ischemic stroke and motivates further studies in this regard.

Dementia with Lewy bodies: Impact of co-pathologies and implications for clinical trial design

Dementia with Lewy bodies (DLB) is clinically defined by the presence of visual hallucinations, fluctuations, rapid eye movement (REM) sleep behavioral disorder, and parkinsonism. Neuropathologically, it is characterized by the presence of Lewy pathology. However, neuropathological studies have demonstrated the high prevalence of coexistent Alzheimer's disease, TAR DNA-binding protein 43 (TDP-43), and cerebrovascular pathologic cases. Due to their high prevalence and clinical impact on DLB individuals, clinical trials should account for these co-pathologies in their design and selection and the interpretation of biomarkers values and outcomes. Here we discuss the frequency of the different co-pathologies in DLB and their cross-sectional and longitudinal clinical impact. We then evaluate the utility and possible applications of disease-specific and disease-nonspecific biomarkers and how co-pathologies can impact these biomarkers. We propose a framework for integrating multi-modal biomarker fingerprints and step-wise selection and assessment of DLB individuals for clinical trials, monitoring target engagement, and interpreting outcomes in the setting of co-pathologies.

White matter hyperintensities in dementia with Lewy bodies are associated with poorer cognitive function and higher dementia stages

Purpose

White matter hyperintensities (WMHs) are frequently found in elderly individuals with or without dementia. However, the association between WMHs and clinical presentations of dementia with Lewy bodies (DLB) has rarely been studied.

Methods

We conducted a retrospective analysis of patients with DLB registered in a dementia database. WMHs were rated visually using the Fazekas scale, and its associated factors including dementia severity, cognitive functions, neuropsychiatric symptoms, and core clinical features were compared among different Fazekas scores. Domains in the Clinical Dementia Rating (CDR), Cognitive abilities Screening Instruments (CASI), and Neuropsychiatric Inventory (NPI) were compared among different Fazekas groups after adjusting for age, sex, education, and disease duration.

Results

Among the 449 patients, 76, 207, 110, and 56 had Fazekas score of 0, 1, 2, and 3, respectively. There was a positive association between dementia severity and WMHs severity, and the mean sums of boxes of the Clinical Dementia Rating (CDR-SB) were 5.9, 7.8, 9.5, and 11.2 (f = 16.84, p < 0.001) for the Fazekas scale scores 0, 1, 2, and 3, respectively. There was a negative association between cognitive performance and WMHs severity, and the mean CASI were 57.7, 45.4, 4.06, and 33.4 (f = 14.22, p < 0.001) for the Fazekas scale scores 0, 1, 2, and 3, respectively. However, WMHs were not associated with the core clinical features of DLB. After adjustment, all cognitive domains in CDR increased as the Fazekas score increased. In addition, performance on all cognitive domains in CASI decreased as the Fazekas score increased (all p < 0.001). Among neuropsychiatric symptoms, delusions, euphoria, apathy, aberrant motor behavior, and sleep disorders were significantly worse in the higher Fazekas groups compared to those in the group with Fazekas score of 0 after adjustment.

Conclusion

WMHs in DLB might contribute to deterioration of cognitive function, neuropsychiatric symptoms, and dementia stages. However, core clinical features were not significantly influenced by WMHs in DLB.

Are there morphological differences between Parkinson's disease-dementia and dementia with Lewy bodies?

Parkinson's disease dementia (PDD) and dementia with Lewy bodies (DLB) are two major neurocognitive disorders in the spectrum of Lewy body diseases that overlap in many clinical and neuropathological features, although they show several differences. Clinically distinguished mainly based on the duration of parkinsonism prior to development of dementia, their morphology is characterized by a variable combination of Lewy body (LB) and Alzheimer's disease (AD) pathologies, the latter usually being more frequent and severe in DLB.

OBJECTIVE

The aims of the study were to investigate essential neuropathological differences between PDD and DLB in a larger cohort of autopsy cases.

METHODS

110 PDD autopsy cases were compared with 78 DLB cases. The major demographic, clinical (duration of illness, final MMSE) and neuropathological data were assessed retrospectively. Neuropathological studies used standardized methods and immunohistochemistry for phospho-tau, β-amyloid (Aß) and α-synuclein, with semiquantitative assessment of the major histological lesions.

RESULTS

PDD patients were significantly older at death than DLB ones (mean 83.9 vs. 79.8 years), with a significantly longer disease duration (mean 9.2 vs. 6.7 years). Braak LB scores and particularly neuritic Braak stages were significantly higher in the DLB group (mean 5.1and 5.1 vs. 4.2 and 4.4, respectively), as were Thal Aβ phases (mean 4.1 vs. 3.0). Diffuse striatal Aβ plaques were considerable in 55% and moderate in 45% of DLB cases, but were extremely rare in PDD. The most significant differences concerned the frequency and degree of cerebral amyloid angiopathy (CAA), being significantly higher in DLB (98.7 vs. 50%, and mean degree of 2.9 vs. 0.72, respectively). Worse prognosis in DLB than in PDD was linked to both increased Braak neuritic stages and more severe CAA.

INTERPRETATION

These and other recent studies imply the association of CAA, more severe concomitant AD pathology, and striatal Aβ load with cognitive decline and more rapid disease process that distinguishes DLB from PDD, while the influence of other cerebrovascular diseases or co-pathologies in both disorders was not specifically examined. The importance of both CAA and tau pathology in DLB and much less in PDD supports the concept of a pathogenetic continuum from Parkinson's disease (PD) - > PDD - > DLB - > DLB + AD and subtypes of AD with LB pathology within the spectrum of age-related proteinopathies.

Cerebral Microvascular Pathology Is a Common Endophenotype Between Traumatic Brain Injury, Cardiovascular Disease, and Dementia: A Hypothesis and Review

Traumatic brain injury (TBI) exposure has been associated with an increased risk of age-related cognitive decline or dementia in multiple epidemiological studies. Current therapeutic interventions in the field of Brain Injury Medicine focus largely on episodic symptom management during the chronic phase of TBI recovery, rather than targeting specific underlying pathological processes. This approach may be especially problematic for secondary age-related cognitive decline or dementia following TBI exposure. Although there are likely multiple pathophysiological mechanisms involved, a growing body of literature demonstrates that cerebral microvascular pathology is a common endophenotype across the spectrum of TBI severity. Similarly, a combination of pre-clinical and clinical research over the past two decades has implicated cerebral microvascular pathology in the initiation and progression of multiple neurodegenerative diseases, including Alzheimer’s disease and other dementias. We hypothesize that cerebral microvascular pathology is a common endophenotype between TBI, cardiovascular disease (CVD), and dementia, which can be targeted through modifiable cardiovascular risk factor reductions during the chronic phase of TBI recovery. We posit that our hypothesis is supported by the currently available scientific literature, as detailed in our review.

The influence of cerebrovascular disease in dementia with Lewy bodies and Parkinson's disease dementia

INTRODUCTION

Lewy body dementia (LBD), including dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), is a common form of neurodegenerative dementia. The frequency and influence of comorbid cerebrovascular disease is not understood but has potentially important clinical management implications.

METHODS

A systematic literature search was conducted (Medline and Embase) for studies including participants with DLB and/or PDD assessing cerebrovascular lesions (imaging and pathological studies). They included white matter changes, cerebral amyloid angiopathy (CAA), cerebral microbleeds (CMB), macroscopic infarcts, micro-infarcts and intracerebral haemorrhage.

RESULTS

Of 4411 articles, 63 studies were included. Cerebrovascular lesions commonly studied included white matter changes (41 studies) and CMB (18 studies). There was an increased severity of white matter changes on magnetic resonance imaging (visualized as white matter hyperintensities, WMH), but not neuropathology, in LBD compared to PD without dementia and age-matched controls. CMB prevalence in DLB was highly variable but broadly similar to Alzheimer's disease (AD) (0-48%), with a lobar predominance. No relationship was found between large cortical or small subcortical infarcts or intracerebral haemorrhage and presence of LBD.

CONCLUSION

The underlying mechanisms of WMH in LBD require further exploration, as their increased severity in LBD was not supported by neuropathological examination of white matter. CMB in LBD had a similar prevalence as AD. There is a need for larger studies assessing the influence of cerebrovascular lesions on clinical symptoms, disease progression and outcomes.

Cerebrovascular disease, neurodegeneration, and clinical phenotype in dementia with Lewy bodies

We investigated whether cerebrovascular disease contributes to neurodegeneration and clinical phenotype in dementia with Lewy bodies (DLB). Regional cortical thickness and subcortical gray matter volumes were estimated from structural magnetic resonance imaging (MRI) in 165 DLB patients. Cortical and subcortical infarcts were recorded and white matter hyperintensities (WMHs) were assessed. Subcortical only infarcts were more frequent (13.3%) than cortical only infarcts (3.1%) or both subcortical and cortical infarcts (2.4%). Infarcts, irrespective of type, were associated with WMHs. A higher WMH volume was associated with thinner orbitofrontal, retrosplenial, and posterior cingulate cortices, smaller thalamus and pallidum, and larger caudate volume. A higher WMH volume was associated with the presence of visual hallucinations and lower global cognitive performance, and tended to be associated with the absence of probable rapid eye movement sleep behavior disorder. Presence of infarcts was associated with the absence of parkinsonism. We conclude that cerebrovascular disease is associated with gray matter neurodegeneration in patients with probable DLB, which may have implications for the multifactorial treatment of probable DLB.

Cognitive Impairment in Parkinson's Disease: Epidemiology, Clinical Profile, Protective and Risk Factors

Cognitive impairment is a common non-motor symptom in Parkinson's Disease (PD) and an important source of patient disability and caregiver burden. The timing, profile and rate of cognitive decline varies widely among individuals with PD and can range from normal cognition to mild cognitive impairment (PD-MCI) and dementia (PDD). Beta-amyloid and tau brain accumulation, oxidative stress and neuroinflammation are reported risk factors for cognitive impairment. Traumatic brain injury and pesticide and tobacco exposure have also been described. Genetic risk factors including genes such as COMT, APOE, MAPT and BDNF may also play a role. Less is known about protective factors, although the Mediterranean diet and exercise may fall in this category. Nonetheless, there is conflicting evidence for most of the factors that have been studied. The use of inconsistent criteria and lack of comprehensive assessment in many studies are important methodological issues. Timing of exposure also plays a crucial role, although identification of the correct time window has been historically difficult in PD. Our understanding of the mechanism behind these factors, as well as the interactions between gene and environment as determinants of disease phenotype and the identification of modifiable risk factors will be paramount, as this will allow for potential interventions even in established PD.

White matter hyperintensities in patients with Parkinson's disease: A systematic review and meta-analysis

INTRODUCTION

Mechanisms driving neurodegeneration in Parkinson's disease (PD) are unclear and neurovascular dysfunction may be a contributing factor. White matter hyperintensities (WMH) are commonly found on brain MRI in patients with PD. It is controversial if they are more prevalent or more severe in PD compared with controls. This systematic review aims to answer this question.

METHODS

A systematic search of electronic databases was conducted for studies of WMH in patients with PD. A qualitative synthesis was done for studies reporting WMH prevalence or WMH scores on a visual rating scale (VRS). In studies reporting total WMH volume, the difference between patients with PD and controls was pooled using random effects meta-analysis.

RESULTS

Among 3860 subjects from 24 studies, 2360 were cases and 1500 controls. Fifteen studies reported WMH scores and four studies reported the prevalence of WMH. On VRS, five studies reported no difference in WMH scores, three found higher WMH scores in PD compared to controls, three reported increased WMH scores either in periventricular or deep white matter, and four reported higher scores only in PD with dementia. In studies reporting WMH volume, there was no difference between patients with PD and controls (pooled standardized mean difference = 0.1, 95%CI: -0.1-0.4, I² = 81%).

CONCLUSION

WMH are not more prevalent or severe in patients with PD than in age-matched controls. PD dementia may have more severe WMH compared to controls and PD with normal cognition. Prospective studies using standardized methods of WMH assessment are needed.

Significance of cerebral amyloid angiopathy and other co-morbidities in Lewy body diseases

Lewy body dementia (LBD) and Parkinson's disease-dementia (PDD) are two major neurocognitive disorders with Lewy bodies (LB) of unknown etiology. There is considerable clinical and pathological overlap between these two conditions that are clinically distinguished based on the duration of Parkinsonism prior to development of dementia. Their morphology is characterized by a variable combination of LB and Alzheimer's disease (AD) pathologies. Cerebral amyloid angiopathy (CAA), very common in aged persons and particularly in AD, is increasingly recognized for its association with both pathologies and dementia. To investigate neuropathological differences between LB diseases with and without dementia, 110 PDD and 60 LBD cases were compared with 60 Parkinson's disease (PD) cases without dementia (PDND). The major demographic and neuropathological data were assessed retrospectively. PDD patients were significantly older than PDND ones (83.9 vs 77.8 years; p < 0.05); the age of LB patients was in between both groups (mean 80.2 years), while the duration of disease was LBD < PDD < PDND (mean 6.7 vs 12.5 and 14.3 years). LBD patients had higher neuritic Braak stages (mean 5.1 vs 4.5 and 4.0, respectively), LB scores (mean 5.3 vs 4.2 and 4.0, respectively), and Thal amyloid phases (mean 4.1 vs 3.0 and 2.3, respectively) than the two other groups. CAA was more common in LBD than in the PDD and PDND groups (93 vs 50 and 21.7%, respectively). Its severity was significantly greater in LBD than in PDD and PDND (p < 0.01), involving mainly the occipital lobes. Moreover, striatal Aβ deposition highly differentiated LBD brains from PDD. Braak neurofibrillary tangle (NFT) stages, CAA, and less Thal Aβ phases were positively correlated with LB pathology (p < 0.05), which was significantly higher in LBD than in PDD < PDND. Survival analysis showed worse prognosis in LBD than in PDD (and PDND), which was linked to both increased Braak tau stages and more severe CAA. These and other recent studies imply the association of CAA-and both tau and LB pathologies-with cognitive decline and more rapid disease progression that distinguishes LBD from PDD (and PDND).

Case Report of a pathologically confirmed vascular parkinsonism with early cognitive impairment and Behavioral disturbance

Background

Vascular Parkinsonism(VaP) is defined as parkinsonism resulting from cerebral vascular disease(CVD), with presence of variable motor and non-motor signs that are corroborated by clinical, anatomic or imaging findings of cerebrovascular disease. Overlapping syndromes with mixed pathologies make VaP difficult to distinguish from primary neurodegenerative parkinsonism.To understand the clinical and pathological features of VaP,we report a case of autopsy confirmed vascular Parkinsonism that was clinical misdiagnosed as idiopathic Parkinson’s disease.Clinical features include early mixed symptoms of dementia,behavioral disturbance and parkinsonism that were similar to Dementia with lewy Body(DLB) and Parkinson disease Dementia(PDD).

Case presentation

A 84-year-old man presented progressive parkinsonism with prominent postural instability, gait impairment, pseudobulbar, early cognitive impairment, irritability, hallucination, urinary symptoms and poor responsiveness to dopaminergic drugs. He was clinically diagnosed as Parkinson disease(PD). In the post-mortem study, we examined Aβ and phospho-tau as pathological biomarker for Alzheimer’s disease(AD), α-synucleing in medulla, pons and midbrain for PD and DLB. Hematoxylin and eosin staining in cerebral cortex, cerebellum and brainstem examines vascular pathological changes and microvascular lesion.Neither Lewy bodies in the substantia nigra ,locus ceruleus and cerebrumnor accumulation of Aβ, neurofibrillary tangles were noted. Instead, there were many cerebral infarctions and widespread arteriosclerosis in the brain. The final brain autopsy supported a diagnosis of VaP not PD.

Conclusions

This case of pathologically confirmed VaP misdiagnosed as idiopathic PD suggested that we must be vigilant about the possibility of VaP for patients with parkinsonisms, cognitive impairments, early behavioral and psychological symptoms,imaging performances of cerebral small vessel disease and other vascular damages.

White matter hyperintensities and risks of cognitive impairment and dementia: A systematic review and meta-analysis of 36 prospective studies

BACKGROUND

White matter hyperintensities of presumed vascular origin (WMH) are one of the imaging features of cerebral small vessel disease. Controversies persist about the effects of WMH on cognitive dysfunction. This meta-analysis aimed to identify the associations of WMH with risks of cognitive impairment and dementia.

METHODS

We searched PubMed, EMBASE and Cochrane Library for prospective studies. Primary analyses of cognitive dysfunction and sub-analyses of specific outcomes and study characteristics were conducted using random-effect models.

RESULTS

Thirty-six prospective studies with 19,040 participants were included. WMH at baseline conferred a 14 % elevated risk of cognitive impairment and all-cause dementia (ACD). WMH also conferred 25 % elevated risk of Alzheimer's disease and 73 % elevated risk of vascular dementia. Risk effects of high-grade WMH and continually increasing WMH (in volume or severity) on ACD were revealed. Periventricular WMH conferred a 1.51-fold excess risk for dementia.

CONCLUSIONS

WMH were associated with increased risk of cognitive dysfunction and could become a neuroimaging indicator of dementia.

Cardiovascular Disease, Diabetes Mellitus, and Hypertension in Lewy Body Disease: A Comparison with Other Dementia Disorders

Background:

Research concerning the potential roles of cardiovascular disease (CaVD) and diabetes mellitus (DM) as risk factors for Lewy body disease (LBD) is limited. These disorders are, however, established risk factors for vascular dementia (VaD) and have been proposed as risk factors for Alzheimer’s disease (AD).

Objective:

The aim of this study was to investigate the prevalence of CaVD and DM in LBD and compare the results with previous findings in cases with AD, VaD, and mixed AD-VaD (MD).

Methods:

Autopsy reports at the Clinical Department of Pathology in Lund from 2001–2018 were analyzed. All cases with a complete neuropathological diagnosis of LBD were selected, not distinguishing between subjects with clinical Parkinson disease dementia and dementia with Lewy bodies, on the condition of a clinical diagnosis of dementia. Clinical data were retrieved through the patients’ medical records and the Swedish National Diabetes Register (NDR) and compared with those of the AD, VaD, and MD cases.

Results:

In LBD, there was less CaVD, significantly less DM (p = 0.002) and likewise significantly less hypertension (p < 0.001) than in VaD. The results of the LBD group were consistent with the results of the AD group.

Conclusion:

Our findings of a low prevalence of CaVD and CaVD risk factors in LBD and in AD argue against the association between these risk factors and their contribution to the development of neurodegenerative diseases.

Genetic architecture of common non-Alzheimer's disease dementias

Frontotemporal dementia (FTD), dementia with Lewy bodies (DLB) and vascular dementia (VaD) are the most common forms of dementia after Alzheimer's disease (AD). The heterogeneity of these disorders and/or the clinical overlap with other diseases hinder the study of their genetic components. Even though Mendelian dementias are rare, the study of these forms of disease can have a significant impact in the lives of patients and families and have successfully brought to the fore many of the genes currently known to be involved in FTD and VaD, starting to give us a glimpse of the molecular mechanisms underlying these phenotypes. More recently, genome-wide association studies have also pointed to disease risk-associated loci. This has been particularly important for DLB where familial forms of disease are very rarely described. In this review we systematically describe the Mendelian and risk genes involved in these non-AD dementias in an effort to contribute to a better understanding of their genetic architecture, find differences and commonalities between different dementia phenotypes, and uncover areas that would benefit from more intense research endeavors.

Brain Lewy-Type Synucleinopathy Density Is Associated with a Lower Prevalence of Atherosclerotic Cardiovascular Disease Risk Factors in Patients with Parkinson's Disease1

BACKGROUND

Some epidemiology studies suggest that atherosclerotic cardiovascular disease (ASCVD) risk factors increase the risk of developing Parkinson's disease (PD). However, conflicting data suggest lower rates of ASCVD in PD.

OBJECTIVE

The objective of this study is to determine, with data from a longitudinal clinicopathological study, whether ASCVD risk factors are associated with a PD diagnosis and/or increased brain or peripheral load of Lewy-type synucleinopathy (LTS).

METHODS

All subjects were followed to autopsy and neuropathological examination in the Arizona Study of Aging and Neurodegenerative Disorders (AZSAND). Multivariable regression models, including age, gender, and smoking history, were used to investigate the association of a PD diagnosis or brain or submandibular gland LTS load with ASCVD risk factors.

RESULTS

150 subjects were included (PD n = 60, controls n = 90). Univariable comparisons and regression models showed a general trend to inverse associations. The multivariable odds ratio (OR) of brain LTS load for carotid artery disease was 0.93 (95% CI: 0.86 to 0.98; p = 0.02), for anticoagulant use 0.95 (95% CI: 0.90 to 0.99; p = 0.04) and for abnormal heart weight 0.96 (95% CI: 0.92 to 0.99; p = 0.01). Composite clinical and overall (clinical + pathology composite risk scores) composite risk scores were also significantly lower in the PD subjects (p = 0.0164 and 0.0187, respectively). Submandibular gland LTS load was not significantly related to ASCVD conditions.

CONCLUSIONS

This study shows associations of higher brain LTS with lower prevalence of both clinical and pathological indices of ASCVD in PD subjects versus age-similar controls. We suggest that this is due to α-synuclein pathology-induced sympathetic denervation in PD.

Association Between Stroke and Parkinson's Disease: a Meta-analysis

Parkinson's disease (PD) and stroke are both associated with aging, but the relationship between these two disorders remains unclear. Recent evidence has shown that they frequently co-occur and are influenced by each another, although some studies have found inconsistent results. We performed this meta-analysis of patients with PD on stroke risk to clarify the relationship between these two disorders on the basis of the studies published from 1975 to July 2019 in the PubMed, EMBASE, and Cochrane Library databases. In total, 13 case-control studies met the inclusion criteria for meta-analysis. The pooled odds ratio (OR) for PD in relation to the stroke risk was 1.72 (95% confidence interval (CI) 1.19-2.49). The OR for the presence of cerebral infarct among PD in the four studies was 1.35 (95% CI 1.04-1.74). Moreover, the OR for the presence of stroke pathology among PD in the four postmortem studies was 1.86 (95% CI 1.17-2.98). In conclusion, our meta-analysis suggests that there is an association between stroke and PD. Sensitivity analysis was used to test the robustness of our results through the sequential removal of each one study at time, in order to investigate if a single study was driving the study results. These results indicate that PD and stroke may have a common pathogenesis and may share preventive treatment measures.

[Clinical and neuroimaging heterogeneity of dementia with Lewy bodies]

AIM

To study clinical characteristics of dementia with Lewy bodies (DLB) depending on neuropsychological, neuroimaging and concomitant cerebrovascular changes as well as on the character of disease onset.

MATERIAL AND METHODS

Forty-five patients with DLB (25 men and 20 women, men age 72.9±7.2 years, illness duration 2.9±2.2) were studied. The diagnosis was made according to international criteria (McKeith, et al, 2017). MRI, clinical/neurological examination and psychometric scales were used.

RESULTS AND CONCLUSION

Clinical, neuropsychological and neuroimaging results reveal the heterogeneity of DLB, which remains poorly investigated. An analysis of the clinical picture, cognitive profile, neuropsychiatric changes and MRI results identified three subtypes of DLB course: 1) typical; 2) with early psychotic manifestation; 3) atypical (mixed). This approach may improve the diagnosis of DLB, prognosis of disease course and treatment effectiveness.

Neuroimaging in Vascular Parkinsonism

PURPOSE OF REVIEW

Being a disease with heterogeneous presentations and unclear consensus on its diagnostic criteria, it is difficult to differentiate vascular parkinsonism (VaP) from other neurodegenerative parkinsonism variants. Ongoing research on structural and functional neuroimaging targeting dopaminergic pathway provides us more insight into the pathophysiology of VaP to improve diagnostic accuracy. The aim of this article is to review how the emerging imaging modalities help the diagnostic process and treatment decision in VaP.

RECENT FINDINGS

Dopamine transporter imaging is a promising tool in differentiating presynaptic parkinsonism and VaP. It also predicts the levodopa responders in VaP. Advanced MRI techniques including volumetry, diffusion tensor imaging and sequences visualising substantia nigra are under development, and they are complementary to each other in detecting structural and functional changes in VaP, which is crucial to ensure the quality of future therapeutic trials for VaP. Dopamine transporter imaging is recommended to patients with suspected VaP. Multimodal MRI in VaP would be an important area to be investigated in the near future.

[Mixed dementia: the role of cerebrovascular pathology]

Alzheimer's disease and vascular dementia are two most common causes of dementia in late life. The combination of Alzheimer's type dementia and vascular dementia is the third most common form of dementia, especially in the elderly. Most clinical forms of dementia are characterized by the presence of 'overlap' symptoms of both neurodegenerative and vascular pathology, which makes it expedient to consider mixed dementia as a separate entity characterized by clinical presentations, course and the rate of progression of cognitive decline. Despite the lack of clinical guidelines for management of patients with mixed dementia, it seems appropriate to use strategies that have shown their effectiveness in various types of cognitive impairment.

[Cerebral microbleeds in cerebrovascular and neurodegenerative diseases with cognitive impairment]

AIM

To study a role of cerebral microbleeds (CMB) in the diagnosis of main cerebrovascular and neurodegenerative diseases with cognitive impairment.

MATERIAL AND METHODS

CMB were studied in 120 patients with Alzheimer's disease (AD), dementia with Lewy bodies (DLB) and vascular dementia using 1.5T MRI in T2 * gradient echo. An impact of CMB on cognitive functions and the relationship with signs of vascular and neurodegenerative lesions of the brain were studied as well. The neuropsychological battery included Montreal Cognitive Assessment scale (MoCA), Addenbrooke's Cognitive Examination (ACE-R), Clock Drawing Test, fluency test and the visual memory test (SCT).

RESULTS

CMB were identified in more than one third of patients with neurodegenerative or cerebrovascular disease. With regard to disease, they were detected preferably in cortical or subcortical areas, respectively. This result can be used in the differential diagnosis. Single subcortical CMB accompanied by a smaller number of lacunae and less severe leukoaraiosis were identified in 48% of patients with DLB. In AD with additional features of DLB and cerebrovascular disease, CMB were more common (60%) that was a predictor of mixed pathology.

CONCLUSION

Leukoaraiosis, if accompanied by CMB, has a great clinical significance in neurodegenerative and cerebrovascular diseases with cognitive impairment. CMB is a marker of severe cognitive impairment and predictor of mixed pathology in the cortical-subcortical localization of CMB and corresponding neuropsychological profile.

Stroke and Coronary Artery Disease Are Associated With Parkinson’s Disease

Background: The relationship between vascular disease and Parkinson’s disease (PD) is controversial. We performed a cross-sectional study to investigate the association of two common vascular diseases (stroke and coronary artery disease [CAD]) with Parkinson’s disease. Methods: We identified 63 and 62 PD cases in two population-based cohorts (Malu rural community and Wuliqiao urban community) and collected information of PD and non-PD by means of questionnaires. Logistic regression analysis was used to investigate the association between stroke, coronary artery disease and PD, after adjusting for age, sex, hypertension, diabetes mellitus, hypercholesterolemia, smoking status, alcohol consumption, tea consumption and body mass index. Results: After adjustment for potential confounders, we found that CAD and stroke were associated with PD in the Malu rural community (CAD: odds ratio [OR]=7.11, 95% confidence intervals [CI]: 3.09-16.40, p<0.001; stroke: OR=6.77, 95% CI: 3.09-14.81, p<0.001) and stroke was associated with PD in the Wuliqiao urban community (OR=2.58, 95% CI: 1.36-4.89, p=0.004), especially in women. In a subgroup analysis of PD with age- and sex-matched controls, the results were similar in the Malu rural community (CAD: OR=12.72, 95% CI: 2.92-55.32, p=0.001; stroke: OR=6.26, 95% CI: 1.83-21.42, p=0.003), whereas in the Wuliqiao urban community the results were different in that CAD (but not stroke) was found to be associated with PD (CAD: OR=2.44, 95% CI: 1.09-5.47, p=0.03; stroke: OR=1.79, 95% CI: 0.77-4.17, p=0.18). Conclusions: Our study suggested that stroke and CAD are associated with PD in two Chinese population-based cohorts, indicating a probable vascular component in the pathogenesis of PD.

An updated diagnostic approach to subtype definition of vascular parkinsonism - Recommendations from an expert working group

This expert working group report proposes an updated approach to subtype definition of vascular parkinsonism (VaP) based on a review of the existing literature. The persistent lack of consensus on clear terminology and inconsistent conceptual definition of VaP formed the impetus for the current expert recommendation report. The updated diagnostic approach intends to provide a comprehensive tool for clinical practice. The preamble for this initiative is that VaP can be diagnosed in individual patients with possible prognostic and therapeutic consequences and therefore should be recognized as a clinical entity. The diagnosis of VaP is based on the presence of clinical parkinsonism, with variable motor and non-motor signs that are corroborated by clinical, anatomic or imaging findings of cerebrovascular disease. Three VaP subtypes are presented: (1) The acute or subacute post-stroke VaP subtype presents with acute or subacute onset of parkinsonism, which is typically asymmetric and responds to dopaminergic drugs; (2) The more frequent insidious onset VaP subtype presents with progressive parkinsonism with prominent postural instability, gait impairment, corticospinal, cerebellar, pseudobulbar, cognitive and urinary symptoms and poor responsiveness to dopaminergic drugs. A higher-level gait disorder occurs frequently as a dominant manifestation in the clinical spectrum of insidious onset VaP, and (3) With the emergence of molecular imaging biomarkers in clinical practice, our diagnostic approach also allows for the recognition of mixed or overlapping syndromes of VaP with Parkinson's disease or other neurodegenerative parkinsonisms. Directions for future research are also discussed.

Are dementia with Lewy bodies and Parkinson's disease dementia the same disease?

BACKGROUND

Dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD), which share many clinical, neurochemical, and morphological features, have been incorporated into DSM-5 as two separate entities of major neurocognitive disorders with Lewy bodies. Despite clinical overlap, their diagnosis is based on an arbitrary distinction concerning the time of onset of motor and cognitive symptoms, namely as early cognitive impairment in DLB and later onset following that of motor symptoms in PDD. Their morphological hallmarks - cortical and subcortical α-synuclein/Lewy body plus β-amyloid and tau pathologies - are similar, but clinical differences at onset suggest some dissimilar profiles. Based on recent publications, including the fourth consensus report of the DLB Consortium, a critical overview is provided herein.

DISCUSSION

The clinical constellations of DLB and PDD include cognitive impairment, parkinsonism, visual hallucinations, and fluctuating attention. Intravitam PET and postmortem studies have revealed a more pronounced cortical atrophy, elevated cortical and limbic Lewy body pathologies, higher Aβ and tau loads in cortex and striatum in DLB compared to PDD, and earlier cognitive defects in DLB. Conversely, multitracer PET studies have shown no differences in cortical and striatal cholinergic and dopaminergic deficits. Clinical management of both DLB and PDD includes cholinesterase inhibitors and other pharmacologic and non-drug strategies, yet with only mild symptomatic effects. Currently, no disease-modifying therapies are available.

CONCLUSION

DLB and PDD are important dementia syndromes that overlap in many clinical features, genetics, neuropathology, and management. They are currently considered as subtypes of an α-synuclein-associated disease spectrum (Lewy body diseases), from incidental Lewy body disease and non-demented Parkinson's disease to PDD, DLB, and DLB with Alzheimer's disease at the most severe end. Cognitive impairment in these disorders is induced not only by α-synuclein-related neurodegeneration but by multiple regional pathological scores. Both DLB and PDD show heterogeneous pathology and neurochemistry, suggesting that they share important common underlying molecular pathogenesis with Alzheimer's disease and other proteinopathies. While we prefer to view DLB and PDD as extremes on a continuum, there remains a pressing need to more clearly differentiate these syndromes and to understand the synucleinopathy processes leading to either one.

Are Major Dementias Triggered by Poor Blood Flow to the Brain? Theoretical Considerations

There is growing evidence that chronic brain hypoperfusion plays a central role in the development of Alzheimer's disease (AD) long before dyscognitive symptoms or amyloid-β accumulation in the brain appear. This commentary proposes that dementia with Lewy bodies (DLB), frontotemporal dementia (FTD), and Creutzfeldt-Jakob disease (CJD) may also develop from chronic brain hypoperfusion following a similar but not identical neurometabolic breakdown as AD. The argument to support this conclusion is that chronic brain hypoperfusion, which is found at the early stages of the three dementias reviewed here, will reduce oxygen delivery and lower oxidative phosphorylation promoting a steady decline in the synthesis of the cell energy fuel adenosine triphosphate (ATP). This process is known to lead to oxidative stress. Virtually all neurodegenerative diseases, including FTD, DLB, and CJD, are characterized by oxidative stress that promotes inclusion bodies which differ in structure, location, and origin, as well as which neurological disorder they typify. Inclusion bodies have one thing in common; they are known to diminish autophagic activity, the protective intracellular degradative process that removes malformed proteins, protein aggregates, and damaged subcellular organelles that can disrupt neuronal homeostasis. Neurons are dependent on autophagy for their normal function and survival. When autophagic activity is diminished or impaired in neurons, high levels of unfolded or misfolded proteins overwhelm and downregulate the neuroprotective activity of unfolded protein response which is unable to get rid of dysfunctional organelles such as damaged mitochondria and malformed proteins at the synapse. The endpoint of this neuropathologic process results in damaged synapses, impaired neurotransmission, cognitive decline, and dementia.

Effect of Vascular Risk Factors on the Progression of Mild Alzheimer's Disease and Lewy Body Dementia

BACKGROUND

Vascular risk factors (VRF) are associated with an increased risk of neurodegenerative disease.

OBJECTIVE

To examine the association between VRF and cognitive decline in patients with Alzheimer's disease (AD) and Lewy body dementia (LBD).

METHODS

We included consecutive referrals with mild AD or LBD to dementia clinics in western Norway from 2005 to 2013. The Mini-Mental Status Exam (MMSE) and Clinical Dementia Rating Scale Sum of Boxes (CDR-SB) were administered at baseline and then annually for up to five years. The VRF include diabetes mellitus, hypertension, hypercholesterolemia, overweight and smoking. Generalized Estimating Equations (GEE) were used to examine the potential association between VRF scores and the change in MMSE and CDR-SB scores, adjusting for age, sex, and the apolipoprotein ɛ4 allele (APOE4).

RESULTS

A total of 200 patients were included (113 AD, 87 LBD) (mean age 76 years, mean baseline MMSE 24.0, mean follow-up time 3.5 years). Smoking was the only VRF significantly associated with a more rapid cognitive decline, however only in the AD group. Being overweight at baseline was associated with a slower cognitive decline. Moreover, hypertension at baseline predicted a slower decline in MMSE scores. In the LBD group diabetes mellitus was found to be associated with a slower increase in CDR-SB scores.

CONCLUSION

With the exception of smoking, VRF at time of dementia diagnosis were not associated with a more rapid cognitive decline.

Dementia with Lewy bodies and Parkinson's disease-dementia: current concepts and controversies

Dementia with Lewy bodies (DLB) and Parkinson's disease-dementia (PDD), although sharing many clinical, neurochemical and morphological features, according to DSM-5, are two entities of major neurocognitive disorders with Lewy bodies of unknown etiology. Despite considerable clinical overlap, their diagnosis is based on an arbitrary distinction between the time of onset of motor and cognitive symptoms: dementia often preceding parkinsonism in DLB and onset of cognitive impairment after onset of motor symptoms in PDD. Both are characterized morphologically by widespread cortical and subcortical α-synuclein/Lewy body plus β-amyloid and tau pathologies. Based on recent publications, including the fourth consensus report of the DLB Consortium, a critical overview is given. The clinical features of DLB and PDD include cognitive impairment, parkinsonism, visual hallucinations, and fluctuating attention. Intravitam PET and post-mortem studies revealed more pronounced cortical atrophy, elevated cortical and limbic Lewy pathologies (with APOE ε4), apart from higher prevalence of Alzheimer pathology in DLB than PDD. These changes may account for earlier onset and greater severity of cognitive defects in DLB, while multitracer PET studies showed no differences in cholinergic and dopaminergic deficits. DLB and PDD sharing genetic, neurochemical, and morphologic factors are likely to represent two subtypes of an α-synuclein-associated disease spectrum (Lewy body diseases), beginning with incidental Lewy body disease-PD-nondemented-PDD-DLB (no parkinsonism)-DLB with Alzheimer's disease (DLB-AD) at the most severe end, although DLB does not begin with PD/PDD and does not always progress to DLB-AD, while others consider them as the same disease. Both DLB and PDD show heterogeneous pathology and neurochemistry, suggesting that they share important common underlying molecular pathogenesis with AD and other proteinopathies. Cognitive impairment is not only induced by α-synuclein-caused neurodegeneration but by multiple regional pathological scores. Recent animal models and human post-mortem studies have provided important insights into the pathophysiology of DLB/PDD showing some differences, e.g., different spreading patterns of α-synuclein pathology, but the basic pathogenic mechanisms leading to the heterogeneity between both disorders deserve further elucidation. In view of the controversies about the nosology and pathogenesis of both syndromes, there remains a pressing need to differentiate them more clearly and to understand the processes leading these synucleinopathies to cause one disorder or the other. Clinical management of both disorders includes cholinesterase inhibitors, other pharmacologic and nonpharmacologic strategies, but these have only a mild symptomatic effect. Currently, no disease-modifying therapies are available.

The Neurovascular Unit Coming of Age: A Journey through Neurovascular Coupling in Health and Disease

The concept of the neurovascular unit (NVU), formalized at the 2001 Stroke Progress Review Group meeting of the National Institute of Neurological Disorders and Stroke, emphasizes the intimate relationship between the brain and its vessels. Since then, the NVU has attracted the interest of the neuroscience community, resulting in considerable advances in the field. Here the current state of knowledge of the NVU will be assessed, focusing on one of its most vital roles: the coupling between neural activity and blood flow. The evidence supports a conceptual shift in the mechanisms of neurovascular coupling, from a unidimensional process involving neuronal-astrocytic signaling to local blood vessels to a multidimensional one in which mediators released from multiple cells engage distinct signaling pathways and effector systems across the entire cerebrovascular network in a highly orchestrated manner. The recently appreciated NVU dysfunction in neurodegenerative diseases, although still poorly understood, supports emerging concepts that maintaining neurovascular health promotes brain health.

[Diagnostic of prodromal dementia with Levy bodies]

The issues of diagnosis of prodromal dementia with Lewy bodies are considered. Despite numerous studies using international diagnostic criteria, clinical and diagnosis are often inconsistent. Early and more accurate detection of dementia with Lewy bodies is needed for prognosis, optimal management and effective pharmacotherapy.

Cerebrovascular Lesions in Mixed Neurodegenerative Dementia: A Neuropathological and Magnetic Resonance Study

BACKGROUND

In elderly brains of demented patients, Alzheimer and Lewy body pathology (LBP) are frequently associated. Cortical microinfarcts (CoMIs) are more observed in Lewy body disease, even in the absence of cerebral amyloid angiopathy (CAA). The present neuropathological and 7.0-tesla MRI studies investigate whether CoMIs are also more frequent in mixed neurodegenerative dementia syndromes.

SUMMARY

Both examinations revealed that CoMIs are increased to different degrees in mixed dementia syndromes according to the severity of the LBP. They were mainly associated with a trend of older age and arterial hypertension in the patients with the most severe LBP. Messages: The increased number of CoMIs in mixed dementia syndromes with LBP is mainly due to the associated cerebrovascular pathology, even in the absence of CAA.

An investigation of cerebrovascular lesions in dementia with Lewy bodies compared to Alzheimer's disease

INTRODUCTION

Cerebrovascular lesions on MRI are common in Alzheimer's disease (AD) dementia, but less is known about their frequency and impact on dementia with Lewy bodies (DLB).

METHODS

White-matter hyperintensities (WMHs) and infarcts on MRI were assessed in consecutive DLB (n = 81) and AD dementia (n = 240) patients and compared to age-matched and sex-matched cognitively normal subjects (CN) from a population-based cohort.

RESULTS

DLB had higher WMH volume compared to CN, and WMH volume was higher in the occipital and posterior periventricular regions in DLB compared to AD. Higher WMH volume was associated with history of cardiovascular disease and diabetes but not with clinical disease severity in DLB. Frequency of infarcts in DLB was not different from CN and AD dementia.

DISCUSSION

In DLB, WMH volume is higher than AD and CN and appears to be primarily associated with history of vascular disease.

Post-mortem assessment in vascular dementia: advances and aspirations

BACKGROUND

Cerebrovascular lesions are a frequent finding in the elderly population. However, the impact of these lesions on cognitive performance, the prevalence of vascular dementia, and the pathophysiology behind characteristic in vivo imaging findings are subject to controversy. Moreover, there are no standardised criteria for the neuropathological assessment of cerebrovascular disease or its related lesions in human post-mortem brains, and conventional histological techniques may indeed be insufficient to fully reflect the consequences of cerebrovascular disease.

DISCUSSION

Here, we review and discuss both the neuropathological and in vivo imaging characteristics of cerebrovascular disease, prevalence rates of vascular dementia, and clinico-pathological correlations. We also discuss the frequent comorbidity of cerebrovascular pathology and Alzheimer's disease pathology, as well as the difficult and controversial issue of clinically differentiating between Alzheimer's disease, vascular dementia and mixed Alzheimer's disease/vascular dementia. Finally, we consider additional novel approaches to complement and enhance current post-mortem assessment of cerebral human tissue.

CONCLUSION

Elucidation of the pathophysiology of cerebrovascular disease, clarification of characteristic findings of in vivo imaging and knowledge about the impact of combined pathologies are needed to improve the diagnostic accuracy of clinical diagnoses.

Topographic distribution of white matter changes and lacunar infarcts in neurodegenerative and vascular dementia syndromes: A post-mortem 7.0-tesla magnetic resonance imaging study

BACKGROUND

White matter changes and lacunar infarcts are regarded as linked to the same underlying small-vessel pathology. On magnetic resonance imaging, white matter changes are frequently observed, while the number of lacunar infarcts is probably underestimated. The present study post-mortem 7.0-tesla magnetic resonance imaging study compares the severity and the distribution of white matter changes and lacunar infarcts in different neurodegenerative and vascular dementia syndromes in order to determine their impact on the disease evolution.

PATIENTS AND METHODS

Eighty-four post-mortem brains consisting of 15 patients with pure Alzheimer's disease and 12 with associated cerebral amyloid angiopathy, 14 patients with frontotemporal lobar degeneration, 7 with Lewy body dementia, 10 with progressive supranuclear palsy, 14 with vascular dementia and 12 control brains were examined. Six hemispheric coronal sections of each brain underwent 7.0-tesla magnetic resonance imaging. Location and severity of white matter changes and lacunar infarcts were evaluated semi-quantitatively in each section separately.

RESULTS

White matter changes predominated in the prefrontal and frontal sections of frontotemporal lobar degeneration and in the post-central section of associated cerebral amyloid angiopathy brains, while overall increased in vascular dementia cases. Lacunar infarcts were more frequent in the vascular dementia brains and mainly increased in the centrum semiovale.

CONCLUSIONS

White matter changes have a different topographic distribution in neurodegenerative diseases and are most severe and extended in vascular dementia. Lacunar infarcts predominate in the deep white matter of vascular dementia compared to the neurodegenerative diseases. Vascular cognitive impairment is mainly linked to white matter changes due to chronic ischaemia as well as to lacunar infarcts due to small-vessel occlusion.

The incidence of post-mortem neurodegenerative and cerebrovascular pathology in mixed dementia

BACKGROUND

The clinical picture of dementia in most aged patients is due to a combination of different neurodegenerative processes and frequently associated to cerebrovascular lesions. They are called mixed dementia (MixD) cases, to be differentiated from those with pure vascular dementia (VaD) and those with Alzheimer's dementia (AD). The present study compares the frequency of different associated lesions in these disease groups.

MATERIALS AND METHODS

Out of a series of 252 autopsied patients 36 with MixD, 20 with VaD and 64 with AD disease were compared concerning the frequency of the associated lesions. Small cerebrovascular lesions were evaluated on a large coronal section of a cerebral hemisphere. Mean values of frequency and severity were compared between the 3 groups.

RESULTS

Of the 120 examined brains 30% were classified as MixD, 17% as VaD and 53% as AD. In 20% of the AD patients Lewy body pathology (LBP) was observed with a low incidence of cerebrovascular lesions, except for cerebral amyloid angiopathy (CAA). The MixD patients had more severe CAA and were significantly older than those with VaD and AD. Lacunar infarcts, on the other hand, were significantly more frequent in the VaD patients.

DISCUSSION

The most responsible vascular lesions in MixD and VaD are different. There is an inverse correlation between the presence of LBP and vascular pathology. MixD has to be considered as the end stage of AD.

Neuropathological basis of nonmotor manifestations of Parkinson's disease

Nonmotor manifestations of Parkinson's disease (PD) can begin well before motor PD begins. It is now clear, from clinical and autopsy studies, that there is significant Lewy-type α-synucleinopathy present outside the nigro-striatal pathway and that this may underlie these nonmotor manifestations. This review discusses neuropathological findings that may underlie nonmotor symptoms that either predate motor findings or occur as the disease progresses. © 2016 International Parkinson and Movement Disorder Society.

The neuropathology and cerebrovascular mechanisms of dementia

The prevalence of dementia is increasing in our aging population at an alarming rate. Because of the heterogeneity of clinical presentation and complexity of disease neuropathology, dementia classifications remain controversial. Recently, the National Plan to address Alzheimer’s Disease prioritized Alzheimer’s disease-related dementias to include: Alzheimer’s disease, dementia with Lewy bodies, frontotemporal dementia, vascular dementia, and mixed dementias. While each of these dementing conditions has their unique pathologic signature, one common etiology shared among all these conditions is cerebrovascular dysfunction at some point during the disease process. The goal of this comprehensive review is to summarize the current findings in the field and address the important contributions of cerebrovascular, physiologic, and cellular alterations to cognitive impairment in these human dementias. Specifically, evidence will be presented in support of small-vessel disease as an underlying neuropathologic hallmark of various dementias, while controversial findings will also be highlighted. Finally, the molecular mechanisms shared among all dementia types including hypoxia, oxidative stress, mitochondrial bioenergetics, neuroinflammation, neurodegeneration, and blood–brain barrier permeability responsible for disease etiology and progression will be discussed.

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

White matter lesions (WML) associated with cerebrovascular disease (CVD) may be observed on magnetic resonance imaging in Parkinson's disease (PD) patients. WML are an important factor contributing to postural, gait, and cognitive impairment in the elderly without PD and worsening the course of Alzheimer's disease (AD). Numerous articles are available on this topic. Whether WML modify and negatively influence the clinical symptoms, and course of PD is a subject of debate. The aim of this review is to examine the available literature on the contribution of WML to PD motor symptoms in relation to clinical characteristics and methods of assessing WML on MRI. After reviewing the database, we identified 19 studies reporting the relationship between WML and PD; ten studies focusing on the impact of WML on the cognitive status in PD were excluded. We analysed altogether nine studies reporting the relationship between WML and motor signs of PD. The review found association between WML severity and freezing of gait, less significant to responsiveness to dopaminergic treatment and postural instability; no negative impact on tremor and falls was observed. The impact of WML on bradykinesia and rigidity was inconsistent. Comorbid WML is associated with worsening axial motor performance, probably independently from the degree of nigrostriatal dopaminergic denervation in PD. Reducing the vascular risk factors that cause WML may be helpful in preventing the development of axial symptoms and ultimately in improving the quality of life of patients with PD. Given the lack of systematic studies, additional research in this field is needed.

The neurobiological basis of cognitive impairment in Parkinson's disease

The recent formalization of clinical criteria for Parkinson's disease with dementia (PDD) codifies many studies on this topic, including those assessing biological correlates. These studies show that the emergence of PDD occurs on the background of severe dopamine deficits with, the main pathological drivers of cognitive decline being a synergistic effect between alpha-synuclein and Alzheimer's disease pathology. The presence of these pathologies correlates with a marked loss of limbic and cortically projecting dopamine, noradrenaline, serotonin, and acetylcholine neurons, although the exact timing of these relationships remains to be determined. Genetic factors, such as triplications in the α-synuclein gene, lead to a clear increased risk of PDD, whereas others, such as parkin mutations, are associated with a reduced risk of PDD. The very recent formalization of clinical criteria for PD with mild cognitive impairment (PD-MCI) allows only speculation on its biological and genetic bases. Critical assessment of animal models shows that chronic low-dose MPTP treatment in primates recapitulates PD-MCI over time, enhancing the current biological concept of PD-MCI as having enhanced dopamine deficiency in frontostriatal pathways as well as involvement of other neurotransmitter systems. Data from other animal models support multiple transmitter involvement in cognitive impairment in PD. Whereas dopamine dysfunction has been highlighted because of its obvious role in PD, the role of the other neurotransmitter systems, neurodegenerative pathologies, and genetic factors in PD-MCI remains to be fully elucidated.

Contribution of cerebrovascular disease in autopsy confirmed neurodegenerative disease cases in the National Alzheimer's Coordinating Centre

Cerebrovascular disease and vascular risk factors are associated with Alzheimer's disease, but the evidence for their association with other neurodegenerative disorders is limited. Therefore, we compared the prevalence of cerebrovascular disease, vascular pathology and vascular risk factors in a wide range of neurodegenerative diseases and correlate them with dementia severity. Presence of cerebrovascular disease, vascular pathology and vascular risk factors was studied in 5715 cases of the National Alzheimer's Coordinating Centre database with a single neurodegenerative disease diagnosis (Alzheimer's disease, frontotemporal lobar degeneration due to tau, and TAR DNA-binding protein 43 immunoreactive deposits, α-synucleinopathies, hippocampal sclerosis and prion disease) based on a neuropathological examination with or without cerebrovascular disease, defined neuropathologically. In addition, 210 'unremarkable brain' cases without cognitive impairment, and 280 cases with pure cerebrovascular disease were included for comparison. Cases with cerebrovascular disease were older than those without cerebrovascular disease in all the groups except for those with hippocampal sclerosis. After controlling for age and gender as fixed effects and centre as a random effect, we observed that α-synucleinopathies, frontotemporal lobar degeneration due to tau and TAR DNA-binding protein 43, and prion disease showed a lower prevalence of coincident cerebrovascular disease than patients with Alzheimer's disease, and this was more significant in younger subjects. When cerebrovascular disease was also present, patients with Alzheimer's disease and patients with α-synucleinopathy showed relatively lower burdens of their respective lesions than those without cerebrovascular disease in the context of comparable severity of dementia at time of death. Concurrent cerebrovascular disease is a common neuropathological finding in aged subjects with dementia, is more common in Alzheimer's disease than in other neurodegenerative disorders, especially in younger subjects, and lowers the threshold for dementia due to Alzheimer's disease and α-synucleinopathies, which suggests that these disorders should be targeted by treatments for cerebrovascular disease.

Prevalence and clinical implication of microbleeds in dementia with lewy bodies in comparison with microbleeds in Alzheimer's disease

Background

Cerebral microbleeds (MBs) have been well investigated in Alzheimer's disease (AD), but not very extensively in non-AD dementias or in dementia with Lewy bodies (DLB).

Aims

To elucidate the clinical significance of MBs in DLB.

Methods

We compared the prevalence, locations and risk factors for MBs in 59 DLB and 81 AD patients. We visually counted MBs in each of the cortical and subjacent areas (frontal, temporal, parietal and occipital), the basal ganglia and the thalamus, and the brainstem and the cerebellar hemispheres on 1.5-tesla T2*-weighted gradient-recalled-echo MRI images. White matter lesions were semiquantified in fluid-attenuated inversion recovery images according to the Fazekas rating scale.

Results

While the prevalence of MBs was comparable, MBs tended to be more abundant in DLB than in AD in all brain areas with the exception of the occipital lobes. The number of MBs was positively associated with the severity of white matter lesions but not with other vascular risk factors in either AD or DLB. The presence of MBs could be associated with cognitive impairment at onset. MB-positive DLB patients showed less impairment on ¹²³I-metaiodobenzylguanidine myocardial scintigraphy (MIBG scintigraphy) images, supporting the notion of an inverse relationship between vascular lesions and Lewy body pathology.

Conclusion

It was suggested that an intricate association between Lewy body pathology, AD-type pathologies and vascular lesions seems to be related to the initial symptoms and results of MIBG scintigraphy in DLB.

Impact of subcortical white matter lesions on dopamine transporter SPECT

Subcortical arteriosclerotic encephalopathy (SAE) can affect the nigrostriatal system and presumably cause vascular parkinsonism (VP). However, in patients with SAE, the differentiation of VP from idiopathic Parkinson's disease (IPS) is challenging. The aim of the present study was to examine the striatal dopamine transporter (DAT) density in patients with parkinsonism and SAE. Fifteen consecutive patients with parkinsonian symptoms displayed SAE, as detected by magnetic resonance imaging (MRI). Fifteen retrospectively chosen, matched patients with diagnosis of IPS without any abnormalities in MRI served as a reference group. DAT SPECT was performed using the tracer ¹²³I-FP-CIT. Scans were acquired on a triple-head SPECT system (Multispect 3, Siemens) and analysed using the investigator-independent BRASS™ software (HERMES). In the SAE group, a DAT deficit was observed in 9/15 patients. In contrast, all patients from the IPS group showed a reduced DAT binding (p = 0.008). The specific binding ratios (BR) of putamen contralateral to the side of the more affected limb versus occipital lobe were in trend higher in patients with SAE versus patients in the IPS-group (p = 0.053). Indices for putaminal asymmetry (p = 0.036) and asymmetry caudate-to-putamen (p = 0.026) as well as the ratio caudate-to-putamen (p = 0.048) were significantly higher in IPS patients having no SAE. DAT deficit was less pronounced in patients with SAE and parkinsonism than in patients with IPS without any abnormalities in the MRI. A potential role of DAT SPECT in the differential diagnosis of VP and IPS requires more assessments within prospective studies.