Neuropathological consensus criteria for the evaluation of Lewy pathology in post-mortem brains: a multi-centre study.

Currently, the neuropathological diagnosis of Lewy body disease (LBD) may be stated according to several staging systems, which include the Braak Lewy body stages (Braak), the consensus criteria by McKeith and colleagues (McKeith), the modified McKeith system by Leverenz and colleagues (Leverenz), and the Unified Staging System by Beach and colleagues (Beach). All of these systems use semi-quantitative scoring (4- or 5-tier scales) of Lewy pathology (LP; i.e., Lewy bodies and Lewy neurites) in defined cortical and subcortical areas. While these systems are widely used, some suffer from low inter-rater reliability and/or an inability to unequivocally classify all cases with LP. To address these limitations, we devised a new system, the LP consensus criteria (LPC), which is based on the McKeith system, but applies a dichotomous approach for the scoring of LP (i.e., "absent" vs. "present") and includes amygdala-predominant and olfactory-only stages. α-Synuclein-stained slides from brainstem, limbic system, neocortex, and olfactory bulb from a total of 34 cases with LP provided by the Newcastle Brain Tissue Resource (NBTR) and the University of Pennsylvania brain bank (UPBB) were scanned and assessed by 16 raters, who provided diagnostic categories for each case according to Braak, McKeith, Leverenz, Beach, and LPC systems. In addition, using LP scores available from neuropathological reports of LP cases from UPBB (n = 202) and NBTR (n = 134), JT (UPBB) and JA (NBTR) assigned categories according to all staging systems to these cases. McKeith, Leverenz, and LPC systems reached good (Krippendorff's α ≈ 0.6), while both Braak and Beach systems had lower (Krippendorff's α ≈ 0.4) inter-rater reliability, respectively. Using the LPC system, all cases could be unequivocally classified by the majority of raters, which was also seen for 97.1% when the Beach system was used. However, a considerable proportion of cases could not be classified when using Leverenz (11.8%), McKeith (26.5%), or Braak (29.4%) systems. The category of neocortical LP according to the LPC system was associated with a 5.9 OR (p < 0.0001) of dementia in the 134 NBTR cases and a 3.14 OR (p = 0.0001) in the 202 UPBB cases. We established that the LPC system has good reproducibility and allows classification of all cases into distinct categories. We expect that it will be reliable and useful in routine diagnostic practice and, therefore, suggest that it should be the standard future approach for the basic post-mortem evaluation of LP.

ß-Amyloid and tau biomarkers and clinical phenotype in dementia with Lewy bodies.

OBJECTIVE: In a multicenter cohort of probable dementia with Lewy bodies (DLB), we tested the hypothesis that ß-amyloid and tau biomarker positivity increases with age, which is modified by APOE genotype and sex, and that there are isolated and synergistic associations with the clinical phenotype. METHODS: We included 417 patients with DLB (age 45-93 years, 31% women). Positivity on ß-amyloid (A+) and tau (T+) biomarkers was determined by CSF ß-amyloid1-42 and phosphorylated tau in the European cohort and by Pittsburgh compound B and AV-1451 PET in the Mayo Clinic cohort. Patients were stratified into 4 groups: A-T-, A+T-, A-T+, and A+T+. RESULTS: A-T- was the largest group (39%), followed by A+T- (32%), A+T+ (15%), and A-T+ (13%). The percentage of A-T- decreased with age, and A+ and T+ increased with age in both women and men. A+ increased more in APOE ε4 carriers with age than in noncarriers. A+ was the main predictor of lower cognitive performance when considered together with T+. T+ was associated with a lower frequency of parkinsonism and probable REM sleep behavior disorder. There were no significant interactions between A+ and T+ in relation to the clinical phenotype. CONCLUSIONS: Alzheimer disease pathologic changes are common in DLB and are associated with the clinical phenotype. ß-Amyloid is associated with cognitive impairment, and tau pathology is associated with lower frequency of clinical features of DLB. These findings have important implications for diagnosis, prognosis, and disease monitoring, as well as for clinical trials targeting disease-specific proteins in DLB. CLASSIFICATION OF EVIDENCE: This study provides Class II evidence that in patients with probable DLB, ß-amyloid is associated with lower cognitive performance and tau pathology is associated with lower frequency of clinical features of DLB.

Subtypes of dementia with Lewy bodies are associated with α-synuclein and tau distribution.

OBJECTIVE: To determine whether Lewy body disease subgroups have different clinical profiles. METHODS: Participants had dementia, autopsy-confirmed transitional or diffuse Lewy body disease (TLBD or DLBD) (n = 244), or Alzheimer disease (AD) (n = 210), and were seen at least twice (mean follow-up 6.2 ± 3.8 years). TLBD and DLBD groups were partitioned based on the presence or absence of neocortical neurofibrillary tangles using Braak staging. Four Lewy body disease subgroups and AD were compared on clinical features, dementia trajectory, and onset latency of probable dementia with Lewy bodies (DLB) or a DLB syndrome defined as probable DLB or dementia with one core feature of parkinsonism or probable REM sleep behavior disorder. RESULTS: In TLBD and DLBD without neocortical tangles, diagnostic sensitivity was strong for probable DLB (87% TLBD, 96% DLBD) and the DLB syndrome (97% TLBD, 98% DLBD) with median latencies <1 year from cognitive onset, and worse baseline attention-visual processing but better memory-naming scores than AD. In DLBD with neocortical tangles, diagnostic sensitivity was 70% for probable DLB and 77% for the DLB syndrome with respective median latencies of 3.7 years and 2.7 years from cognitive onset, each associated with tangle distribution. This group had worse baseline attention-visual processing than AD, but comparable memory-naming impairment. TLBD with neocortical tangles had 48% diagnostic sensitivity for probable DLB and 52% for the DLB syndrome, with median latencies >6 years from cognitive onset, and were cognitively similar to AD. Dementia trajectory was slowest for TLBD without neocortical tangles, and fastest for DLBD with neocortical tangles. CONCLUSIONS: The phenotypic expression of DLB was associated with the distribution of α-synuclein and tau pathology.

The Relationship between the Most Common Subtypes of Dementia and Orthostatic Hypotension in Older Adults.

BACKGROUND: It is crucial to evaluate the causes of morbidity and mortality in elderly patients with dementia, such as orthostatic hypotension (OH), which may affect their daily life activities, reduce the quality of life, and increase the caregiver burden. OBJECTIVE: We aimed to investigate the relationship between OH and the most common subtypes of dementia in detail. METHODS: A total of 268 older adults with dementia diagnosed with Alzheimer's disease (AD), dementia with Lewy bodies (DLB), vascular dementia (VaD), and behavioral variant frontotemporal dementia (bvFTD), and 539 older adults without dementia were included in this prospective study. Comprehensive geriatric assessment including comorbidity, medication evaluation, and the head-up tilt test was also performed. RESULTS: Of the participants, 13.8, 8.3, 6.4, and 4.8% had AD, DLB, bvFTD, and VaD, respectively. After adjusting for age, gender, the presence of comorbidities, and usage of OH-induced drugs; AD, DLB, and VaD were associated with OH (odds ratio [OR]: 2.23 confidence interval [CI] 95% 1.31-3.80; p = 0.003; OR: 3.68 CI 95% 1.98-6.83; p < 0.001, and OR: 3.56 CI 95% 1.46-8.69; p = 0.005, respectively). Furthermore, VaD was independently related to diastolic OH (OR: 4.19 CI 95% 1.66-10.57; p = 0.002), whereas AD and DLB were not. CONCLUSIONS: This study shows that elderly patients with DLB, AD, and VaD often have OH, a disabling autonomic dysfunction feature. Moreover, diastolic OH may play a role in the development of VaD. Therefore, considering potential complications of OH, it is essential to evaluate OH in the follow-up and management of those patients.

Most cases with Lewy pathology in a population-based cohort adhere to the Braak progression pattern but 'failure to fit' is highly dependent on staging system applied.

Braak et al.'s 2003 paper detailing the caudo-rostral progression of Lewy body pathology (LP) formed the foundation of current understanding of disease spread in Parkinson's disease (PD); however, its methods are difficult to recreate and consequently multiple new staging systems emerged to recapitulate Braak's staging system using standard neuropathological methods and to account for other patterns of LP. Studies using these systems have documented widely variable rates of cases that 'fail to fit' expected patterns of LP spread. This could be due to population differences, features of individual systems, or may constitute under-recognized patterns of disease. We examined 324 neuropathological cases from the Honolulu Asia Aging Study and applied four different LP staging systems to determine the proportion of cases adhering to different staging methodologies and those that 'fail to fit' expected patterns of LP. Of 141 cases with LP (24: PD, 8: Dementia with Lewy bodies (DLB), 109: Incidental Lewy body disease (ILBD)), our application of Braak et al., 2003 classified 83.7%, Müller et al., 2005 classified 87.9%, Beach et al., 2009 classified 100%, and Leverenz et al., 2008 classified 98.6%. There were significant differences in the cases classifiable by the Leverenz and Beach systems versus the Braak and Müller systems (p < 0.001 for each). In this population-based autopsy cohort with a high prevalence of ILBD, the majority of cases were consistent with the progression characterized by the Braak et al. however, the determination of cases as atypical is highly dependent on the staging system applied.

INDEL Length and Haplotypes in the ß-Synuclein Gene: A Key to Differentiate Dementia with Lewy Bodies?

Lewy body diseases (LBD) include Parkinson's disease (PD) and dementia with Lewy bodies (DLB) and together with Alzheimer's disease (AD) they show an important neuropathological and clinical overlap. The human alpha- and beta-synuclein genes (SNCA and SNCB) are key factors for the development of Lewy body diseases. Here, we aimed to analyze the genotype distribution of potentially functional SNPs in SNCA and SNCB, perform haplotype analysis for SNCB, and to identify functional insertion and deletion (INDEL) variations within the regulatory region of SNCB which might be responsible for the drastically diminished beta-synuclein levels reported for pure DLB. Thus, we genotyped brain samples from AD, DLB, PD, and healthy controls for two SNCA and four SNCB SNPs. We also analyzed INDEL variations upstream of SNCB, determined SNCB expression levels, and correlated INDEL lengths with expression levels. Applying Fisher's exact, chi-square, ANOVA tests, and the ΔΔCt method, we found disease-specific genotype distribution of SNCA and SNCB SNPs. Additionally, we identified three INDEL variations upstream of SNCB and showed that the INDEL allele lengths were associated with SNCB expression levels. INDEL alleles associated with low SNCB expression were accumulated in pure DLB. Finally, one major and four minor DLB specific SNCB haplotypes were identified with Haploview and Arlequin. In summary, our study showed that different SNCA and SNCB genotypes are associated with the development of either PD or DLB, and that the frequencies of genotypes associated with low SNCB expression are elevated in DLB.

Clinical Subtypes of Dementia with Lewy Bodies Based on the Initial Clinical Presentation.

BACKGROUND: Dementia with Lewy bodies (DLB) is a heterogeneous disease in which clinical presentation, symptoms, and evolution widely varies between patients. OBJECTIVE: To investigate the existence of clinical subtypes in DLB based on the initial clinical presentation. METHODS: 81 patients with a clinical diagnosis of probable DLB were consecutively included. All patients underwent a neurological evaluation including a structured questionnaire about neuropsychiatric symptoms and sleep, an assessment of motor impairment (Unified Parkinson Disease Rating Scale subscale III), and a formal neuropsychological evaluation. Onset of core symptoms (hallucinations, parkinsonism, and fluctuations) and dementia were systematically reviewed from medical records. We applied a K-means clustering method based on the initial clinical presentation. RESULTS: Cluster analysis yielded three different groups. Patients in cluster I (cognitive-predominant, n = 46) presented more frequently with cognitive symptoms (95.7%, n = 44, p < 0.001), and showed a longer duration from onset to DLB diagnosis (p < 0.001) than the other clusters. Patients in cluster II (neuropsychiatric-predominant, n = 22) were older at disease onset (78.1±5 versus 73.6±6.1 and 73.6±4.2 in clusters I and III, respectively, both p < 0.01), presented more frequently with psychotic symptoms (77.3%, n = 17), and had a shorter duration until the onset of hallucinations (p < 0.001). Patients in cluster III (parkinsonism-predominant, n = 13) showed a shorter time from onset to presence of parkinsonism (p < 0.001) and dementia (0.008). CONCLUSIONS: Three clinical subtypes of DLB can be defined when considering the differential initial presentations. The proposed subtypes have distinct clinical profiles and progression patterns.

Distinct patterns of amyloid-dependent tau accumulation in Lewy body diseases.

BACKGROUND: In addition to Lewy body pathology, amyloid-ß plaques and neurofibrillary tangles that are characteristic for Alzheimer's disease are also frequently found in Lewy body diseases. OBJECTIVES: The objective of this study was to investigate tau accumulation patterns in dementia with Lewy bodies and other Lewy body diseases using in vivo 18 F-AV-1451 PET. METHODS: The study included 12 Parkinson's disease (PD) patients with normal cognition, 22 PD patients with cognitive impairment, and 18 dementia with Lewy bodies patients. In addition, 25 Alzheimer's disease patients and 25 healthy controls were included for comparison. All participants underwent 18 F-AV-1451 and 18 F-florbetaben PET scans, and cortical binding values were compared between the controls and each disease group. RESULTS: When compared with the controls, dementia with Lewy bodies patients showed slightly increased 18 F-AV-1451 binding in the primary sensorimotor and visual cortices and the parieto-temporal cortices, which failed to survive multiple comparisons. Amyloid-positive dementia with Lewy bodies patients showed significantly increased binding in the same regions when compared with controls, and even greater binding in the primary sensorimotor and visual cortices than Alzheimer's disease. Meanwhile, binding in the lateral and medial temporal cortices was less prominent than in Alzheimer's disease. In dementia with Lewy bodies, 18 F-AV-1451 binding in the occipital cortex correlated with 18 F-florbetaben binding. Amyloid-negative patients with normal cognition, patients with cognitive impairment, and dementia with Lewy bodies patients did not show increased 18 F-AV-1451 binding. CONCLUSIONS: Dementia with Lewy bodies patients may harbor 18 F-AV-1451 binding patterns distinct from Alzheimer's disease, with greater involvement of the primary cortices and less involvement of the temporal cortex. Tau burden increases in the Lewy body disease spectrum, and amyloid may play an important role in the accumulation of neocortical tau in Lewy body diseases. © 2017 International Parkinson and Movement Disorder Society.

Regional analysis and genetic association of nigrostriatal degeneration in Lewy body disease.

BACKGROUND: A number of genetic loci are associated with risk for Parkinson's disease (PD) based on genome-wide association studies; however, the relationship between genetic variants and nigrostriatal degeneration, which is the structural correlate of parkinsonism, has not been reported. OBJECTIVES: We quantified nigrostriatal dopaminergic integrity with image analysis of putaminal tyrosine hydroxylase immunoreactivity in 492 brains with Lewy body disease and used this pathologic endophenotype to explore possible association with PD genetic variants. METHODS: The study cases had Lewy-related pathology and variable degrees of nigrostriatal degeneration. They were assigned to one of the following clinical subgroups according to their predominant clinical syndrome: parkinsonism-predominant, parkinsonism+dementia, and dementia-predominant. In addition to putaminal tyrosine hydroxylase immunoreactivity, semiquantitative scoring was used to assess substantia nigra neuronal loss. A total of 29 PD genetic risk variants were genotyped on each case. RESULTS: When compared with controls, tyrosine hydroxylase immunoreactivity was reduced in Lewy body cases in the dorsolateral (79%) and ventromedial (57%) putamen. The dorsolateral region was better preserved in dementia-predominant cases than in cases with parkinsonism. Dorsolateral putaminal tyrosine hydroxylase immunoreactivity correlated with neuronal loss in the ventrolateral substantia nigra. Genetic analyses showed no significant association of PD risk variants with putaminal tyrosine hydroxylase immunoreactivity. CONCLUSIONS: The results confirm regional differences in putaminal dopaminergic degeneration and vulnerability of nigrostriatal pathway in Lewy body disorders with parkinsonism. The lack of association with PD genetic risk variants suggests that they may not be associated with quantitative endophenotypes of nigrostriatal degeneration, but more likely related to the risk of disease per se. © 2017 International Parkinson and Movement Disorder Society.

A clinicopathological approach to the diagnosis of dementia.

The most definitive classification systems for dementia are based on the underlying pathology which, in turn, is categorized largely according to the observed accumulation of abnormal protein aggregates in neurons and glia. These aggregates perturb molecular processes, cellular functions and, ultimately, cell survival, with ensuing disruption of large-scale neural networks subserving cognitive, behavioural and sensorimotor functions. The functional domains affected and the evolution of deficits in these domains over time serve as footprints that the clinician can trace back with various levels of certainty to the underlying neuropathology. The process of phenotyping and syndromic classification has substantially improved over decades of careful clinicopathological correlation, and through the discovery of in vivo biomarkers of disease. Here, we present an overview of the salient features of the most common dementia subtypes - Alzheimer disease, vascular dementia, frontotemporal dementia and related syndromes, Lewy body dementias, and prion diseases - with an emphasis on neuropathology, relevant epidemiology, risk factors, and signature signs and symptoms.

Differential diagnosis between patients with probable Alzheimer's disease, Parkinson's disease dementia, or dementia with Lewy bodies and frontotemporal dementia, behavioral variant, using quantitative electroencephalographic features.

The objective of this work was to develop and evaluate a classifier for differentiating probable Alzheimer's disease (AD) from Parkinson's disease dementia (PDD) or dementia with Lewy bodies (DLB) and from frontotemporal dementia, behavioral variant (bvFTD) based on quantitative electroencephalography (QEEG). We compared 25 QEEG features in 61 dementia patients (20 patients with probable AD, 20 patients with PDD or probable DLB (DLBPD), and 21 patients with bvFTD). Support vector machine classifiers were trained to distinguish among the three groups. Out of the 25 features, 23 turned out to be significantly different between AD and DLBPD, 17 for AD versus bvFTD, and 12 for bvFTD versus DLBPD. Using leave-one-out cross validation, the classification achieved an accuracy, sensitivity, and specificity of 100% using only the QEEG features Granger causality and the ratio of theta and beta1 band powers. These results indicate that classifiers trained with selected QEEG features can provide a valuable input in distinguishing among AD, DLB or PDD, and bvFTD patients. In this study with 61 patients, no misclassifications occurred. Therefore, further studies should investigate the potential of this method to be applied not only on group level but also in diagnostic support for individual subjects.

Multimodal EEG-MRI in the differential diagnosis of Alzheimer's disease and dementia with Lewy bodies.

Differential diagnosis of Alzheimer's disease (AD) and dementia with Lewy bodies (DLB) remains challenging; currently the best discriminator is striatal dopaminergic imaging. However this modality fails to identify 15-20% of DLB cases and thus other biomarkers may be useful. It is recognised electroencephalography (EEG) slowing and relative medial temporal lobe preservation are supportive features of DLB, although individually they lack diagnostic accuracy. Therefore, we investigated whether combined EEG and MRI indices could assist in the differential diagnosis of AD and DLB. Seventy two participants (21 Controls, 30 AD, 21 DLB) underwent resting EEG and 3 T MR imaging. Six EEG classifiers previously generated using support vector machine algorithms were applied to the present dataset. MRI index was derived from medial temporal atrophy (MTA) ratings. Logistic regression analysis identified EEG predictors of AD and DLB. A combined EEG-MRI model was then generated to examine whether there was an improvement in classification compared to individual modalities. For EEG, two classifiers predicted AD and DLB (model: χ(2) = 22.1, df = 2, p < 0.001, Nagelkerke R(2) = 0.47, classification = 77% (AD 87%, DLB 62%)). For MRI, MTA also predicted AD and DLB (model: χ(2) = 6.5, df = 1, p = 0.01, Nagelkerke R(2) = 0.16, classification = 67% (77% AD, 52% DLB). However, a combined EEG-MRI model showed greater prediction in AD and DLB (model: χ(2) = 31.1, df = 3, p < 0.001, Nagelkerke R(2) = 0.62, classification = 90% (93% AD, 86% DLB)). While suggestive and requiring validation, diagnostic performance could be improved by combining EEG and MRI, and may represent an alternative to dopaminergic imaging.

Assessing Fluctuating Cognition in Dementia Diagnosis: Interrater Reliability of the Clinician Assessment of Fluctuation.

Fluctuating cognition (FC) is a core feature of dementia with Lewy bodies (DLB) but is challenging to assess. This study assessed the reliability and validity of the Clinician Assessment of Fluctuation (CAF), which assesses FC in patients with dementia. Interrater agreement of CAF outcomes (FC present and FC severe) was evaluated between physicians and nonphysicians in 141 patients with Alzheimer's disease (AD) or DLB. Frequency of CAF outcomes by clinical and neuropathological diagnosis was examined. We found that interrater reliability was fair on FC present and almost perfect on FC severe, and both outcomes were higher in patients with clinical DLB than with clinical AD and were qualitatively more often endorsed in cases with neuropathological evidence of Lewy bodies. We conclude that the CAF is a reliable measure of FC and can be valuable in differential dementia diagnosis.

Multisystem Lewy body disease and the other parkinsonian disorders.

Here we prioritize as multisystem Lewy body disease (MLBD) those genetic forms of Parkinson's disease that point the way toward a mechanistic understanding of the majority of sporadic disease. Pathological diagnosis of genetic subtypes offers the prospect of distinguishing different mechanistic trajectories with a common mutational etiology, differing outcomes from varying allelic bases, and those disease-associated variants that can be used in gene-environment analysis. Clearly delineating parkinsonian disorders into subclasses on the basis of molecular mechanisms with well-characterized outcome expectations is the basis for refining these forms of neurodegeneration as research substrate through the use of cell models derived from affected individuals while ensuring that clinically collected data can be used for therapeutic decisions and research without increasing the noise and confusion engendered by the collection of data against a range of historically defined criteria.

[Mental disorders due to brain lesions in the DSM-5 in the light of the previous versions]. / Les troubles mentaux liés à des lésions cérébrales dans le DSM-5 à la lumière des versions précédentes.

The DSM-5 introduces major modifications in the category of mental disorders due to brain lesions compared to the previous DSM versions, which are reviewed in this paper. The description of the category Major neurocognitive disorder, as a substitute for dementia, seems to fit better for patients and families, and more adapted to many neurodegenerative cognitive disorders for which memory impairment is not predominant. Similarly, the introduction of the category of Mild neurocognitive disorder appears to be an improvement although some difficulty still remains for distinguishing mild cognitive disorder from normal aging. The addition of new etiological categories such as fronto-temporal NCD or NCD with Lewy bodies should also to be considered as a significant improvement. Despite these advances, to circumscribe the mental disorders due to brain lesions to cognitive deficits and biological mechanisms remains highly questionable, and does not provide an adequate care for the patients and families if not complemented by a psychological and environmental approach.

[Dementia with Lewy bodies].

Current concepts on the clinical presentations, diagnosis and treatment of dementia with Lewy bodies (DLB), that makes up 10% percent of dementia cases, are considered. The nosological status of DLB and the correlation between DLB and Parkinson's disease are reviewed in the historical context. The authors suggest approaches to the formulation of diagnosis and coding of DLB in according to ICD-10. A role of cholinesterase inhibitors, antipsychotic drugs, levodopa, razagiline and other drugs in the treatment of DLB is analyzed.

Focal atrophy on MRI and neuropathologic classification of dementia with Lewy bodies.

OBJECTIVE: To determine the association between the focal atrophy measures on antemortem MRI and postmortem neuropathologic classification of dementia with Lewy bodies (DLB) using the Third Report of the DLB Consortium criteria. METHODS: We retrospectively identified 56 subjects who underwent antemortem MRI and had Lewy body (LB) pathology at autopsy. Subjects were pathologically classified as high (n = 25), intermediate (n = 22), and low likelihood DLB (n = 9) according to the Third Report of the DLB Consortium criteria. We included 2 additional pathologic comparison groups without LBs: one with low likelihood Alzheimer disease (AD) (control; n = 27) and one with high likelihood AD (n = 33). The associations between MRI-based volumetric measurements and the pathologic classification of DLB were tested with analysis of covariance by adjusting for age, sex, and MRI-to-death interval. RESULTS: Antemortem hippocampal and amygdalar volumes increased from low to intermediate to high likelihood DLB (p < 0.001, trend test). Smaller hippocampal and amygdalar volumes were associated with higher Braak neurofibrillary tangle stage (p < 0.001). Antemortem dorsal mesopontine gray matter (GM) atrophy was found in those with high likelihood DLB compared with normal control subjects (p = 0.004) and those with AD (p = 0.01). Dorsal mesopontine GM volume decreased from low to intermediate to high likelihood DLB (p = 0.01, trend test). CONCLUSION: Antemortem hippocampal and amygdalar volumes increase and dorsal mesopontine GM volumes decrease in patients with low to high likelihood DLB according to the Third Report of the DLB Consortium criteria. Patients with high likelihood DLB typically have normal hippocampal volumes but have atrophy in the dorsal mesopontine GM nuclei.

Staging of Lewy-related pathology in dementia.

OBJECTIVE: Lewy-related pathology is the characteristic feature of Parkinson's disease with and without dementia and dementia with Lewy bodies (DLB). There are two neuropathological staging systems for Lewy-related pathology commonly employed today: the staging system for Parkinson-related pathology by Braak et al., and the staging system by the Consortium on DLB. There are also several modified systems based on these two scales. METHODS: We applied a total of eight different staging systems for Lewy-related pathology to 36 consecutive demented patients with various dementia disorders. RESULTS: The staging systems varied considerably in number of unclassifiable cases (range 0 ­ 16 out of 36 cases), while the diagnostic agreement between the systems that were able to classify all or the very majority of cases varied only slightly (weighted κ 0.86 ­ 0.92 and Spearman's σ 0.80 ­ 1.0). CONCLUSION: The different staging systems for Lewy-related pathology that exist today vary in staging procedure and proportion of unclassifiable cases. The choice of system may affect the stage of Lewy-related pathology and ultimately final diagnosis.

Lewy pathology and neurodegeneration in premotor Parkinson's disease.

The foremost motor manifestations of Parkinson's disease are resting tremor, cogwheel rigidity, hypokinesia/bradykinesia, and postural instability. Epidemiological and clinical data reveal that a wide variety of additional complaints (nonmotor symptoms), also considerably impar patients' quality of life parallel to the chronic-progressive neurodegenerative disorder. This article reviews the neuropathology and anatomy of Lewy pathology-related neurodegeneration in relation to selected nonmotro and prodromal dysfunctions.

The organization and anatomy of narrative comprehension and expression in Lewy body spectrum disorders.

OBJECTIVE: Patients with Lewy body spectrum disorders (LBSD) such as Parkinson's disease, Parkinson's disease with dementia, and dementia with Lewy bodies exhibit deficits in both narrative comprehension and narrative expression. The present research examines the hypothesis that these impairments are due to a material-neutral deficit in organizational executive resources rather than to impairments of language per se. We predicted that comprehension and expression of narrative would be similarly affected and that deficits in both expression and comprehension of narrative would be related to the same anatomic distribution of prefrontal disease. METHOD: We examined 29 LBSD patients and 26 healthy seniors on their comprehension and expression of narrative discourse. For comprehension, we measured accuracy and latency in judging events with high and low associativity from familiar scripts such as "going fishing." The expression task involved maintaining the connectedness of events while narrating a story from a wordless picture book. RESULTS: LBSD patients were impaired on measures of narrative organization during both comprehension and expression relative to healthy seniors. Measures of organization during narrative expression and comprehension were significantly correlated with each other. These measures both correlated with executive measures but not with neuropsychological measures of lexical semantics or grammar. Voxel-based morphometry revealed overlapping regressions relating frontal atrophy to narrative comprehension, narrative expression, and measures of executive control. CONCLUSIONS: Difficulty with narrative discourse in LBSD stems in part from a deficit of organization common to comprehension and expression. This deficit is related to prefrontal cortical atrophy in LBSD.