Neocortical Lewy Body Disease Research Articles

Tau maturation in clinicopathological spectrum of Lewy body and Alzheimer’s disease

AbstractBackgroundIn Alzheimer’s disease neuropathologic change (ADNC), maturation of neurofibrillary tangles and tau pathology are characterized by posttranslational modifications of tau. ANDC and Lewy body disease (LBD) commonly co‐exist in aging brains and there are overlapping clinical syndromes and heterogeneity in clinical features among cases with mixed ADNC and LBD pathology. Given this clinical and pathological overlap, we examined the postmortem expression of tau conformational epitopes that mark various stages of tangle maturation in clinicopathologic spectrum of Alzheimer’s disease (AD) and LBD.MethodAutopsy‐confirmed cases with diffuse neocortical LBD with/without ADNC (n = 59) were selected (Table1). We used digital histology methods to measure percent area occupied (%AO) with pathology in three regions (middle frontal, anterior cingulate, and superior temporal cortices) immunohistochemically stained with MJF‐R13 (α‐synuclein), NAB228 (beta‐amyloid), and tau monoclonal antibodies marking phosphorylated (AT8), early conformational (MC1, preferentially reactive in pre‐tangles), and C‐terminally truncated tau epitopes (TauC3, preferentially reactive in mature intracellular and ghost tangles). Linear models tested the group comparisons, and correlation between α‐synuclein or beta‐amyloid with outcome of average neocortical tau. In models, %AO were log‐transformed, and age and sex were included as covariates.Resultα‐synuclein was strongly correlated with early tau epitopes labelled with AT8 (β = 1.37, p<0.001) and MC1 (β = 1.20, p<0.001), but not with mature tau epitopes detected by TauC3 (p = 0.38). There were significant positive correlations between all tau epitopes and beta‐amyloid, including TauC3 immunoreactive tau (p≤0.013) (Figure1). In the mixed pathology group, those with clinical LBD had a positive association between α‐synuclein and MC1 (β = 1.61, p = 0.014) and AT8 (β = 1.67, p = 0.005) positive tau, while those with clinical AD had no correlation between α‐synuclein and tau epitopes. There was greater MC1 (β = 3.40, p<0.001), AT8 (β = 3.59, p<0.001), and TauC3 (β = 1.43, p = 0.005) pathology in patients with clinical AD compared to clinical LBD.ConclusionIn LBD, higher α‐synuclein is associated with greater phosphorylated and early tau conformations, but not later conformation of mature tau, which was selectively associated with beta‐amyloid pathology. Our findings suggest that tau pathology may modify the clinical expression of synucleinopathies and C‐terminal truncation of tau may be more closely related to AD pathophysiology than synucleinopathy.

Relative Contributions of Mixed Pathologies to Cognitive and Functional Symptoms in Brain Donors Exposed to Repetitive Head Impacts.

Exposure to repetitive head impacts (RHI) is associated with later-life cognitive symptoms and neuropathologies, including chronic traumatic encephalopathy (CTE). Cognitive decline in community cohorts is often due to multiple pathologies; however, the frequency and contributions of these pathologies to cognitive impairment in people exposed to RHI are unknown. Here, we examined the relative contributions of 13 neuropathologies to cognitive symptoms and dementia in RHI-exposed brain donors. Neuropathologists examined brain tissue from 571 RHI-exposed donors and assessed for the presence of 13 neuropathologies, including CTE, Alzheimer disease (AD), Lewy body disease (LBD), and transactive response DNA-binding protein 43 (TDP-43) inclusions. Cognitive status was assessed by presence of dementia, Functional Activities Questionnaire, and Cognitive Difficulties Scale. Spearman rho was calculated to assess intercorrelation of pathologies. Additionally, frequencies of pathological co-occurrence were compared to a simulated distribution assuming no intercorrelation. Logistic and linear regressions tested associations between neuropathologies and dementia status and cognitive scale scores. The sample age range was 18-97 years (median = 65.0, interquartile range = 46.0-76.0). Of the donors, 77.2% had at least one moderate-severe neurodegenerative or cerebrovascular pathology. Stage III-IV CTE was the most common neurodegenerative disease (43.1%), followed by TDP-43 pathology, AD, and hippocampal sclerosis. Neuropathologies were intercorrelated, and there were fewer unique combinations than expected if pathologies were independent (p < 0.001). The greatest contributors to dementia were AD, neocortical LBD, hippocampal sclerosis, cerebral amyloid angiopathy, and CTE. In this sample of RHI-exposed brain donors with wide-ranging ages, multiple neuropathologies were common and correlated. Mixed neuropathologies, including CTE, underlie cognitive impairment in contact sport athletes. ANN NEUROL 2024;95:314-324.

Characterizing a Language Phenotype of Dementia with Lewy Bodies: A Clinicopathological Series (P13-6.009)

<h3>Objective:</h3> We report on three individuals with semantic variant primary progressive aphasia (svPPA) whose post-mortem pathology was consistent with diffuse neocortical Lewy body disease (LBD). We believe this is a heretofore unrecognized phenotype of LBD. <h3>Background:</h3> The present conception of primary dementias pairs clinical syndromes with neuropathologies, proven on necropsy or indirectly implicated by biomarkers. Each pairing is a clinicopathological entity. There is an increasing focus in the field of neurodegenerative disease to better characterize clinicopathological disorders, so as to target research and treatment approaches. SvPPA clinically manifests with progressive loss of semantic knowledge and is commonly associated with TDP-43 type C proteinopathy as well as Alzheimer’s(AD) and other tau pathologies. We report on three instances of svPPA associated with LBD pathology. We believe this is the first such report in the literature. <h3>Design/Methods:</h3> Our institution’s brain bank was queried for clinicopathological cases with a clinical diagnosis of svPPA and neuropathologic diagnosis of LBD. Three cases met the international consensus criteria for svPPA and were included in this study. <h3>Results:</h3> Three males aged 60–76 satisfied our inclusion criteria. Two subjects had significant temporal atrophy, and one had substantia nigral pallor. DAT scan was available in one subject, which was a negative study. All subjects fit the neuropathological consensus criteria for LBD with a diffuse neocortical distribution. In addition, all subjects had moderate vascular pathology and AD pathology (2-high ADNC, 1-intermediate). One case was also found with limbic associated Stage 1 TDP-43 proteinopathy. <h3>Conclusions:</h3> Here we propose a novel language variant of Lewy body disease. Although rare, LBD should be included as a differential diagnosis in individuals with svPPA. In the future, characterizing phenotypes of LBD will assist in more precise targeting of research and treatment strategies. <b>Disclosure:</b> Dr. Merhi has nothing to disclose. Anna C Sullivan has nothing to disclose. Miss Bhavaraju has nothing to disclose. Dr. Walker has nothing to disclose. Dr. Bieniek has nothing to disclose. Dr. Abdullah has nothing to disclose. Dr. Salardini has received personal compensation in the range of $0-$499 for serving on a Speakers Bureau for Biogen. The institution of Dr. Salardini has received research support from NIH/NIA. The institution of Dr. Salardini has received research support from Taylor Family. Dr. Salardini has received publishing royalties from a publication relating to health care. Dr. Rini has nothing to disclose. An immediate family member of Dr. Parker has received personal compensation for serving as an employee of Rochal Industries, Rochal Parners. An immediate family member of Dr. Parker has received personal compensation in the range of $5,000-$9,999 for serving as an officer or member of the Board of Directors for Sanara Med Tech. An immediate family member of Dr. Parker has stock in Sanara Med Tech. An immediate family member of Dr. Parker has stock in Rochal Industries. An immediate family member of Dr. Parker has stock in Rochal Parnters. The institution of Dr. Parker has received research support from Texas Alzheimer’s Research and Care Consortium. The institution of an immediate family member of Dr. Parker has received research support from Rochal Industries. An immediate family member of Dr. Parker has received intellectual property interests from a discovery or technology relating to health care. An immediate family member of Dr. Parker has received publishing royalties from a publication relating to health care. Dr. Parker has received personal compensation in the range of $500-$4,999 for serving as a Grand Rounds Speaker with Univ of Texas Tyler. An immediate family member of Dr. Parker has received personal compensation in the range of $0-$499 for serving as a NIH Review Committees Member with NIH. An immediate family member of Dr. Parker has a non-compensated relationship as a Chairwoman of the Board - Ann Salamone with BioMed SA that is relevant to AAN interests or activities.

The presence of Alzheimer’s disease pathology in dementia with Lewy bodies is related to increased neocortical α‐synuclein load and different α‐synuclein morphology

AbstractBackgroundThe presence of Alzheimer’s disease (AD) type pathology in dementia with Lewy bodies (DLB) has been linked to a more rapid disease progression. We aimed to examine the relation between load of AD‐type pathology and load and morphology of α‐synuclein pathology in DLB brains.MethodWe included 50 donors from the Netherlands Brain Bank fulfilling clinical criteria for ‘probable DLB’ and limbic or neocortical Lewy body disease. Levels of AD‐type pathology according to NIA‐AA guidelines were either absent to low (pure DLB, n = 15), or intermediate to high (mixed DLB/AD, n = 35). We visually rated α‐synuclein‐positive and amyloid‐β‐positive morphologies, and we quantitatively measured amyloid‐β, hyperphosphorylated tau (HPF‐tau) and α‐synuclein load in fifteen brain regions. Regional amyloid‐β and HPF‐tau levels in DLB donors were compared to eight AD donors without α‐synuclein pathology (pure AD).ResultMixed DLB/AD compared to pure DLB donors showed a shorter disease duration (6 ± 3 vs. 8 ± 3 years, p = 0.021), more diffuse intraneuronal α‐synuclein positivity (p = 0.002) but not more glial α‐synuclein positivity, and a higher overall α‐synuclein load (F = 25.7, p &lt; 0.001), specifically in the parietal (p = 0.006), temporal (p = 0.002) and occipital cortex (p = 0.006). Mixed DLB/AD was related to more capillary cerebral amyloid angiopathy (CAA) (49% vs. 7%, p &lt; 0.001). Within cortical regions, α‐synuclein load was most strongly related to amyloid‐β and HPF‐tau load in the temporal (Pearson’s r = 0.38 and 0.50 respectively) and occipital cortex (r = 0.43 and 0.42 respectively). While controlling for age at death, mixed DLB/AD compared to pure AD showed lower HPF‐tau load in frontal (p = 0.043) and parietal cortices (p = 0.002), but not in temporal cortex (p = 0.48), and no differences in amyloid‐β load in the frontal (p = 0.57), parietal (p = 0.56) and temporal cortex (p = 0.10).ConclusionThe presence of AD‐type pathology in DLB was related to more diffuse intraneuronal α‐synuclein positivity, a higher neocortical α‐synuclein load and more capillary CAA. This study provides evidence for different neuropathological profiles in DLB, which may contribute to clinical heterogeneity in this disease.

Neuropathological characterization of Lemur tyrosine kinase 2 (LMTK2) in Alzheimer\u2019s disease and neocortical Lewy body disease

Alzheimer’s disease (AD) and neocortical Lewy body disease (LBD) are the most common neurodegenerative dementias, with no available curative treatment. Elucidating pathomechanism and identifying novel therapeutic targets are of paramount importance. Lemur tyrosine kinase 2 (LMTK2) is involved in several physiological and pathological cellular processes. Herewith a neuropathological characterization is presented in AD and neocortical LBD samples using chromogenic and fluorescent LMTK2 immunohistochemistry on post-mortem brain tissues and compared them to age-matched controls (CNTs). LMTK2 immunopositivity was limited to the neuronal cytoplasm. Neurons, including tau-positive tangle-bearing ones, showed decreased chromogenic and immunofluorescent labelling in AD in every cortical layer compared to CNT and neocortical LBD. Digital image analysis was performed to measure the average immunopositivity of groups. Mean grey values were calculated for each group after measuring the grey scale LMTK2 signal intensity of each individual neuron. There was significant difference between the mean grey values of CNT vs. AD and neocortical LBD vs. AD. The moderate decrease in neocortical LBD suggests the effect of coexisting AD pathology. We provide neuropathological evidence on decreased neuronal LMTK2 immunolabelling in AD, with implications for pathogenesis.

Lewy Body Pathology and Chronic Traumatic Encephalopathy Associated With Contact Sports.

Traumatic brain injury has been associated with increased risk of Parkinson disease and parkinsonism, and parkinsonism and Lewy body disease (LBD) can occur with chronic traumatic encephalopathy (CTE). To test whether contact sports and CTE are associated with LBD, we compared deceased contact sports athletes (n = 269) to cohorts from the community (n = 164) and the Boston University Alzheimer disease (AD) Center (n = 261). Participants with CTE and LBD were more likely to have β-amyloid deposition, dementia, and parkinsonism than CTE alone (p < 0.05). Traditional and hierarchical clustering showed a similar pattern of LBD distribution in CTE compared to LBD alone that was most frequently neocortical, limbic, or brainstem. In the community-based cohort, years of contact sports play were associated with neocortical LBD (OR = 1.30 per year, p = 0.012), and in a pooled analysis a threshold of >8 years of play best predicted neocortical LBD (ROC analysis, OR = 6.24, 95% CI = 1.5-25, p = 0.011), adjusting for age, sex, and APOE ɛ4 allele status. Clinically, dementia was significantly associated with neocortical LBD, CTE stage, and AD; parkinsonism was associated with LBD pathology but not CTE stage. Contact sports participation may increase risk of developing neocortical LBD, and increased LBD frequency may partially explain extrapyramidal motor symptoms sometimes observed in CTE.

Methylation changes and aberrant expression of FGFR3 in Lewy body disease neurons

Lewy body disease (LBD) is characterized by accumulation of aggregated α-synuclein in the central nervous system as eosinophilic cytoplasmic inclusions called Lewy bodies. According to their distribution pattern, it is classified into brainstem LBD, limbic LBD and diffuse neocortical LBD. It has been reported that α-synuclein affects various points in the MAPK cascade but its relationship with FGF receptors, which are the most upstream of the pathway, has not been previously investigated. We discovered that among the four FGFRs, FGFR3 showed neuronal upregulation in LBD brains histopathologically. Further examination using neuron-specific methylome analysis revealed that the gene body of FGFR3 was hypermethylated in LBD, suggesting its increased transcription. Altered methylation was not observed in the non-neuronal genome. Altered methylation status was associated with the severity of α-synuclein pathology.

Neurodegenerative disease concomitant proteinopathies are prevalent, age-related and APOE4-associated.

Lewy bodies commonly occur in Alzheimer's disease, and Alzheimer's disease pathology is frequent in Lewy body diseases, but the burden of co-pathologies across neurodegenerative diseases is unknown. We assessed the extent of tau, amyloid-β, α-synuclein and TDP-43 proteinopathies in 766 autopsied individuals representing a broad spectrum of clinical neurodegenerative disease. We interrogated pathological Alzheimer's disease (n = 247); other tauopathies (n = 95) including Pick's disease, corticobasal disease and progressive supranuclear palsy; the synucleinopathies (n = 164) including multiple system atrophy and Lewy body disease; the TDP-43 proteinopathies (n = 188) including frontotemporal lobar degeneration with TDP-43 inclusions and amyotrophic lateral sclerosis; and a minimal pathology group (n = 72). Each group was divided into subgroups without or with co-pathologies. Age and sex matched logistic regression models compared co-pathology prevalence between groups. Co-pathology prevalence was similar between the minimal pathology group and most neurodegenerative diseases for each proteinopathy: tau was nearly universal (92-100%), amyloid-β common (20-57%); α-synuclein less common (4-16%); and TDP-43 the rarest (0-16%). In several neurodegenerative diseases, co-pathology increased: in Alzheimer's disease, α-synuclein (41-55%) and TDP-43 (33-40%) increased; in progressive supranuclear palsy, α-synuclein increased (22%); in corticobasal disease, TDP-43 increased (24%); and in neocortical Lewy body disease, amyloid-β (80%) and TDP-43 (22%) increased. Total co-pathology prevalence varied across groups (27-68%), and was increased in high Alzheimer's disease, progressive supranuclear palsy, and neocortical Lewy body disease (70-81%). Increased age at death was observed in the minimal pathology group, amyotrophic lateral sclerosis, and multiple system atrophy cases with co-pathologies. In amyotrophic lateral sclerosis and neocortical Lewy body disease, co-pathologies associated with APOE ɛ4. Lewy body disease cases with Alzheimer's disease co-pathology had substantially lower Mini-Mental State Examination scores than pure Lewy body disease. Our data imply that increased age and APOE ɛ4 status are risk factors for co-pathologies independent of neurodegenerative disease; that neurodegenerative disease severity influences co-pathology as evidenced by the prevalence of co-pathology in high Alzheimer's disease and neocortical Lewy body disease, but not intermediate Alzheimer's disease or limbic Lewy body disease; and that tau and α-synuclein strains may also modify co-pathologies since tauopathies and synucleinopathies had differing co-pathologies and burdens. These findings have implications for clinical trials that focus on monotherapies targeting tau, amyloid-β, α-synuclein and TDP-43.

TISSUE MICROARRAY AND QUANTITATIVE NEUROPATHOLOGY: A HIGH THROUGHPUT METHODOLOGY FOR NEUROPATHOLOGICAL ASSESSMENT OF LARGE SCALE COHORTS

A tissue microarray (TMA) has previously been developed for use in assessment of neurodegenerative diseases. We investigated the variation of pathology loads in semi-quantitative score categories and how pathology load related to disease progression. Post-mortem tissue from 146 cases were used; Alzheimer's disease (AD) (n=36), Lewy body disease (LBD) (n=56), Mixed AD/dementia with Lewy bodies (n = 14) and controls (n=40). TMA blocks (one per case) were constructed using tissue cores from 15 brain regions including cortical and subcortical regions. TMA tissue sections were stained for hyperphosphorylated tau (HP-T), β amyloid and α-synuclein (αsyn), and quantified using an automated image analysis system. Cases classified as Braak stage VI displayed a wide variation in HP-T pathology in the entorhinal cortex (interquartile range, 4.13%-44.03%). The interquartile range for β amyloid in frontal cortex in cases classified as Thal phase 5 was 6.75%-17.03% and for αsyn in the cingulate in cases classified as McKeith neocortical LBD was 0.2%- 0.58%. In AD and control cases, HP-T load predicted the Braak stage (p<0.001), β amyloid load predicted Thal phase (p<0.001) and αsyn load in LBD cases predicted McKeith type of LBD (p<0.001). Quantitative data from TMA assessment highlight the range in pathological load across cases classified with ‘severe’ pathology and is beneficial to further elucidate the heterogeneity of neurodegenerative diseases. Quantifying pathology in multiple brain regions may allow identification of novel clinico-pathological phenotypes for the improvement of intra vitam stratification of clinical cohorts according to underlying pathologies.

Quantitative neuropathology: an update on automated methodologies and implications for large scale cohorts

A tissue microarray (TMA) has previously been developed for use in assessment of neurodegenerative diseases. We investigated the variation of pathology loads in semi-quantitative score categories and how pathology load related to disease progression. Post-mortem tissue from 146 cases were used; Alzheimer’s disease (AD) (n = 36), Lewy body disease (LBD) (n = 56), mixed AD/dementia with Lewy bodies (n = 14) and controls (n = 40). TMA blocks (one per case) were constructed using tissue cores from 15 brain regions including cortical and subcortical regions. TMA tissue sections were stained for hyperphosphorylated tau (HP-T), β amyloid and α-synuclein (αsyn), and quantified using an automated image analysis system. Cases classified as Braak stage VI displayed a wide variation in HP-T pathology in the entorhinal cortex (interquartile range 4.13–44.03%). The interquartile range for β amyloid in frontal cortex in cases classified as Thal phase 5 was 6.75–17.03% and for αsyn in the cingulate in cases classified as McKeith neocortical LBD was 0.04–0.58%. In AD and control cases, HP-T load predicted the Braak stage (p < 0.001), β amyloid load predicted Thal phase (p < 0.001) and αsyn load in LBD cases predicted McKeith type of LBD (p < 0.001). Quantitative data from TMA assessment highlight the range in pathological load across cases classified with ‘severe’ pathology and is beneficial to further elucidate the heterogeneity of neurodegenerative diseases. Quantifying pathology in multiple brain regions may allow identification of novel clinico-pathological phenotypes for the improvement of intra vitam stratification of clinical cohorts according to underlying pathologies.

Neuropathologically mixed Alzheimer's and Lewy body disease: burden of pathological protein aggregates differs between clinical phenotypes.

Multiple different pathological protein aggregates are frequently seen in human postmortem brains and hence mixed pathology is common. Mixed dementia on the other hand is less frequent and neuropathologically should only be diagnosed if criteria for more than one full blown disease are met. We quantitatively measured the amount of hyperphosphorylated microtubule associated tau (HP-τ), amyloid-β protein (Aβ) and α-synuclein (α-syn) in cases that were neuropathologically diagnosed as mixed Alzheimer's disease (AD) and neocortical Lewy body disease (LBD) but clinically presented either as dementia due to AD or LBD, the latter including dementia with Lewy bodies (DLB) and Parkinson's disease dementia (PDD). Our study group consisted of 28 cases (mean age, 76.11 SE: ±1.29 years; m:f, 17:11) of which 19 were neuropathologically diagnosed as mixed AD/DLB. Clinically, 8 mixed AD/DLB cases were diagnosed as AD (cAD), 8 as DLB (cDLB) and 3 as PDD (cPDD). In addition, we investigated cases that were both clinically and neuropathologically diagnosed as either AD (pure AD; n = 5) or DLB/neocortical LBD (pure DLB; n = 4). Sections from neocortical, limbic and subcortical areas were stained with antibodies against HP-τ, Aβ and α-syn. The area covered by immunopositivity was measured using image analysis. cAD cases had higher HP-τ loads than both cDLB and cPDD and the distribution of HP-τ in cAD was similar to the one observed in pure AD whilst cDLB showed comparatively less hippocampal HP-τ load. cPDD cases showed lower HP-τ and Aβ loads and higher α-syn loads. Here, we show that in neuropathologically mixed AD/DLB cases both the amount and the topographical distribution of pathological protein aggregates differed between distinct clinical phenotypes. Large-scale clinicopathological correlative studies using a quantitative methodology are warranted to further elucidate the neuropathological correlate of clinical symptoms in cases with mixed pathology.

Relation of neuropathology with cognitive decline among older persons without dementia

Objective: Although it is now widely accepted that dementia has a long preclinical phase during which neuropathology accumulates and cognition declines, little is known about the relation of neuropathology with the longitudinal rate of change in cognition among older persons without dementia. We quantified the burden of the neuropathologies of the three most common causes of dementia [i.e., Alzheimer’s disease (AD), cerebrovascular disease (CVD), and Lewy body disease (LBD)] and examined their relation with cognitive decline in a large cohort of persons without dementia proximate to death.Methods: A total of 467 deceased participants without dementia from two longitudinal clinical-pathologic studies, Rush Memory and Aging Project and Religious Orders Study, completed a mean of 7 annual evaluations including 17 cognitive tests. Neuropathologic examinations provided quantitative measures of AD (i.e., amyloid load, tangle density), CVD (i.e., macroscopic infarcts, microinfarcts), and neocortical Lewy bodies. Random coefficient models were used to examine the relation of the neuropathologies with rates of global cognitive decline as well as decline in four specific cognitive systems.Results: At autopsy, 82% of persons without dementia had amyloid, 100% had tangles, 29% had macroscopic infarcts, 25% had microinfarcts, and 6% had neocortical Lewy bodies. Global cognition declined a mean of 0.034 unit per year (SE = 0.003, p < 0.001). In separate analyses, amyloid, tangles (p-values <0.001) and neocortical Lewy bodies (p = 0.015) were associated with an increased rate of global cognitive decline; macroscopic infarcts and microinfarcts were not. Further, when analyzed simultaneously, amyloid, tangles, and neocortical Lewy bodies remained associated with global cognitive decline (p-values <0.024). Finally, measures of AD were associated with decline in three of four systems, including episodic memory (i.e., tangles), semantic memory (i.e., amyloid and tangles), and working memory (i.e., amyloid). Lewy bodies also were associated with decline in three of four systems (i.e., semantic memory, working memory, and perceptual speed).Interpretation: The neuropathologies of the common causes of dementia, particularly AD and neocortical LBD, are associated with decline in multiple cognitive abilities among older persons without dementia.

Mild cognitive impairment associated with limbic and neocortical lewy body disease: a clinicopathological study

There are little data on the relationship between Lewy body disease and mild cognitive impairment syndromes. The Mayo Clinic aging and dementia databases in Rochester, Minnesota, and Jacksonville, Florida were queried for cases who were diagnosed with mild cognitive impairment between 1 January 1996 and 30 April 2008, were prospectively followed and were subsequently found to have autopsy-proven Lewy body disease. The presence of rapid eye movement sleep behaviour disorder was specifically assessed. Mild cognitive impairment subtypes were determined by clinical impression and neuropsychological profiles, based on prospective operational criteria. The diagnosis of clinically probable dementia with Lewy bodies was based on the 2005 McKeith criteria. Hippocampal volumes, rate of hippocampal atrophy, and proton magnetic resonance spectroscopy were assessed on available magnetic resonance imaging and spectroscopy scans. Eight subjects were identified; six were male. Seven developed dementia with Lewy bodies prior to death; one died characterized as mild cognitive impairment. The number of cases and median age of onset (range) for specific features were: seven with rapid eye movement sleep behaviour disorder-60 years (27-91 years), eight with cognitive symptoms-69 years (62-89 years), eight with mild cognitive impairment-70.5 years (66-91 years), eight with parkinsonism symptoms-71 years (66-92 years), six with visual hallucinations-72 years (64-90 years), seven with dementia-75 years (67-92 years), six with fluctuations in cognition and/or arousal-76 years (68-92 years) and eight dead-76 years (71-94 years). Rapid eye movement sleep behaviour disorder preceded cognitive symptom onset in six cases by a median of 10 years (2-47 years) and mild cognitive impairment diagnosis by a median of 12 years (3-48 years). The mild cognitive impairment subtypes represented include: two with single domain non-amnestic mild cognitive impairment, three with multi-domain non-amnestic mild cognitive impairment, and three with multi-domain amnestic mild cognitive impairment. The cognitive domains most frequently affected were attention and executive functioning, and visuospatial functioning. Hippocampal volumes and the rate of hippocampal atrophy were, on average, within the normal range in the three cases who underwent magnetic resonance imaging, and the choline/creatine ratio was elevated in the two cases who underwent proton magnetic resonance spectroscopy when they were diagnosed as mild cognitive impairment. On autopsy, six had neocortical-predominant Lewy body disease and two had limbic-predominant Lewy body disease; only one had coexisting high-likelihood Alzheimer's disease. These findings indicate that among Lewy body disease cases that pass through a mild cognitive impairment stage, any cognitive pattern or mild cognitive subtype is possible, with the attention/executive and visuospatial domains most frequently impaired. Hippocampal volume and proton magnetic resonance spectroscopy data were consistent with recent data in dementia with Lewy bodies. All cases with rapid eye movement sleep behaviour disorder and mild cognitive impairment were eventually shown to have autopsy-proven Lewy body disease, indicating that rapid eye movement sleep behaviour disorder plus mild cognitive impairment probably reflects brainstem and cerebral Lewy body disease.

A clinico-pathological study of subtypes in Parkinson's disease

We have carried out a systematic review of the case files of 242 donors with pathologically verified Parkinson's disease at the Queen Square Brain Bank for Neurological Disorders in an attempt to corroborate the data-driven subtype classification proposed by Lewis and colleagues (Heterogeneity of Parkinson's disease in the early clinical stages using a data driven approach. J Neurol Neurosurg Psychiatry 2005; 76: 343-8). Cases were segregated into earlier disease onset (25%), tremor dominant (31%), non-tremor dominant (36%) and rapid disease progression without dementia (8%) subgroups. We found a strong association between a non-tremor dominant disease pattern and cognitive disability. The earlier disease onset group had the longest duration to death, and greatest delay to the onset of falls and cognitive decline. Patients with a tremor dominant disease pattern did not live significantly longer than non-tremor dominant patients and showed no difference in mean time to onset of falls and hallucinations. Rapid disease progression was associated with older age, early depression and early midline motor symptoms, and in 70% of the cases, tremulous onset. The non-tremor dominant subgroup had a significantly higher mean pathological grading of cortical Lewy bodies than all other groupings (P < 0.05) and more cortical amyloid-beta plaque load and cerebral amyloid angiopathy than early disease onset and tremor dominant groups (P = 0.047). An analysis of cases with pathologically defined neocortical Lewy body disease confirmed the link between bradykinetic onset, cognitive decline and Lewy body deposition in the neocortex. Although neuropathological examination failed to distinguish the other subtypes, the classification scheme was supported by an analysis of clinical data that were independent of the basic subgroup definitions.

The neuropathology of probable Alzheimer disease and mild cognitive impairment

Mixed pathologies are common in older persons with dementia. Little is known about mixed pathologies in probable Alzheimer disease (AD) and about the spectrum of neuropathology in mild cognitive impairment (MCI). The objective of this study was to investigate single and mixed common age-related neuropathologies in persons with probable AD and MCI. The study included 483 autopsied participants from the Religious Orders Study and the Rush Memory and Aging Project with probable AD (National Institute of Neurological and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association criteria), MCI (amnestic and nonamnestic), or no cognitive impairment. We excluded 41 persons with clinically possible AD and 14 with other dementias. We documented the neuropathology of AD (National Institute on Aging-Reagan criteria), macroscopic cerebral infarcts, and neocortical Lewy body (LB) disease. Of 179 persons (average age, 86.9 years) with probable AD, 87.7% had pathologically confirmed AD, and 45.8% had mixed pathologies, most commonly AD with macroscopic infarcts (n = 54), followed by AD with neocortical LB disease (n = 19) and both (n = 8). Of the 134 persons with MCI, 54.4% had pathologically diagnosed AD (58.7% amnestic; 49.2% nonamnestic); 19.4% had mixed pathologies (22.7% amnestic; 15.3% nonamnestic). Macroscopic infarcts without pathologically diagnosed AD accounted for 4.5% of probable AD, 13.3% of amnestic MCI, and 18.6% of nonamnestic MCI. Pure neocortical LB disease was uncommon in all persons with cognitive impairment (<6%). Microscopic infarcts (without macroscopic infarcts) were common as a mixed pathology, but rarely accounted for a clinical diagnosis of probable AD (n = 4) or MCI (n = 3). Clinically diagnosed probable AD and MCI, even amnestic MCI, are pathologically heterogeneous disorders, with many persons exhibiting mixed pathologies.

Dopamine cell loss in the periaqueductal gray in multiple system atrophy and Lewy body dementia

Experimental studies indicate that dopaminergic neurons in the ventral periaqueductal gray matter (PAG) are involved in maintenance of wakefulness. Excessive daytime sleepiness (EDS) is a common manifestation of multiple system atrophy (MSA) and dementia with Lewy bodies (DLB) but involvement of these neurons has not yet been explored. We sought to determine whether there is loss of dopaminergic neurons in the ventral PAG in MSA and DLB. We studied the midbrain obtained at autopsy from 12 patients (9 male, 3 female, age 61 +/- 3) with neuropathologically confirmed MSA, 12 patients (11 male, 1 female, age 79 +/- 4) with diagnosis of DLB and limbic or neocortical Lewy body disease, and 12 controls (7 male, 5 female, ages 67 +/- 4). Fifty-micron sections were immunostained for tyrosine hydroxylase (TH) or alpha-synuclein and costained with thionin. Cell counts were performed every 400 mum throughout the ventral PAG using stereologic techniques. Compared to the total estimated cell numbers in controls (21,488 +/- 8,324 cells), there was marked loss of TH neurons in the ventral PAG in both MSA (11,727 +/- 5,984; p < 0.01) and DLB (5,163 +/- 1,926; p < 0.001) cases. Cell loss was more marked in DLB than in MSA. There were characteristic alpha-synuclein inclusions in the ventral PAG in both MSA and DLB. There is loss of putative wake-active ventral periaqueductal gray matter dopaminergic neurons in both multiple system atrophy and dementia with Lewy bodies, which may contribute to excessive daytime sleepiness in these conditions.

Neuropathology of dementia in Parkinson's disease: A prospective, community‐based study

Twenty-two patients with Parkinson's disease drawn from a community-based study were followed prospectively until their deaths. Even though 18 patients had dementia, none fulfilled Braak and Braak or The National Institute on Aging and Ronald and Nancy Reagan Institute of the Alzheimer's Association, whereas all patients had limbic or neocortical Lewy body disease. The Lewy body score and Braak and Braak stage were significantly associated with the rate of cognitive decline, but only the Lewy body score was associated with the rate of cognitive decline in the univariate analyses. This study strongly suggests that Lewy body disease is the main substrate driving the progression of cognitive impairment in Parkinson's disease.