Corticobasal Degeneration Cases Research Articles

Fulminant corticobasal degeneration: a distinct variant with predominant neuronal tau aggregates

Corticobasal degeneration typically progresses gradually over 5–7 years from onset till death. Fulminant corticobasal degeneration cases with a rapidly progressive course were rarely reported (RP-CBD). This study aimed to investigate their neuropathological characteristics. Of the 124 autopsy-confirmed corticobasal degeneration cases collected from 14 centres, we identified 6 RP-CBD cases (4.8%) who died of advanced disease within 3 years of onset. These RP-CBD cases had different clinical phenotypes including rapid global cognitive decline (N = 2), corticobasal syndrome (N = 2) and Richardson’s syndrome (N = 2). We also studied four corticobasal degeneration cases with an average disease duration of 3 years or less, who died of another unrelated illness (Intermediate-CBD). Finally, we selected 12 age-matched corticobasal degeneration cases out of a cohort of 110, who had a typical gradually progressive course and reached advanced clinical stage (End-stage-CBD). Quantitative analysis showed high overall tau burden (p = 0.2) and severe nigral cell loss (p = 0.47) in both the RP-CBD and End-stage-CBD groups consistent with advanced pathological changes, while the Intermediate-CBD group (mean disease duration = 3 years) had milder changes than End-stage-CBD (p < 0.05). These findings indicated that RP-CBD cases had already developed advanced pathological changes as those observed in End-stage-CBD cases (mean disease duration = 6.7 years), but within a significantly shorter duration (2.5 years; p < 0.001). Subgroup analysis was performed to investigate the cellular patterns of tau aggregates in the anterior frontal cortex and caudate by comparing neuronal-to-astrocytic plaque ratios between six RP-CBD cases, four Intermediate-CBD and 12 age-matched End-stage-CBD. Neuronal-to-astrocytic plaque ratios of Intermediate-CBD and End-stage-CBD, but not RP-CBD, positively correlated with disease duration in both the anterior frontal cortex and caudate (p = 0.02). In contrast to the predominance of astrocytic plaques we previously reported in preclinical asymptomatic corticobasal degeneration cases, neuronal tau aggregates predominated in RP-CBD exceeding those in Intermediate-CBD (anterior frontal cortex: p < 0.001, caudate: p = 0.001) and End-stage-CBD (anterior frontal cortex: p = 0.03, caudate: p = 0.01) as demonstrated by its higher neuronal-to-astrocytic plaque ratios in both anterior frontal cortex and caudate. We did not identify any difference in age at onset, any pathogenic tau mutation or concomitant pathologies that could have contributed to the rapid progression of these RP-CBD cases. Mild TDP-43 pathology was observed in three RP-CBD cases. All RP-CBD cases were men. The MAPT H2 haplotype, known to be protective, was identified in one RP-CBD case (17%) and 8 of the matched End-stage-CBD cases (67%). We conclude that RP-CBD is a distinct aggressive variant of corticobasal degeneration with characteristic neuropathological substrates resulting in a fulminant disease process as evident both clinically and pathologically. Biological factors such as genetic modifiers likely play a pivotal role in the RP-CBD variant and should be the subject of future research.

Primary Tau Pathology, Not Copathology, Correlates With Clinical Symptoms in PSP and CBD.

Distinct neuronal and glial tau pathologies define corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP). Additional Alzheimer disease, TDP-43, and Lewy body copathologies are also common. The interplay of these pathologies with clinical symptoms remains unclear as individuals can present with corticobasal syndrome, frontotemporal dementia, PSP, or atypical Parkinsonism and may have additional secondary impairments. We report clinical, pathological, and genetic interactions in a cohort of CBD and PSP cases. Neurofibrillary tangles and plaques were common. Apolipoprotein E (APOE)ε4 carriers had more plaques while PSP APOEε2 carriers had fewer plaques. TDP-43 copathology was present and age-associated in 14% of PSP, and age-independent in 33% of CBD. Lewy body copathology varied from 9% to 15% and was not age-associated. The primary FTD-Tau burden-a sum of the neuronal, astrocytic and oligodendrocytic tau-was not age-, APOE-, or MAPT-related. In PSP, FTD-Tau, independent of copathology, associated with executive, language, motor, and visuospatial impairments, while PSP with Parkinsonism had a lower FTD-Tau burden, but this was not the case in CBD. Taken together, our results indicate that the primary tauopathy burden is the strongest correlate of clinical PSP, while copathologies are principally determined by age and genetic risk factors.

4-Repeat tau seeds and templating subtypes as brain and CSF biomarkers of frontotemporal lobar degeneration.

To address the need for more meaningful biomarkers of tauopathies, we have developed an ultrasensitive tau seed amplification assay (4R RT-QuIC) for the 4-repeat (4R) tau aggregates of progressive supranuclear palsy (PSP), corticobasal degeneration (CBD), and other diseases with 4R tauopathy. The assay detected seeds in 106-109-fold dilutions of 4R tauopathy brain tissue but was orders of magnitude less responsive to brain with other types of tauopathy, such as from Alzheimer's disease cases. The analytical sensitivity for synthetic 4R tau fibrils was ~ 50fM or 2fg/sample. A novel dimension of this tau RT-QuIC testing was the identification of three disease-associated classes of 4R tau seeds; these classes were revealed by conformational variations in the in vitro amplified tau fibrils as detected by thioflavin T fluorescence amplitudes and FTIR spectroscopy. Tau seeds were detected in postmortem cerebrospinal fluid (CSF) from all neuropathologically confirmed PSP and CBD cases but not in controls. CSF from living subjects had weaker seeding activities; however, mean assay responses for cases clinically diagnosed as PSP and CBD/corticobasal syndrome were significantly higher than those from control cases. Altogether, 4R RT-QuIC provides a practical cell-free method of detecting and subtyping pathologic 4R tau aggregates as biomarkers.

Clinicopathologic subtype of Alzheimer's disease presenting as corticobasal syndrome

IntroductionThe corticobasal syndrome (CBS) is associated with several neuropathologic disorders, including corticobasal degeneration and Alzheimer's disease (AD). MethodIn this report, we studied 43 AD patients with CBS (AD-CBS) and compared them with 42 AD patients with typical amnestic syndrome (AD-AS), as well as 15 cases of corticobasal degeneration and CBS pathology. ResultsUnlike AD-AS, AD-CBS had prominent motor problems, including limb apraxia (90%), myoclonus (81%), and gait disorders (70%). Alien limb phenomenon was reported in 26% and cortical sensory loss in 14%. Language problems were also more frequent in AD-CBS, and memory impairment was less frequent. AD-CBS had more tau pathology in perirolandic cortices but less in superior temporal cortex than AD-AS. In addition, AD-CBS had greater neuronal loss in the substantia nigra. DiscussionAD-CBS is a clinicopathological subtype of AD with an atypical distribution of Alzheimer-type tau pathology. Greater neuronal loss in the substantia nigra may contribute to Parkinsonism which is not a feature of typical AD.

Corticobasal degeneration.

Corticobasal degeneration (CBD) is a rare neurodegenerative disease characterized by the predominance of pathological 4 repeat tau deposition in various cell types and anatomical regions. Corticobasal syndrome (CBS) is one of the clinical phenotypes associated with CBD pathology, manifesting as a progressive asymmetric akinetic-rigid, poorly levodopa-responsive parkinsonism, with cerebral cortical dysfunction. CBD can manifest as several clinical phenotypes, and similarly, CBS can also have a pathologic diagnosis other than CBD. This chapter discusses the clinical manifestations of pathologically confirmed CBD cases, the current diagnostic criteria, as well as the pathologic and neuroimaging findings of CBD/CBS. At present, therapeutic options for CBD remain symptomatic. Further research is needed to improve the clinical diagnosis of CBD, as well as studies on disease-modifying therapies for this relentlessly progressive neurodegenerative disorder.

Corticobasal degeneration with TDP-43 pathology presenting with progressive supranuclear palsy syndrome: a distinct clinicopathologic subtype.

Corticobasal degeneration (CBD) is a clinically heterogeneous tauopathy, which has overlapping clinicopathologic and genetic characteristics with progressive supranuclear palsy (PSP). This study aimed to elucidate whether transactive response DNA-binding protein of 43kDa (TDP-43) pathology contributes to clinicopathologic heterogeneity of CBD. Paraffin-embedded sections of the midbrain, pons, subthalamic nucleus, and basal forebrain from 187 autopsy-confirmed CBD cases were screened with immunohistochemistry for phospho-TDP-43. In cases with TDP-43 pathology, additional brain regions (i.e., precentral, cingulate, and superior frontal gyri, hippocampus, medulla, and cerebellum) were immunostained. Hierarchical clustering analysis was performed based on the topographical distribution and severity of TDP-43 pathology, and clinicopathologic and genetic features were compared between the clusters. TDP-43 pathology was observed in 45% of CBD cases, most frequently in midbrain tegmentum (80% of TDP-43-positive cases), followed by subthalamic nucleus (69%). TDP-43-positive CBD was divided into TDP-limited (52%) and TDP-severe (48%) by hierarchical clustering analysis. TDP-severe patients were more likely to have been diagnosed clinically as PSP compared to TDP-limited and TDP-negative patients (80 vs 32 vs 30%, P < 0.001). The presence of downward gaze palsy was the strongest factor for the antemortem diagnosis of PSP, and severe TDP-43 pathology in the midbrain tectum was strongly associated with downward gaze palsy. In addition, tau burden in the olivopontocerebellar system was significantly greater in TDP-positive than TDP-negative CBD. Genetic analyses revealed that MAPT H1/H1 genotype frequency was significantly lower in TDP-severe than in TDP-negative and TDP-limited CBD (65 vs 89 vs 91%, P < 0.001). The homozygous minor allele frequencies in GRN rs5848 and TMEM106B rs3173615 were not significantly different between the three groups. In conclusion, the present study indicates that CBD with severe TDP-43 pathology is a distinct clinicopathologic subtype of CBD, characterized by PSP-like clinical presentations, severe tau pathology in the olivopontocerebellar system, and low frequency of MAPT H1 haplotype.

Ultrasensitive and selective detection of 3-repeat tau seeding activity in Pick disease brain and cerebrospinal fluid.

The diagnosis and treatment of diseases involving tau-based pathology such as Alzheimer disease and certain frontotemporal dementias is hampered by the inability to detect pathological forms of tau with sufficient sensitivity, specificity and practicality. In these neurodegenerative diseases, tau accumulates in self-seeding filaments. For example, Pick disease (PiD) is associated with frontotemporal degeneration and accumulation of 3-repeat (3R) tau isoforms in filaments constituting Pick bodies. Exploiting the self-seeding activity of tau deposits, and using a 3R tau fragment as a substrate, we have developed an assay (tau RT-QuIC) that can detect tau seeds in 2µl aliquots of PiD brain dilutions down to 10-7-10-9. PiD seeding activities were 100-fold higher in frontal and temporal lobes compared to cerebellar cortex. Strikingly, this test was 103- to 105-fold less responsive when seeded with brain containing predominant 4-repeat (4R) tau aggregates from cases of corticobasal degeneration, argyrophilic grain disease, and progressive supranuclear palsy. Alzheimer disease brain, with 3R+4R tau deposits, also gave much weaker responses than PiD brain. When applied to cerebrospinal fluid samples (5µl), tau RT-QuIC analyses discriminated PiD from non-PiD cases. These findings demonstrate that abnormal tau aggregates can be detected with high sensitivity and disease-specificity in crude tissue and fluid samples. Accordingly, this tau RT-QuIC assay exemplifies a new approach to diagnosing tauopathies and monitoring therapeutic trials using aggregated tau itself as a biomarker.

Differentiating cognitive impairment due to corticobasal degeneration and Alzheimer disease.

To identify clinical features that reliably differentiate individuals with cognitive impairment due to corticobasal degeneration (CBD) and Alzheimer disease (AD). Clinical features were compared between individuals with autopsy-proven CBD (n = 17) and AD (n = 16). All individuals presented with prominent cognitive complaints and were evaluated annually with semistructured interviews, detailed neurologic examinations, and neuropsychological testing. Substantial overlap was observed between individuals with dementia due to CBD and AD concerning presenting complaints, median (range) duration of symptoms before assessment (CBD = 3.0 [0-5.0] years, AD = 2.5 [0-8.0] years; p = 0.96), and median (range) baseline dementia severity (Clinical Dementia Rating Sum of Boxes: CBD = 3.5 [0-12.0], AD = 4.25 [0.5-9.0], p = 0.49). Subsequent emergence of asymmetric motor/sensory signs, hyperreflexia, gait abnormalities, parkinsonism, falls, urinary incontinence, and extraocular movement abnormalities identified individuals with CBD, with ≥3 discriminating features detected in 80% of individuals within 3.1 years (95% confidence interval 2.9-3.3) of the initial assessment. Individuals with CBD exhibited accelerated worsening of illness severity and declines in episodic memory, executive functioning, and letter fluency. Semiquantitative pathologic assessment revealed prominent tau pathology within the frontal and parietal lobes of CBD cases. Comorbid AD neuropathologic change was present in 59% (10 of 17) of CBD cases but did not associate with the clinical phenotype, rate of dementia progression, or dementia duration. CBD may mimic AD dementia early in its disease course. Interval screening for discriminating clinical features may improve antemortem diagnosis in individuals with CBD and prominent cognitive symptoms.

Astrogliopathy predominates the earliest stage of corticobasal degeneration pathology

SEE KOBYLECKI AND MANN DOI101093/AWW267 FOR A SCIENTIFIC COMMENTARY ON THIS ARTICLE: Animal models have shown that tau seeding and propagation are strain- and neural network-specific. The study of preclinical cases is valuable to gain insights into early pathological features of corticobasal degeneration and its progression. Three preclinical corticobasal degeneration cases and six age-matched end-stage corticobasal degeneration cases were included in this study. Tau immunohistochemistry performed in 20 brain regions and quantitative assessment of regional tau load using image analysis were performed. Semi-quantitative grading of tau-positive cellular lesions and neuronal loss in the frontal, parietal and temporal cortices, striatum, substantia nigra and subthalamic nucleus were assessed. All preclinical cases were clinically asymptomatic but had widespread tau lesions in the typically affected regions in corticobasal degeneration and the pathognomonic astrocytic plaques were the most prominent lesion type in the anterior frontal and striatal regions. Mean total tau load (sum of all regional tau load) of end-stage corticobasal degeneration cases were nine times greater than that of the preclinical cases (P = 0.04) and less tau load was found in all regions of the preclinical cases. An anterior-to-posterior tau load ratio in the frontal cortex in preclinical cases was 12-fold greater than in end-stage corticobasal degeneration cases. Relatively greater tau burden in the anterior frontal cortex, striatum and subthalamic nucleus suggests the striatal afferent connection to the dorsolateral prefrontal cortex and basal ganglia circuitry are the earliest neural network connections affected by corticobasal degeneration-related tau pathology. Differential distribution of the tau pathology to selective cortical regions in these preclinical cases implies phenotypic presentation may be predetermined at a very early stage of the disease process. Neuronal loss of the substantia nigra was either absent or very mild in the preclinical cases and was moderate to severe in end-stage corticobasal degeneration cases (P < 0.05). Our findings suggest that a threshold of pathological burden in the 'right' anatomical regions needs to be reached before the onset of clinical symptoms. The early prominence of the astrocytic plaques in relation to sparse neuronal lesions leads one to speculate that corticobasal degeneration may begin as an astrogliopathy at a very early disease stage but neuronal lesions gradually take over as the predominant lesion type in advanced disease.

Histopathological and immunohistochemical study of spinal cord tissues in neurodegenerative diseases

To investigate histopathology and proteinopathy in the spinal cord of patients with common neurodegenerative diseases. Spinal cord tissues from clinically and neuropathologically confirmed neruodegnerative diseases were enrolled in this study, including 3 cases of multiple system strophy, 4 cases of amyotrophic lateral sclerosis, 5 cases of Alzheimer's disease (AD, included 2 cases of AD combined with Parkinson's disease), 2 cases of progressive supranuclear palsy, 1 case of dementia with lewy body and 1 case of corticobasal degeneration from 1955 to 2013 at Chinese People's Liberation Army General Hospital. Four normal control cases were also included. Routine HE and Gallyas-Braak staining, and immunohistochemical stainings for anti-PHF tau (AT8), anti-α-synuclein, anti-TDP-43 and anti-ubiquitin were performed. Examination of the spinal cord in 3 cases with multiple system strophy revealed severe neuron loss in the intermediolateral nucleus of thoracic segment and Onuf's nucleus of the sacral segment, along with moderate neuron loss in the anterior horn of the cervical segment and mild myelin pallor in the anterior funiculus and anterolateral funiculus in the cervical and thoracic segments. Large amount of argentophilic, ubiquitin and synuclein positive oligodendroglial cytoplasmic inclusions were found widely distributed in the anterior horn and the anterior funiculus and anterolateral funiculus of the full spinal cord. Severe neuron loss and several morphological changes with gliosis in the anterior horn and severe loss of myelin in the anterior funiculus and anterolateral funiculus of the full spinal cord were observed in 4 cases of amyotrophic lateral sclerosis, 2 of which were found with Bunina bodies in neurons of the anterior horn. Three amyotrophic lateral sclerosis cases had ubiquitin-positive neuronal inclusions and TDP-43 positive neuronal and glial inclusions in the anterior horn at cervical and lumbar segments. A few argentophilic, tau positive neurofibrillary tangles (NFTs) and neuropil threads in the anterior horn at cervical and lumbar segments were found in 4 AD cases. Examination of spinal cord in 2 cases with Parkinson's disease combined with AD and 1 case with dementia with lewy body revealed severe neuron loss in the intermediolateral nucleus of thoracic segment, and a few synuclein positive lewy bodies and neuritis were also observed. There was mild neuron loss in the anterior horn at cervical and lumbar segments, along with some argentophilic, tau positive globous NFTs and many argentophilic, tau positive neutrophil threads were observed in 2 progressive supranuclear palsy cases and 1 corticobasal degeneration case. Each common neurodegenerative diseases of the spinal cord including multiple system strophy, amyotrophic lateral sclerosis and Parkinson's disease has its own specific histopathology and proteinopathy characteristics.

Early Stage of Progressive Supranuclear Palsy: A Neuropathological Study of 324 Consecutive Autopsy Cases.

Diagnosing clinical progressive supranuclear palsy (PSP) is challenging. We hypothesize that there are more cases of pathological PSP than have been clinically identified, but its diagnosis is challenging because the initial lesions and progression of PSP have not yet been clarified. The purpose of our study was to clarify the incidence of PSP in consecutive autopsy cases and identify pathological characteristics of early PSP. We investigated 324 consecutive autopsy patients from a general geriatric hospital (age, mean±SD=82.5±8.7 years). Paraffin sections of the midbrain were immunostained with anti 4-repeat tau antibodies (RD4). We selected cases showing RD4-positive neurofibrillary tangles and tufted astrocytes in the midbrain sections. Then, we used anti-phosphorylated tau antibody to immunostain sections from the basal ganglia, subthalamic nucleus, midbrain, pons, medulla, and cerebellum. Of the 324 patients, 35 had RD4-positive structures in the midbrain. From these 35 cases, we excluded those for which autopsies confirmed definite PSP (n=5) and cases of corticobasal degeneration (n=1), Alzheimer's disease (n=11), dementia of grain (n=10), and neurofibrillary tangles predominant forms of senile dementia (n=2), leaving 8 cases. We diagnosed these 8 cases as pure PSP-type tauopathy. Pure PSP-type tauopathy was detected in 2.5% of the consecutive autopsy cases, and this incidence was 1.6 times greater than that of neuropathologically definite PSP. This pure PSP-type tauopathy likely indicates preclinical stages of PSP. Furthermore, the novel neuropathological finding, which we term "preclinical PSP," is unique and has not previously been reported. In order to elucidate the causes and pathological mechanisms of PSP, preclinical PSP should be investigated further.

Astrocytic inclusions in progressive supranuclear palsy and corticobasal degeneration.

Tufted astrocytes (TAs) in progressive supranuclear palsy (PSP) and astrocytic plaques (APs) in corticobasal degeneration (CBD) have been regarded as the pathological hallmarks of major sporadic 4-repeat tauopathies. To better define the astrocytic inclusions in PSP and CBD and to outline the pathological features of each disease, we reviewed 95 PSP cases and 30 CBD cases that were confirmed at autopsy. TAs exhibit a radial arrangement of thin, long, branching accumulated tau protein from the cytoplasm to the proximal processes of astrocytes. APs show a corona-like arrangement of tau aggregates in the distal portions of astrocytic processes and are composed of fuzzy, short processes. Immunoelectron microscopic examination using quantum dot nanocrystals revealed filamentous tau accumulation of APs located in the immediate vicinity of the synaptic structures, which suggested synaptic dysfunction by APs. The pathological subtypes of PSP and CBD have been proposed to ensure that the clinical phenotypes are in accordance with the pathological distribution and degenerative changes. The pathological features of PSP are divided into 3 representative subtypes: typical PSP type, pallido-nigro-luysian type (PNL type), and CBD-like type. CBD is divided into three pathological subtypes: typical CBD type, basal ganglia- predominant type, and PSP-like type. TAs are found exclusively in PSP, while APs are exclusive to CBD, regardless of the pathological subtypes, although some morphological variations exist, especially with regard to TAs. The overlap of the pathological distribution of PSP and CBD makes their clinical diagnosis complicated, although the presence of TAs and APs differentiate these two diseases. The characteristics of tau accumulation in both neurons and glia suggest a different underlying mechanism with regard to the sites of tau aggregation and fibril formation between PSP and CBD: proximal-dominant aggregation of TAs and formation of filamentous NFTs in PSP in contrast to the distal-dominant aggregation of APs and formation of less filamentous pretangles in CBD.

FDG-PET in pathologically confirmed spontaneous 4R-tauopathy variants

The 4-repeat (4R)-tauopathies can be clinically heterogeneous and difficult to diagnose. An FDG-PET pattern of hypometabolism has been previously reported in clinically suspected 4R-tauopathies. Considering that pathological confirmation has not been used as inclusion criteria in these studies, however, the possibility exists that atypical cases were excluded. We studied pathologically confirmed cases of 4R-tauopathies to determine if FDG-PET patterns of hypometabolism different than those previously described exist. We identified all autopsy confirmed 4R-tauopathies with FDG-PET imaging performed between 2010 and 2013 within the Mayo Clinic database. Clinical features and FDG-PET imaging were compared to a group of normal controls. Ten patients, seven of which had autopsy-confirmed progressive supranuclear palsy (PSP), were identified. We also identified two cases with globular glial tauopathy (GGT) and one case of corticobasal degeneration (CBD). The overall predominant imaging findings included bilateral caudate hypometabolism in nine cases, mild asymmetric thalamic hypometabolism in eight, midbrain hypometabolism in seven, and bilateral hypometabolism in the supplementary motor area in seven. No differences were observed between PSP and GGT. The one CBD case had asymmetric parietal hypometabolism that was not seen in the PSP and GGT cases. As previously described, 4R-tauopathies are associated with frontal, caudate, midbrain and thalamic hypometabolism on FDG-PET. This is the first report of FDG-PET in GGT, and although our series was limited, no features distinguish GGT from PSP. There was some evidence that parietal hypometabolism may be suggestive of CBD.

Argyrophilic Grains Are Reliable Disease-Specific Features of Corticobasal Degeneration

Argyrophilic grains are discrete punctate structures that bind to silver stains; they can be observed within the neuropil of the limbic system, particularly in the elderly. It has been reported that argyrophilic grains are more frequent in patients with corticobasal degeneration (CBD) compared with the elderly population in general. To determine the frequency and significance of argyrophilic grains in CBD, we examined the temporal lobes from 35 patients with autopsy-proven CBD (mean age, 69.1 years) and 28 patients with argyrophilic grain disease (mean age, 95.7 years). Grain distributions and densities were evaluated semiquantitatively using Gallyas-Braak stains and immunohistochemistry with AT8 and RD4 antibodies. Argyrophilic grains were observed in all CBD cases (100%) despite a lower average age at death in this population. We also observed the following features that were specific to argyrophilic grains in CBD: 1) grains were likely to be widespread throughout the temporal lobe, 2) grains were consistently found with abundant argyrophilic threads, and 3) the ultrastructure of grains contained paired helical filaments with a periodicity of 120 to 130 nm. In conclusion, we confirm that argyrophilic grains in CBD are specifically related to the 4-repeat tau pathology of CBD and are not simply a result of aging.

DOPAMINE TRANSPORTER (DAT) IMAGING CAN BE NORMAL WITH NEUROPATHOLOGICALLY CONFIRMED CORTIOBASAL DEGENERATION

ObjectiveTo report 3 cases of Corticobasal Degeneration with normal DAT scans.BackgroundCorticobasal degeneration (CBD) is a progressive neurodegenerative condition associated with neuronal and glial tau pathology (including astrocytic plaques) in gray...

Posterior cortical atrophy: correlation between clinical, neuropsychological, magnetic resonance and positron emission tomography Imaging

Background Posterior cortical atrophy is a rare syndrome and considered to be a spectrum of Alzheimer’s disease. Cases of corticobasal degeneration, dementia with Lewy Body, and prion diseases, such as Creutzfeldt-Jakob disease, have also been described with such a syndrome. Despite the similar pathological findings seen in Alzheimer’s disease, patients with posterior cortical atrophy present with prominent visuoperceptual impairment which is disproportional to impairment in other cognitive domains. Frequently, these patients are initially seen in ophthalmology clinics due to their visual complaints, and often the diagnosis is delayed. Recently, Positron Emission Tomography based on the identification of amyloid burden in the brain gained momentum as a diagnostic imaging option in patients with Alzheimer’s disease. Here we present a case of a 79 year old woman with a visual disturbance, and contrast her clinical presentation with neuropsychological testing and Magnetic Resonance and Positron Emission Tomography imaging to demonstrate the utility of diagnostic tools in patients with a presumed diagnosis of posterior cortical atrophy.

THE CLINICAL FEATURES OF NON-ALZHEIMER TAUOPATHIES: A SYSTEMATIC REVIEW

Corticobasal degeneration (CBD), Pick's disease (PiD) and progressive supranuclear palsy (PSP) are the most common tauopathies after Alzheimer's disease. The traditional view of CBD and PSP as movement disorders and...

Characterising the uncommon corticobasal syndrome presentation of sporadic Creutzfeldt-Jakob disease

BackgroundCorticobasal syndrome (CBS), which encompasses cortical sensory loss, alien limb, bradykinesia, rigidity, limb apraxia and dystonia, is the classic presentation of corticobasal degeneration (CBD). It may occur in other neurodegenerative disorders including sporadic Creutzfeldt-Jakob disease (sCJD). Current CBD diagnostic criteria outline features of CBS but fail to distinguish CBD from other causative pathologies. ObjectivesTo characterise the CBS presentation of sCJD (sCJD-CBS) in the context of existing CBD diagnostic criteria. MethodData of two new cases of sCJD-CBS and seven patients identified from the Australian National Creutzfeldt-Jakob Disease Registry database was reviewed. Additional data from 11 published cases was incorporated to illustrate the natural history of sCJD-CBS. Comparison was made with pathologically diagnosed CBD cases with ante-mortem CBS presentation (CBD-CBS). ResultssCJD-CBS accounts for 1.8% of all Australian sCJD cases. Compared to CBD-CBS, disease progression is more rapid in sCJD-CBS (median time to diagnosis 48 vs.1.5 months, p < 0.001; and disease duration until death 68 vs. 5 months, p < 0.001). Although no clinical features separate the two, alien limb and myoclonus tend to occur early in sCJD-CBS following initial ‘sensory’ disturbance in the affected limb. Consistent with sCJD, distinctive diffusion weighted imaging (DWI) abnormalities on magnetic resonance imaging may also occur in sCJD-CBS. ConclusionsCJD should be suspected in patients presenting with CBS when clinical progression is rapid and accompanied by DWI abnormalities, even without cerebrospinal fluid 14-3-3 protein detection and electroencephalographic periodic sharp wave complexes. We propose the addition of rapid (<12months) progression to akinetic-mutism or death and DWI abnormalities as exclusions in future CBD diagnostic criteria.

心筋へのMIBG集積低下をみとめ，交感神経節に限局するLewy小体を合併した大脳皮質基底核変性症の1剖検例

We report on an autopsy case of corticobasal degeneration (CBD) with Lewy bodies in only the sympathetic ganglia. A 79-year-old man showed walking disturbance as an initial symptom, and developed dementia and bradykinesia within the next 2 years. Neurological examination revealed parkinsonism-like akinesia and rigidity in the trunk and neck without resting tremor. Brain magnetic resonance imaging showed frontal lobe atrophy predominantly on the right side. Cardiac uptake of meta-iodobenzylguanidine (MIBG) was reduced (H/M ratio: 1.14). A diagnosis of dementia with Lewy bodies (DLB) was made, but L-dopa treatment was not effective. Seven years later he died of pneumonia. On pathological examination, the frontal cortex and white matter were degenerated, predominantly on the right side. Gallyas-Braak silver staining and AT-8 immunostaining revealed neurofibrillary tangles, pretangles, argyrophilic threads, and astrocytic plaques in the cerebral cortex and basal ganglia, confirming the diagnosis of CBD. Lewy bodies, which were not seen in the central nervous system, were seen only in the sympathetic ganglia, and a severe loss of nerve fibers was apparent in the sympathetic nerve endings in the heart. MIBG is currently used to differentiate DLB from other parkinsonisms, such as CBD, multiple system atrophy, and progressive supranuclear palsy, because reduced cardiac uptake of MIBG represents a pathological change in the sympathetic nerve endings in the heart. However, the distribution of Lewy bodies cannot be determined from this finding. Thus, MIBG should not be used alone to confirm a diagnosis of DLB; other neurodegenerative diseases with incidental Lewy body disease, as in the present case, must be also considered.

Neuropathological features of corticobasal degeneration presenting as corticobasal syndrome or Richardson syndrome.

Patients with corticobasal degeneration can present with several different clinical syndromes, making ante-mortem diagnosis a challenge. Corticobasal syndrome is the clinical phenotype originally described for corticobasal degeneration, characterized by asymmetric rigidity and apraxia, cortical sensory deficits, dystonia and myoclonus. Some patients do not develop these features, but instead have clinical features consistent with the Richardson syndrome presentation of progressive supranuclear palsy, characterized by postural instability, early unexplained falls, vertical supranuclear gaze palsy, symmetric motor disability and dysphagia. The aim of this study was to identify differences in corticobasal degeneration presenting with corticobasal syndrome (n = 11) or Richardson syndrome (n = 15) with respect to demographic, clinical and neuropathological features. Corticobasal degeneration cases were also compared with patients with pathologically proven progressive supranuclear palsy with Richardson syndrome (n = 15). Cases with corticobasal degeneration, regardless of presentation, shared histopathological and tau biochemical characteristics, but they had differing densities of tau pathology in neuroanatomical regions that correlated with their clinical presentation. In particular, those with corticobasal syndrome had greater tau pathology in the primary motor and somatosensory cortices and putamen, while those with Richardson syndrome had greater tau pathology in limbic and hindbrain structures. Compared with progressive supranuclear palsy, patients with corticobasal degeneration and Richardson syndrome had less neuronal loss in the subthalamic nucleus, but more severe neuronal loss in the medial substantia nigra and greater atrophy of the anterior corpus callosum. Clinically, they had more cognitive impairment and frontal behavioural dysfunction. The results suggest that Richardson syndrome can be a clinicopathological presentation of corticobasal degeneration. Atrophy of anterior corpus callosum may be a potential neuroimaging marker to differentiate corticobasal degeneration from progressive supranuclear palsy in patients with Richardson syndrome.