Typical Progressive Supranuclear Palsy Research Articles

Cerebral Tau Deposition in Comorbid Progressive Supranuclear Palsy and Amyotrophic Lateral Sclerosis: An [18F]-Flortaucipir and 7T MRI Study

Introduction: Progressive supranuclear palsy (PSP) is a four-repeat tauopathy characterized by multiple clinicopathologic subtypes. Advanced neuroimaging techniques have shown an early ability to distinguish PSP subtypes noninvasively for improved diagnosis. This study utilized tau PET imaging and MRI techniques at 7T to determine the neuroimaging profile of a participant with comorbid PSP and amyotrophic lateral sclerosis (ALS). Method: [18F]-flortaucipir PET imaging was performed on one participant with PSP-ALS, one participant with typical PSP (Richardson’s syndrome; PSP-RS), and 15 healthy control volunteers. Standardized uptake value ratio (SUVR) in each brain region was compared between PSP participants and controls. Quantitative susceptibility mapping (QSM) and inflow-based vascular-space occupancy MRI at 7T were performed on the two PSP participants and on two age-matched healthy controls to evaluate for differences in regional brain iron content and arteriolar cerebral blood volume (CBVa), respectively. Results: In the participant with PSP-ALS, the precentral gyrus demonstrated the highest [18F]-flortaucipir uptake of all brain regions relative to controls (z-score 1.94). In the participant with PSP-RS, [18F]-flortaucipir uptake relative to controls was highest in subcortical regions, including the pallidum, thalamus, hippocampus, and brainstem (z-scores 1.08, 1.41, 1.49, 1.32, respectively). Susceptibility values as a measure of brain iron content were higher in the globus pallidus and substantia nigra than in the midbrain and pons in each participant, regardless of group. CBVa values tended to be higher in the subcortical gray matter in PSP participants than in controls, although large measurement variability was noted in controls across multiple regions. Conclusion: In vivo tau PET imaging of an individual with PSP-ALS overlap demonstrated increased tau burden in the motor cortex that was not observed in PSP-RS or control participants. Consistent with prior PET studies, tau burden in PSP-RS was mainly observed in subcortical regions, including the brainstem and basal ganglia. QSM data suggest that off-target binding to iron may account for some but not all of the increased [18F]-flortaucipir uptake in the basal ganglia in PSP-RS. These findings support existing evidence that tau PET imaging can distinguish among PSP subtypes by detecting distinct regional patterns of tau deposition in the brain. Larger studies are needed to determine whether CBVa is sensitive to changes in brain microvasculature in PSP.

Rainwater Charitable Foundation criteria for the neuropathologic diagnosis of progressive supranuclear palsy

Neuropathologic criteria for progressive supranuclear palsy (PSP) proposed by a National Institute of Neurological Disorders and Stroke (NINDS) working group were published in 1994 and based on the presence of neurofibrillary tangles in basal ganglia and brainstem. These criteria did not stipulate detection methods or incorporate glial tau pathology. In this study, a group of 14 expert neuropathologists scored digital slides from 10 brain regions stained with hematoxylin and eosin (H&E) and phosphorylated tau (AT8) immunohistochemistry. The cases included 15 typical and atypical PSP cases and 10 other tauopathies. Blinded to clinical and neuropathological information, raters provided a categorical diagnosis (PSP or not-PSP) based upon provisional criteria that required neurofibrillary tangles or pretangles in two of three regions (substantia nigra, subthalamic nucleus, globus pallidus) and tufted astrocytes in one of two regions (peri-Rolandic cortices, putamen). The criteria showed high sensitivity (0.97) and specificity (0.91), as well as almost perfect inter-rater reliability for diagnosing PSP and differentiating it from other tauopathies (Fleiss kappa 0.826). Most cases (17/25) had 100% agreement across all 14 raters. The Rainwater Charitable Foundation criteria for the neuropathologic diagnosis of PSP feature a simplified diagnostic algorithm based on phosphorylated tau immunohistochemistry and incorporate tufted astrocytes as an essential diagnostic feature.

Association of Tripartite Motif Containing 11 rs564309 With Tau Pathology in Progressive Supranuclear Palsy.

Intronic variant rs564309 in tripartite motif containing 11 (TRIM11) is associated with clinical phenotypic differences in progressive supranuclear palsy (PSP), whereby the minor allele (A) is more common in atypical PSP than typical PSP (PSP-Richardson's syndrome). However, rs564309 has not been investigated relative to neuropathological outcomes. Evaluate the association of rs564309 with the neuropathologically assessed severity of tau pathology, as measured by semi-quantitative scores for neurofibrillary tangles, tufted astrocytes, neuropil threads, and oligodendroglial coiled bodies. 797 neuropathologically confirmed PSP cases were genotyped for TRIM11 rs564309 and assessed for tau pathology across 20 neuroanatomical regions. Tau pathology measures and age at death were examined for association with TRIM11 rs564309-A using multivariable linear regression models. TRIM11 rs564309-A was associated with increased neurofibrillary tangles pathology (P = 0.050), but was not significantly associated with age at death, neuropil threads, coiled bodies, or tufted astrocytes tau pathology scores. TRIM11 rs564309 may influence burden of neurofibrillary tangles tau pathology in PSP; further study is warranted. © 2020 International Parkinson and Movement Disorder Society.

Incipient progressive supranuclear palsy is more common than expected and may comprise clinicopathological subtypes: a forensic autopsy series.

We investigated 998 serial Japanese forensic autopsy cases (0-101years old, mean age 61.7±21.9), with no case selection, using immunohistochemistry to detect cases with progressive supranuclear palsy (PSP). Twenty-nine cases (mean age 82.3±7.2years, 11 males, 18 females) fulfilled the National Institute of Neuronal Disorders and Stroke (NINDS)-PSP pathological criteria (2.9% of all cases, 4.6% of cases over 60). All had neuronal and glial inclusions in the basal ganglia and brainstem. However, 13 cases had low tau pathology and were categorized as atypical PSP. In addition to PSP pathology, multiple types of astrocytic inclusions and comorbid proteinopathies, particularly a high prevalence of argyrophilic grain disease, were found. All cases had not been diagnosed with PSP and had preserved daily functioning prior to death. However, 14 (48.3%), 11 (37.9%), and 16 (55.2%) cases showed signs of dementia, depressive state, and gait disturbance, respectively. Sixteen accidental death cases (55.2%), including from falls and getting lost, and 11 suicide cases (37.9%) appear to have a relationship with incipient PSP pathology. Cluster analysis using the distribution and amount of 4-repeat-tau pathology classified the cases into three subgroups: Group 1 (10 cases) had typical PSP pathology and seven cases (70.0%) had dementia as the most frequent symptom; Group 2 (7 cases) had significantly higher frequency of gait disorder (6 cases, 85.7%), and less neocortical tau pathology than Group 1; Group 3 (12 cases) had relatively mild PSP pathology and high argyrophilic grain burdens. Granular-shaped astrocytes were the dominant astrocytic inclusion in all cases. We conclude that in forensic cases incipient PSP occurs with a higher prevalence than expected. If these findings can be extrapolated to other population-based cohorts, PSP may be more common than previously thought.

Progressive supranuclear palsy (PSP): Richardson syndrome and other PSP variants.

Phenotypic heterogeneity of progressive supranuclear palsy (PSP) has been increasingly reported in the literature and can be the source of incorrect clinical diagnosis particularly in the early stages of the disease when the classically associated symptoms of early falls and supranuclear gaze palsy may not be apparent. In addition to Richardson syndrome (RS), several atypical clinical phenotypes have been described. Advances in genetic, neuroimaging, and biochemical/molecular technologies contribute to the identification of these clinical subtypes in the context of typical PSP pathological findings. Our goal is to review the phenomenology reported in the literature that is associated with confirmed histopathological changes consistent with a PSP diagnosis and to highlight the clinical spectrum of PSP. A systematic review of the literature in PubMed through July 2015 using MeSH terms and key words related to PSP was conducted. Articles describing PSP classifications, diagnostic criteria, and case reports were reviewed and summarized. Additional PSP phenotypes not seen in recent clinicopathological studies are included. These include primary lateral sclerosis, pallido-nigro-luysian degeneration, axonal dystrophy, and multiple system atrophy in the spectrum of atypical PSP variants beyond the traditionally classified PSP subtypes. This review is intended to help with the diagnostic challenges of atypical PSP variants. We believe that large multicenter clinicopathological studies will help expand our understanding of etiology and specific mechanisms of neurodegeneration and will aid in the appropriate interpretation of outcomes when conducting clinical and basic science research.

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.

An autopsied case of progressive supranuclear palsy presenting with cerebellar ataxia and severe cerebellar involvement

A Japanese male patient presented with gait disturbance at the age of 69 years. His principal symptom was cerebellar ataxia for several years. He was initially diagnosed as having olivopontocerebellar atrophy because dysarthria and ataxia gradually developed, and head CT scan showed apparent atrophy of the cerebellum and brainstem and dilatation of the fourth ventricle. Later, he showed vertical gaze palsy, dysphagia, retrocollis, parkinsonism, axial dominant rigidity and grasp reflex, and therefore, the diagnosis was modified to progressive supranuclear palsy (PSP). Progressive atrophy of the frontotemporal lobe, cerebellum and brainstem, and dilatation of the lateral, third and fourth ventricles were evident on MRI. Gastrostomy and tracheotomy were performed 9 and 10 years after onset, respectively, and the patient died after 11 years disease duration. At autopsy the brain weighed 1000 g and showed atrophy of the frontotemporal lobe, cerebellum and brainstem. Neurofibrillary tangles, mainly globose-type revealed by Gallyas-Braak silver staining, were extensively observed in the cerebral cortex and subcortical grey matter. Numerous glial fibrillary tangles, including tuft-shaped astrocytes and coiled bodies, and extensive argyrophilic threads were also recognized, particularly in the frontal lobe, basal ganglia, cerebellar white matter, brainstem and spinal cord. The Purkinje cell layer showed severe neuron loss with Bergmann's gliosis, and the dentate nucleus showed severe neuron loss with grumose degeneration. Tau-positive/Gallyas-positive inclusions in the Purkinje cells and the glial cells of the Purkinje cell layer were observed. Pathological findings of the present patient were consistent with the diagnosis of PSP, but the olivopontocerebellar involvement, particularly in the cerebellum, was generally more severe, and the quantity of tau-positive/Gallyas-positive structures were more abundant than in typical PSP cases. The existence of a distinct, rare PSP subtype with severe olivopontocerebellar involvement, "PSP-C", which tends to be clinically misdiagnosed as spinocerebellar degeneration in the early disease stage, is noteworthy. The present case corresponded to this rare subtype of PSP.

Autopsy-proven progressive supranuclear palsy presenting as behavioral variant frontotemporal dementia

Background: Progressive supranuclear palsy (PSP) is a neurodegenerative disorder pathologically characterized by neuronal loss, gliosis and tau-positive neurofibrillary tangles in basal ganglia, brainstem and cerebellar nuclei. Five presenting clinical syndromes of PSP are well-described: (i) the classic Richardson's syndrome; (ii) asymmetric parkinsonism with tremor; (iii) freezing of gait; (iv) asymmetric limb apraxia, and (v) apraxia of speech. Aim: To determine whether autopsy-proven PSP cases may present with another clinical phenotype. Methods: Medical records of 66 autopsy-proven PSP cases between 1973 and 2010 were reviewed to determine whether all could be classified into one of five well-defined syndromes listed above. Three cases presented with prominent behavioral and personality changes, meeting diagnosis of behavioral variant frontotemporal dementia. MRI midbrain and pons volumes and pons/midbrain ratios were compared to healthy controls and typical PSP cases. Results: All three bvFTD cases developed at least one PSP symptom or sign that emerged up to 5 years after initial presentation. One case was re-diagnosed as PSP 6 years after presentation as bvFTD. Compared to controls, midbrain volume was significantly smaller in both bvFTD (p = .03) and PSP cases (p = .008), without significant difference between PSP and bvFTD cases (.44). However pontine volumes were similar across all three groups. Conclusions: While most autopsy-confirmed PSP cases present with one of the five well-described syndromes, there are cases that may present as bvFTD. In these, at least one cardinal symptom or sign of PSP later emerges, associated with smaller midbrain volume and increased pons/midbrain ratio. Thus underlying PSP pathology should be considered in these cases.

An autopsied case of progressive supranuclear palsy, initially diagnosed as spinocerebellar degeneration with severe olivopontocerebellar involvement

A Japanese female patient presented with dysarthria and gait disturbance with ataxia at the age of 63. She was initially diagnosed with spinocerebellar degeneration because a head CT showed atrophy of the cerebellum and brainstem, and dilatation of the fourth ventricle. Symptoms including abnormal behavior, dementia, vertical gaze palsy, dysphagia, retrocollis, axial rigidity, grasp reflex and positive Babinski's sign were gradually observed. Tegmental atrophy of the brainstem and dilatation of the third ventricle were apparent on images. The diagnosis was modified to progressive supranuclear palsy (PSP), 6 years after the onset of symptoms. Gastrostomy and tracheotomy were performed 7 and 8 years after onset, respectively, and the patient died one year later. At autopsy the brain weighed 1,030g and showed atrophy of the frontal lobe and cerebellum. The brainstem was also atrophic, particularly in the tegmentum and pontine base. Neurofibrillary tangles, mainly globose-type, were widespread in the subcortical structure, particularly in the globus pallidus, subthalamic nucleus, nucleus of the oculomotor nerve, substantia nigra, locus ceruleus, pontine nucleus, and the inferior olivary nucleus. Numerous glial fibrillary tangles and argyrophilic threads were also observed particularly in the frontal lobe, basal ganglia, brainstem and cerebellar white matter. The cerebellar dentate nucleus showed neuron loss with grumose degeneration and the Purkinje neuron layer showed neuron loss and Bergmann's gliosis with torpedoes. Tau positive inclusions in the Purkinje neurons, Bergmann glias and dentate nucleus neurons were observed. Pathological findings were consistent with the diagnosis of PSP but the olivopontocerebellar involvement and the quantity of Gallyas-positive/tau-positive structures were generally more severe than in typical PSP cases. According to these clinicopathologic findings and a review of the literature, we speculate on the existence of a PSP subtype with severe olivopontocerebellar involvement that tends to be clinically misdiagnosed as spinocerebellar degeneration.

Neuropathology of variants of progressive supranuclear palsy

Neurodegenerative tauopathies, of which progressive supranuclear palsy (PSP) is one of the most common, are clinically heterogeneous, reflecting differences in distribution and biochemical composition of tau pathology. This review highlights the range of clinical and pathologic presentations of PSP and its variants. Progressive supranuclear palsy is a 4R tauopathy with neuronal and glial tau-immunoreactive lesions in neuroanatomically specific nuclei in the basal ganglia, diencephalon, brainstem and cerebellum, with restricted involvement of the neocortex. Hierarchical cluster analyses of clinical and pathologic features of PSP indicate that there are distinct clinicopathologic variants of PSP. In variants of PSP presenting with focal cortical syndromes, such as frontotemporal dementia, corticobasal syndrome and apraxia of speech, there is greater cortical pathology than in typical PSP. In variants of PSP presenting with levodopa-responsive Parkinsonism, as well as pure akinesia and gait failure, there is less cortical pathology and more severe degeneration in the cardinal nuclei - globus pallidus, subthalamic nucleus and substantia nigra - than in typical PSP. Clinical variants in PSP reflect varying anatomical distribution of tau pathology, but they share histopathologic, biochemical and genetic features with typical PSP. The basis for anatomical selective vulnerability in PSP and its variants remains to be determined.

Clinical and neuropathologic features of progressive supranuclear palsy with severe pallido-nigro-luysial degeneration and axonal dystrophy

Pallido-nigro-luysial atrophy (PNLA) is a rare disorder that in many cases has histopathological features similar to progressive supranuclear palsy (PSP). In a pathological series of over 400 cases of PSP, eight cases were noted to have features similar to those described in PNLA, including severe atrophy and neuronal loss in the globus pallidus, substantia nigra and subthalamic nucleus, in addition to many axonal spheroids in the globus pallidus and substantia nigra. These eight cases of PSP-PNLA were compared to 11 typical PSP cases with quantitative neuropathologic indices and assessment of demographics, clinical features and the timing of clinical features. PSP-PNLA cases were younger, had longer disease duration and more often were not initially diagnosed with PSP; in the end, they did not differ from PSP with respect to any major clinical feature. The clinical course of PSP-PNLA, however, was different, with earlier gait abnormalities and difficulty with handwriting, but later falls, rigidity and dysphagia than PSP. Pathologically, the same types of lesions were detected in both PSP and PSP-PNLA, but there were differences in the distribution and density of tau-pathology, with less tau-pathology in motor cortex, striatum, pontine nuclei and cerebellum in PSP-PNLA. These clinical and pathological findings suggest that PSP-PNLA should be considered a variant of PSP.

Frontal presentation in progressive supranuclear palsy

Progressive supranuclear palsy (PSP) is a progressive hypokinetic rigid disorder with supranuclear gaze palsy and frequent falls. Although clinical consensus criteria are available, an atypical presentation may lead to clinical misdiagnosis in the initial phase. In the present study we investigated the clinical presentation of PSP and its relationship to initial clinical diagnosis and survival. We ascertained patients with PSP in a prospective cohort by nationwide referral from neurologists and nursing home physicians. All patients underwent a structural interview and clinical examination before entering the study. Medical records were reviewed for the presence of symptoms during the first 2 years. A total of 152 patients ascertained between 2002 and 2005 fulfilled the international consensus criteria for PSP. Categorical principal component analysis of clinical symptoms within the first 2 years showed apart from a cluster of typical PSP symptoms, the clustering of cognitive dysfunction and behavioral changes. Further analysis showed that 20% of patients had a predominant frontal presentation with less than two other PSP symptoms. Survival analysis showed that this subgroup had a similar prognosis to that of the total group of patients with PSP. There exists a subgroup of patients with progressive supranuclear palsy (PSP) with a predominant frontal presentation, who progressed into typical PSP over the course of the disease.

Atypical progressive supranuclear palsy underlying progressive apraxia of speech and nonfluent aphasia

Progressive supranuclear palsy (PSP) is a clinicopathological entity typically presenting as an akinetic rigid syndrome with early falls, axial rigidity, vertical supranuclear gaze palsy and levodopa resistance. Pathological features consist of tau deposition in neuronal and glial cells located mainly in subcortical and brainstem structures. Rare cases with the pathological diagnosis of atypical PSP have been described in which neocortical tau deposition is more widespread than what is usually seen in typical PSP. Progressive nonfluent aphasia (PNFA) is a syndrome characterized by spontaneous nonfluent speech and early preserved comprehension of language. Apraxia of speech (AOS) is a motor speech disorder that may be a feature of PNFA. We report the clinical and pathological findings of four cases that presented with features most consistent with PNFA predominated by AOS. Pathological features in these four cases included the typical features of PSP subcortically and in brainstem structures, but combined with tau-positive neuronal and glial pathology in the neocortex. Comprehensive semiquantitative analyses of tau burden including neurofibrillary tangles and pretangles, coiled bodies, tufted astrocytes and threads were undertaken in the four cases of atypical PSP and compared to 10 cases of typical PSP. Semiquantitative analysis demonstrated that in atypical PSP, the pathology shifts from subcortical grey and brainstem regions, commonly affected in typical PSP, towards neocortical regions. This shift in pathology accounts for the presentation of PNFA and AOS observed in our patients, as well as the lack of classic features of PSP. These cases demonstrate that atypical PSP can present as AOS and PNFA without the classic features of PSP. Supported by grants AG 16574 and AG 07216 from the National Institute on Aging, and the Society for Progressive Supranuclear Palsy brain bank. We extend our appreciation to the patients and families for participating in research on aging and dementia. We appreciate the generous donation of antibodies for our studies from Dr. Peter Davies, Albert Einstein College of Medicine, Bronx, NY. Case 4 has already been published. This study was presented at the 9th International Conference on Alzheimer’s Disease and Related Disorders, July 17–22, 2004 in Philadelphia, Pennsylvania, USA.

Genetic linkage of autosomal dominant progressive supranuclear palsy to 1q31.1

Progressive supranuclear palsy (PSP) is a disorder of unknown pathogenesis. Familial clusters of PSP have been reported related to mutations of protein tau. We report the linkage of a large Spanish family with typical autosomal dominant PSP to a new locus in chromosome 1. Four members of this family had typical PSP, confirmed by neuropathology in one case. At least five ancestors had similar disease. Other members of the family have incomplete phenotypes. The power of the linkage analysis was increased by detecting presymptomatic individuals with 18F-fluoro-dopa and 18F-deoxyglucose positron emission tomography. We screened the human genome with 340 polymorphic markers and we enriched the areas of interest with additional markers. The disease status was defined according to the clinical and positron emission tomography data. We excluded linkage to the tau gene in chromosome 17. PSP was linked, in this family, to one area of 3.4 cM in chromosome 1q31.1, with a maximal multipoint < OD score of +3.53. This area contains at least three genes, whose relevance in PSP is unknown. We expect to further define the gene responsible for PSP, which could help to understand the pathogenesis of this disease and to design effective treatment.

Characteristics of two distinct clinical phenotypes in pathologically proven progressive supranuclear palsy: Richardson's syndrome and PSP-parkinsonism

The clinical diagnosis of progressive supranuclear palsy (PSP) relies on the identification of characteristic signs and symptoms. A proportion of pathologically diagnosed cases do not develop these classic features, prove difficult to diagnose during life and are considered as atypical PSP. The aim of this study was to examine the apparent clinical dichotomy between typical and atypical PSP, and to compare the biochemical and genetic characteristics of these groups. In 103 consecutive cases of pathologically confirmed PSP, we have identified two clinical phenotypes by factor analysis which we have named Richardson's syndrome (RS) and PSP-parkinsonism (PSP-P). Cases of RS syndrome made up 54% of all cases, and were characterized by the early onset of postural instability and falls, supranuclear vertical gaze palsy and cognitive dysfunction. A second group of 33 (32%) were characterized by asymmetric onset, tremor, a moderate initial therapeutic response to levodopa and were frequently confused with Parkinson's disease (PSP-P). Fourteen cases (14%) could not be separated according to these criteria. In RS, two-thirds of cases were men, whereas the sex distribution in PSP-P was even. Disease duration in RS was significantly shorter (5.9 versus 9.1 years, P < 0.001) and age at death earlier (72.1 versus 75.5 years, P = 0.01) than in PSP-P. The isoform composition of insoluble tangle-tau isolated from the basal pons also differed significantly. In RS, the mean four-repeat:three-repeat tau ratio was 2.84 and in PSP-P it was 1.63 (P < 0.003). The effect of the H1,H1 PSP susceptibility genotype appeared stronger in RS than in PSP-P (odds ratio 13.2 versus 4.5). The difference in genotype frequencies between the clinical subgroups was not significant. There were no differences in apolipoprotein E genotypes. The classic clinical description of PSP, which includes supranuclear gaze palsy, early falls and dementia, does not adequately describe one-third of cases in this series of pathologically confirmed cases. We propose that PSP-P represents a second discrete clinical phenotype that needs to be clinically distinguished from classical PSP (RS). The different tau isoform deposition in the basal pons suggests that this may ultimately prove to be a discrete nosological entity.

Distribution of tuft-shaped astrocytes in the cerebral cortex in progressive supranuclear palsy.

The deposition of abnormal levels of tau protein is a major neuropathological feature of progressive supranuclear palsy (PSP), and the presence of tuft-shaped astrocytes is a neuropathological hallmark of PSP. We examined the topographic distribution of tuft-shaped astrocytes in the cerebral hemisphere by Gallyas-Braak silver staining in three Japanese autopsy cases of typical PSP. The distribution of tuft-shaped astrocytes was relatively uniform between cases. Tuft-shaped astrocytes were identified predominantly in posterior frontal areas such as the precentral gyrus and premotor and supplementary motor areas (Brodmann areas 4, 6 and 8). Tuft-shaped astrocytes were most dense in areas of cortical convexity, and they were more abundant in the crests of the cerebral gyri than in the valleys of the cerebral sulci. The temporal, parietal and occipital cortices, including the hippocampal formation and cingulate gyrus, were relatively free of tuft-shaped astrocytes. We confirmed involvement of the cerebral cortex in the pathology of PSP, and showed the widespread presence of tuft-shaped astrocytes, particularly in the precentral gyrus and premotor and supplementary motor areas, to be an essential neuropathological feature of PSP. The extra-pyramidal and pyramidal signs, supranuclear oculomotor abnormalities and other cortical signs associated with PSP may be related to the high density of tuft-shaped astrocytes in the precentral gyrus and premotor and supplementary motor areas. Dementia, apraxia, aphasia and frontal lobe signs may also result, at least in part, from this cortical involvement.

Proton magnetic resonance spectroscopy in corticobasal degeneration and progressive supranuclear palsy

Background: Corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) each have distinctive clinical features, but diagnosis is often uncertain. Our purpose was to evaluate whether localized, single‐voxel proton magnetic resonance spectroscopy (1H‐MRS) could distinguish between typical CBD and PSP patients.Methods: The study included 10 patients with CBD, nine with PSP and eight age‐matched normal healthy subjects. A single‐voxel method of 8 cm3 (2 × 2 × 2 cm) was used for 1H‐MRS. The volume of interest was selected at the frontoparietal cortex and the lentiform nucleus.Results: Patients with CBD had significantly reduced ratios of N‐acetylaspartate to choline‐containing compounds (NAA/Cho), N‐acetylaspartate to creatine and phosphocreatine (NAA/Cr) in the frontoparietal cortex and lentiform nucleus compared with the normal subjects. Patients with PSP had significantly reduced NAA/Cho and NAA/Cr ratios in the lentiform nucleus, but not in the frontoparietal cortex compared with normal subjects. There was a significant difference in the NAA/Cho in the frontoparietal lobe between CBD and PSP patients.Conclusion: 1H‐MRS may indicate different regional patterns of neuronal involvement in CBD and PSP. We suggest that this could be helpful in the differentiation and diagnostic evaluation of CBD and PSP patients.

Expression and activity of antioxidants in the brain in progressive supranuclear palsy

Recent evidence implicates oxidative stress in the pathophysiology of progressive supranuclear palsy (PSP). Thus, we undertook a study of the activity and localization of two essential antioxidant systems (superoxide dismutase [SOD] enzymes and total glutathione) in the human post-mortem PSP and control brain. Marked increases in SOD1 (Cu/ZnSOD) activity and glutathione levels were measured within most PSP brain regions examined, whereas, only the subthalamic nucleus exhibited a significant increase (+68%) in SOD2 (MnSOD) activity. Two additional cases with mild pathological abnormalities were studied. The first (case A) may represent an example of an asymptomatic PSP case, while the second (case B) had mild pathological abnormalities consistent with typical PSP. In case A, only the STN had elevated levels of SOD activity, in the absence of an increase in tissue glutathione content. In case B, SOD activities and tissue glutathione content were elevated in several regions. Immunolocalization of the SOD1 and SOD2 proteins in paraffin-embedded tissue sections revealed a marked increase in the density of SOD immunopositive profiles (particularly glia) in the typical PSP brain, particularly within the white matter. Together, our data argues strongly in favor of the involvement of oxidative stress in the etiology and progression of PSP, and suggests that deficit in SOD or glutathione metabolism are not causative.

The tau gene in progressive supranuclear palsy: exclusion of mutations in coding exons and exon 10 splice sites, and identification of a new intronic variant of the disease-associated H1 haplotype in Italian cases

Mutations in coding exons or exon 10 5′-splice-site of the gene for microtubule-associated protein tau can cause chromosome 17-linked frontotemporal dementia and parkinsonism (FTDP-17). We sequenced the 11 coding exons plus exon-intron boundaries of the tau gene in 15 cases of progressive supranuclear palsy (PSP), and found no mutations in coding exons or exon ten 5′-splice sites. These data indicate that typical PSP is not associated with tau gene mutations similar to those causing FTDP-17. We also observed a +39ΔG base change in the intron following exon 4 in three out of 69 PSP cases (all three Italians), whereas it was not found in 150 Dutch controls and once in 112 Italian controls. The +39ΔG variant arose in the context of the PSP-associated tau H1 haplotype. Although a pathogenic role cannot be entirely excluded, +39ΔG is likely to be a rare polymorphism that may be in linkage disequilibrium with a biologically relevant locus inside or near to the tau gene.

Astrocytic plaques and tufts of abnormal fibers do not coexist in corticobasal degeneration and progressive supranuclear palsy.

Corticobasal degeneration (CBD) and progressive supranuclear palsy (PSP) are characterized by their unique clinical features and neuronal pathology. Although astrocytic plaques and tufts of abnormal fibers have been suggested to be specific histopathologic markers, recent studies have revealed significant clinicopathologic overlap between CBD and PSP. Based on the distinctive camera lucida profile of astrocytic inclusions on Gallyas-Braak silver staining, we found that astrocytic plaques and tufts of abnormal fibers did not coexist in the same patient among 30 cases of clinically diagnosed CBD, PSP and atypical Parkinson's disease. Using Tau immunohistochemistry it was difficult to verify the absence of tufts of abnormal fibers. A morphometric analysis revealed that the two groups classified by the presence or absence of astrocytic plaques and tufts of abnormal fibers exhibited significant differences in the density of ballooned neurons and neurofibrillary tangles and degeneration of the subcortical nuclei. Assessment using the NINDS neuropathologic criteria revealed that the cases with astrocytic plaques and tufts of abnormal fibers closely correspond to CBD and typical PSP, respectively. In addition, the cases lacking either of these two astrocytic inclusions had atypical PSP according to the NINDS criteria, and were associated with novel tau-positive astrocytes (spiny astrocytes). We thus conclude that astrocytic plaques and tufts of abnormal fibers are highly characteristic structures for CBD and typical PSP, respectively. We emphasize the importance of strict differentiation between different astrocytic inclusions not only for diagnosis, but also for further studies for elucidation of their role in the disease mechanisms of CBD and PSP.