Relation between clinical findings and progression of cerebral cortical pathology in MM1-type sporadic Creutzfeldt-Jakob disease: proposed staging of cerebral cortical pathology

Vacuoles related to tissue neuron-astrocyte ratio and infiltration of macrophages/monocytes contribute to hyperintense brain signals on diffusion-weighted magnetic resonance imaging in sporadic Creutzfeldt-Jakob disease

BACKGROUND

Radiological features in patients with sporadic Creutzfeldt-Jakob disease (sCJD) are hyperintensity of the cerebral cortex and the basal ganglia displayed by diffusion-weighted magnetic resonance imaging (DW-MRI). We performed a quantitative study on neuropathological and radiological findings.

METHODS

Patient 1 received a definite diagnosis of MM1-type sCJD, while patient 2 received a definite diagnosis of MM1 + 2-type sCJD. Two DW-MRI scans were performed on each patient. DW-MRI was either taken the day before or on the day of the patient's death, and several hyperintense or isointense areas were marked as a region of interest (ROI). Mean signal intensity of the ROI was measured. Pathological quantitative assessments of the vacuoles, astrocytosis, infiltration of monocytes/macrophages, and proliferation of microglia was performed. Vacuole load (% area vacuole), glial fibrillary acidic protein (GFAP), CD68, and Iba-1 load were calculated. We defined spongiform change index (SCI) to indicate vacuoles related to a tissue neuron-astrocyte ratio. We assessed the correlation of intensity of the last DW-MRI and the pathological findings as well as association of changes of the signal intensity on the sequential images and the pathological findings.

RESULT

We observed a strong positive correlation between SCI and DW-MRI intensity. In the analysis using serial DW-MRI and pathological findings, we found that CD68 load was significantly larger in areas where signal intensity decreased, as compared to those areas where hyperintensity remained unchanged.

CONCLUSION

DW-MRI intensity in sCJD is associated with the ratio of neuron to astrocyte in the vacuoles and the infiltration of macrophages and/or monocytes.

Systematic Review of Clinical and Pathophysiological Features of Genetic Creutzfeldt-Jakob Disease Caused by a Val-to-Ile Mutation at Codon 180 in the Prion Protein Gene

Genetic Creutzfeldt-Jakob disease (gCJD) is a subtype of genetic prion diseases (gPrDs) caused by the accumulation of mutated pathological prion proteins (PrPSc). gCJD has a phenotypic similarity with sporadic CJD (sCJD). In Japan, gCJD with a Val to Ile substitution at codon 180 (V180I-gCJD) is the most frequent gPrD, while the mutation is extremely rare in countries other than Japan and Korea. In this article, we aim to review previously elucidated clinical and biochemical features of V180I-gCJD, expecting to advance the understanding of this unique subtype in gCJD. Compared to classical sCJD, specific clinical features of V180I-gCJD include older age at onset, a relatively slow progression of dementia, and a lower positivity for developing myoclonus, cerebellar, pyramidal signs, and visual disturbance. Diffuse edematous ribboning hyperintensity of the cerebral cortex, without occipital lobes in diffusion-weighted magnetic resonance imaging, is also specific. Laboratory data reveal the low positivity of PrPSc in the cerebrospinal fluid and periodic sharp wave complexes on an electroencephalogram. Most patients with V180I-gCJD have been reported to have no family history, probably due to the older age at onset, and clinical and biochemical features indicate the specific phenotype associated with the prion protein gene mutation.

Brain Imaging in Epilepsy-Focus on Diffusion-Weighted Imaging

Epilepsy is a common neurological disorder; 1% of people worldwide have epilepsy. Differentiating epileptic seizures from other acute neurological disorders in a clinical setting can be challenging. Approximately one-third of patients have drug-resistant epilepsy that is not well controlled by current antiepileptic drug therapy. Surgical treatment is potentially curative if the epileptogenic focus is accurately localized. Diffusion-weighted imaging (DWI) is an advanced magnetic resonance imaging technique that is sensitive to the diffusion of water molecules and provides additional information on the microstructure of tissue. Qualitative and quantitative analysis of peri-ictal, postictal, and interictal diffusion images can aid the differential diagnosis of seizures and seizure foci localization. This review focused on the fundamentals of DWI and its associated techniques, such as apparent diffusion coefficient, diffusion tensor imaging, and tractography, as well as their impact on epilepsy in terms of differential diagnosis, epileptic foci determination, and prognosis prediction.

An autopsy case of MV2K-type sporadic Creutzfeldt-Jakob disease presenting with characteristic clinical, radiological, and neuropathological findings

In Japan, because MV2-type sporadic Creutzfeldt-Jakob disease (CJD) is rare, little is known about its clinical and neuropathological characteristics. An autopsy case of MV2K-type sporadic CJD is presented, and the characteristic clinical, radiological, and neuropathological findings are discussed. The patient was a Japanese woman who died at the age of 72 years. Her initial symptom was rapidly progressive dementia. She then developed truncal ataxia and delusions. Approximately nine months after onset, she exhibited akinetic mutism. The total clinical course was 11 months. Magnetic resonance imaging revealed hyperintensity areas in the basal ganglia, thalamus, and hippocampus on diffusion-weighted images. In the cerebral cortex, this finding was slight and inconspicuous. Electroencephalography revealed no periodic sharp wave complexes. Prion protein (PrP) gene analysis revealed no mutations, and polymorphic codon 129 exhibited methionine and valine heterozygosity. In the cerebrospinal fluid, levels of both total tau and 14-3-3 proteins were elevated. Grossly, the brain weighed 1050 g before fixation and exhibited diffuse cortical atrophy. On histopathological examination, extensive fine vacuole-type spongiform degeneration was noted in the cerebral cortex. Numerous kuru plaques were observed in the cerebellum. PrP immunohistochemistry revealed extensive diffuse synaptic- and perineuronal-type PrP deposits in the cerebral cortex. Kuru plaques were strongly immunoreactive for PrP. Western blot analysis of brain tissue samples revealed mixed type 2 and intermediate type. Systematic and comprehensive investigations of both clinical and neuropathological aspects are required for accurate diagnosis.

System degeneration in an MM1-type sporadic Creutzfeldt-Jakob disease case with an unusually prolonged akinetic mutism state

Methionine/methionine type 1 (MM1-type) sporadic Creutzfeldt-Jakob disease (sCJD), known as the ‘classic type,’ shows typical clinicopathological sCJD findings. In general, patients reach an akinetic mutism state within a few months of disease onset and die soon after if supportive therapies are not administered. Here, we describe remarkable neuropathologic observations of MM1-type sCJD in a 48-year-old, Japanese man with an unusually prolonged akinetic mutism state. In the early disease stages, the patient exhibited abnormal behaviour with gait disturbance and rapidly progressive cognitive dysfunction. Diffusion-weighted magnetic resonance imaging revealed extensive cerebral cortical hyperintensity. Prion protein (PrP) gene analysis revealed no mutations, and the polymorphic codon 129 exhibited methionine homozygosity. Although the patient remained stable with tube feeding for more than 2 years after reaching the akinetic mutism state, he died because of central respiratory failure 30 months after disease onset. Neuropathologic investigation showed extensive devastating lesions, such as status spongiosus, and typical spongiform changes could no longer be observed in the cerebral neocortex. Conspicuous pyramidal tract degeneration was observed. However, the regions commonly preserved in MM1-type sCJD pathology were still relatively preserved. Immunostaining revealed extensive diffuse synaptic-type PrP deposition in the grey matter. The pathological findings suggested that sCJD is a neurodegenerative disease that shows system degeneration; there are primary and secondary degenerative regions and distinct preserved regions, even in cases with prolonged disease duration. In addition, it is considered that there is a limited survival period for MM1-type sCJD, even if active symptomatic treatment is provided.

Multimodal MRI staging for tracking progression and clinical-imaging correlation in sporadic Creutzfeldt-Jakob disease

Diffusion imaging is very useful for the diagnosis of sporadic Creutzfeldt-Jakob disease, but it has limitations in tracking disease progression as mean diffusivity changes non-linearly across the disease course. We previously showed that mean diffusivity changes across the disease course follow a quasi J-shaped curve, characterized by decreased values in earlier phases and increasing values later in the disease course. Understanding how MRI metrics change over-time, as well as their correlations with clinical deficits are crucial steps in developing radiological biomarkers for trials. Specifically, as mean diffusivity does not change linearly and atrophy mainly occurs in later stages, neither alone is likely to be a sufficient biomarker throughout the disease course. We therefore developed a model combining mean diffusivity and Volume loss (MRI Disease-Staging) to take into account mean diffusivity's non-linearity. We then assessed the associations between clinical outcomes and mean diffusivity alone, Volume alone and finally MRI Disease-Staging. In 37 sporadic Creutzfeldt-Jakob disease subjects and 30 age- and sex-matched healthy controls, high angular resolution diffusion and high-resolution T1 imaging was performed cross-sectionally to compute z-scores for mean diffusivity (MD) and Volume. Average MD and Volume were extracted from 41 GM volume of interest (VOI) per hemisphere, within the images registered to the Montreal Neurological Institute (MNI) space. Each subject's volume of interest was classified as either "involved" or "not involved" using a statistical threshold of ± 2 standard deviation (SD) for mean diffusivity changes and/or -2 SD for Volume. Volumes of interest were MRI Disease-Staged as: 0 = no abnormalities; 1 = decreased mean diffusivity only; 2 = decreased mean diffusivity and Volume; 3 = normal ("pseudo-normalized") mean diffusivity, reduced Volume; 4 = increased mean diffusivity, reduced Volume. We correlated Volume, MD and MRI Disease-Staging with several clinical outcomes (scales, score and symptoms) using 4 major regions of interest (Total, Cortical, Subcortical and Cerebellar gray matter) or smaller regions pre-specified based on known neuroanatomical correlates. Volume and MD z-scores correlated inversely with each other in all four major ROIs (cortical, subcortical, cerebellar and total) highlighting that ROIs with lower Volumes had higher MD and vice-versa. Regarding correlations with symptoms and scores, higher MD correlated with worse Mini-Mental State Examination and Barthel scores in cortical and cerebellar gray matter, but subjects with cortical sensory deficits showed lower MD in the primary sensory cortex. Volume loss correlated with lower Mini-Mental State Examination, Barthel scores and pyramidal signs. Interestingly, for both Volume and MD, changes within the cerebellar ROI showed strong correlations with both MMSE and Barthel. Supporting using a combination of MD and Volume to track sCJD progression, MRI Disease-Staging showed correlations with more clinical outcomes than Volume or MD alone, specifically with Mini-Mental State Examination, Barthel score, pyramidal signs, higher cortical sensory deficits, as well as executive and visual-spatial deficits. Additionally, when subjects in the cohort were subdivided into tertiles based on their Barthel scores and their percentile of disease duration/course ("Time-Ratio"), subjects in the lowest (most impaired) Barthel tertile showed a much greater proportion of more advanced MRI Disease-Stages than the those in the highest tertile. Similarly, subjects in the last Time-Ratio tertile (last tertile of disease) showed a much greater proportion of more advanced MRI Disease-Stages than the earliest tertile. Therefore, in later disease stages, as measured by time or Barthel, there is overall more Volume loss and increasing MD. A combined multiparametric quantitative MRI Disease-Staging is a useful tool to track sporadic Creutzfeldt-Jakob- disease progression radiologically.

Analysis of Chinese patients with sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare, incurable, and fatal neurodegenerative disorder. The objective of this study was to describe the clinical features and survival time of Chinese sCJD patients, and to explore the associations between clinical data and survival. In this study, we analysed the clinical data of 21 sCJD patients in a tertiary care hospital and used all Chinese case material available from 152 patients with sCJD in literatures between 2008 and 2018. The mean age of onset of all 173 deceased patients was 61.44 year-olds (y), with the highest incidence in the population of 60 to 69 y. The most common manifestation at disease onset was progressive dementia. With the progression of the disease, the four main clinical symptoms and signs were developed, including myoclonus, visual or cerebella disturbance, pyramidal or extrapyramidal dysfunction, and akinetic mutism. Extrapyramidal symptoms were more frequently observed. The mean survival time was 7.34 months, and 82.10% of cases died within 1 year after disease onset. The follow-up showed that the survival time was longer and the myoclonus sign was more frequently presented in younger-onset sCJD patients. Patients with abnormalities only in cortical regions had a higher frequency of pyramidal dysfunction than patients having lesions in both cortex and basal ganglia. The findings of this study might provide some insight into the clinical characteristics of sCJD patients in China, but further studies could examine the presences of clinical features and survival time in patients with early age of onset in a prospective manner.

The Braak hypothesis in prion disease with a focus on Creutzfeldt-Jakob disease

This review considers whether the Braak hypothesis on protein propagation could account for prion disease, particularly Creutzfeldt-Jakob disease (CJD). In CJD, we can speculate on the pathological onset region to some degree in reference to the clinical symptoms and magnetic resonance imaging findings. Although relating the Braak hypothesis to prion disease is not straightforward, the following could be proposed based on experimental and previously reported case observations. Pathogenic abnormal prion protein (PrP) deposition in the central nervous system (CNS) probably begins several months or years before clinical symptom onset, signifying the potentiality of a preclinical stage, similar to α-synuclein deposition in Parkinson's disease (PD) and amyloid-β/tau deposition in Alzheimer's disease (AD). Unlike in PD and AD, the initial clinical symptoms of CJD vary by case, and thus the onset lesions must also be various and multiple in the CNS. Based on the pathological findings, particularly of PrP deposition extensively observed in the CNS gray matter of autopsy cases, it could be speculated that in the early disease stage, including the preclinical stage, abnormal PrP spreads from the onset region without directionality or hierarchy. Because each CNS region shows either vulnerability to or resistance against PrP deposition and pathological progression in prion disease, the lesion distribution shows system degeneration. Although pathologically combined cases of type 1 and type 2 PrP patterns are often recognized, type 1 and type 2 PrP patterns must never shift toward each other during the disease course; in other words, the original type of PrP deposition in each region presumably remains unchanged in each case. According to the several observations and corresponding speculations, there are at least partial similarities between prion disease and protein propagation, as explained by the Braak hypothesis, in terms of pathological lesion progression, but several noted contradictions preclude the hypothesis from comprehensively accounting for prion disease.

Detection of Pathognomonic Biomarker PrPSc and the Contribution of Cell Free-Amplification Techniques to the Diagnosis of Prion Diseases

Transmissible spongiform encephalopathies or prion diseases are rapidly progressive neurodegenerative diseases, the clinical manifestation of which can resemble other promptly evolving neurological maladies. Therefore, the unequivocal ante-mortem diagnosis is highly challenging and was only possible by histopathological and immunohistochemical analysis of the brain at necropsy. Although surrogate biomarkers of neurological damage have become invaluable to complement clinical data and provide more accurate diagnostics at early stages, other neurodegenerative diseases show similar alterations hindering the differential diagnosis. To solve that, the detection of the pathognomonic biomarker of disease, PrP^Sc, the aberrantly folded isoform of the prion protein, could be used. However, the amounts in easily accessible tissues or body fluids at pre-clinical or early clinical stages are extremely low for the standard detection methods. The solution comes from the recent development of in vitro prion propagation techniques, such as Protein Misfolding Cyclic Amplification (PMCA) and Real Time-Quaking Induced Conversion (RT-QuIC), which have been already applied to detect minute amounts of PrP^Sc in different matrixes and make early diagnosis of prion diseases feasible in a near future. Herein, the most relevant tissues and body fluids in which PrP^Sc has been detected in animals and humans are being reviewed, especially those in which cell-free prion propagation systems have been used with diagnostic purposes.

Clinicopathological findings of a long-term survivor of V180I genetic Creutzfeldt-Jakob disease

The clinical characteristics of genetic Creutzfeldt-Jakob disease (gCJD) with a V180I mutation in the PRNP gene (V180I gCJD) are unique: elderly-onset, gradual progression, sporadic fashion, and cortical oedematous hyper-intensity on diffusion-weighted MRI (DW-MRI). This phenotype may become a potential target of future clinical therapeutic trials. The average disease duration of V180I gCJD patients is 23–27 months; however, considerably long-term survivors are also reported. The factors influencing survival and the clinicopathological characteristics of long-term survivors remain unknown. Herein, we report clinicopathological findings of a long-term survivor of V180I gCJD. A 78-year old woman was admitted to our hospital due to dementia and left hand tremor approximately 1.5 months after symptom onset. Neurological examination revealed dementia, frontal signs, and left hand tremor at admission. She had no family history of dementia or other neurological disease. DW-MRI revealed cortical oedematous hyper-intensities in the bilateral frontal lobes and the right temporal and parietal lobes. PRNP gene analysis indicated a V180I mutation with methionine homozygosity at codon 129. The symptoms gradually progressed, and she died of aspiration pneumonia 61 months after symptom onset. Neuropathological examination revealed severe cerebral atrophy with moderate to severe gliosis, but the brainstem was well preserved. Various-sized and non-confluent vacuole type spongiform changes were extensively observed in the cerebral cortices. Prion protein (PrP) immunostaining revealed weak and synaptic-type PrP deposits in the cerebral cortices. We consider that long-term tube feeding, and very mild brainstem involvement may be associated with the long-term survival of our V180I gCJD patient.

Correlating diffusion-weighted MRI intensity with type 2 pathology in mixed MM-type sporadic Creutzfeldt-Jakob disease

The existence of affected subjects with both abnormal prion protein (PrP^Sc) types has been reported, and their clinical features were somewhat similar to the dominant PrP^Sc type but varied in sporadic Creutzfeldt-Jakob disease (sCJD). Presently, the antemortem identification of both PrP^Sc types in sCJD is not possible. In this study, we attempted to clinically predict the concurrence of MM-type sCJD with another PrP^Sc type in the same individual. We retrospectively identified seven MM-type sCJD cases with both fine vacuole-type spongiform (FV) and large confluent vacuole-type spongiform change (LCV) among 49 sCJD cases. We reviewed clinical features, pathological findings, and radiological abnormalities in these seven cases. We also conducted a regional systemic study with five brains to associate the spongiform-change pattern with hyperintensity on magnetic resonance diffusion-weighted imaging (DWI) using the signal intensity index (SII). In the case series study, the one patient with dominant LCV showed longer disease duration, later onset of typical symptoms, no periodic sharp wave complexes in electroencephalography, and negative 14-3-3 protein findings compared to the six FV-dominant patients. LCV-dominant lesions tended to show higher intensity on DWI than did the FV-dominant lesions in respective patients. In the regional systemic study, LCV-dominant regions showed significantly higher SII on DWI than did the FV-dominant regions. In conclusion, mixed MM-type sCJD generally showed the clinical features of the phenotype that was dominant in pathological distribution. The SII may be clinically useful for investigating the concurrence of PrP^Sc type 2 in cases with the typical clinical course of MM1-type sCJD.

Autopsied case of sporadic Creutzfeldt-Jakob disease classified as MM1+2C-type

We encountered an autopsy case of sporadic Creutzfeldt-Jakob disease (CJD) pathologically classified as MM1+2C-type, where Western blot analysis of prion protein (PrP) mainly showed type-1 scrapie PrP (PrP^Sc ) but also, partially, mixed type-2 PrP^Sc . A Japanese woman complained of visual disorder at the age of 86 years and then showed disorientation and memory disturbances. Magnetic resonance imaging (MRI) showed cerebral cortical hyperintensity on diffusion-weighted images. The patient died 2 months after the onset of symptoms; her condition did not reach the akinetic mutism state and periodic sharp-wave complexes on electroencephalography and myoclonus were not recognized. The brain weighed 1100 g and neuropathological examination showed extensive fine vacuole-type spongiform changes in the cerebral cortex. In some cortical regions, large confluent vacuole-type spongiform changes were also present. Gliosis and hypertrophic astrocytosis were generally mild, and tissue rarefaction of the neuropil and neuronal loss were not apparent. PrP immunostaining showed diffuse synaptic-type PrP deposition in the cerebral gray matter, but some regions with large confluent vacuoles showed perivacuolar-type deposition. We speculated, based on the clinicopathological findings and previous reports, that most MM1-type sporadic CJD cases may be associated with type-2 PrP^Sc , at least partially, within certain regions of the cerebrum.

An autopsied case of MM1-type sporadic Creutzfeldt-Jakob disease with pathology of Wernicke encephalopathy

An 83-year-old Japanese man presented with gait disturbance followed by rapidly-progressive cognitive impairment. Magnetic resonance diffusion-weighted images showed extensive hyperintense regions in the cerebral cortex. Four weeks after symptom onset, myoclonus appeared, and the patient developed difficulty swallowing; intravenous peripheral continuous infusions without vitamin supplementation were administered during the last two months of the patient’s life. The patient reached the akinetic mutism state and died 12 weeks after symptom onset due to sepsis. The brain weighed 940 g and showed general cerebral atrophy. Extensive spongiform change were observed in the cerebral cortex, striatum, thalamus, and cerebellar cortex, but gliosis was generally mild. Numerous newly-developed hemorrhage foci were observed in the mammillary body, the areas adjacent to the third and fourth ventricles, and the periaqueduct of the midbrain; however, proliferation of capillaries and endothelium and collections of macrophages were relatively inconspicuous. These findings suggested comorbidity with the acute stage of Wernicke encephalopathy (WE). Immunostaining showed extensive diffuse synaptic-type prion protein deposition in the gray matter. According to the neuropathological, genetic, and molecular findings, the present case was finally diagnosed as MM1-type sporadic Creutzfeldt-Jakob disease (CJD) with WE. We should remain alert to the diagnosis of WE when CJD is suspected, and it is necessary to consider the complications of both diseases. This report emphasizes the importance of pathological investigations for the diagnosis of CJD, WE, and the coexistence of both.

Autopsy case of V180I genetic Creutzfeldt-Jakob disease presenting with early disease pathology

The patient was a Japanese woman who experienced a decrease in activity and gait disturbance as the initial symptoms at the age of 86, followed by disorientation and memory dysfunction. Magnetic resonance imaging showed extensive cortical regions with hyperintensity in diffusion-weighted images, and these regions showed swelling in T2-weighted and fluid-attenuated inversion recovery (FLAIR) images. The medial occipital cortex and striatum showed no apparent hyperintensity on diffusion-weighted imaging (DWI). Mild myoclonus was detected, and the patient died 10 months after the onset of symptoms; she did not enter the akinetic mutism state. The patient's brain weighed 1050 g, and neuropathological examination showed extensive characteristic various-sized and non-confluent (VaSNoC) vacuoles in the cerebral cortex. These vacuoles were observable macroscopically by loupe on images of hematoxylin and eosin-stained tissue. Gliosis, hypertrophic astrocytosis, and neuron loss were generally mild in character. Prion protein (PrP) immunostaining showed very mild diffuse-synaptic-type PrP deposition in the cerebral gray matter. These clinicopathological findings led us to several conclusions relative to the early disease pathology of V180I genetic Creutzfeldt-Jakob disease: (i) spongiform change was not found in the medial occipital cortex, which corresponds to the results of DWI; (ii) VaSNoC-type spongiform changes, extensively recognized in the cerebral cortex, corresponded to the DWI findings showing continued hyperintensity with higher brightness, and T2-weighted and FLAIR images findings showing a swelling; and (iii) spongiform changes first appear in the deeper layer and subsequently in the superficial layer in the cerebral cortex.

Pathological progression of genetic Creutzfeldt-Jakob disease with a PrP V180I mutation

In comparison to sporadic Creutzfeldt-Jakob disease (sCJD) with MM1-type and MM2- cortical (MM2C)-type, genetic CJD with a prion protein gene V180I mutation (V180I gCJD) is clinically characterized by onset at an older age, slower progress, and the absence of visual disturbances or cerebellar symptoms. In terms of pathological characteristics, gliosis and neuronal loss are generally milder in degree, and characteristic spongiform change can be observed at both the early and advanced stages. However, little is known on the progress of spongiform change over time or its mechanisms. In this study, to elucidate the pathological course of V180I gCJD, statistical analysis of the size and dispersion of the major diameters of vacuoles in six V180I gCJD cases was performed, with five MM1-type sCJD and MM2C-type sCJD cases as controls. As a result, V180I gCJD showed no significant difference in vacuolar diameter regardless of disease duration. In addition, the dispersion of the major diameters of vacuoles in V180I gCJD was larger than that in the MM1-type, which was smaller than that in the MM2C-type. We speculated that the absence of difference in the size of the vacuoles regardless of disease duration suggests that tissue rarefaction does not result from the expansion of vacuole size and increase in number of vacuoles in V180Ig CJD. These features were considered to be significant pathological findings of V180I gCJD.

An autopsied case of corticobasal degeneration presenting with frontotemporal dementia followed by myoclonus

A Japanese woman developed frontotemporal dementia (FTD)-like symptoms of abnormal behavior, such as stereotyped behavior and disinhibition. The patient developed these symptoms at the age of 59 years, although aphasia symptoms were not apparent at early disease stages. Progressive parkinsonism was dominant on the left side, and conspicuous myoclonus was recognized in the late disease stage. MRI indicated severe, right side-dominant frontotemporal lobe atrophy with white matter degeneration. Brainstem and cerebellar atrophy were also observed. The patient underwent gastrostomy 7 years after the onset of her symptoms and died at the age of 70 years. Neuropathological examination showed diffuse neuron loss with gliosis and tissue rarefaction in the frontotemporal lobe, particularly in the right anterior portion of the frontal lobe. Spongiform changes and ballooned neurons were also observed in the frontotemporal cortex, particularly in the superficial layer and deeper layers, respectively. Gallyas-Braak silver staining and anti-phosphorylated tau immunostaining indicated numerous argyrophilic and tau-positive structures, including pretangles, astrocytic plaques, coiled bodies and neuropil threads. We speculate that the myoclonus observed in the present case was at least partly caused by or related to the spongiform change and ballooned neurons in the cerebral cortex. The clinical phenotypes of corticobasal degeneration (CBD) vary considerably, and the clinical presentation of the present patient was compatible with frontal behavioral-spatial syndrome in the early disease stage. However, in the later disease stages, her symptoms were reflective of corticobasal syndrome. Because it is not rare for the clinical phenotype to change along with disease progression in cases of CBD, we should consider CBD in cases presenting with FTD at symptom onset.

An autopsy case of Creutzfeldt-Jakob disease with a prion protein gene codon 180 mutation presenting with pathological laughing and an exaggerated startle reaction

A 78-year-old Japanese woman presented with slow progressive disorientation and memory disturbances. Pathological laughing was observed at an early disease stage and continued for several months. Around the same time, the patient began to exhibit an exaggerated startle reaction and mild myoclonus. The pathological laughing and startle reaction disappeared before the patient reached an akinetic mutism state approximately 16 months after symptom onset. MRI showed extensive hyperintensity of the cerebral cortex and striatum on diffusion-weighted images, and swelling in the cerebral cortex on T2-weighted and fluid attenuated inversion recovery images. A prion protein (PrP) gene analysis revealed a V180I mutation with methionine homozygosity at codon 129. Neuropathological examination showed extensive spongiform changes with characteristic various-sized and non-confluent (VaSNoC) vacuoles in the cerebral neocortex and striatum. Gliosis and hypertrophic astrocytosis were generally mild in character. Neurons were relatively preserved in number. We believe that pathological laughing and an exaggerated startle reaction are possible pathognomonic findings of V180I genetic Creutzfeldt-Jakob disease. Based on the pathological findings of the present case, the presence of the VaSNoC-type spongiform changes with relative preservation of the neurons in the cerebral cortex and a lack of apparent brainstem involvement are associated at least in part with the pathological laughing and startle reaction.

MM1-type sporadic Creutzfeldt-Jakob disease with 1-month total disease duration and early pathologic indicators

A 62-year-old man presented with abnormal behavior and cognitive impairment. Diffusion-weighted images (DWI) obtained on MRI showed extensive hyperintense regions in the cerebral cortex and striatum. Myoclonus was recognized, and the patient died 1 month after the onset; his condition did not reach the akinetic mutism state. The brain weighed 1300 g and showed no apparent atrophy. Extensive spongiform changes were observed in the cerebral neocortex, striatum, thalamus and cerebellar cortex, but gliosis was mild or absent. Neuropil rarefaction and neuron loss were not apparent. Mild proliferation of anti- GFAP-positive astrocytes was observed in the cerebral cortex, but unaffected regions were noted. Regions without spongiform changes and GFAP-positive astrocytes included the hippocampal formation and subiculum. PrP immunostaining showed extensive diffuse synaptic-type PrP deposition in the gray matter, including the hippocampal region, but it was also mild. PrP gene analysis revealed no mutation with methionine homozygosity at polymorphic codon 129. Western blot analysis of proteinase K-resistant PrP indicated type 1 PrP^Sc . The clinicopathological findings of the present case confirm several hypotheses: (i) the earliest pathologic evidence observed by HE staining in CJD are spongiform changes; (ii) DWI hyperintense regions indicate these spongiform changes; and (iii) regions without spongiform changes, gliosis and proliferation of GFAP-positive astrocytes, but with PrP deposition, exist in the early disease stage.

Creutzfeldt-Jakob disease

This review will explore the clinical and pathological findings of the various forms of Creutzfeldt-Jakob disease (CJD). Clinical findings of CJD are characterized by rapidly progressive cognitive dysfunction, diffusion-weighted magnetic resonance imaging (DWI) hyperintensity, myoclonus, periodic sharp-wave complexes on electroencephalogram and akinetic mutism state. Neuropathologic findings of CJD are characterized by spongiform changes in gray matter, gliosis-particularly hypertrophic astrocytosis-neuropil rarefaction, neuron loss and prion protein (PrP) deposition. The earliest pathological symptom observed by HE staining in the cerebral cortex is spongiform change. This spongiform change begins several months before clinical onset, and is followed by gliosis. Subsequently, neuropil rarefaction appears, followed by neuron loss. Regions showing fine vacuole-type spongiform change reflect synaptic-type PrP deposition and type 1 PrP^Sc deposition, whereas regions showing large confluent vacuole-type spongiform changes reflect perivacuolar-type PrP deposition and type 2 PrP^Sc deposition. Hyperintensities of the cerebral gray matter observed in DWI indicate the pathology of the spongiform change in CJD. The cerebral cortical lesions with large confluent vacuoles and type 2 PrP^Sc show higher brightness and more continuous hyperintensity on DWI than those with fine vacuoles and type 1 PrP^Sc . CJD cases showing diffuse myelin pallor of cerebral white matter have been described as panencephalopathic-type, and this white matter pathology is mainly due to secondary degeneration caused by cerebral cortical involvement, particularly in regard to neuron loss. In conclusion, clinical and neuroimaging findings and neuropathologic observations are well matched in both typical and atypical cases in CJD. The clinical diagnosis of CJD is relatively easy for typical CJD cases such as the MM1-type. However, even in atypical cases it seems that clinical findings can be used for an accurate diagnosis.

Dura mater graft-associated Creutzfeldt-Jakob disease with 30-year incubation period

Over 60% of all patients with dura mater graft-associated Creutzfeldt-Jakob disease (dCJD) have been diagnosed in Japan. The incubation period has ranged from 1 to 30 years and the age at onset from 15 to 80 years. Here, we report a 77-year-old male Japanese autopsied dCJD case with the longest incubation period so far in Japan. He received a cadaveric dural graft at the right cranial convexity following a craniotomy for meningioma at the age of 46. At 30 years post-dural graft placement, disorientation was observed as an initial symptom of dCJD. He rapidly began to present with inconsistent speech, cognitive impairment and tremor of the left upper extremity. Occasional myoclonic jerks were predominantly observed on the left side. Brain MRI presented hyperintense signals on diffusion-weighted and T2-weighted images, at the right cerebral cortex. The most hyperintense lesion was located at the right parietal lobe, where the dura mater graft had been transplanted. Single-photon emission CT scan showed markedly decreased cerebral blood flow at the right parietal lobe. EEG revealed diffuse and slow activities with periodic sharp-wave complex discharges seen in the right parietal, temporal and occipital lobes. He died of pneumonia 9 months after onset. Brain pathology revealed non-plaque-type dCJD. Laterality of neuropathological changes, including spongiform change, neuronal loss, gliosis or PrP deposits, was not evident. Western blot analysis showed type 1 PrP^CJD . Alzheimer-type pathology and PSP-like pathology were also observed.

An autopsied case of MM1 + MM2-cortical with thalamic-type sporadic Creutzfeldt-Jakob disease presenting with hyperintensities on diffusion-weighted MRI before clinical onset

A 78-year-old Japanese man presented with rapidly progressive dementia and gait disturbances. Eight months before the onset of clinical symptoms, diffusion-weighted magnetic resonance imaging (DWI) demonstrated hyperintensities in the right temporal, right parietal and left medial occipital cortices. Two weeks after symptom onset, DWI showed extensive hyperintensity in the bilateral cerebral cortex, with regions of higher brightness that existed prior to symptom onset still present. Four weeks after clinical onset, periodic sharp wave complexes were identified on an electroencephalogram. Myoclonus was observed 8 weeks after clinical onset. The patient reached an akinetic mutism state and died 5 months after onset. Neuropathological examination showed widespread cerebral neocortical involvement of fine vacuole-type spongiform changes with large confluent vacuole-type spongiform changes. Spongiform degeneration with neuron loss and hypertrophic astrocytosis was also observed in the striatum and medial thalamus. The inferior olivary nucleus showed severe neuron loss with hypertrophic astrocytosis. Prion protein (PrP) immunostaining showed widespread synaptic-type PrP deposition with perivacuolar-type PrP deposition in the cerebral neocortex. Mild to moderate PrP deposition was also observed extensively in the basal ganglia, thalamus, cerebellum and brainstem, but it was not apparent in the inferior olivary nucleus. PrP gene analysis showed no mutations, and polymorphic codon 129 showed methionine homozygosity. Western blot analysis of protease-resistant PrP showed both type 1 scrapie type PrP (PrP^Sc ) and type 2 PrP^Sc . Based on the relationship between the neuroimaging and pathological findings, we speculated that cerebral cortical lesions with large confluent vacuoles and type 2 PrP^Sc would show higher brightness and continuous hyperintensity on DWI than those with fine vacuoles and type 1 PrP^Sc . We believe the present patient had a combined form of MM1 + MM2-cortical with thalamic-type sporadic Creutzfeldt-Jakob disease (sCJD), which suggests a broader spectrum of sCJD clinicopathological findings.

Factors influencing the survival period in Japanese patients with sporadic Creutzfeldt-Jakob disease

Although Japanese cases of sporadic Creutzfeldt-Jakob disease (sCJD) generally involve longer survival periods compared to those from other countries, details regarding the factors influencing survival are unclear. To determine the influence of certain factors on survival, we retrospectively assessed 51 Japanese MM1-type sCJD patients with respect to background, clinical course, and disease management. No significant differences were found between men and women, tracheotomy and nontracheotomy patients, or patients treated in public and other types of hospitals. Although the survival period of tube-fed patients was significantly longer than that of patients who were not tube fed, survival of patients fed via a nasal tube did not differ significantly from that of gastrostomy-fed patients. The proportion of tube-fed patients was 68.6% (35/51). Disease duration was not significantly associated with age or year of onset. However, it was associated with time from onset to first recognition of myoclonus, first recognition of periodic sharp-wave complexes on electroencephalogram, and progression to the akinetic mutism state. Mechanical ventilation was not performed for any patient. Because the total disease duration increased in cases with a slowly progressive clinical course as a natural outcome, we concluded that the most crucial factor contributing to the prolonged survival of Japanese sCJD patients was tube feeding once the akinetic mutism state had been reached.