Distinct neuropsychological characteristics in Creutzfeldt-Jakob disease

Baseline neuropsychological profiles in prion disease predict survival time

OBJECTIVE

Few studies have captured the neuropsychological profile of sporadic Creutzfeldt-Jakob disease (sCJD) with neuropsychological testing, and little is known about cognitive predictors of survival. We characterized baseline neuropsychological performance in sCJD and investigated associations with survival.

METHODS

sCJD participants who completed the MMSE (n = 118), 61 sCJD of whom also completed a neuropsychological battery at baseline, and 135 age-matched healthy controls, were included. Composite scores of global cognition, memory, executive functions, visuospatial, and language were derived. Cox proportional hazard models estimated survival time, controlling for age and education. Additional models adjusted for Barthel Index and PRNP codon 129 polymorphism.

RESULTS

sCJD participants performed significantly worse than controls on all cognitive tasks and composites with most showing very large effect sizes. The three tests showing the largest group differences were delayed verbal recall (Hedges'g = 4.08, P < 0.0001), Stroop Inhibition (Hedges'g = 3.14, P < 0.0001), and Modified Trails (Hedges'g = 2.94, P < 0.0001). Memory (95%) and executive functioning (87%) composites were most commonly impaired. Poorer global (HR = 0.65, P < 0.0001), visuospatial (HR = 0.82, P < 0.0001), and memory (HR = 0.82, P = 0.01) composites predicted shorter survival. Visuospatial cognition remained a significant predictor even after adjusting for all other cognitive composites; each standard deviation decrease in visuospatial cognition was associated with an 18% higher chance of death (HR = 0.82, P < 0.003). Global (HR = 0.68, P = 0.03) and visuospatial (HR = 0.82, P = 0.001) composites remained significant predictors after controlling for Barthel Index and codon 129.

INTERPRETATION

sCJD participants exhibit a broad range of cognitive impairments, with memory and executive functioning deficits in the vast majority. Neuropsychological assessment, particularly of visuospatial abilities, informs prognostication in sCJD.

Neuropsychological Symptoms in Sporadic Creutzfeldt-Jakob Disease Patients in Germany

BACKGROUND

The polymorphism at codon 129 of the prion protein gene (PRNP) and the PrPSc types 1 and 2 belong to a molecular classification of sporadic Creutzfeldt-Jakob disease (sCJD) that correlates well with the clinical and neuropathological phenotype of sCJD.

OBJECTIVE

The aim of the study was to perform the first detailed evaluation of neuropsychological deficits in a large group of definite sCJD patients with known molecular subtype.

METHODS

We analyzed neuropsychological symptoms in a cohort of 248 sCJD patients with known M129 V polymorphism of PRNP and prion protein type.

RESULTS

Neuropsychological symptoms were very frequent in our patients (96%) and occurred as early as in the first third of the disease course. Besides amnesia and impaired attention (89% each), frontal lobe syndrome (75%), aphasia (63%), and apraxia (57%) were the most common neuropsychological deficits. There was no statistically significant difference with regard to frequency of neuropsychological symptoms between the subtypes. In MV2 and VV2 patients, the onset of neuropsychological symptoms was significantly later than in all other subtypes.

CONCLUSION

We provide the first detailed analysis of neuropsychological symptoms in a large group of sCJD patients with known M129 V genotype and prion protein type. We suggest that the rate of progression of neuropsychological symptoms is subtype-specific. These data may improve the diagnosis in atypical sCJD subtypes.

Wernicke-Korsakoff syndrome as a rare phenotype of sporadic Creutzfeldt-Jakob disease

We reported the case of a patient with Wernicke-Korsakoff syndrome (WKs) as an early clinical manifestation of sporadic Creutzfeld-Jakob disease (sCJD). The 66-year-old female complained of dizziness and imbalance which mostly occurred while walking. A neurological examination revealed a triad of symptoms characteristic for WKs such as gaze paresis, ataxia of limbs and trunk as well as memory disturbances with confabulations. The disturbances increased during the course of the disease, which led to the death of the patient four months after the appearance of the signs. The patient was finally diagnosed with sCJD disease. The most useful ancillary examination results supporting sCJD diagnosis were brain diffusion DWI MRI (diffusion weighted magnetic resonance imaging) and the presence of 14-3-3 protein in CSF (cerebrospinal fluid). Since that manifestation of sCJD is very unique other causes should be taken into consideration while making a final diagnosis.

Quantitative Magnetic Resonance Abnormalities in Creutzfeldt-Jakob Disease and Fatal Insomnia

BACKGROUND

Quantitative neuroimaging might unveil abnormalities in prion diseases that are not perceivable at visual inspection. On the other hand, scarce studies have quantified volumetric changes in prion diseases.

OBJECTIVES

We aim to characterize volumetric and diffusion tensor imaging (DTI) changes in patients with prion diseases who presented with either Creutzfeldt-Jakob disease (CJD) or fatal insomnia (FI) phenotype.

METHODS

Twenty patients with prion diseases- 15 with CJD and 5 with fatal insomnia (FI)- and 40 healthy controls were examined with a 3-Tesla magnetic resonance imaging scanner. Images were segmented and normalized with SPM12. DTI maps were obtained with FMRIB Software Library. Whole-brain voxel-wise and region-of-interest analyses of volumetric and DTI changes were performed with SPM12. White matter (WM) changes were also analyzed with tract-based spatial statistics. Semiquantitive assessment of neuropathological parameters was compared with DTI metrics in thalamus from 11 patients.

RESULTS

Patients with CJD and FI presented significant atrophy in thalamus and cerebellum. In CJD, mean diffusivity (MD) was decreased in striatum and increased in subcortical WM, while both increased and decreased values were observed across different thalamic nuclei. In FI, MD was increased in thalamus and cerebellum. Spongiform change and PrPSc deposition were more intense in thalamus in CJD than in FI, although no significant correlations arose with MD values in the nuclei studied.

CONCLUSION

Volumetric and DTI abnormalities suggest a central common role of the thalamus in prion diseases. We report, for the first time, quantitative MRI changes in FI, and provide further evidence of WM involvement in prion diseases.

The language disorder of prion disease is characteristic of a dynamic aphasia and is rarely an isolated clinical feature

BACKGROUND

Akinetic mutism is a key diagnostic feature of prion diseases, however, their rapidly progressive nature makes detailed investigation of the language disorder in a large cohort extremely challenging. This study aims to position prion diseases in the nosology of language disorders and improve early clinical recognition.

METHODS

A systematic, prospective investigation of language disorders in a large cohort of patients diagnosed with prion diseases. 568 patients were included as a sub-study of the National Prion Monitoring Cohort. All patients had at least one assessment with the MRC Scale, a milestone-based functional scale with language and non-language components. Forty patients, with early symptoms and able to travel to the study site, were also administered a comprehensive battery of language tests (spontaneous speech, semantics, syntax, repetition, naming, comprehension and lexical retrieval under different conditions).

RESULTS

5/568 (0.9%) patients presented with leading language symptoms. Those with repeated measurements deteriorated at a slower rate in language compared to non-language milestones. Amongst the subgroup of 40 patients who underwent detailed language testing, only three tasks-semantic and phonemic fluency and sentence comprehension-were particularly vulnerable early in the disease. These tasks were highly correlated with performance on non-verbal executive tests. Patients were also impaired on a test of dynamic aphasia.

CONCLUSION

These results provide evidence that the language disorder in prion disease is rarely an isolated clinical or cognitive feature. The language abnormality is indicative of a dynamic aphasia in the context of a prominent dysexecutive syndrome, similar to that seen in patients with the degenerative movement disorder progressive supranuclear palsy (PSP).

The cognitive profile of prion disease: a prospective clinical and imaging study

Objectives

Prion diseases are dementing illnesses with poorly defined neuropsychological features. This is probably because the most common form, sporadic Creutzfeldt-Jakob disease, is often rapidly progressive with pervasive cognitive decline making detailed neuropsychological investigation difficult. This study, which includes patients with inherited, acquired (iatrogenic and variant) and sporadic forms of the disease, is the only large-scale neuropsychological investigation of this patient group ever undertaken and aimed to define a neuropsychological profile of human prion diseases.

Methods

A tailored short cognitive examination of all of the patients (n = 81), with detailed neuropsychological testing in a subset with mild disease (n = 30) and correlation with demographic, clinical, genetic (PRNP mutation and polymorphic codon 129 genotype), and other variables (MRI brain signal change in cortex, basal ganglia or thalamus; quantitative research imaging, cerebrospinal fluid 14-3-3 protein).

Results

Comparison with healthy controls showed patients to be impaired on all tasks. Principal components analysis showed a major axis of fronto-parietal dysfunction that accounted for approximately half of the variance observed. This correlated strongly with volume reduction in frontal and parietal gray matter on MRI. Examination of individual patients' performances confirmed early impairment on this axis, suggesting characteristic cognitive features in mild disease: prominent executive impairment, parietal dysfunction, a largely expressive dysphasia, with reduced motor speed.

Interpretation

Taken together with typical neurological features, these results complete a profile that should improve differential diagnosis in a clinical setting. We propose a tailored neuropsychological battery for early recognition of clinical onset of symptoms with potential for use in clinical trials involving at-risk individuals.

Sporadic Creutzfeldt-Jakob disease presenting as progressive nonfluent aphasia with speech apraxia

Progressive non-fluent aphasia (PNFA) is typically associated with pathological changes consistent with frontotemporal lobar degeneration. A 65-year-old male presented with effortful speech, markedly impaired naming and features of speech apraxia, consistent with PNFA. Perceptuospatial function, calculation and executive function were intact. Brain SPECT showed left perisylvian hypoperfusion. He deteriorated profoundly over the subsequent eight months, with appearances on diffusion-weighted magnetic resonance imaging typical of sporadic Creutzfeldt-Jakob disease, which was confirmed pathologically at postmortem examination. While the presence of PNFA with speech apraxia is thought to predict underlying tauopathy, sporadic Creutzfeldt-Jakob disease may mimic this presentation and present in a highly circumscribed form not previously described.

Posterior cortical atrophy: advice for diagnosis and implications for management

SUMMARY The clinical presentation of Alzheimer’s disease (AD) is heterogeneous, especially in individuals with an early age at onset, where the presenting symptoms may be language, behavior or visual impairment. Posterior cortical atrophy (PCA) refers to a syndrome where visual processing and other posterior functions are the initial symptoms. While the majority of PCA cases reflect the underlying AD, a proportion of cases are caused by dementia with Lewy bodies, corticobasal degeneration or prion disease. PCA is sometimes not recognized until late into the disease or misattributed to anxiety or malingering owing to its low frequency, the early age at onset and the relatively atypical symptoms. This article describes the PCA syndrome, emphasizing its clinical features and how it relates to early-onset AD variants. In order to aid identification of this syndrome, the neuroimaging and neuropsychological features, as well as biomarkers of the underlying pathology, are also described briefly. Finally, the implications for treatment, compensatory strategies and rehabilitation, as well as management of comorbidities, are discussed.

Variant Creutzfeldt-Jakob disease: neuropsychological profile in an extended series of cases

Neuropsychological data on an extended series of cases of variant Creutzfeldt-Jakob Disease (vCJD) are presented, complementing earlier findings from smaller sample studies of this condition. Distinct neuropsychological features in this extended series included relatively preserved verbal knowledge, immediate verbal memory span, and elementary visual processing. This sparing contrasted with ubiquitous impairment in every vCJD patient on timed tests of verbal fluency and digit-symbol substitution. There were also high rates of impairment on tests of memory, and of visuoperceptual and visuospatial reasoning. Our findings lend support to the view that distinctive neuropsychological features may be one of the diagnostic markers of the condition.

MRI detection of the cerebellar syndrome in Creutzfeldt-Jakob disease

Creutzfeldt-Jakob Disease (CJD) is characterized by bilateral basal ganglia hyperintensities on T2W and diffusion-weighted imaging (DWI) magnetic resonance imaging (MRI) scans, consistent with its extrapyramidal neurological manifestations. MRI is diagnostically uninformative about the cerebellar symptoms, equally prominent in CJD. This study was undertaken to explain this apparent paradox. Eleven CJD patients with definite cerebellar or brain stem symptoms were selected from a large prospective study, as well as 11 healthy controls matched for age and gender. All subjects participated in a standardized MRI protocol, including SPGR, fluid-attenuated inversion recovery (FLAIR), DWI and diffusion tensor imaging (DTI). All subjects underwent detailed examination by a neurologist blinded to the radiological findings, who predicted the expected site of cerebral abnormalities. MRI showed good sensitivity for the abnormalities predicted in the cortex (80-90%) and basal ganglia (100%). None of the standard MRI sequences, including DWI, DTI, and FLAIR, revealed any tissue abnormalities in cerebellum or brain stem. Apparent diffusion coefficient (ADC) values, however, were substantially and significantly elevated in several cerebellar structures, where also the volumetric (VBM) analysis revealed elevated cerebrospinal fluid volume, suggesting focal cerebellar atrophy in these CJD patients. In patients with CJD, DWI appears sensitive to the reduced diffusivity in cortex and basal ganglia but insensitive to cerebellar involvement. We propose that the radiological hallmark of cerebellar pathology in CJD is atrophy, revealed quantitatively by both VBM and elevated diffusivity, which is identifiable on ADC maps but poorly visualized in nonquantitative DWI images.

The syndrome of progressive posterior cortical dysfunction: A multiple case study and review

Dementia presenting with prominent higher order visual symptoms may be observed in a range of neurodegenerative conditions and is often challenging to diagnose.

OBJECTIVES

To describe cases of progressive dementia presenting with prominent visual cortical symptoms.

METHODS

We conducted a retrospective search of cases of progressive dementia with predominant visual symptoms, seen at our dementia unit from 1996 to 2006.

RESULTS

Twelve patients (5 men, 7 women) were identified, with ages ranging from 49 to 67 years. At the first examination, the duration of the symptoms ranged from one to ten years and the Mini-Mental State Examination scores from 7 to 27. Eleven patients presented with predominant visuospatial symptoms (partial or complete Balint syndrome) and one with visuoperceptive impairment. Other reported manifestations were: constructional apraxia in 11 patients, partial or complete Gerstmann syndrome in ten, ideomotor apraxia in nine, hemineglect or extinction in four patients, alien hand phenomenon in three, and prosopagnosia in one patient. Memory loss was reported by ten patients, but was not the main complaint in any of these cases. Insight was relatively preserved in five patients even after a long period following the onset of symptoms. Six patients developed parkinsonism during evolution. Clinical diagnoses were possible or probable AD in seven patients, cortico-basal degeneration in four, and dementia with Lewy body in one.

CONCLUSIONS

Clinicians should consider this condition especially in presenile patients with slowly progressive higher-order visual symptoms. Although described in association with different conditions, it may also occur in Alzheimer disease.

Trophic factors in cerebrospinal fluid and spinal cord of patients with tropical spastic paraparesis, HIV, and Creutzfeldt-Jakob disease

HTLV-1-associated myelopathy/tropical spastic paraparesis (TSP/HAM) is a chronic CNS disease characterized by axomyelinic degeneration of the long axons of corticospinal tracts. Levels of NGF, NT-3, NT-4/5, BDNF, GDNF, CNTF, and FGF-2 were measured in the cerebrospinal fluid (CSF) of 21 TSP/HAM patients and 20 controls. NGF, BDNF, and FGF-2 levels were also determined in 19 patients with HIV motor cognitive motor syndrome, and in 21 subjects diagnosed with Creutzfeldt Jakob disease (CJD). No significant differences were detected in the concentrations of NGF, BDNF, NT-3, NT-4/5, GDNF, and CNTF in the CSF between TSP/HAM patients and controls. FGF-2 was significantly lower in the CSF of the three groups of patients compared with controls; the HIV group exhibited the lowest values. HIV patients differed from TSP/HAM in their significantly higher levels of NGF and lower levels of BDNF and FGF-2, whereas CJD patients differed only in their higher levels of NGF. Immunohistochemical studies were done of trophic factors (NGF and FGF-2) and neurotrophin receptors (trkA and p75) in spinal cord and motor cortical areas from anatomopathological cases of TSP/HAM. Results indicated that NGF is expressed in motoneurons and oligodendrocytes of the posterior column of the spinal cord. FGF-2 was detected in motoneurons and spinal cord vessels. p75 receptor was detected in cortical neurons. The absence of a significant change in the trophic factor levels in TSP/HAM may be attributed to a selective axonal lesion in a slow process.

MCP-1 and murine prion disease: separation of early behavioural dysfunction from overt clinical disease

Prion diseases are chronic, fatal neurodegenerative conditions of the CNS. We have investigated the role of monocyte chemoattractant protein-1 (MCP-1) in the ME7 model of murine prion disease. MCP-1 expression increased in the CNS throughout disease progression and was positively correlated with microglial activation. We subsequently compared the inflammatory response, pathology and behavioural changes in wild-type (wt) mice and MCP-1 knockout mice (MCP-1-/-) inoculated with ME7. Late-stage clinical signs were delayed by 4 weeks in MCP-1-/- mice, and survival time increased by 2-3 weeks. By contrast, early changes in affective behaviours and locomotor activity were not delayed in onset. There was also no difference in microglial activation or neuronal death in the hippocampus and thalamus of wt mice and MCP-1-/- mice. These results highlight an important dissociation between prolonged survival, early behavioural dysfunction and hippocampal/thalamic pathology when considering therapeutic intervention for human prion diseases and other chronic neurodegenerative conditions.

Qualitative neuropsychological performance characteristics in frontotemporal dementia and Alzheimer's disease

BACKGROUND

Frontotemporal dementia (FTD) and Alzheimer's disease are clinically distinct disorders, yet neuropsychological studies have had variable success in distinguishing them. A possible reason is that studies typically rely on overall accuracy scores, which may obscure differences in reasons for failure.

OBJECTIVES

To explore the hypothesis that analysis of qualitative performance characteristics and error types, in addition to overall numerical scores, would enhance the neuropsychological distinction between FTD and Alzheimer's disease.

METHODS

38 patients with FTD and 73 with Alzheimer's disease underwent assessment of language, visuospatial abilities, memory, and executive function, using a neuropsychological screening instrument and standard neuropsychological tests. In each of these cognitive domains, performance characteristics and error types were documented, in addition to numerical scores on tests.

RESULTS

Whereas comparison of neuropsychological test scores revealed some group differences, these did not occur consistently across tests within cognitive domains. However, analysis of performance characteristics and error types revealed qualitative differences between the two groups. In particular, FTD patients displayed features associated with frontal lobe dysfunction, such as concrete thought, perseveration, confabulation, and poor organisation, which disrupted performance across the range of neuropsychological tests.

CONCLUSIONS

Numerical scores on neuropsychological tests alone are of limited value in differentiating FTD and Alzheimer's disease, but performance characteristics and error types enhance the distinction between the two disorders. FTD is associated with a profound behavioural syndrome that affects performance on cognitive assessment, obscuring group differences. Qualitative information should be included in neuropsychological research and clinical assessments.

EEG findings in dementia with Lewy bodies causing diagnostic confusion with sporadic Creutzfeldt-Jakob disease

Two patients with pathologically confirmed dementia with Lewy bodies (DLB) had electroencephalogram recordings reported to show periodic discharges suggestive or typical of Creutzfeldt-Jakob disease. These findings caused diagnostic confusion and necessitated appropriate precautions for prion disease at postmortem examination. Periodic sharp wave complexes have occasionally been reported in DLB and should not therefore dissuade one from the diagnosis when other clinical and neuropsychological features are consistent with validated diagnostic criteria.

The neuropsychology of variant CJD: a comparative study with inherited and sporadic forms of prion disease

OBJECTIVE

To assess cognitive function in variant Creutzfeldt-Jakob disease (vCJD). We describe the neuropsychological profiles of 10 cases and compare these data with cross sectional data obtained from patients with histologically confirmed sporadic CJD and cases with inherited prion disease with confirmed mutations in the prion protein gene.

METHODS

Patients referred to the Specialist Cognitive Disorders Clinic at the National Hospital for Neurology and Neurosurgery and the National Prion Clinic at St Mary's Hospital, London for further investigation of suspected CJD were recruited into the study. The neuropsychological test battery evaluated general intelligence, visual and verbal memory, nominal skills, literacy skills, visual perception and visuospatial functions, and visuospatial and executive function.

RESULTS

The results indicate that moderate to severe cognitive decline is a characteristic feature of vCJD. Specifically, verbal and visual memory impairments and executive dysfunction were pervasive in all disease groups. Nominal skills were impaired in variant and sporadic CJD, significantly so when compared with the inherited prion disease group. Perceptual impairment was less frequent in the vCJD group than in the sporadic and inherited groups.

CONCLUSION

This study confirms the occurrence of generalised cognitive decline in patients with vCJD. Although decline in cognitive function ultimately affects all domains, there is a suggestion that some components of visual perception may be spared in vCJD. The results also suggest that nominal function may be preserved in some cases with inherited prion disease.

Clinical course in young patients with sporadic Creutzfeldt-Jakob disease

Sporadic Creutzfeldt-Jakob disease (sCJD) is a rare neurodegenerative disease with the greatest incidence occurring in patients between 60 and 70 years old. Younger patients may also be affected. In this study, we used all case material available from 52 patients with sCJD aged 50 years or younger at disease onset, who were identified between 1993 and 2003 in Germany. The objective of this study was to describe the psychiatric and neurological features of these young patients with emphasis on the different codon 129 genotypes and PrP types, and to compare them with elder patients with sCJD and patients with variant CJD. We also gave particular attention to electroencephalogram, magnetic resonance imaging, and 14-3-3 results, as well as to the neuropathological lesion profile. The clinical syndrome in young patients differs from elder patients with CJD with respect to clinical signs, disease duration, technical investigations, and neuropathological lesion profile. The psychiatric symptoms in young patients with sCJD are similar to the psychiatric symptoms expressed by patients with variant CJD; however, in contrast with the variant cases, young patients with sCJD experience development of prominent dementia early in the disease course.

Neuronal and astrocytic responses involving the serotonergic system in human spongiform encephalopathies

The relationships between the degree of cortical prion protein (PrP) deposition, tissue vacuolation and astrocytosis were studied in the frontal cortex of 27 cases of human spongiform encephalopathy, encompassing 13 cases of sporadic Creutzfeldt-Jakob disease (sCJD), four cases of familial CJD (fCJD) (one owing to E200K mutation, one owing to 144 bp insertion, one owing to P102L mutation and one owing to A117V mutation), five cases of iatrogenic CJD (iCJD) owing to growth hormone therapy and five cases of variant CJD (vCJD). The size and number of tryptophan hydroxylase (TPH) positive cells in the dorsal raphe were determined as an index of the function of the brain's serotonergic system. The amount of PrP deposited in frontal cortex in vCJD was significantly greater than that in both sCJD and iCJD, which did not differ significantly from each other. The extent of grey matter deposition of PrP correlated with that of white matter deposition. Deposition of PrP as plaques was greater in cases of sCJD bearing valine at codon 129 of PrP gene, especially when homozygous. However, all cases of vCJD displayed florid plaque formation yet these were homozygous for methionine at codon 129. Prion protein deposition as plaques was greater in cases of sCJD with 2A PrP isotype than those with 1 PrP isotype, similar to that seen in cases of vCJD all of which are 2B PrP isotype. There were no significant differences in the extent of astrocytosis between the different aetiological groups, in either grey or white matter, as visualized with glial fibrillary acidic protein (GFAP) or 5HT-2A receptor (5HT-2AR) immunostaining, although there was a strong correlation between the severity of 5HT-2AR and GFAP reactions within both grey and white matter. The extent of PrP deposition within the grey, but not white, matter correlated with the degree of astrocytosis for both GFAP and 5HT-2AR and the extent of tissue vacuolation in grey and white matter, although the latter did not correlate with degree of astrocytosis for either GFAP or 5HT-2AR. Astrocytes may be responding directly to the presence of PrP within the tissue, rather than the vacuolar damage to neurones. Although S100beta immunoreactivity was present in astrocytes in control cases, no S100beta staining was seen in astrocytes in either grey or white matter in most CJD cases. There were no differences in the number of TPH-positive cells between CJD and control cases, although the mean TPH-positive cell size was significantly greater, and cells were more intensely stained, in CJD compared to controls, suggesting a pathological overactivity of the brain's serotonergic system in CJD. This may result in excessive release of 5HT within the brain triggering increased 5HT-2AR expression within activated astrocytes leading to release and depletion of S100beta protein from such cells. The clinical symptoms of fluctuating attention and arousal could be mediated, at least in part, by such alterations in function of the serotonergic system.