Neuropsychological differences between frontotemporal dementia and Alzheimer's disease: a review

Overlapping and distinct phenotypic profiles in Alzheimer's disease and late onset epilepsy: a biologically-based approach

Due to shared hippocampal dysfunction, patients with Alzheimer's dementia and late-onset epilepsy (LOE) report memory decline. Multiple studies have described the epidemiological, pathological, neurophysiological, and behavioral overlap between Alzheimer's Disease and LOE, implying a bi-directional relationship. We describe the neurobiological decline occurring at different spatial in AD and LOE patients, which may explain why their phenotypes overlap and differ. We provide suggestions for clinical recognition of dual presentation and novel approaches for behavioral testing that reflect an "inside-out," or biologically-based approach to testing memory. New memory and language assessments could detect-and treat-memory impairment in AD and LOE at an earlier, actionable stage.

Recognition subtests of the Repeatable Battery for the Assessment of Neuropsychological Status: evidence for a cortical vs. subcortical distinction

INTRODUCTION

Within clinical neuropsychology, a classic diagnostic distinction is made between cortical and subcortical disorders, especially based on their memory profiles. Typically, this is based on the comparison of recall and recognition trials, where individuals with cortical conditions do not tend to benefit (i.e., score well) on recognition trials and individuals with subcortical conditions do. Although the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) is a widely used brief cognitive battery, there is a lack of evidence to support this measure's utility in distinguishing between the memory profiles of these conditions.

METHOD

Thirty-six mild Alzheimer's disease (AD), 55 Parkinson's disease (PD), and 105 essential tremor (ET) participants (N = 196) were administered the RBANS with additional Story and Figure Recognition subtests. Group differences on recall and recognition scores (Total Correct, Hits or True Positives, False Positive Errors, and discriminability index) were examined across the three groups, while controlling for the influence of age and gender.

RESULTS

As expected, individuals with AD had poorer recognition scores compared to the other clinical groups across tasks (all p-values < .05), while the ET sample largely performed comparably to the PD sample. With the exception of comparable Figure Recognition and Recall in the PD sample, all groups exhibited significantly greater recognition Hit performance compared to Recall (all p-values < .05).

CONCLUSIONS

The group differences in performance across RBANS recognition subtests suggest support for traditional "cortical" and "subcortical" profiles. However, all groups, including the mild AD sample, demonstrated a benefit from recognition cues compared to free recall. Overall, these findings support the inclusion of the newly developed Story and Figure Recognition subtests in future clinical practice and research endeavors.

Recall and recognition subtests of the repeatable battery for the assessment of neuropsychological status and their relationship to biomarkers of Alzheimer's disease

Recently, two new recognition subtests for the Repeatable Battery for the Assessment of Neuropsychological Status (RBANS) were developed and initially validated in a cohort of older adults who were cognitively intact or classified as amnestic Mild Cognitive Impairment (MCI) or mild Alzheimer's disease (AD). The current paper extends that validation by comparing the recall and recognition subtests of the RBANS, including the existing and recently developed scores, to three commonly used biomarkers in AD in an expanded sample from the initial validation. One hundred fifty-four older adults (65 intact, 46 MCI, 43 AD) were administered the RBANS, which included the recently developed subtests for Story Recognition and Figure Recognition (hits, false positives, total correct), as part of a study on memory and biomarkers. Participants also completed magnetic resonance imaging to obtain hippocampal volumes, positron emission tomography to obtain amyloid plaque deposition, and a blood draw to obtain APOE ε4 status. Whereas correlations between recall scores and biomarkers tended to be moderate (average r = ±0.48), these correlations were comparable across the three recognition total scores (average r = ±0.42), but tended to be lower for recognition hits (average r = ±0.28) and false positives (average r = ±0.38). These results further validate the existing and recently developed recognition scores on the RBANS as providing useful information about brain and genetic pathology in older adults with intact and impaired cognitive functioning.

The Eyes Are More Eloquent Than Words: Anticipatory Looking as an Index of Event Memory in Alzheimer's Disease

Alzheimer's disease (AD) is a disorder in which individuals experience a difficulty in maintaining event memory for when, where, who, and what. However, verbal deficiency, one of the other symptoms of AD, may prevent a precise diagnosis of event memory because existing tests are based on verbal instructions by the tester and verbal response from patient. Therefore, non-verbal methods are essential to evaluate event memory in AD. The present study, using eye tracking, investigated whether AD patients deployed anticipatory looking to target acts related to future events based on previous experience when an identical video was presented to them twice. The results revealed the presence of anticipatory looking, although AD patients were unable to verbally report the content of the video. Our results illustrate that AD patients have a one-time event memory better than previously thought.

Clinical Characterization of Atypical Primary Progressive Aphasia in a 3-Year Longitudinal Study: A Case Report

The logopenic variant of primary progressive aphasia (lvPPA) is the most recent variant of primary progressive aphasia (PPA) to be identified; thus far, it has been poorly investigated. Despite being typically associated with Alzheimer disease (AD), lvPPA has recently been linked to frontotemporal lobe degeneration (FTLD), with distinctive cognitive and neural features that are worthy of further investigation. Here, we describe the neuropsychological and linguistic profile, as well as cerebral abnormalities, of an individual exhibiting PPA and carrying a pathogenetic variant in the GRN gene, from a 3-year longitudinal perspective. The individual's initial profile resembled lvPPA because it was characterized by word-finding difficulties and phonological errors in spontaneous speech in addition to sentence repetition and phonological short-term memory impairments. The individual's structural and metabolic imaging data demonstrated left temporal and bilateral frontal atrophy and hypometabolism, respectively. On follow-up, as the pathology progressed, dysprosody, stereotypical speech patterns, agrammatism, and orofacial apraxia appeared, suggesting an overlap with the nonfluent variant of PPA (nfvPPA). Severe sentence comprehension impairment also became evident. Our longitudinal and multidisciplinary diagnostic approach allowed us to better characterize the progression of a GRN-positive lvPPA profile, providing neuropsychological and imaging indicators that might be helpful to improve classification between different PPA variants and to address a nosological issue. Finally, we discuss the importance of early diagnosis of PPA given the possible overlap between different PPA variants during the progression of the pathology.

Alzheimer's Disease or Behavioral Variant Frontotemporal Dementia? Review of Key Points Toward an Accurate Clinical and Neuropsychological Diagnosis

Alzheimer's disease (AD) and frontotemporal dementia (FTD) are the most common neurodegenerative early-onset dementias. Despite the fact that both conditions have a very distinctive clinical pattern, they present with an overlap in their cognitive and behavioral features that may lead to misdiagnosis or delay in diagnosis. The current review intends to summarize briefly the main differences at the clinical, neuropsychological, and behavioral levels, in an attempt to suggest which aspects would facilitate an adequate diagnosis in a clinical setting, especially in Latin American and low- and middle-income countries, where the resources needed for a differential diagnosis (such as MRI or biomarkers) are not always available. A timely diagnosis of AD and FTD have significant implications for the medical management and quality of life of patients and careers.

Social Cognition Deficits Are Pervasive across Both Classical and Overlap Frontotemporal Dementia Syndromes

Objectives

Frontotemporal dementia (FTD) syndromes are a complex group of disorders characterised by profound changes in behaviour and cognition. Many of the observed behavioural abnormalities are now recognised to be due to impaired social cognition. While deficits in emotion recognition and empathy are well-recognised in behavioural-variant (Bv)FTD, limited information exists about the nature of social cognitive impairment in the language variant primary progressive aphasia (PPA) that includes progressive non-fluent aphasia (PNFA) and semantic dementia (SD), and in the motor variants FTD amyotrophic lateral sclerosis (FTD-ALS) and FTD progressive supranuclear palsy (FTD-PSP). This prospective study sought to explore the nature and profile of social cognition deficits across the spectrum of FTD.

Methods

Sixty patients on the FTD spectrum, i.e., classical (16 with BvFTD and 20 with PPA) and overlap FTD syndromes (13 with FTD-ALS and 11 with FTD-PSP) were evaluated by means of the social cognition tasks, the Interpersonal Reactivity Index (IRI) for empathy, and pictures of facial affect (POFA) for emotion recognition. General cognition and behaviour were also assessed.

Results

A significant impairment in emotion recognition and empathy was detected in both the classical and overlap FTD syndromes. The recognition of positive emotions was relatively preserved compared to that of negative emotions. Among the FTD subtypes, maximal impairment of empathy was demonstrated in FTD-PSP.

Conclusion

Social cognition impairment is pervasive across the spectrum of FTD disorders, and tests of emotion recognition and empathy are clinically useful to identify the nature of behavioural problems in both classical and overlap FTD. Our findings also have implications for understanding the neural basis of social cognition in FTD.

Recall and Recognition in Alzheimer's Disease and Frontotemporal Dementia

BACKGROUND

It has long been debated whether performance on recall and recognition tests depends on the same or different memory systems and whether performance on these two tasks is dissociated in clinical populations. According to Dual process theories of recall, performance on recall and recognition tests dissociates in the relative reliance on frontal lobe related activities; in fact, the recall test requires more strategic retrieval of memoranda than the recognition task. By contrast, Dual process theories of recognition posit that performance on these tests differs in the relative contribution of recollection and familiarity memory processes in the two tasks: both recollection and familiarity contribute to recognition judgments, but only recollection supports recall performance.

OBJECTIVE

The aim of this study was to clarify the cognitive processes involved in recall and recognition in patients with dementia.

METHODS

We administered a 15-word recall task followed by a yes/no recognition paradigm to 28 patients with Alzheimer's disease (AD), 22 patients with the behavioral variant of frontotemporal dementia (bvFTD), and 45 normal controls (NCs).

RESULTS

Results showed that on the delayed recall task, bvFTD patients performed much better than AD patients but the two groups did not differ on any index of recognition performance.

CONCLUSION

The present data support the hypothesis that the performance of the two groups is expression of the different reliance on recollection (more impaired in the AD than in the bvFTD group) and familiarity (similarly impaired in the two groups) in performance on recall and recognition tasks.

Recommendations to distinguish behavioural variant frontotemporal dementia from psychiatric disorders

The behavioural variant of frontotemporal dementia (bvFTD) is a frequent cause of early-onset dementia. The diagnosis of bvFTD remains challenging because of the limited accuracy of neuroimaging in the early disease stages and the absence of molecular biomarkers, and therefore relies predominantly on clinical assessment. BvFTD shows significant symptomatic overlap with non-degenerative primary psychiatric disorders including major depressive disorder, bipolar disorder, schizophrenia, obsessive-compulsive disorder, autism spectrum disorders and even personality disorders. To date, ∼50% of patients with bvFTD receive a prior psychiatric diagnosis, and average diagnostic delay is up to 5-6 years from symptom onset. It is also not uncommon for patients with primary psychiatric disorders to be wrongly diagnosed with bvFTD. The Neuropsychiatric International Consortium for Frontotemporal Dementia was recently established to determine the current best clinical practice and set up an international collaboration to share a common dataset for future research. The goal of the present paper was to review the existing literature on the diagnosis of bvFTD and its differential diagnosis with primary psychiatric disorders to provide consensus recommendations on the clinical assessment. A systematic literature search with a narrative review was performed to determine all bvFTD-related diagnostic evidence for the following topics: bvFTD history taking, psychiatric assessment, clinical scales, physical and neurological examination, bedside cognitive tests, neuropsychological assessment, social cognition, structural neuroimaging, functional neuroimaging, CSF and genetic testing. For each topic, responsible team members proposed a set of minimal requirements, optimal clinical recommendations, and tools requiring further research or those that should be developed. Recommendations were listed if they reached a ≥ 85% expert consensus based on an online survey among all consortium participants. New recommendations include performing at least one formal social cognition test in the standard neuropsychological battery for bvFTD. We emphasize the importance of 3D-T1 brain MRI with a standardized review protocol including validated visual atrophy rating scales, and to consider volumetric analyses if available. We clarify the role of 18F-fluorodeoxyglucose PET for the exclusion of bvFTD when normal, whereas non-specific regional metabolism abnormalities should not be over-interpreted in the case of a psychiatric differential diagnosis. We highlight the potential role of serum or CSF neurofilament light chain to differentiate bvFTD from primary psychiatric disorders. Finally, based on the increasing literature and clinical experience, the consortium determined that screening for C9orf72 mutation should be performed in all possible/probable bvFTD cases or suspected cases with strong psychiatric features.

Bioinformatic Analysis Reveals Phosphodiesterase 4D-Interacting Protein as a Key Frontal Cortex Dementia Switch Gene

The mechanisms that initiate dementia are poorly understood and there are currently no treatments that can slow their progression. The identification of key genes and molecular pathways that may trigger dementia should help reveal potential therapeutic reagents. In this study, SWItch Miner software was used to identify phosphodiesterase 4D-interacting protein as a key factor that may lead to the development of Alzheimer’s disease, vascular dementia, and frontotemporal dementia. Inflammation, PI3K-AKT, and ubiquitin-mediated proteolysis were identified as the main pathways that are dysregulated in these dementias. All of these dementias are regulated by 12 shared transcription factors. Protein–chemical interaction network analysis of dementia switch genes revealed that valproic acid may be neuroprotective for these dementias. Collectively, we identified shared and unique dysregulated gene expression, pathways and regulatory factors among dementias. New key mechanisms that lead to the development of dementia were revealed and it is expected that these data will advance personalized medicine for patients.

Functionally distinct language and Theory of Mind networks are synchronized at rest and during language comprehension

Communication requires the abilities to generate and interpret utterances and to infer the beliefs, desires, and goals of others ("Theory of Mind"; ToM). These two abilities have been shown to dissociate: individuals with aphasia retain the ability to think about others' mental states; and individuals with autism are impaired in social reasoning, but their basic language processing is often intact. In line with this evidence from brain disorders, functional MRI (fMRI) studies have shown that linguistic and ToM abilities recruit distinct sets of brain regions. And yet, language is a social tool that allows us to share thoughts with one another. Thus, the language and ToM brain networks must share information despite being implemented in distinct neural circuits. Here, we investigated potential interactions between these networks during naturalistic cognition using functional correlations in fMRI. The networks were functionally defined in individual participants, in terms of preference for sentences over nonwords for language, and for belief inference over physical-event processing for ToM, with both a verbal and a nonverbal paradigm. Although, across experiments, interregion correlations within each network were higher than between-network correlations, we also observed above-baseline synchronization of blood oxygenation level-dependent signal fluctuations between the two networks during rest and story comprehension. This synchronization was functionally specific: neither network was synchronized with the executive control network (functionally defined in terms of preference for a harder over easier version of an executive task). Thus, coordination between the language and ToM networks appears to be an inherent and specific characteristic of their functional architecture. NEW & NOTEWORTHY Humans differ from nonhuman primates in their abilities to communicate linguistically and to infer others' mental states. Although linguistic and social abilities appear to be interlinked onto- and phylogenetically, they are dissociated in the adult human brain. Yet successful communication requires language and social reasoning to work in concert. Using functional MRI, we show that language regions are synchronized with social regions during rest and language comprehension, pointing to a possible mechanism for internetwork interaction.

Predicting progression to Alzheimer's disease in subjects with amnestic mild cognitive impairment using performance on recall and recognition tests

The research of reliable procedures for predicting cognitive decline or stability in persons with amnestic mild cognitive impairment (a-MCI) is a major goal for the early identification of subjects in the prodromal stages of dementia. The aim of this study was to evaluate whether different memory performances on two procedures commonly used for the neuropsychological assessment of episodic memory (i.e., free recall and recognition) might be a key in predicting a-MCI patients' subsequent progression to Alzheimer's disease (AD). For this purpose, 80 patients diagnosed with a-MCI at the first assessment and followed-up for at least 3 years were included. During this time, 41 subjects remained in a stable condition of cognitive impairment or improved (stable-MCI) and 39 patients converted to AD dementia (converter-MCI). Sixty-two age- and education-matched healthy individuals were also recruited as healthy controls (HC). Baseline memory performance on the free recall (5th immediate and 15-min delayed) and yes/no recognition (the sensitivity measure d') of a 15-word list were analyzed. Results showed that stable-MCIs forgot significantly more information from immediate to delayed recall of the word list than HC, but exhibited a pronounced improvement of memory performance in the recognition test format. On the contrary, converter-MCIs showed diminished sensitivity in benefiting from cues for recognizing studied words. Word list recognition correctly classified group membership with good overall accuracy, which was higher compared to the classification of converter and stable a-MCIs provided by free recall; therefore, it could be a useful diagnostic tool for predicting progression to AD dementia from the prodromal stage.

Neuropsychology and neuroimaging profiles of amyloid-positive versus amyloid-negative amnestic mild cognitive impairment patients

Introduction

Patients with amnestic mild cognitive impairment (aMCI) are heterogeneous as regard to their amyloid status. The present study aimed at highlighting the neuropsychological, brain atrophy, and hypometabolism profiles of amyloid-positive (Aβpos) versus amyloid-negative (Aβneg) aMCI patients.

Methods

Forty-four aMCI patients and 24 Aβneg healthy controls underwent neuropsychological, structural magnetic resonance imaging and 18F-fluorodeoxyglucose positron emission tomography scans. Data were compared between groups in specific regions of interest and voxelwise with statistical parametric mapping.

Results

When directly comparing Aβpos to Aβneg aMCI, the former had lower performances in episodic memory tests (P = .02 to P < .001) while the latter had worse scores in working memory (P = .01) and language (P < .005). Compared to Aβneg healthy controls, both aMCI subgroups showed similar profiles of atrophy and hypometabolism, with no difference between both aMCI subgroups.

Conclusion

In a sample of aMCI patients recruited and scanned in the same center, the main difference at baseline between Aβpos and Aβneg aMCI concerned the neuropsychological profile, but not the structural magnetic resonance imaging or 18F-fluorodeoxyglucose positron emission tomography profiles of brain alterations.

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Amyloid-positive (Aβpos) amnestic mild cognitive impairment (aMCI) had lower performances than amyloid-negative (Aβneg) aMCI in episodic memory.

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Aβneg aMCI had lower performances than Aβpos aMCI in working memory and language.

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Aβneg and Aβpos aMCI did not differ in terms of brain atrophy or metabolism.

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Cognition is more efficient than neuroimaging to discriminate Aβneg from Aβpos aMCI.

Violence in older people with mental illness

Aggression is common in older people with mental illness, with 15–43% of community referrals to old age psychiatry services and 44–65% of older people with Alzheimer's disease living in the community exhibiting such behaviour. In psychiatric in-patient units, assaults on staff are most common on wards for elderly people with organic mental illness. There is little high-quality research into the management of aggressive behaviour in dementia. We consider the available literature, which has shown certain behavioural measures and different classes of medication to be of benefit. We discuss factors associated with violence in elderly people with mental illness and potential management options.

Can visuospatial measures improve the diagnosis of Alzheimer's disease?

Introduction

Overlapping and evolving symptoms lead to ambiguity in the diagnosis of dementia. Visuospatial function relies on parietal lobe function, which may be affected in the early stages of Alzheimer's disease (AD). This review evaluates visuospatial dysfunction in patients with AD, frontotemporal dementia, dementia with Lewy bodies, and vascular dementia to determine the diagnostic and prognostic potential of visuospatial tasks in AD.

Methods

A systematic search of studies (1960–2016) investigating visuospatial dysfunction in dementia was conducted.

Results

Tests measuring construction, specifically Block Design and Clock Drawing Test, and visual memory, specifically Rey-Osterrieth Complex Figure recall and topographical tasks, show the greatest diagnostic potential in dementia. The Benton visual retention, Doors and People, and topographical memory tests show potential as prognostic markers.

Discussion

Tests of visuospatial function demonstrate significant diagnostic and prognostic potential in dementia. Further studies with larger samples of pathologically confirmed cases are required to verify clinical utility.

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Memory deficits have been demonstrated in Alzheimer's and non-Alzheimer's dementias.

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Parietal lobes are uniquely affected in the early stages of Alzheimer's disease.

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Visuospatial tasks demonstrate significant diagnostic and prognostic potential.

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Computerized test protocols have been developed to test aspects of visuospatial function and memory.

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Novel topographical memory tasks demonstrated the greatest prognostic potential.

False Recognition in Behavioral Variant Frontotemporal Dementia and Alzheimer's Disease-Disinhibition or Amnesia?

Episodic memory recall processes in Alzheimer's disease (AD) and behavioral variant frontotemporal dementia (bvFTD) can be similarly impaired, whereas recognition performance is more variable. A potential reason for this variability could be false-positive errors made on recognition trials and whether these errors are due to amnesia per se or a general over-endorsement of recognition items regardless of memory. The current study addressed this issue by analysing recognition performance on the Rey Auditory Verbal Learning Test (RAVLT) in 39 bvFTD, 77 AD and 61 control participants from two centers (India, Australia), as well as disinhibition assessed using the Hayling test. Whereas both AD and bvFTD patients were comparably impaired on delayed recall, bvFTD patients showed intact recognition performance in terms of the number of correct hits. However, both patient groups endorsed significantly more false-positives than controls, and bvFTD and AD patients scored equally poorly on a sensitivity index (correct hits—false-positives). Furthermore, measures of disinhibition were significantly associated with false positives in both groups, with a stronger relationship with false-positives in bvFTD. Voxel-based morphometry analyses revealed similar neural correlates of false positive endorsement across bvFTD and AD, with both patient groups showing involvement of prefrontal and Papez circuitry regions, such as medial temporal and thalamic regions, and a DTI analysis detected an emerging but non-significant trend between false positives and decreased fornix integrity in bvFTD only. These findings suggest that false-positive errors on recognition tests relate to similar mechanisms in bvFTD and AD, reflecting deficits in episodic memory processes and disinhibition. These findings highlight that current memory tests are not sufficient to accurately distinguish between bvFTD and AD patients.

Evaluating Behavior in Mouse Models of the Behavioral Variant of Frontotemporal Dementia: Which Test for Which Symptom?

The behavioral variant of frontotemporal dementia (bvFTD) is a neurodegenerative disease affecting people in their early sixties, characterized by dramatic changes in individual and social behavior. Despite the heterogeneity in the presentation of the clinical symptoms of bvFTD, some characteristic changes can be highlighted. Social disinhibition, changes in food preferences as well as loss of empathy and apathy are commonly described. This is accompanied by a characteristic and dramatic atrophy of the prefrontal cortex with the accumulation of protein aggregates in the neurons in this area. Several causative mutations in different genes have been discovered, allowing the development of transgenic animal models, especially mouse models. In mice, attention has been focused on the histopathological aspects of the pathology, but now studies are taking interest in assessing the behavioral phenotype of FTD models. Finding the right test corresponding to human symptoms is quite challenging, especially since the frontal cortex is much less developed in mice than in humans. Although challenging, the ability to detect relevant prefrontal cortex impairments in mice is crucial for therapeutic approaches. In this review, we aim to present the approaches that have been used to model the behavioral symptoms of FTD and to explore other relevant approaches to assess behavior involving the prefrontal cortex, as well as the deficits associated with FTD.

Deficits in Everyday Function Differ in AD and FTD

Alzheimer disease (AD) and frontotemporal dementia (FTD) are 2 neurodegenerative diseases with differing cognitive and neuropathologic profiles. Although both diseases ultimately result in functional disability, differences in the profiles of everyday functioning between the 2 groups have not been well characterized. The present study examines potential differences in the types of everyday functional limitations present in these 2 dementias. The present study compared individuals with AD (N=240) or FTD (N=13). The Everyday Cognition (ECog) scale was used to measure distinct domains of everyday cognition: everyday memory, everyday language, everyday visuospatial ability, and a variety of everyday executive abilities. A total ECog score was used to represent global disability level. The groups showed equivalent levels of global disability. However, AD group exhibited worse Everyday Memory and Everyday Visuospatial abilities than the FTD group. Contrary to expectation, FTD was not more impaired in everyday executive abilities. Results remained similar when accounting for severity of cognitive impairment or disease duration. Findings suggest that a somewhat different pattern of everyday functional difficulties can be seen across dementia types.

N-methyl-d-aspartate glutamate receptor (NMDA-R) antibodies in mild cognitive impairment and dementias

The N-methyl-d-aspartate glutamate receptor (NMDA-R) plays a central role in learning and memory and has therefore a potential role in the pathophysiology of neuropsychiatric disorders. Recently, we detected NMDA-R autoantibodies in aged healthy volunteers without neuropsychiatric disorders. Since studies showing the involvement of NMDA-R antibodies in mild cognitive impairment and different forms of dementia are rare, we examined NMDA-R antibodies (Abs) in serum of 46 patients with Alzheimer's disease (AD), 26 patients with subcortical ischemic vascular dementia (SIVD), 18 patients with frontotemporal dementia (FTD), 11 patients with Lewy body disease (LBD) and 33 patients with mild cognitive impairment (MCI) and in 21 healthy aged, gender-matched volunteers. While IgM and/or IgA NMDA-R Abs were present in all groups, IgG was only detected in one AD sample. Seropositivity could be correlated with the presence of co-symptoms: MCI and AD patients suffering from depression and AD and SIVD patients with a psychosis were almost all NMDA-R Ab positive. We conclude that the presence of NMDA-R Abs in dementia could influence the incidence of comorbid depressive and/or psychotic states.

Validation of the Addenbrooke's Cognitive Examination III in frontotemporal dementia and Alzheimer's disease

BACKGROUND/AIMS

The aims of this study were to validate the newly developed version of the Addenbrooke's Cognitive Examination (ACE-III) against standardised neuropsychological tests and its predecessor (ACE-R) in early dementia.

METHODS

A total of 61 patients with dementia (frontotemporal dementia, FTD, n = 33, and Alzheimer's disease, AD, n = 28) and 25 controls were included in the study.

RESULTS

ACE-III cognitive domains correlated significantly with standardised neuropsychological tests used in the assessment of attention, language, verbal memory and visuospatial function. The ACE-III also compared very favourably with its predecessor, the ACE-R, with similar levels of sensitivity and specificity.

CONCLUSION

The results of this study provide objective validation of the ACE-III as a screening tool for cognitive deficits in FTD and AD.

Contrasting prefrontal cortex contributions to episodic memory dysfunction in behavioural variant frontotemporal dementia and Alzheimer's disease

Recent evidence has questioned the integrity of episodic memory in behavioural variant frontotemporal dementia (bvFTD), where recall performance is impaired to the same extent as in Alzheimer's disease (AD). While these deficits appear to be mediated by divergent patterns of brain atrophy, there is evidence to suggest that certain prefrontal regions are implicated across both patient groups. In this study we sought to further elucidate the dorsolateral (DLPFC) and ventromedial (VMPFC) prefrontal contributions to episodic memory impairment in bvFTD and AD. Performance on episodic memory tasks and neuropsychological measures typically tapping into either DLPFC or VMPFC functions was assessed in 22 bvFTD, 32 AD patients and 35 age- and education-matched controls. Behaviourally, patient groups did not differ on measures of episodic memory recall or DLPFC-mediated executive functions. BvFTD patients were significantly more impaired on measures of VMPFC-mediated executive functions. Composite measures of the recall, DLPFC and VMPFC task scores were covaried against the T1 MRI scans of all participants to identify regions of atrophy correlating with performance on these tasks. Imaging analysis showed that impaired recall performance is associated with divergent patterns of PFC atrophy in bvFTD and AD. Whereas in bvFTD, PFC atrophy covariates for recall encompassed both DLPFC and VMPFC regions, only the DLPFC was implicated in AD. Our results suggest that episodic memory deficits in bvFTD and AD are underpinned by divergent prefrontal mechanisms. Moreover, we argue that these differences are not adequately captured by existing neuropsychological measures.

Neurocognitive speed associates with frontotemporal lobar degeneration TDP-43 subtypes

Frontotemporal lobar degeneration (FTLD) is pathologically heterogeneous with the TAR DNA binding protein 43 kDa (TDP-43) proteinopathy the most common substrate. Previous work has identified atrophy patterns across TDP-43 subtypes with Type A showing greater frontotemporal and parietal atrophy, Type C predominantly anterior temporal, and Type B predominantly posterior frontal. Despite neuroanatomical correlates of involvement, neuropsychological findings have been inconsistent. The current study utilized broader neurocognitive domains based on aggregated neuropsychological measures to distinguish between subtypes. We hypothesized that patterns of neurocognitive domain impairments would predict FTLD-TDP subtype. Fifty-one patients, aged 38-87, were identified post mortem with pathologically confirmed FTLD with TDP-43. Participants were classified into subtypes A, B, or C. Patients had completed neuropsychological assessments as part of their clinical evaluation. Six cognitive domains were created: Language; Cognitive Speed; Memory; Learning; Visuoperception; and Fluency. Binary logistic regression was conducted. All but three patients could be classified as FTLD-TDP Types A, B, or C: 26 as Type A; nine as Type B; and 13 as Type C. Cognitive Speed scores were associated with Types A and C (p < 0.001 and p = 0.003, respectively). Impaired performances on the Trail Making Test differentiated Types A and C. Worse Boston Naming Test and Logical Memory (Immediate) (p < 0.05) scores also increased the likelihood of Type C phenotype. Findings suggest Cognitive Speed associates with TDP-43 subtypes. Type C also demonstrated language-specific involvement. Differences between TDP-43 subtypes further supports the notion of differences in pathophysiology or topography across these types.

Behavioral disturbances differentiate frontotemporal lobar degeneration subtypes and Alzheimer's disease: evidence from the Frontal Behavioral Inventory

BACKGROUND

Behavioral assessment is useful for the diagnosis of frontotemporal lobar degeneration (FTLD). We explored the ability of the Frontal Behavioral Inventory (FBI) to discriminate between patients with distinct subtypes of FTLD and patients with Alzheimer's disease (AD), as well as the influence of demographic variables on FBI scores.

METHODS

The FBI was administered to the caregivers of 87 patients diagnosed with FTLD [64 behavioral variant FTLD, 19 aphasic variant FTLD (primary progressive aphasia), and 4 motor/extrapyramidal variant (corticobasal syndrome)] and 30 patients with AD. Patients with AD were older than patients with FTLD. The two groups did not differ with respect to duration of illness, level of education, or sex ratio.

RESULTS

Age significantly predicted disinhibited positive behaviors, such as perseverations and irritability, whereas education did not contribute to FBI ratings. Classification accuracy for the discrimination of AD and mixed FTLD groups was 81%. Moreover, 88.3% and 83.7% accuracy was achieved for the discrimination of AD and behavioral variant FTLD, and AD and primary progressive aphasia groups, respectively. The Total Negative subscale of the FBI, which summarizes the presence of deficit (negative) behaviors, was the best discriminator. A cut-off score of 17 provided 83% sensitivity and 98% specificity in distinguishing between FTLD and AD patients.

CONCLUSIONS

The FBI is a sensitive and specific tool for the differential diagnosis of FTLD from AD. The optimal cut-off point for the detection of FTLD patients was lower than that initially proposed.

Common and unique gray matter correlates of episodic memory dysfunction in frontotemporal dementia and Alzheimer's disease

Conflicting evidence exists regarding the integrity of episodic memory in the behavioral variant of frontotemporal dementia (bvFTD). Recent converging evidence suggests that episodic memory in progressive cases of bvFTD is compromised to the same extent as in Alzheimer's disease (AD). The underlying neural substrates of these episodic memory deficits, however, likely differ contingent on dementia type. In this study we sought to elucidate the neural substrates of episodic memory performance, across recall and recognition tasks, in both patient groups using voxel-based morphometry (VBM) analyses. We predicted that episodic memory dysfunction would be apparent in both patient groups but would relate to divergent patterns of neural atrophy specific to each dementia type. We assessed episodic memory, across verbal and visual domains, in 19 bvFTD, 18 AD patients, and 19 age- and education-matched controls. Behaviorally, patient groups were indistinguishable for immediate and delayed recall, across verbal and visual domains. Whole-brain VBM analyses revealed regions commonly implicated in episodic retrieval across groups, namely the right temporal pole, right frontal lobe, left paracingulate gyrus, and right anterior hippocampus. Divergent neural networks specific to each group were also identified. Whereas a widespread network including posterior regions such as the posterior cingulate cortex, parietal and occipital cortices was exclusively implicated in AD, the frontal and anterior temporal lobes underpinned the episodic memory deficits in bvFTD. Our results point to distinct neural changes underlying episodic memory decline specific to each dementia syndrome.

Language, executive function and social cognition in the diagnosis of frontotemporal dementia syndromes

Frontotemporal dementia (FTD) represents a spectrum of non-Alzheimer's degenerative conditions associated with focal atrophy of the frontal and/or temporal lobes. Frontal and temporal regions of the brain have been shown to be strongly involved in executive function, social cognition and language processing and, thus, deficits in these domains are frequently seen in patients with FTD or may even be hallmarks of a specific FTD subtype (i.e. relatively selective and progressive language impairment in primary progressive aphasia). In this review we have attempted to delineate how language, executive function, and social cognition may contribute to the diagnosis of FTD syndromes, namely the behavioural variant FTD as well as the language variants of FTD including the three subtypes of primary progressive aphasia (PPA): non-fluent/agrammatic, semantic and logopenic. This review also addresses the extent to which deficits in these cognitive areas contribute to the differential diagnosis of FTD versus Alzheimer's disease (AD). Finally, early clinical determinants of pathology are briefly discussed and contemporary challenges to the diagnosis of FTD are presented.

Schizophrenia and frontotemporal dementia: shared causation?

The relationship between specific genes and particular diseases in neuropsychiatry is unclear, and newer studies focus on shared domains of neurobiological and cognitive pathology across different disorders. This paper reviews the evidence for an association between schizophrenia and frontotemporal dementia, including symptom similarity, familial co-morbidity, and neuroanatomical changes. Genetic as well as epigenetic findings from both schizophrenia and frontotemporal dementia are also discussed. As a result, we introduce the hypothesis of a shared susceptibility for certain subgroups of schizophrenia and frontotemporal dementia. This common causation may involve the same gene(s) at different stages of life: early in schizophrenia and late in frontotemporal dementia. Additionally, we provide a rationale for future research that should emphasize both genetic and cognitive parallels between certain forms of schizophrenia and frontotemporal dementia in a synergistic, coordinated way, placing both in the context of aberrant lateralization patterns.

Shared cognitive and behavioral impairments in epilepsy and Alzheimer's disease and potential underlying mechanisms

Seizures in patients with Alzheimer's disease (AD) have been examined by many investigators over the last several decades, and there are diverse opinions about their potential relevance to AD pathophysiology. Some studies suggest that seizures appear to be a fairly uncommon co-morbidity, whereas other studies report a higher incidence of seizures in patients with AD. It was previously thought that seizures play a minor role in AD pathophysiology because of their low frequency, and also because they may only be noticed during late stages of AD, suggesting that seizures are likely to be a consequence of neurodegeneration rather than a contributing factor. However, clinical reports indicate that seizures can occur early in the emergence of AD symptoms, particularly in familial AD. In this case, seizures may be an integral part of the emerging pathophysiology. This view has been supported by evidence of recurrent spontaneous seizures in transgenic mouse models of AD in which familial AD is simulated. Additional data from transgenic animals suggest that there may be a much closer relationship between seizures and AD than previously considered. There is also evidence that seizures facilitate production of amyloid β (Aβ) and can cause impairments in cognition and behavior in both animals and humans. However, whether seizures play a role in the early stages of AD pathogenesis is still debated. Therefore, it is timely to review the similarities and differences between AD and epilepsy, as well as data suggesting that seizures may contribute to cognitive and behavioral dysfunction in AD. Here we focus on AD and temporal lobe epilepsy (TLE), a particular type of epilepsy that involves the temporal lobe, a region that influences behavior and is critical to memory. We also consider potential neurobiological mechanisms that support the view that the causes of seizures in TLE may be related to the causes of cognitive dysfunction in AD. We suggest that similar underlying mechanisms may exist for at least some of the aspects of AD that are also found in TLE.

Progress in frontotemporal dementia research

Frontotemporal dementia (FTD) is the second most common type of presenile dementia and is the most common form of dementia with the onset before 60 years of age. Its typical symptoms include behavioral disorders, affective symptoms, and language disorders. The FTD is a genetically and pathologically heterogeneous degenerative disorder. Animal models have provided more insights into the pathogenic mechanisms. There are currently no medications that are specifically approved for the treatment of FTD by the Food and Drug Administration. In this article, we review the recent advances in the molecular pathogenesis, pathology, animal models, and therapy for FTD. Better understanding of the pathogenesis and the use of animal models will help develop novel therapeutic strategies and provide new targets for FTD treatment.

Presenting neuropsychological testing profile of autopsy-confirmed frontotemporal lobar degeneration

AIMS

We aimed to investigate how neuropsychological test measures at presentation might differentiate frontotemporal lobar degeneration (FTLD) from Alzheimer's disease (AD).

METHODS

We compared autopsy-confirmed FTLD and definite AD with Clinical Dementia Rating ≤1. Factor scores and t values of each neuropsychological test measure were compared between FTLD and AD patients. Logistic regression analyses were applied to identify independent predictors within test measures for the differentiation of FTLD from AD.

RESULTS

Factor analyses showed that the memory domain was more severely impaired in AD than in FTLD, whereas the language and attention domains were more severely impaired in FTLD than in AD. Multiple logistic regression analysis showed that Letter Fluency, Boston Naming Test and delayed memory recall remained independent predictors of FTLD compared to AD. However, test measures did not discriminate between FTLD-tau and FTLD-ubiquitin.

CONCLUSION

We confirm that memory and language function tests discriminate between FTLD and AD.

"Keep up the good work"! A case study of the effects of a specific cognitive training in Alzheimer's disease

Alzheimer's disease (AD) is a neurodegenerative condition characterized by significant impairment in multiple cognitive domains. In recent years, the development of cognitive trainings in AD has received significant attention. In the present case study we designed a cognitive training program (GEO, Geographical Exercises for cognitive Optimization) based on an errorless paradigm and tailored to the patient's cultural interests. The aim of this training was to investigate the potential for acquiring and possibly retaining both procedural and verbal knowledge in early-stage AD. This study involved an 80-year-old female patient diagnosed with early-stage AD, and 10 matched healthy subjects. Participants were asked to perform the two GEO training tasks: a "puzzle-like" task for procedural memory, and an "association" task for verbal memory. Both the patient and the healthy controls were subsequently trained with GEO using the same two tasks for 2 months. Although the patient's performance before training in both tasks was poor compared to healthy controls, after the training these differences disappeared. Our results showed that the patient was able to acquire new procedural abilities and verbal knowledge, and that her achievements were stable at the follow-up testing scheduled 3 months after the end of the intervention. This case study suggests a potentially useful strategy for cognitive training in AD.

Abnormal network connectivity in frontotemporal dementia: evidence for prefrontal isolation

INTRODUCTION

Degraded social function, disinhibition, and stereotypy are defining characteristics of frontotemporal dementia (FTD), manifesting in both the behavioral variant of frontotemporal dementia (bvFTD) and semantic dementia (SD) subtypes. Recent neuroimaging research also associates FTD with alterations in the brain's intrinsic connectivity networks. The present study explored the relationship between neural network connectivity and specific behavioral symptoms in FTD.

METHODS

Resting-state functional magnetic resonance imaging was employed to investigate neural network changes in bvFTD and SD. We used independent components analysis (ICA) to examine changes in frontolimbic network connectivity, as well as several metrics of local network strength, such as the fractional amplitude of low-frequency fluctuations, regional homogeneity, and seed-based functional connectivity. For each analysis, we compared each FTD subgroup to healthy controls, characterizing general and subtype-unique network changes. The relationship between abnormal connectivity in FTD and behavior disturbances was explored.

RESULTS

Across multiple analytic approaches, both bvFTD and SD were associated with disrupted frontolimbic connectivity and elevated local connectivity within the prefrontal cortex. Even after controlling for structural atrophy, prefrontal hyperconnectivity was robustly associated with apathy scores. Frontolimbic disconnection was associated with lower disinhibition scores, suggesting that abnormal frontolimbic connectivity contributes to positive symptoms in dementia. Unique to bvFTD, stereotypy was associated with elevated default network connectivity in the right angular gyrus. The behavioral variant was also associated with marginally higher apathy scores and a more diffuse pattern of prefrontal hyperconnectivity than SD.

CONCLUSIONS

The present findings support a theory of FTD as a disorder of frontolimbic disconnection leading to unconstrained prefrontal connectivity. Prefrontal hyperconnectivity may represent a compensatory response to the absence of affective feedback during the planning and execution of behavior. Increased reliance upon prefrontal processes in isolation from subcortical structures appears to be maladaptive and may drive behavioral withdrawal that is commonly observed in later phases of neurodegeneration.

Astrocytic cytoskeletal atrophy in the medial prefrontal cortex of a triple transgenic mouse model of Alzheimer's disease

Alzheimer's disease (AD) is a progressive neurodegenerative disorder characterized by the loss of cognitive functions, reflecting pathological damage to the medial prefrontal cortex (mPFC) as well as to the hippocampus and the entorhinal cortex. Astrocytes maintain the internal homeostasis of the CNS and are fundamentally involved in neuropathological processes, including AD. Here, we analysed the astrocytic cytoskeletal changes within the mPFC of a triple transgenic mouse model of AD (3 × Tg-AD) by measuring the surface area and volume of glial fibrillary acidic protein (GFAP)-positive profiles in relation to the build-up and presence of amyloid-β (Aβ), and compared the results with those found in non-transgenic control animals at different ages. 3 × Tg-AD animals showed clear astroglial cytoskeletal atrophy, which appeared at an early age (3 months; 33% and 47% decrease in GFAP-positive surface area and volume, respectively) and remained throughout the disease progression at 9, 12 and 18 months old (29% and 36%; 37% and 35%; 43% and 37%, respectively). This atrophy was independent of Aβ accumulation, as only a few GFAP-positive cells were localized around Aβ aggregates, which suggests no direct relationship with Aβ toxicity. Thus, our results indicate that the progressive reduction in astrocytic branching and domain in the mPFC can account for the integrative dysfunction leading to the cognitive deficits and memory disturbances observed in AD.

Executive deficits are related to the inferior frontal junction in early dementia

Executive functions describe a wide variety of higher order cognitive processes that allow the flexible modification of thought and behaviour in response to changing cognitive or environmental contexts. Their impairment is common in neurodegenerative disorders. Executive deficits negatively affect everyday activities and hamper the ability to cope with other deficits, such as memory impairment in Alzheimer's disease or behavioural disorders in frontotemporal lobar degeneration. Our study aimed to characterize the neural correlates of executive functions by relating respective deficits to regional hypometabolism in early dementia. Executive functions were assessed with two classical tests, the Stroop and semantic fluency test and various subtests of the behavioural assessment of the dysexecutive syndrome test battery capturing essential aspects of executive abilities relevant to daily living. Impairments in executive functions were correlated with reductions in brain glucose utilization as measured by [(18)F]fluorodeoxyglucose positron emission tomography and analysed voxelwise using statistical parametric mapping in 54 subjects with early dementia, mainly Alzheimer's disease and frontotemporal lobar degeneration, and its prodromal stages: subjective and mild cognitive impairment. Although the analysis revealed task-specific frontoparietal networks, it consistently showed that hypometabolism in one region in the left lateral prefrontal cortex-the inferior frontal junction area-was related to performance in the various neuropsychological tests. This brain region has recently been related to the three component processes of cognitive control-working memory, task switching and inhibitory control. Group comparisons additionally showed hypometabolism in this area in Alzheimer's disease and frontotemporal lobar degeneration. Our study underlines the importance of the inferior frontal junction area for cognitive control in general and for executive deficits in early dementia.

Early astrocytic atrophy in the entorhinal cortex of a triple transgenic animal model of Alzheimer's disease

The EC (entorhinal cortex) is fundamental for cognitive and mnesic functions. Thus damage to this area appears as a key element in the progression of AD (Alzheimer's disease), resulting in memory deficits arising from neuronal and synaptic alterations as well as glial malfunction. In this paper, we have performed an in-depth analysis of astroglial morphology in the EC by measuring the surface and volume of the GFAP (glial fibrillary acidic protein) profiles in a triple transgenic mouse model of AD [3xTg-AD (triple transgenic mice of AD)]. We found significant reduction in both the surface and volume of GFAP-labelled profiles in 3xTg-AD animals from very early ages (1 month) when compared with non-Tg (non-transgenic) controls (48 and 54%, reduction respectively), which was sustained for up to 12 months (33 and 45% reduction respectively). The appearance of Aβ (amyloid β-peptide) depositions at 12 months of age did not trigger astroglial hypertrophy; nor did it result in the close association of astrocytes with senile plaques. Our results suggest that the AD progressive cognitive deterioration can be associated with an early reduction of astrocytic arborization and shrinkage of the astroglial domain, which may affect synaptic connectivity within the EC and between the EC and other brain regions. In addition, the EC seems to be particularly vulnerable to AD pathology because of the absence of evident astrogliosis in response to Aβ accumulation. Thus we can consider that targeting astroglial atrophy may represent a therapeutic strategy which might slow down the progression of AD.

Differential diagnosis of behavioral variant of fronto-temporal dementia (bvFTD)

Background

The aim of the paper is the differential diagnosis of various types of Fronto-Temporal Dementia (FTD), with the focus on its behavioural variant (bvFTD).

Material/Method

Material and Method. Screening was done in order to assess the depth of dementia with the short version of MMSE, while evaluation of various variants of FTD was performed with the use of such neuropsychological tests as Newcomb and Chicago Fluency Tests, Wechsler Memory Scale - III (WMS-III), Western Aphasia Battery (WAB-R), and the Boston Naming Test (BNT). Behaviour was evaluated with a Polish version of the Frontal Behavioral Inventory (FBInv). The inventory consists of 24 questions which enable an evaluation of social behaviour disorders. The study included 112 patients - 68 men and 46 women treated in the Reintegrative -Training Centre of the Foundation for Persons with Brain Dysfunctions in Kraków and in the Clinic for Developmental Psychiatry, Psychotic Disorders and Old Age Psychiatry, of the Medical University at Gdańsk, who were suffering from various types of dementia.

Results

It was found that FTD patients scored the highest, while the VAD patients scored somewhat lower in the FBInv. At the same time the scores obtained by PPA patients were higher in comparison to the control groups, but not as high as in the case of patients with FTD. In the process of the neurotherapy of FTD patients we found a reduction of the behavioral disturbances, despite the progression of the illness.

Conclusions

The results obtained in the present study confirmed the diagnostic value of FBInv in the differential diagnosis of various types of FTD and in the evaluation of neurotherapy efficacy.

Primary progressive aphasias and their contribution to the contemporary knowledge about the brain-language relationship

Primary progressive aphasia (PPA), typically resulting from a neurodegenerative disease such as frontotemporal dementia/Pick Complex or Alzheimer's disease, is a heterogeneous clinical condition characterized by a progressive loss of specific language functions with initial sparing of other cognitive domains. Based on the constellation of symptoms, PPA has been classified into a nonfluent, semantic, or logopenic variant. This review of the literature aims to characterize the speech and language impairment, cognition, neuroimaging, pathology, genetics, and epidemiology associated with each of these variants. Some therapeutic recommendations, theoretical implications, and directions for future research have been also provided.

[Early onset dementia]

BACKGROUND

It is estimated that 1,200 people under the age of 65 have been diagnosed with dementia in Norway. This article provides an overview of the types of dementia frequently seen in younger patients.

MATERIAL AND METHODS

The article is based on a non-systematic search in PubMed, as well as the authors' own clinical and research experience.

RESULTS

Alzheimer's disease, frontotemporal dementia, vascular dementia and dementia with Lewy bodies, are the most common types of dementia occurring more often in younger than in older patients. The cognitive symptoms are more variable in younger patients than in older. Only a small percentage of early onset dementia is caused by genetic factors. There are few diagnostic tools available for this age group and it takes considerable time to reach a correct diagnosis. Early diagnosis allows the patient and carer to plan for the future.

INTERPRETATION

Physicians should be aware that dementia can occur in younger people, and more diagnostic assessments should be developed for this patient group. Better coordination from the public health authority and municipalities is needed to provide respite care for early onset dementia patients and their carers.

Quality of life and depression in carers of patients with early onset dementia

OBJECTIVE

To investigate the quality of life (QoL) and depression and its correlates in carers living with early onset dementia (EOD) patients.

METHOD

The subjects were 49 carers, either married to or cohabiting with EOD patients, 38 with Alzheimer's disease and 11 with other types of dementia. The Quality of Life - Alzheimer Disease scale (QoL-AD) and Geriatric Depression Scale-15 items (GDS-15) were used.

RESULTS

The mean QoL score for the carers was 37.9 (SD 5.5) and the mean GDS-15 score 5.1 (SD 2.9). Linear regression analyses with QoL and GDS-15 score as dependent variables were performed. Increased age of the carer (B = 0.32) and greater insight of the patients (B = -0.186) were significantly associated with a better QoL for the carer. Being married (B = 2.10), having children together with the patient (B = 1.61) and being the carer of a patient with cardiovascular disease (B = 2.28) were associated significantly with a higher GDS-15 score, whereas being the carer of a patient who received domiciliary nursing care (B = -2.29) was significantly associated with a lower GDS-15 score.

CONCLUSION

The QoL for carers of EOD patients corresponds positively with the increased age of carers and with patients' insight into their condition. Increased depressive symptomatology in carers was associated with being married, having offspring and caring for a patient with dementia and a co-morbid cardiovascular disease. A reduction in depression was seen in carers when the patients received domiciliary nursing care.

Wisconsin card sorting test as a measure of executive function impairments in stroke patients

The Wisconsin Card Sorting Test (WCST) is among the most frequently administered neuropsychological tests. It is assumed that successful completion of this test requires engagement of executive functions (EF). One of the most common origins of EF impairments is ischemic stroke. The present study intends to evaluate the diagnostic use of the WCST as a measure of these impairments in poststroke patients. Forty-four patients (8 women and 36 men) who had recent unilateral stroke (22 left hemisphere, 22 right hemisphere) participated in the study. The overall accuracy of the WCST in classifying stroke survivors as having executive disorders was poor. Nevertheless, statistical analysis revealed its negative predictive power to be greater than positive predictive power (i.e., normal scores on the WCST reliably indicated the absence of executive disorders in 8 or more out of 10). Performance on the WCST is clearly influenced by severity of the executive disorders. Namely, patients with severe impairment of EF (as measured by go/no-go, fluency, and other EF tests) performed more poorly on the WCST than patients with lesser impairment or those with no impairment at all, the latter group's results being indistinguishable. In addition, this study highlights a three-factor solution to the WCST, which accounted for 90.3% of the variance. The scores that most strongly loaded on Factors 1 to 3 were, in order: percentage of conceptual-level responses, number of trials to complete the first category, and failures to maintain the set of responses. Finally, an analysis using multivariate analysis of variance, with the anterior versus posterior site and left versus right side of the lesion as independent variables, revealed a relatively weak effect of lesion location on the WCST performance. In particular, with respect to all test scores, there is only one significant interaction between the site and side of lesion was obtained (F(₁(,)₂₄) = 4.12; p < .05; i.e., the number of categories achieved was significantly smaller after damage to the frontal lobe on the left than on the right side, whereas the laterality effect was not significant after nonfrontal lesions). In conclusion, to ascertain the cerebral substrates of poststroke executive dysfunction, there is a need to apply more accurate tests than the WCST. The study highlights the importance of a multicomponent approach to executive functioning in stroke patients.

Serotonin transporter and saitohin genes in risk of Alzheimer's disease and frontotemporal lobar dementia: preliminary findings

Serotonergic transmission impairment and abnormal phosphorylation of tau protein have been implicated in the physiopathology of Alzheimer's disease (AD) and frontotemporal lobar dementia (FTLD). Associations between a functional polymorphism (5-HTTLPR), in the promoter region of the serotonin transporter gene, and susceptibility to sporadic AD and FTLD have been reported. A polymorphism (Q7R) in saitohin gene inside the microtubule-associated protein tau gene has also been related to dementia. To determine the possible role of the two polymorphisms in susceptibility to AD and FTLD, we performed a case-control study collecting 218 Italian sporadic dementia patients and 54 controls. We found a significant excess of 5-HTTLPR short alleles and an interaction between 5-HTTLPR and Q7R polymorphisms in demented subjects. Our study confirms the role of 5-HTTLPR as a potential susceptibility factor for sporadic dementia in the Italian population, and suggests a possible interaction between 5-HTTLPR and Q7R polymorphisms in neurodegenerative diseases.

Conceptual evolution in Alzheimer's disease: implications for understanding the clinical phenotype of progressive neurodegenerative disease

Over the past several decades, our understanding of Alzheimer's disease (AD) has seen an evolution from the dichotomous concept of normal versus AD in the dementia state to a more accurate and complete appreciation of AD as a progressive disorder with clinical, biological, and pathological features occurring along a continuum from normal to end-stage disease. Integrating our understanding of the relationships and interplay between the clinical, biological, and pathological features of AD may allow the identification of AD at even preclinical, completely asymptomatic stages of the disease. This review attempts to summarize the clinical stages of AD in terms of epidemiology, historical evolution of disease stage diagnoses, cognitive/neuropsychologic features, psychiatric/behavioral manifestations, and functional decline in the context of our developing understanding of the biological processes responsible for the pathogenesis of AD described in detail in the accompanying articles.

Longitudinal rates of lobar atrophy in frontotemporal dementia, semantic dementia, and Alzheimer's disease

This study compared rates of regional atrophy in Alzheimer disease (AD), frontotemporal dementia (FTD), and semantic dementia (SD). Cross-sectional studies have shown that different dementia syndromes are associated with different patterns of regional brain tissue loss. Rates of atrophy over time may be useful for differential diagnosis, and could be used to monitor disease progression, serving as an outcome measure for clinical trials. We studied patients with AD (n=12), FTD (n=13), SD (n=20), and normal controls (n=23) longitudinally with structural magnetic resonance imaging, using BRAINS2 software to measure frontal, temporal, and parietal lobe volumes. In FTD the rate of frontal lobe atrophy over 1 year was greater than in any other group, whereas SD showed the highest rate in the temporal lobes. Atrophy in these regions progressed twice as quickly in FTD and SD compared with AD. Atrophy was not significantly faster for AD in any brain region compared with the other groups. Regional atrophy over time was significantly faster in FTD and SD compared with AD, and the regions of greatest atrophy were specific for each syndrome. Measuring specific regions of cerebral volume changes by serial neuroimaging may serve as a useful biomarker outcome measure for clinical trials in neurodegenerative diseases.

Emotion regulation deficits in frontotemporal lobar degeneration and Alzheimer's disease

We examined instructed and spontaneous emotion regulation in patients with frontotemporal lobar degeneration (FTLD, N = 32), which presents with profound emotional and personality changes; patients with Alzheimer's disease (AD, N = 17), which presents with profound memory impairment; and neurologically normal controls (N = 25). Participants were exposed to an aversive acoustic startle stimulus (115 dB) under 3 different conditions: (a) unwarned without instructions to down-regulate, (b) warned without instructions to down-regulate, and (c) warned with instructions to down-regulate. In the last 2 conditions, the warning took the form of a 20-s countdown. In all conditions, visible aspects of the startle response were assessed by measuring overall somatic activity and coding emotional facial expressions. FTLD patients, AD patients, and control participants showed similar patterns of down-regulation in somatic activity across the 3 startle trials. However, differences between the 3 groups emerged in the amount of emotional facial behavior expressed in the startle trials. There were no group differences in response in the unwarned condition, indicating that the startle response was intact in the patients. In the warned with instructions condition, both FTLD and AD patients were moderately impaired in down-regulatory ability compared with controls. In the warned without instructions condition, AD patients and normal controls spontaneously down-regulated their emotional responses, but FTLD patients did not. These findings illuminate specific problems that these patients have in the emotional realm.

Frontotemporal dementia selectively impairs transitive reasoning about familiar spatial environments

Although patients with frontotemporal dementia (FTD) are known to exhibit a wide range of cognitive and personality difficulties, some evidence suggests that there may be a degree of selectivity in their reasoning impairments. Based on a recent review of the neuroimaging literature on reasoning, the authors hypothesized that the presence or absence of familiar content may have a selective impact on the reasoning abilities of patients with FTD. Specifically, the authors predicted that patients with frontal-variant FTD would be more impaired when reasoning about transitive arguments involving familiar spatial environments than when reasoning about identical logical arguments involving unfamiliar spatial environments. As predicted, patients with FTD were less accurate than normal controls only when the content of arguments involved familiar spatial environments. These results indicate a degree of selectivity in the cognitive deficits of this patient population and suggest that the frontal-temporal lobe system may play a necessary role in reasoning about familiar material.

Empathy and emotion recognition in semantic dementia: a case report

Recent studies have demonstrated that patients suffering from frontotemporal lobar degeneration (FTLD) show impairments in empathy and emotional processing. In this study, we examined two different aspects of these abilities in a patient with semantic dementia (SD), a variant of FTLD. The first aspect was the assessment of the cognitive and emotional components of empathy through the Interpersonal Reactivity Index. The second was the naming and comprehension of emotions using the Ekman 60 Faces Test. The patient's emotion word knowledge was spared and the emotional aspects of empathy preserved. Conversely, the patient performed below average for all of the basic emotions when an emotion word had to be matched with a picture. When picture-to-picture matching was tested, however, the patient was able to recognize happiness. This case is a good example of a dissociation of covert and overt emotional functioning in SD. Results are discussed in terms of the impaired empathic behavior and emotional functioning in FTLD.