Behavioral disorders in the frontal and temporal variants of frontotemporal dementia

The emotional brain: combining insights from patients and basic science

Emotional dysfunction occurs commonly in neurological disease, although the study of this phenomenon has been relatively neglected. In this introduction to the special issue of Neurocase, we review some key processes underlying normal emotional function and we link these processes to their putative neuroanatomical substrates. Emotions are multimodal phenomena involving the coordinated activation of thoughts, somatic musculature, and the autonomic system in response to shifting environmental demands. Key facets of emotional function include appraisal, reactivity, regulation, emotional understanding, and empathy. These processes are carried out via interactions between the frontal and temporal lobes and insula, and subcortical structures including the amygdala, basal ganglia, hypothalamus and brainstem. A thorough understanding of emotional dysfunction in neurological disease will require a sophisticated approach to studying emotion, which takes into account these various processes and links them to neuroanatomical changes.

Propagation of tau misfolding from the outside to the inside of a cell

Tauopathies are neurodegenerative diseases characterized by aggregation of the microtubule-associated protein Tau in neurons and glia. Although Tau is normally considered an intracellular protein, Tau aggregates are observed in the extracellular space, and Tau peptide is readily detected in the cerebrospinal fluid of patients. Tau aggregation occurs in many diseases, including Alzheimer disease and frontotemporal dementia. Tau pathology begins in discrete, disease-specific regions but eventually involves much larger areas of the brain. It is unknown how this propagation of Tau misfolding occurs. We hypothesize that extracellular Tau aggregates can transmit a misfolded state from the outside to the inside of a cell, similar to prions. Here we show that extracellular Tau aggregates, but not monomer, are taken up by cultured cells. Internalized Tau aggregates displace tubulin, co-localize with dextran, a marker of fluid-phase endocytosis, and induce fibrillization of intracellular full-length Tau. These intracellular fibrils are competent to seed fibril formation of recombinant Tau monomer in vitro. Finally, we observed that newly aggregated intracellular Tau transfers between co-cultured cells. Our data indicate that Tau aggregates can propagate a fibrillar, misfolded state from the outside to the inside of a cell. This may have important implications for understanding how protein misfolding spreads through the brains of tauopathy patients, and it is potentially relevant to myriad neurodegenerative diseases associated with protein misfolding.

Neurodegenerative diseases target large-scale human brain networks

During development, the healthy human brain constructs a host of large-scale, distributed, function-critical neural networks. Neurodegenerative diseases have been thought to target these systems, but this hypothesis has not been systematically tested in living humans. We used network-sensitive neuroimaging methods to show that five different neurodegenerative syndromes cause circumscribed atrophy within five distinct, healthy, human intrinsic functional connectivity networks. We further discovered a direct link between intrinsic connectivity and gray matter structure. Across healthy individuals, nodes within each functional network exhibited tightly correlated gray matter volumes. The findings suggest that human neural networks can be defined by synchronous baseline activity, a unified corticotrophic fate, and selective vulnerability to neurodegenerative illness. Future studies may clarify how these complex systems are assembled during development and undermined by disease.

New approaches to the treatment of frontotemporal lobar degeneration

PURPOSE OF REVIEW

Treatment approaches for frontotemporal lobar degeneration (FTLD) are rapidly evolving with improved understanding of the disease. This brief review highlights recent advances.

RECENT FINDINGS

Early-onset dementia has a devastating impact on families and rids its victims of their most productive and rewarding years. Over the past 10 years, FTLD has emerged as the commonest cause of dementia under the age of 60 years, outstripping even Alzheimer's disease in prevalence. Remarkable progress has occurred in our understanding of FTLD both as a set of distinctive clinical syndromes and as a set of disorders with unique genetic and pathological profiles. Although there are no Food and Drug Administration-approved medications for FTLD, new evidence of specific genetic and neurochemical defects is beginning to provide a strong rationale for pharmacological treatment.

SUMMARY

Behavioral changes, which are common in behavioral variant frontotemporal dementia and semantic dementia, often respond to treatment with selective serotonin reuptake inhibitors. Memantine also holds promise to treat neuropsychiatric symptoms, but more prospective trials are needed.With better understanding of pathogenic molecular pathways involving microtubule-associated protein tau, progranulin and TDP-43, potential disease-modifying therapies are being studied in animal models and approaching human trials.

Dissociable effects of prefrontal and anterior temporal cortical lesions on stereotypical gender attitudes

Clinical observations of patients with ventral frontal and anterior temporal cortical lesions reveal marked abnormalities in social attitudes. A previous study in seven patients with ventral prefrontal lesions provided the first direct experimental evidence for abnormalities in social attitudes using a well-established measure of gender stereotypes, the Implicit Association Test (IAT). Here, we were able to test whether these first findings could be reproduced in a larger sample of 154 patients with penetrating head injuries, and to determine the differential effects of ventromedial prefrontal (vmPFC) and ventrolateral prefrontal (vlPFC) cortical lesions on IAT performance. In addition, we investigated the role of the superior anterior temporal lobe (aTL), recently shown to represent conceptual social knowledge. First, we used a linear regression model to identify the role of each of the three regions, while controlling for the extent of damage to other regions. We found that larger lesions in either the vmPFC or the superior aTL were associated with increased stereotypical attitudes, whereas larger lesions in the vlPFC were associated with decreased stereotypical attitudes. Second, in a confirmatory analysis, we grouped patients by lesion location and compared their performance on the IAT with that of healthy volunteers. Compared to controls, patients with lesions in either the vmPFC or the superior aTL showed increased stereotypical attitudes, whereas patients with lesions in the vlPFC showed decreased stereotypical attitudes. The functional contributions of these regions in social attitudes are discussed.

Sensitivity of current criteria for the diagnosis of behavioral variant frontotemporal dementia

BACKGROUND

Diagnosis of behavioral variant frontotemporal dementia (bvFTD) relies on criteria that are constraining and potentially ambiguous. Some features are open to clinical interpretation and their prevalence unknown. This study investigated the sensitivity of current diagnostic criteria in a large group of patients with bvFTD.

METHODS

Forty-five patients with clear evidence of bvFTD as judged by progressive clinical decline (>3 years) with marked frontal features and significant frontal brain atrophy on brain MRI were included. Thirty-two have died; pathologic confirmation of frontotemporal lobar degeneration was found in all 18 coming to autopsy. We established the prevalence of core and supportive diagnostic features at presentation and with disease progression.

RESULTS

Only 25/45 patients (56%) showed all five core features necessary for a diagnosis of bvFTD at initial presentation and 33/45 (73%) as their disease progressed. Two core features, emotional blunting and loss of insight, were never observed in 25% and 13% of cases. Executive dysfunction, hyperorality, mental inflexibility, and distractibility were the only supportive features present in >50% of cases at initial presentation. Although not a diagnostic feature, impaired activities of daily living was present in 33/45 patients (73%).

CONCLUSIONS

Strict application of the criteria misses a significant proportion of patients. Many supportive features have low prevalence and are clinically not useful. Revision of the criteria to include level of certainty (definite, probable, possible) dependent on the number of features present and the presence of ancillary information (e.g., brain atrophy, neuropsychological abnormalities, impaired activities of daily living) is encouraged.

Neuroanatomy of apathy and disinhibition in frontotemporal lobar degeneration

OBJECTIVE

To investigate the neural basis for the behavioral symptoms of frontotemporal lobar degeneration (FTLD) that cause the greatest caregiver distress.

BACKGROUND

FTLD is a progressive neurodegenerative disease associated with behavioral disturbances. Group studies have related these behaviors to volume loss on MRI.

METHODS

Forty caregivers of patients with the clinical diagnosis of FTLD completed the Neuropsychiatric Inventory. Twelve neuropsychiatric symptoms and the associated caregiver distress were assessed. Optimized voxel-based morphometry identified significant atrophy in subgroups of FTLD patients with isolated behavioral symptoms corresponding to the most distressing behaviors, and we correlated cortical atrophy directly with these distressing behavioral disorders in an unbiased group analysis.

RESULTS

The greatest stressors for caregivers were apathy and disinhibition (p < 0.005 for both contrasts). Partially distinct areas of cortical atrophy were associated with these behaviors in both individual patients with these symptoms and group-wide analyses, including the dorsal anterior cingulate cortex and dorsolateral prefrontal cortex in apathetic patients, and the medial orbital frontal cortex in disinhibited patients.

CONCLUSIONS

Caregiver stress in families of FTLD patients is due in large part to apathy and disinhibition. The anatomic distribution of cortical loss corresponding to these distressing social behaviors includes partially distinct areas within the frontal lobe.

Social conceptual impairments in frontotemporal lobar degeneration with right anterior temporal hypometabolism

Inappropriate social behaviours are early and distinctive symptoms of the temporal and frontal variants of frontotemporal lobar degeneration (FTLD). Knowledge of social behaviour is essential for appropriate social conduct. It is unknown, however, in what way this knowledge is degraded in FTLD. In a recent functional MRI study, we have identified a right-lateralized superior anterior temporal lobe (aTL) region showing selective activation for 'social concepts' (i.e. concepts describing social behaviour: e.g. 'polite', 'stingy') as compared with concepts describing less socially relevant animal behaviour ('animal function concepts': e.g. 'trainable', 'nutritious'). In a further fMRI study, superior aTL activation was independent of the context of actions and feelings associated with these social concepts. Here, we investigated whether the right superior sector of the aTL is necessary for context-independent knowledge of social concepts. We assessed neuronal glucose uptake using 18-fluoro-deoxy-glucose-positron emission tomography (FDG-PET) and a novel semantic discrimination task which probed knowledge of social and animal function concepts in patients with FTLD (n = 29) and corticobasal syndrome (n = 18). FTLD and corticobasal syndrome groups performed equally poorly on animal function concepts but FTLD patients showed more pronounced impairments on social concepts than corticobasal syndrome patients. FTLD patients with right superior aTL hypometabolism, as determined on individual ROI analyses, were significantly more impaired on social concepts than on animal function concepts. FTLD patients with selective impairments for social concepts, as determined on individual neuropsychological profiles, showed higher levels of inappropriate social behaviours ('disinhibition') and demonstrated more pronounced hypometabolism in the right superior aTL, the left temporal pole and the right lateral orbitofrontal and dorsomedial prefrontal cortex as compared with FTLD patients showing selective impairments of animal function concepts. Combining both FTLD subgroup analyses, based on anatomical and neuropsychological criteria, by using inclusive masks, revealed the right superior aTL as associated with selective impairments of social concepts in both analyses. These results corroborate the hypothesis that the right aTL is necessary for representing conceptual social knowledge. Further, we provide first evidence for the potential importance of conceptual social knowledge impairments as contributing to behavioural symptoms of FTLD.

Understanding social dysfunction in the behavioural variant of frontotemporal dementia: the role of emotion and sarcasm processing

Social interaction is profoundly affected in the behavioural form of frontotemporal dementia (bvFTD) yet there are few means of objectively assessing this. Diagnosis of bvFTD is based on informant report, however a number of individuals with a clinical profile consistent with the disease have no imaging abnormality and seem to remain stable, with doubt about the presence of underlying neurodegenerative pathology. We aimed to quantify aspects of the behavioural disorder and link it to the underlying level of atrophy in socially relevant brain regions. We tested individuals with either bvFTD (N = 26) or Alzheimer's disease (N = 9) and 16 controls using The Awareness of Social Inference Test (TASIT) to assess their ability to identify emotion and sarcasm in video vignettes. A subset of bvFTD patients (N = 21) and controls (N = 12) were scanned using MRI within 6 months of assessment. There was marked impairment in the ability of bvFTD patients whose scans showed abnormalities to recognize sarcastic, but not sincere statements. Their capacity to interpret negative emotion was also impaired, and this appeared to be a major factor underlying the deficit in sarcasm recognition. Clinically diagnosed bvFTD patients whose scans were normal, Alzheimer's disease patients and controls had no difficulty in appreciating both types of statement. In a multivariate imaging analysis it was shown that the sarcasm (and emotion recognition) deficit was dependent on a circuit involving the lateral orbitofrontal cortex, insula, amygdala and temporal pole, particularly on the right. Performance on a more global test of cognitive function, the Addenbrooke's Cognitive Examination did not have a unique association with these regions. The TASIT is an objective test of social dysfunction in bvFTD which indexes the frontotemporal volume loss in bvFTD patients and provides an objective measure for separating behavioural patients who are likely to decline from those who may remain stable. These results provide additional evidence for the role of the orbitofrontal cortex and related structures in the processing of socially relevant signals, particularly those where negative emotion recognition is important.

The primary cognitive deficit among males with fragile X-associated tremor/ataxia syndrome (FXTAS) is a dysexecutive syndrome

Fragile X-associated tremor/ataxia syndrome (FXTAS) is a neurodegenerative disorder associated with a premutation trinucleotide repeat expansion in the fragile X mental retardation 1 gene. Symptoms include gait ataxia, action tremor, and cognitive impairment. The objectives of the study were to clarify the nature of the dysexecutive syndrome observed in FXTAS and to assess the contribution of executive impairment to deficits in nonexecutive cognitive functions. Compared to controls, men with FXTAS demonstrated significant executive impairment, which was found to mediate group differences in most other cognitive abilities. Asymptomatic premutation carriers performed similarly to controls on all but two measures of executive functioning. These findings suggest that the impairment of nonexecutive cognitive skills in FXTAS is in large part secondary to executive dysfunction.

Neural correlates of caregiver burden in cortical basal syndrome and frontotemporal dementia

AIMS

To determine areas of atrophy in patients that are associated with caregiver burden.

METHODS

We measured caregiver burden, dementia and neuropsychiatric scores in 22 patients with corticobasal syndrome (CBS) and 25 with frontotemporal dementia (FTD), and in 14 healthy controls. We used voxel-based morphometry to correlate caregiver burden with gray matter loss.

RESULTS

Increased dementia and behavioral disturbances contributed to higher burden scores in CBS patients, while behavioral disturbances alone significantly affected burden scores in frontal-variant FTD (FTD-fv) patients. In CBS patients, caregiver burden scores correlated with atrophy in left inferior and middle temporal gyri.

CONCLUSIONS

Caregivers of FTD-fv patients had significantly higher burden scores than caregivers of CBS patients. Damage to areas important in semantic knowledge appears critical in increased burden for CBS caregivers.

A 6-month, open-label study of memantine in patients with frontotemporal dementia

OBJECTIVE

To evaluate safety and effects on cognition and behavior of memantine 20 mg/day in the treatment of patients with frontotemporal dementia (FTD).

METHODS

This was a single-center, 6-month, open, uncontrolled study. Sixteen outpatients with a diagnosis of FTD were enrolled.

RESULTS

On the CIBIC plus 26 weeks after baseline four of the 16 patients were minimally improved, four were unchanged, seven were minimally worse and one patient was moderately worse. Neither the Neuropsychiatric Inventory nor the Frontal Behavioral Inventory demonstrated statistically significant differences in behavior between baseline and final visit. There was an increase in the total Alzheimer's Disease Assessment Scale score, reflecting a decline in cognitive performance. Executive functions as well as activities of daily living and extrapyramidal motor symptoms (EPMS) remained unchanged during the trial.

CONCLUSION

The number of patients was small, so that the evidence given by statistical tests is limited. Thus, the present study can only show trends regarding drug effects. As memantine is well-tolerated, further randomized and controlled studies should be conducted to evaluate drug efficacy.

Changes in dietary or eating behavior in frontotemporal dementia versus Alzheimer's disease

BACKGROUND

Changes in dietary or eating behavior are common in dementia and may help distinguish between different dementing illnesses.

OBJECTIVE

To evaluate and characterize differences in dietary and eating behavior among patients with early frontotemporal dementia (FTD) versus Alzheimer's disease (AD).

METHODS

This study administered the Food-Related Problems Questionnaire (FRPQ) to caregivers of 16 patients with FTD and 16 comparable patients with AD. The FRPQ was evaluated at initial presentation when patients presented for a diagnostic evaluation.

RESULTS

Compared with the AD patients, the FTD patients had significantly more changes on the FRPQ. Subscale analysis indicated that the FTD patients showed impairment of observed satiety, improper taking of food, and inappropriate responses when food was not available.

CONCLUSIONS

The use of food-related questionnaires, such as the FRPQ, can help distinguish FTD patients, early in their course, from those with AD and can further characterize the altered dietary and eating behavior.

Fear conditioning in frontotemporal lobar degeneration and Alzheimer's disease

Emotional blunting and abnormal processing of rewards and punishments represent early features of frontotemporal lobar degeneration (FTLD). Better understanding of the physiological underpinnings of these emotional changes can be facilitated by the use of classical psychology approaches. Fear conditioning (FC) is an extensively used paradigm for studying emotional processing that has rarely been applied to the study of dementia. We studied FC in controls (n = 25), Alzheimer's disease (n = 25) and FTLD (n = 25). A neutral stimulus (coloured square on a computer screen) was repeatedly paired with a 1 s burst of 100 db white noise. Change in skin conductance response to the neutral stimulus was used to measure conditioning. Physiological-anatomical correlations were examined using voxel-based morphometry (VBM). Both patient groups showed impaired acquisition of conditioned responses. However, the basis for this deficit appeared to differ between groups. In Alzheimer's disease, impaired FC occurred despite normal electrodermal responses to the aversive stimulus. In contrast, FTLD patients showed reduced skin conductance responses to the aversive stimulus, which contributed significantly to their FC deficit. VBM identified correlations with physiological reactivity in the amygdala, anterior cingulate cortex, orbitofrontal cortex and insula. These data indicate that Alzheimer's disease and FTLD both show abnormalities in emotional learning, but they suggest that in FTLD this is associated with a deficit in basic electrodermal response to aversive stimuli, consistent with the emotional blunting described with this disorder. Deficits in responses to aversive stimuli could contribute to both the behavioural and cognitive features of FTLD and Alzheimer's disease. Further study of FC in humans and animal models of dementia could provide a valuable window into these symptoms.

Psychotic symptoms in frontotemporal dementia: prevalence and review

BACKGROUND/AIMS

Although most patients with frontotemporal dementia (FTD) present with neuropsychiatric symptoms, the frequency of psychotic symptoms is unclear. This study aims to determine the prevalence of psychotic symptoms in a large cohort of well-diagnosed and followed FTD patients compared to age-matched patients with Alzheimer's disease (AD) and to further review the literature on psychosis in FTD.

METHODS

Delusions, hallucinations and paranoia were evaluated among 86 patients who met consensus criteria for FTD, had frontotemporal changes on functional neuroimaging and were followed for 2 years. They were compared to 23 patients with early-onset AD on a caregiver-administered psychiatric questionnaire.

RESULTS

Among the FTD patients, only 2 (2.3%) had delusions, 1 of whom had paranoid ideation; no FTD patient had hallucinations. This was significantly less than the AD patients, 4 (17.4%) of whom had delusions and paranoia. Other investigations fail to establish a significant association of psychosis with FTD.

CONCLUSIONS

These findings, and a literature review, indicate that psychotic symptoms are rare in FTD, possibly due to limited temporal-limbic involvement in this disorder.

Parietal lobe deficits in frontotemporal lobar degeneration caused by a mutation in the progranulin gene

OBJECTIVE

To describe the clinical, neuropsychologic, and radiologic features of a family with a C31LfsX35 mutation in the progranulin gene CCDS11483.1).

DESIGN

Case series.

PATIENTS

A large British kindred (DRC255) with a PGRN mutation was assessed. Affected individuals presented with a mean age of 57.8 years (range, 54-67 years) and a mean disease duration of 6.1 years (range, 2-11 years).

RESULTS

All patients exhibited a clinical and radiologic phenotype compatible with frontotemporal lobar degeneration based on current consensus criteria. However, unlike sporadic frontotemporal lobar degeneration, parietal deficits, consisting of dyscalculia, visuoperceptual /visuospatial dysfunction, and/or limb apraxia, were a common feature, and brain imaging showed posterior extension of frontotemporal atrophy to involve the parietal lobes. Other common clinical features included language output impairment with either dynamic aphasia or nonfluent aphasia and a behavioral syndrome dominated by apathy.

CONCLUSION

We suggest that parietal deficits may be a prominent feature of PGRN mutations and that these deficits may be caused by disruption of frontoparietal functional pathways.

A novel transgenic mouse expressing double mutant tau driven by its natural promoter exhibits tauopathy characteristics

The neurofibrillary-tangles (NTFs), characteristic of tauopathies including Alzheimer's-disease (AD), are the pathological features which correlate best with dementia. The objective of our study was to generate an authentic transgenic (tg) animal model for NFT pathology in tauopathy/AD. Previous NFT-tg mice were driven by non-related/non-homologous promoters. Our strategy was to use the natural tau promoter for expressing the human-tau (htau) gene with two mutations K257T/P301S (double mutant, DM) associated with severe phenotypes of frontotemporal-dementia in humans. Cellular, biochemical, behavioral and electrophysiological studies were subsequently conducted. The tg mice showed a tolerated physiological level of the DM-htau protein, mostly in cortex and hippocampus. The mice demonstrated tauopathy-like characteristics, which increased with age, that included NFT-related pathology, astrogliosis, argyrophilic plaque-like (amyloid-free) structures in brain, with memory deficits and signs of anxiety. Moreover, the tg mice showed a robust synaptic plasticity deficit selectively expressed in a severe impairment in their ability to maintain hippocampal long-term-potentiation (LTP) in response to stimulation of the perforant path, providing evidence that "tau-pathology only" is sufficient to cause this memory and learning-associated deficit. This is a unique mutant-htau-tg model which presents a wide spectrum of features characteristic of tauopathy/AD, which does not show unrelated motor deficits described in other models of tauopathy. In addition, expressing the DM-htau in a neuronal cell model resulted in tau-aggregation, as well as impaired microtubule arrangement. Both animal and cell models, which were regulated under the natural tau promoter (of rat origin), provide authentic and reliable models for tauopathy, and offer valuable tools for understanding the molecular events underlying tauopathies including AD.

Diagnostic criteria for the behavioral variant of frontotemporal dementia (bvFTD): current limitations and future directions

The most widely established diagnostic criteria for the behavioral variant of frontotemporal dementia have now been in use for almost a decade. Although consensus criteria have provided a much needed standard for frontotemporal dementia research, a growing body of evidence suggests that revisions are needed to improve their applicability. In this article, we discuss the limitations of current diagnostic criteria and propose the establishment of an international consortium to revise diagnostic and research criteria for the behavioral variant of frontotemporal dementia.

A model for management of behavioral symptoms in frontotemporal lobar degeneration

Frontotemporal lobar degeneration is a neurologic condition that manifests profound behavioral, personality, and language symptoms. These changes, often unique to each person, may include social misconduct, eating disturbances, apathy, emotional blunting, childlike behavior, habits and rituals, executive dysfunction, and marked difficulty with speech and language. These symptoms occur as the result of cell loss in discrete areas of the brain, the frontal and/or anterior temporal lobes. Little is known about effective management of the behavioral symptoms that result from this disease. The purpose of this paper is to describe a model that could be used in the assessment and potential management of frontotemporal lobar degeneration behavioral symptoms. Suggestions for interventions are given for some of the more common FTD behaviors. The impact of behavioral symptoms on the family caregiver is discussed along with strategies for supportive services and recommendations for future study.

The tauopathy associated with mutation +3 in intron 10 of Tau: characterization of the MSTD family

Multiple system tauopathy with presenile dementia (MSTD) is an inherited disease caused by a (g) to (a) transition at position +3 in intron 10 of Tau. It belongs to the spectrum of frontotemporal dementia and parkinsonism linked to chromosome 17 with mutations in Tau (FTDP-17T). Here we present the longitudinal clinical, neuropsychological, neuroimaging, neuropathological, biochemical and genetic characterization of the MSTD family. Presenting signs were consistent with the behavioural variant of frontotemporal dementia in 17 of 21 patients. Two individuals presented with an atypical form of progressive supranuclear palsy and two others with either severe postural imbalance or an isolated short-term memory deficit. Memory impairment was present at the onset in 15 patients, with word finding difficulties and stereotyped speech also being common. Parkinsonism was first noted 3 years after the onset of symptoms. Neuroimaging showed the most extensive grey matter loss in the hippocampus, parahippocampal gyrus and frontal operculum/insular cortex of the right hemisphere and, to a lesser extent, in the anterior cingulate gyrus, head of the caudate nucleus and the posterolateral orbitofrontal cortex and insular cortex bilaterally. Neuropathologically, progressive nerve cell loss, gliosis and coexistent neuronal and/or glial deposits consisting mostly of 4-repeat tau were present in frontal, cingulate, temporal and insular cortices, white matter, hippocampus, parahippocampus, basal ganglia, selected brainstem nuclei and spinal cord. Tau haplotyping indicated that specific haplotypes of the wild-type allele may act as modifiers of disease presentation. Quantitative neuroimaging has been used to analyse the progression of atrophy in affected individuals and for predicting disease onset in an asymptomatic mutation carrier. This multidisciplinary study provides a comprehensive description of the natural history of disease in one of the largest known families with FTDP-17T.

Spontaneous social behaviors discriminate behavioral dementias from psychiatric disorders and other dementias

OBJECTIVE

Changes in social behavior are often the first symptoms of neurodegenerative disease. Patients with frontotemporal lobar degeneration (FTLD) often go undiagnosed, or are misclassified as psychiatric patients, because in the absence of cognitive deficits, nonexperts fail to recognize these social changes as dementia symptoms. The object of this study was to improve screening for behavioral dementias in primary care and mental health settings by quantifying spontaneous social behaviors specific to FTLD.

METHOD

In a university hospital dementia clinic, examiners blind to subject diagnosis performed 1 hour of cognitive testing, then completed the Interpersonal Measure of Psychopathy, an 18-item checklist of observed inappropriate behaviors. Patients then underwent a multidisciplinary evaluation to derive a neurodegenerative or psychiatric diagnosis. Data were collected from 288 subjects: 45 Alzheimer's disease (National Institute of Neurologic and Communicative Disorders and Stroke-Alzheimer's Disease and Related Disorders Association research criteria); 40 frontotemporal dementia, 21 semantic dementia, and 13 progressive nonfluent aphasia (Neary research criteria); 14 corticobasal degeneration and 21 progressive supranuclear palsy (Litvan research criteria); 37 dementia with Lewy bodies (McKeith research criteria); 16 vascular dementia (Ischemic Vascular Disease research criteria); 29 mixed vascular and Alzheimer's disease (Alzheimer's Disease Diagnostic and Treatment Centers criteria); and 35 primary psychiatric disorder (DSM-IV) patients and 17 normal older controls. The study was conducted from March 2002 to January 2005.

RESULTS

Statistical item analyses demonstrated specific patterns of social behavior that differentiated both frontotemporal dementia and semantic dementia patients from (1) nondementing older adults, (2) nondementing individuals with psychiatric conditions, (3) individuals with cerebrovascular disease, and (4) individuals with other neurodegenerative disorders. Semantic dementia patients verbally and physically interrupted evaluations, spoke perseveratively and tangentially, and resisted clinician redirection. Frontotemporal dementia patients were apathetic or disinhibited and were unconcerned about meeting clinician expectations.

CONCLUSION

Specific, abnormal, interpersonal behaviors can alert nonexperts to the need for specialized dementia referral.

Medical management of frontotemporal dementia

There are no Food and Drug Administration (FDA)-approved medications for the medical management of frontotemporal dementia and its related disorders, so all management recommendations are necessarily off-label and borrowed from experience with Alzheimer's disease, psychiatric disease, and related medical illnesses. Six areas of pharmacotherapeutic consideration are prevention (primary and secondary), intellectual decline, behavioral disorders (such as depression, anxiety, and psychosis), sleep disorders, frequently associated disorders (including motor neuron disease), and abrupt decline. In addition to pharmacotherapy, important lifestyle issues confronting the clinician include driving cessation, securing any weapons maintained at home, assisted living, and caregiver burnout.

Cognitive-behavioral profiles of neurodegenerative dementias: beyond Alzheimer's disease

The neurocognitive and behavioral profiles of vascular dementia and vascular cognitive impairment, dementia with Lewy bodies and Parkinson's disease with dementia, and dementia syndromes associated with frontotemporal lobar degenerations are compared and contrasted with Alzheimer's dementia (AD). Vascular dementia/vascular cognitive impairment is characterized by better verbal memory performance, worse quantitative executive functioning, and prominent depressed mood. Dementia with Lewy bodies and Parkinson's disease with dementia are equally contrasted with AD by defective processing of visual information, better performance on executively supported verbal learning tasks, greater attentional variability, poorer qualitative executive functioning, and the presence of mood-congruent visual hallucinations. The frontal variant of frontotemporal lobar degeneration (frontotemporal dementia) differs from AD by better multimodal retention on learning tasks, different patterns of generative word fluency, defective qualitative executive functioning, and by markedly impairment of comportment. For temporal variants of frontotemporal lobar degenerations, progressive aphasia and semantic dementia, worse language performance relative to AD is typically characteristic.

Clinical presentation of prodromal frontotemporal dementia

BACKGROUND

Misrecognition of symptoms in the early stages of frontotemporal dementia (FTD) frequently contributes to diagnostic delay. Three frameworks have been proposed for the clinical identification of prodromal FTD: (1) cognitive profiling, (2) the presence of behavioral/psychiatric symptoms in the absence of memory complaints, and (3) a combined approach of cognitive, behavioral, and neuroimaging features.

OBJECTIVE

To evaluate current conceptual frameworks for the clinical recognition of prodromal FTD with current empirical evidence.

METHOD

We performed a comprehensive PsychINFO and MEDLINE database search to identify articles investigating the prodromal symptoms of FTD.

CONCLUSIONS

The 3 frameworks capture important aspects of the clinical picture of prodromal FTD but require further refinement. The prodromal stage of FTD is characterized by both cognitive and behavioral features. Diagnostic accuracy will likely be improved by considering a combination of cognitive and behavioral features, because some features overlap with prodromes for Alzheimer's disease and vascular dementia.

Frontotemporal dementia to Alzheimer's disease

Behavioral manifestations may dominate the clinical picture of the frontal variant of frontotemporal dementia (fv-FTD) for a long time before the appearance of true cognitive deficits. On the other hand, a deficit in the episodic memory domain represents the main manifestation of Alzheimer's disease (AD), Many behavioral disorders have been described in the clinical course of both FTD and AD; however, apathy and personality changes characterize frontal dementias, while depression dominates in AD, at least in the earlier stages. Depending on the distribution of neural damage, different patterns of noncognitive manifestations may be expected in different subtypes of FTD, Recent research on the social cognition deficit in FTD has offered new insights into the relationship between cognition and behavior, suggesting that some aspects of the behavioral changes in dementia may be generated by impairment in this domain.

Neuropsychological deficits in frontotemporal dementia and Alzheimer's disease: a meta-analytic review

We sought to identify the cognitive tests that best discriminate between Alzheimer's disease (AD) and frontotemporal dementia (FTD). A comprehensive search of all studies examining the cognitive performance of persons diagnosed with AD and FTD, published between 1980 and 2006, was conducted. Ninety-four studies were identified, comprising 2936 AD participants and 1748 FTD participants. Weighted Cohen's d effect sizes, percentage overlap statistics, confidence intervals and fail-safe Ns were calculated for each cognitive test that was used by two or more studies. The most discriminating cognitive tests were measures of orientation, memory, language, visuomotor function and general cognitive ability. Although there were large and significant differences between groups on these measures, there was substantial overlap in the scores of the AD and FTD groups. Age, education, years since diagnosis and diagnostic criteria did not significantly contribute to the group differences. Given the large overlap in the test performance of persons diagnosed with AD and FTD, cognitive tests should be used cautiously and in conjunction with a medical history, behavioural observations, imaging and information from relatives when making differential diagnoses.

Episodic memory and regional atrophy in frontotemporal lobar degeneration

It has been unclear to what extent memory is affected in frontotemporal lobar degeneration (FTLD). Since patients usually have atrophy in regions implicated in memory function, the frontal and/or temporal lobes, one would expect some memory impairment, and that the degree of atrophy in these regions would be inversely related to memory function. The purposes of this study were (1) to assess episodic memory function in FTLD, and more specifically patients' ability to episodically re-experience an event, and determine its source; (2) to examine whether memory performance is related to quantified regional brain atrophy. FTLD patients (n=18) and healthy comparison subjects (n=14) were assessed with cued recall, recognition, "remember/know" (self-reported re-experiencing) and source recall, at 30 min and 24h after encoding. Regional gray matter volumes were assessed with high resolution structural MRI concurrently to testing. Patients performed worse than comparison subjects on all memory measures. Gray matter volume in the left medial temporal lobe was positively correlated with recognition, re-experiencing, and source recall. Gray matter volume in the left posterior temporal lobe correlated significantly with recognition, at 30 min and 24h, and with source recall at 30 min. Estimated familiarity at 30 min was positively correlated with gray matter volume in the left inferior parietal lobe. In summary, episodic memory deficits in FTLD may be more common than previously thought, particularly in patients with left medial and posterior temporal atrophy.

Frontotemporal lobar degeneration: clinical and pathological relationships

Frontotemporal lobar degeneration (FTLD) encompasses a heterogeneous group of clinical syndromes that include frontotemporal dementia (FTD), frontotemporal dementia with motor neurone disease (FTD/MND), progressive non-fluent aphasia (PNFA), semantic dementia (SD) and progressive apraxia (PAX). Clinical phenotype is often assumed to be a poor predictor of underlying histopathology. Advances in immunohistochemistry provide the opportunity to re-examine this assumption. We classified pathological material from 79 FTLD brains, blind to clinical diagnosis, according to topography of brain atrophy and immunohistochemical characteristics. There were highly significant relationships to clinical syndrome. Atrophy was predominantly frontal and anterior temporal in FTD, frontal in FTD/MND, markedly asymmetric perisylvian in PNFA, asymmetric bitemporal in SD and premotor, parietal in PAX. Tau pathology was found in half of FTD and all PAX cases but in no FTD/MND or SD cases and only rarely in PNFA. FTD/MND, SD and PNFA cases were ubiquitin and TDP-43 positive. SD cases were associated with dystrophic neurites without neuronal cytoplasmic or intranuclear inclusions (FTLD-U, type 1), FTD/MND with numerous neuronal cytoplasmic inclusions (FTLD-U, type 2 ) and PNFA with neuronal cytoplasmic inclusions, dystrophic neurites and neuronal intranuclear inclusions (FTLD-U, type 3). MAPT mutations were linked to FTD and PGRN mutations to FTD and PNFA. The findings demonstrate predictable relationships between clinical phenotype and both topographical distribution of brain atrophy and immunohistochemical characteristics. The findings emphasise the importance of refined delineation of both clinical and pathological phenotype in furthering understanding of FTLD and its molecular substrate.

Neuroimaging of white matter in aging and dementia

Clinical neuroscientists have focused increasing attention on white matter connections in the brain and on the effects of aging and disease on these connections. Recent advances in magnetic resonance imaging (MRI) analysis have given researchers new tools for quantifying and visualizing white matter to better relate white matter structure and function. The goals of this article are (a) to acquaint the reader with both established and newer methods for imaging and quantifying white matter anatomy and pathology; and (b) to review recent findings on white matter pathology in aging and dementia. Computer-assisted quantification appears to offer better statistical power than visual rating scales for detecting these relationships. New MR modalities such as diffusion imaging can detect white matter abnormalities not shown with conventional acquisition sequences. These newer techniques hold promise for early detection of disease and for delineating functional connections between brain areas.

Latent profile analysis in frontotemporal lobar degeneration and related disorders: clinical presentation and SPECT functional correlates

Background

Frontotemporal Lobar Degeneration (FTLD) thus recently renamed, refers to a spectrum of heterogeneous conditions. This same heterogeneity of presentation represents the major methodological limit for the correct evaluation of clinical designation and brain functional correlates. At present, no study has investigated clinical clusters due to specific cognitive and behavioural disturbances beyond current clinical criteria.

The aim of this study was to identify clinical FTLD presentation, based on cognitive and behavioural profile, and to define their SPECT functional correlations.

Methods

Ninety-seven FTLD patients entered the study. A clinical evaluation and standardised assessment were preformed, as well as a brain SPECT perfusion imaging study. Latent Profile Analysis on clinical, neuropsychological, and behavioural data was performed. Voxel-basis analysis of SPECT data was computed.

Results

Three specific clusters were identified and named "pseudomanic behaviour" (LC1), "cognitive" (LC2), and "pseudodepressed behaviour" (LC3) endophenotypes. These endophenotypes showed a comparable hypoperfusion in left temporal lobe, but a specific pattern involving: medial and orbitobasal frontal cortex in LC1, subcortical brain region in LC2, and right dorsolateral frontal cortex and insula in LC3.

Conclusion

These findings provide evidence that specific functional-cluster symptom relationship can be delineated in FTLD patients by a standardised assessment. The understanding of the different functional correlates of clinical presentations will hopefully lead to the possibility of individuating diagnostic and treatment algorithms.

A case-controlled study of altered visual art production in Alzheimer's and FTLD

OBJECTIVE

To characterize dementia-induced changes in visual art production.

BACKGROUND

Although case studies show altered visual artistic production in some patients with neurodegenerative disease, no case-controlled studies have quantified this phenomenon across groups of patients.

METHOD

Forty-nine subjects [18 Alzheimer disease, 9 frontotemporal dementia (FTD), 9 semantic dementia (SD), 15 healthy older controls (NC)] underwent formal neuropsychologic testing of visuospatial, perceptual, and creative functioning, and produced 4 drawings. Subjective elements of drawings were rated by an expert panel that was blind to diagnosis.

RESULTS

Despite equal performance on standard visuospatial tests, dementia groups produced distinct patterns of artistic features that were significantly different from NCs. FTDs used more disordered composition and less active mark-making (P<0.05). Both FTDs and SDs drawings were rated as more bizarre and demonstrated more facial distortion than NCs (P<0.05). Also, SDs drastically failed a standardized test of divergent creativity. Alzheimer disease artwork was more similar to controls than to FTDs or SDs, but showed a more muted color palette (P<0.05) and trends toward including fewer details, less ordered compositions, and occasional facial distortion.

CONCLUSIONS

These group differences in artistic style likely resulted from disease-specific focal neurodegeneration, and elucidate the contributions of particular brain regions to the production of visual art.

Apathie et pathologies neuro-dégénératives : physiopathologie, évaluation diagnostique et traitement

Apathy is usually defined as a lack of motivation leading to reduced interest and participation in various activities. From a pathophysiological viewpoint, the most common cause of apathy is dysfunction of the frontal lobes, following either direct lesion of the frontal cortex or damage to regions tightly connected to the latter (such as the basal ganglia). The frontal-subcortical circuits often seem to be involved. Apathy is a common behavioral consequence of neurodegenerative disorders (Alzheimer's disease, parkinsonian syndromes, fronto-temporal dementia). The methods for detecting apathy and assessing its severity are various, the main difficulty being to disentangle apathy and depression. The treatment of apathy per se remains anecdotal and, to date, little research into the efficacy of medication therapy has been performed.

Social concepts are represented in the superior anterior temporal cortex

Social concepts such as "tactless" or "honorable" enable us to describe our own as well as others' social behaviors. The prevailing view is that this abstract social semantic knowledge is mainly subserved by the same medial prefrontal regions that are considered essential for mental state attribution and self-reflection. Nevertheless, neurodegeneration of the anterior temporal cortex typically leads to impairments of social behavior as well as general conceptual knowledge. By using functional MRI, we demonstrate that the anterior temporal lobe represents abstract social semantic knowledge in agreement with this patient evidence. The bilateral superior anterior temporal lobes (Brodmann's area 38) are selectively activated when participants judge the meaning relatedness of social concepts (e.g., honor-brave) as compared with concepts describing general animal functions (e.g., nutritious-useful). Remarkably, only activity in the superior anterior temporal cortex, but not the medial prefrontal cortex, correlates with the richness of detail with which social concepts describe social behavior. Furthermore, this anterior temporal lobe activation is independent of emotional valence, whereas medial prefrontal regions show enhanced activation for positive social concepts. Our results demonstrate that the superior anterior temporal cortex plays a key role in social cognition by providing abstract conceptual knowledge of social behaviors. We further speculate that these abstract conceptual representations can be associated with different contexts of social actions and emotions through integration with frontolimbic circuits to enable flexible evaluations of social behavior.

Driving abilities in frontotemporal dementia patients

OBJECTIVE

To evaluate driving competency and the relationship between neuropsychiatric symptoms and driving behavior in frontotemporal dementia (FTD) patients.

METHODS

Fifteen patients with a diagnosis of FTD and 15 healthy controls were administered a driving simulation task. Measures of driving performance and neuropsychiatric symptoms were assessed.

RESULTS

The FTD patients received more speeding tickets, ran more stop signs and were involved in more off-road crashes and collisions than the controls. The patients' overall average speed was significantly higher. Driving performance was correlated with agitated behavior.

CONCLUSIONS

Behavioral changes characteristic of FTD patients have an impact on their driving skills leading to inappropriate driving behavior.

Longitudinal changes of cerebral glucose metabolism in semantic dementia

BACKGROUND

Semantic dementia (SD).

OBJECTIVE

To identify the pattern of decline of cerebral glucose metabolism in SD using cerebral (18)F-fluoro-2-desoxy-D-glucose positron emission tomography scanning ((18)F-FDG-PET).

METHODS

Eight patients with SD underwent (18)F-FDG-PET at baseline and at re-examination in average 15 months later.

RESULTS

Compared with healthy control subjects, patients with SD showed a significant asymmetrical (left > right) hypometabolism of the temporal lobes, particularly of the anterior poles, at baseline. At follow-up, we observed a deterioration of cognitive abilities. However, in addition to the temporal lobes no other cortical or subcortical region showed a significant reduction of glucose metabolism except the anterior cingulate cortex (pcorr < 0.05).

CONCLUSION

Subtle functional changes suffice to produce significant neuropsycho- logical deterioration.

Behavioral disturbances in the course of frontotemporal dementia

BACKGROUND

Behavioral disturbances are prominent in frontotemporal dementia (FTD), and their occurrence has been the topic of several investigations. Nonetheless, the prevalence and severity of behavioral disturbances of patients with FTD in different degrees of dementia severity have rarely been studied.

OBJECTIVE

The aim of this study was to assess and compare the prevalence and severity of behavioral disturbances in patients with mild FTD and in patients with moderate/severe dementia.

METHODS

We included 21 outpatients with mild FTD [Clinical Dementia Rating (CDR) = 1] and 19 patients with moderate or severe dementia (CDR = 2 or 3) in this study. Behavioral disturbances were assessed using the Neuropsychiatric Inventory (NPI).

RESULTS

We found a statistically significant difference in the total NPI scores between patients with mild FTD and patients with moderate or severe FTD, the latter scoring higher. Apathy was the most prevalent symptom in both patient groups (90.5 and 100%). Except appetite and eating disturbance, which appeared in 77.8% of the patients with moderate/severe dementia, all other symptoms were clearly less common (<50%).

CONCLUSION

The results highlight the variability of behavioral disturbances in mild and moderate/severe stages of FTD.

Tratando os sintomas comportamentais e psicológicos da demência (SCPD)

Os transtornos neuropsiquiátricos na demência, também denominados de sintomas comportamentais e psicológicos da demência (SCPD), têm prevalência elevada no curso clínico da doença de Alzheimer e de outras desordens relacionadas. A relevância dessas manifestações é bem reconhecida, estando relacionada a evolução clínica mais desfavorável, maior sobrecarga do cuidador e maior incidência de institucionalização, entre outros fatores. O objetivo desta conferência clínica é procurar responder a algumas questões relacionadas a este tema, com o intuito de oferecer aos leitores uma breve atualização sobre o assunto. Os seguintes tópicos foram selecionados para discussão: se a nomenclatura SCPD é adequada para denominar essas manifestações clínicas; se há uma forma de classificar e como diagnosticar esses sintomas; qual a sua prevalência, seu impacto no curso clínico das demências e quais os fatores de risco associados ao seu aparecimento; quais as bases fisiopatológicas conhecidas; e, finalmente, como abordar esses pacientes e também suas famílias e cuidadores, do ponto de vista terapêutico, tanto em relação a intervenções farmacológicas quanto não farmacológicas.

Frontotemporal dementia to Alzheimer's disease

Behavioral manifestations may dominate the clinical picture of the frontal variant of frontotemporal dementia (fv-FTD) for a long time before the appearance of true cognitive deficits. On the other hand, a deficit in the episodic memory domain represents the main manifestation of Alzheimer's disease (AD). Many behavioral disorders have been described in the clinical course of both FTD and AD; however, apathy and personality changes characterize frontal dementias, while depression dominates in AD, at least in the earlier stages. Depending on the distribution of neural damage, different patterns of noncognitive manifestations may be expected in different subtypes of FTD. Recent research on the social cognition deficit in FTD has offered new insights into the relationship between cognition and behavior, suggesting that some aspects of the behavioral changes in dementia may be generated by impairment in this domain.

Orbitofrontal dysfunction related to both apathy and disinhibition in frontotemporal dementia

Orbitofrontal metabolic impairment is characteristic of the frontal variant of frontotemporal dementia (fv-FTD), as are early changes in emotional and social conduct. Two main types of behavioral disturbances have been distinguished in fv-FTD patients: apathetic and disinhibited manifestations. In this study, we searched for relationships between brain metabolism and presence of apathetic or disinhibited behavior. Metabolic activity and behavioral data were collected in 41 fv-FTD patients from European PET centers. A conjunction analysis of the PET data showed an expected impairment of metabolic activity in the anterior cingulate, ventromedial and orbital prefrontal cortex, the dorsolateral prefrontal cortex and the left anterior insula in fv-FTD subjects compared to matched controls. A correlation was observed between disinhibition scores on the Neuropsychiatric Inventory scale and a cluster of voxels located in the posterior orbitofrontal cortex (6, 28, -24). Comparison of brain activity between apathetic and nonapathetic fv-FTD patients from two centers also revealed a specific involvement of the posterior orbitofrontal cortex in apathetic subjects (4, 22, -22). The results confirm that the main cerebral metabolic impairment in fv-FTD patients affects areas specializing in emotional evaluation and demonstrate that decreased orbitofrontal activity is related to both disinhibited and apathetic syndromes in fv-FTD.

Voxel-based morphometry in tau-positive and tau-negative frontotemporal lobar degenerations

BACKGROUND

The identification of specific, diagnostically useful predictors of protein dysfunction in the frontotemporal lobar degenerations (FTLD) is a problem of great clinical and biological interest. Correlations between regional patterns of tissue loss and specific proteinopathies have not been established.

OBJECTIVE

Specific brain imaging correlates of protein tau dysfunction were sought using voxel-based morphometry in FTLD subgroups with and without tau pathology.

METHODS

Seventeen patients with pathologically or genetically confirmed diagnoses of FTLD who had undergone volumetric brain magnetic resonance imaging (MRI) were identified retrospectively and tau-positive (n = 9) and tau-negative (n = 8) subgroups were defined. MRI data were compared with healthy age- and sex-matched controls using voxel-based morphometry implemented in a statistical parametric mapping software package.

RESULTS

Compared with controls, tau-positive and tau-negative subgroups had extensive common areas of regional brain atrophy predominantly affecting the frontal and anterior temporal lobes. No specific brain imaging features were identified for either subgroup.

CONCLUSION

Patterns of frontotemporal atrophy do not predict the presence or absence of tau pathology; conversely, different immunohistochemical profiles are associated with similar patterns of regional vulnerability to neuronal loss in FTLD.

Anatomical and functional alterations in semantic dementia: a voxel-based MRI and PET study

Rare studies have used magnetic resonance imaging (MRI) and voxel-based morphometry (VBM) to assess atrophy, and only two positron emission tomography (PET) studies used SPM to examine functional changes in semantic dementia (SD). Our aim was to highlight both morphological and functional abnormalities in a same group of 10 SD patients, in the entire brain, using a "state of the art" methodology (optimized VBM procedure, PET data corrected for partial volume effects and voxel-based analyses). We also used an extensive neuropsychological battery. We showed that main alterations concerned the left temporal lobe, in accordance with the striking impairment of semantic memory in SD patients, as well as the hippocampal region, which may partly explain their moderate episodic memory deficits. Hypometabolism was more extensive than grey matter loss in both temporal lobes, and specifically concerned the orbitofrontal areas, consistent with the moderate impairment of executive functions and behavioural changes. While PET is more sensitive than MRI, there is striking concordance between morphological and functional abnormalities, which contrasts with the discordance observed in Alzheimer's disease and might be a typical feature of SD.