Epidemiology of frontotemporal lobar degeneration

A few epidemiologic studies have dealt with the prevalence of frontotemporal lobar degeneration (FTLD), including Pick's disease. The aim of this study was to review the epidemiologic studies of FTLD in western countries and to compare them with those in Japan. A community-based study of early-onset dementia in London revealed that 12% of cases with frontotemporal dementia (FTD) fulfilled the Lund-Manchester criteria in contrast to 34% of cases with Alzheimer's disease (AD) in a sample of 185 cases. The Cambridge Group has recently examined the prevalence of early-onset dementia in a community-based study. Of 108 cases, 15.7% had FTLD and 25% had AD. FTLD included 13 FTD cases, and 2 each with semantic dementia (SD) and nonfluent progressive aphasia (PA). Almost one third of cases with FTLD (29%) had a positive family history. Of our consecutive 330 outpatients with dementia (hospital setting without age limitation), 42 (12.7%) had FTLD and 215 (65.1%) had AD. In our series of patients, 22 FTD, 15 SD and 5 PA cases were identified. There was no family history in all subtypes of FTLD. Epidemiologic studies, both community-based and hospital-based, demonstrate that FTLD is a more common cause of early-onset dementia than previously recognized. Regarding the subtypes of FTLD, in Japan, compared with the data from the UK, FTD is less common, SD may be more common and PA is equally common. The reason for this discrepancy is supposed to be mainly based on the role of heredity.     

Hospital admission circumstances and prevalence of frontotemporal lobar degeneration: a multicenter psychiatric state hospital study in Germany

Frontotemporal lobar degeneration (FTLD) is a heterogenous, non-Alzheimer's disease, dementia complex with variable clinical presentation. We carried out a prospective nationwide hospital-based clinico-epidemiologic study in geriatric psychiatry to estimate the prevalence and admission circumstances of patients with FTLD. During a 4-week period 33 patients with clinical FTLD were prospectively ascertained in 36 psychiatric state hospitals in Germany with a total catchment area of >20,000,000 people. The relative portion of FTLD patients within the primary dementia population accounted for 1.9%. The estimated prevalence of FTLD in Germany was 47.9/100,000 population aged between 45 and 79 years. The admission circumstances were mainly behavioral disturbances (54.5%), unclear syndromes of dementia (18.1%) and further remarkably heterogeneous psychiatric syndromes. FTLD is a common cause of dementia in geriatric psychiatry with a variable clinical presentation that could mimic most of the major psychiatric diseases. Patients with FTLD may be older than previously assumed (mean age at admission 63.9 years) and show their maximum age-related prevalence between 60 and 70 years (78.7/100,000).     

Hippocampal shape analysis in Alzheimer's disease and frontotemporal lobar degeneration subtypes

Hippocampal pathology is central to Alzheimer's disease (AD) and other forms of dementia such as frontotemporal lobar degeneration (FTLD). Autopsy studies have shown that certain hippocampal subfields are more vulnerable than others to AD and FTLD pathology, in particular the subiculum and cornu ammonis 1 (CA1). We conducted shape analysis of hippocampi segmented from structural T1 MRI images on clinically diagnosed dementia patients and controls. The subjects included 19 AD and 35 FTLD patients [13 frontotemporal dementia (FTD), 13 semantic dementia (SD), and 9 progressive nonfluent aphasia (PNFA)] and 21 controls. Compared to controls, SD displayed severe atrophy of the whole left hippocampus. PNFA and FTD also displayed atrophy on the left side, restricted to the hippocampal head in FTD. Finally, AD displayed most atrophy in left hippocampal body with relative sparing of the hippocampal head. Consistent with neuropathological studies, most atrophic deformation was found in CA1 and subiculum areas in FTLD and AD.     

Hippocampal atrophy on MRI in frontotemporal lobar degeneration and Alzheimer's disease

BACKGROUND: Hippocampal atrophy on magnetic resonance imaging (MRI) is an early characteristic of Alzheimer's disease. However, hippocampal atrophy may also occur in other dementias, such as frontotemporal lobar degeneration (FTLD). OBJECTIVE: To investigate hippocampal atrophy on MRI in FTLD and its three clinical subtypes, in comparison with Alzheimer's disease, using volumetry and a visual rating scale. METHODS: 42 patients with FTLD (17 frontotemporal dementia, 13 semantic dementia, and 12 progressive non-fluent aphasia), 103 patients with Alzheimer's disease, and 73 controls were included. Hippocampal volumetry and the easily applicable medial temporal lobe atrophy (MTA) rating scale were applied to assess hippocampal atrophy. RESULTS: Multivariate analysis of variance for repeated measures showed an effect of diagnostic group on hippocampal volume. There was a significant diagnosis by side (left v right) interaction. Both FTLD and Alzheimer's disease showed hippocampal atrophy compared with controls. Results of the visual MTA rating scale confirmed these findings. Within the FTLD subtypes there were marked differences in hippocampal atrophy. Frontotemporal dementia and semantic dementia showed bilateral hippocampal atrophy, and in semantic dementia the left hippocampus was smaller than in Alzheimer's disease. No significant hippocampal atrophy was detected in non-fluent progressive aphasia. CONCLUSIONS: Hippocampal atrophy is not only a characteristic of Alzheimer's disease but also occurs in FTLD. The three clinical subtypes of FTLD show different patterns of hippocampal atrophy.     

Frontotemporal lobar degeneration – tau as a pied piper?

Frontotemporal lobar degeneration (FTLD) is the second most-common form of cortical dementia in the presenium after Alzheimer disease. Clinically three disease entities can be distinguished: frontotemporal dementia, semantic dementia, and primary progressive aphasia. The underlying neuropathology can be classified into disorders with tau pathology (including Pick disease, corticobasal degeneration, progressive supranuclear palsy, and familial frontotemporal dementia with parkinsonism linked to chromosome 17 – FTDP-17), and into disorders that lack tau abnormalities (including dementia lacking distinctive histology and motor neuron disease inclusion dementia). The recent discovery of tau gene mutations in FTDP-17 brought tau to the center stage, but led to the erroneous trend of collectively grouping all forms of FTLD as tauopathies. However, clinicopathological and genetic studies strongly suggest that the majority of sporadic and familial FTLD cases are not associated with tau pathology and/or tau gene mutations. Furthermore, recent studies have linked several autosomal dominantly inherited familial frontotemporal dementia cases to a variety of gene loci on different chromosomes. Thus, this review is intended to summarize our current knowledge about the sporadic and familial FTLD disorders that lack tau pathology, and shall further strengthen the view that FTLD is heterogeneous, both in terms of clinicopathological phenotypes as well as genetic backgrounds. Electronic Publication     

The situation of caregiver counselling in patients with frontotemporal lobar dementia in old psychiatry

Caregiver counselling is an indispensable feature of current concepts for dementia treatment. Self-support groups and psychoeducative programms for caregivers of patients with Alzheimer's disease may reduce the burden of nursing and psychological strain. Specific caregiver needs from patients with frontotemporal lobar dementia (FTLD [frontotemporal dementia, semantic dementia, progressive aphasia, corticobasal degeneration]) are only partially taken into account. We conducted a German wide epidemiologic study which revealed that specific counselling for supporting relatives and caregivers of patients with FTLD is only fragmentary in hospital services for old age psychiatry. In most cases, they are referred to the local Alzheimer's disease Associations (89 %). Besides that, the existence of large hospital care units has significant negative repercussions on psychosocial supply for caregivers of patients with FTLD. To establish decentralized support units by these hospitals would lead to a significant improvement of medical and social care in this field.     

Comparison of family histories in FTLD subtypes and related tauopathies

Pedigrees from 269 patients with frontotemporal lobar degeneration (FTLD), including frontotemporal dementia (FTD), FTD with ALS (FTD/ALS), progressive nonfluent aphasia, semantic dementia (SD), corticobasal degeneration, and progressive supranuclear palsy were analyzed to determine the degree of heritability of these disorders. FTD/ALS was the most and SD the least heritable subtype. FTLD syndromes appear to have different etiologies and recurrence risks.     

EEG abnormalities in frontotemporal lobar degeneration

The EEG appearances in patients with frontotemporal lobar degeneration (FTLD) were compared with those in patients with Alzheimer disease (AD). EEG abnormalities were found in 61% of FTLD patients, with the degree of EEG abnormality increasing with dementia severity. There was no significant difference in the severity of EEG abnormality between the FTLD and AD patient groups. These data suggest a need for reappraisal of the role of the EEG in the diagnostic differentiation of FTLD from AD.     

Measurements of the amygdala and hippocampus in pathologically confirmed Alzheimer disease and frontotemporal lobar degeneration

BACKGROUND: Differentiating between Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD) can be difficult, particularly in the earliest stages of the diseases. Patterns of atrophy on magnetic resonance imaging may help distinguish these diseases and aid diagnosis. OBJECTIVE: To assess the diagnostic utility of magnetic resonance imaging-derived amygdala and hippocampal volumes from patients with pathologically proved AD and FTLD. DESIGN: Cross-sectional volumetric magnetic resonance imaging study of the hippocampus and amygdala. SETTING: Specialist cognitive disorders clinic.Subjects Thirty-seven subjects, including 10 patients with pathologically proved AD, 17 patients with pathologically proved FTLD, and 10 age-matched control subjects. MAIN OUTCOME MEASURES: Hippocampal and amygdala volumes. RESULTS: Geometric mean amygdala and hippocampal volumes were, respectively, 15.0% (95% confidence interval [CI], 4.2%-24.5%) and 16.4% (95% CI, 5.9%-25.6%) lower in the AD than in the control group. In FTLD, the equivalent differences were 43.1% (95% CI, 31.9%-52.6%) in the amygdala and 36.1% (95% CI, 27.5%-43.7%) in the hippocampus. Volumes were significantly lower in the FTLD than in the AD group (P<.01 in both regions). Within the FTLD clinical subgroups, there was evidence of a difference in pattern of atrophy with greater asymmetry (left smaller than right) in semantic dementia compared with frontal variant FTLD (P<.001). On average, the left hippocampus was 14% smaller in semantic dementia than in frontal variant FTLD, whereas the right hippocampus was 37% larger. On average, the left amygdala was 39% smaller in semantic dementia than in frontal variant FTLD, whereas the right amygdala was only 1% smaller. CONCLUSIONS: Hippocampal atrophy is not specific to AD or FTLD. However, severe or asymmetrical amygdala atrophy should suggest FTLD. Atrophy patterns follow clinical syndromes rather than pathology.     

Different patterns of magnetic resonance imaging atrophy for frontotemporal lobar degeneration syndromes

BACKGROUND: Frontotemporal lobar degeneration (FTLD) is an uncommon degenerative dementia that presents with focal cognitive and behavioral deficits. OBJECTIVE: To determine the correlation of the different presentations of FTLD with structural neuroimaging findings. DESIGN AND PATIENTS: In a blinded study, we retrospectively evaluated the clinical presentations and magnetic resonance imaging (MRI) patterns of atrophy in 59 patients with FTLD and 26 patients with probable Alzheimer disease at a memory disorders clinic. RESULTS: Analysis of variance revealed a significant difference in the patterns of atrophy in the FTLD and Alzheimer disease groups. Patients with FTLD presenting with altered personal conduct had significant bifrontal atrophy, whereas patients presenting with semantic dementia had significant left temporal and bifrontal atrophy compared with other groups. Disinhibited behavior and hyperphagia correlated with right frontal atrophy, and fluent, anomic aphasia correlated with left temporal atrophy. CONCLUSIONS: We found that the type of clinical presentation of FTLD correlates with specific areas of atrophy. Our method of analysis may be useful to elicit further anatomic-behavioral relationships in degenerative brain disorders.     

Invited article: the Alzheimer disease-frontotemporal lobar degeneration spectrum

Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD) are two frequent forms of primary neurodegenerative dementias. Despite distinctive clinical diagnostic criteria for both brain disorders, differential diagnosis is often complicated by overlapping symptomatology. As we learn more about brain pathology and genetic makeup underlying these dementia disorders, evidence is accumulating for a clinical, pathologic, and genetic spectrum of neurodegenerative brain diseases in which AD and FTLD occur along one continuum. This has important implications for molecular diagnostic testing and genetic counseling of patients with dementia. In this light, we review the molecular genetics of AD and FTLD assessing how AD genes can be implicated in FTLD and conversely FTLD genes in AD, by modifying disease susceptibility. Herein, we focus on recent exciting findings providing further support for an AD-FTLD spectrum.     

Frequency of early and late-onset dementias in a Japanese memory disorders clinic

The aim of this study was to compare the diagnostic profiles of patients with early (age<65 years) and late (age>or=65 years) onset of dementia in a memory disorders clinic in Japan. A total of 512 consecutive memory clinic patients were evaluated using clinical information and results of examinations. Diagnosis of dementia was made according to DSM-III-R, and that of subtypes according to standard diagnostic criteria. A total of 464 patients met the criteria for dementia. Amongst late-onset patients (n=430), Alzheimer's disease (AD) (48.1%) was the most frequent cause of dementia, followed by AD with cerebrovascular disease (CVD) (31.4%), vascular dementia (VaD) (9.1%), dementia with Lewy bodies (DLB) (3.7%), frontotemporal lobar degeneration (FTLD) (1.6%), and others (5.8%). On the contrary, amongst early onset patients (n=34), the most common dementia diagnosis was AD (38.2%), followed by VaD (23.5%), FTLD (14.7%), AD with CVD (5.9%), DLB (2.9%), and others (17.6%). FTLD and VaD were significantly more common in the early onset group. All patients, but one, with DLB and Parkinson's disease dementia were late-onset. The relative frequencies of AD, VaD, and DLB in our series are consistent with epidemiologic findings in several Western countries; however, the frequency of FTLD is not consistent with the previous findings presenting high frequency in late-onset patients in some Western countries.     

Ubiquitin-positive inclusions and progression of pathology in frontotemporal dementia and motor neurone disease identifies a group with mainly early pathology

Frontotemporal lobar degeneration (FTLD) with tau-negative, ubiquitin-positive inclusions has been a topic of major interest in recent years, with this group now accounting for the majority of tau-negative cases of frontotemporal degeneration. The severity of neurodegeneration in FTLD is dependent on the stage of disease and is substantial even in the earliest stages. Elucidating the pathogenesis of FTLD requires evaluation of changes during the earliest possible stage of disease. However, the long survival of most frontotemporal dementia cases means that cases with early neuropathology are not frequently encountered. Cases of FTLD with the shortest survival are those with coexisting motor neurone disease (FTLD + MND), making these the ideal group for studying early FTLD pathology. It is not clear, however, what the pathological contribution of MND is in these cases. This study evaluates the pathology of 20 cases of FTLD (11 with no clinical signs of MND and nine with FTLD + MND) as well as 10 cases of MND without dementia. Our findings indicate that the deposition of ubiquitin does not play a key role in the neurodegenerative process in FTLD, and that the severity of neurodegeneration in FTLD is similar in cases with and without clinical MND.     

Longitudinal patterns of regional change on volumetric MRI in frontotemporal lobar degeneration

The aim of this study was to assess the longitudinal patterns of regional change in the different syndromic variants of frontotemporal lobar degeneration (FTLD). Ten patients with semantic dementia, 7 with progressive non-fluent aphasia and 29 with frontotemporal dementia had two serial volumetric MR scans. Fluid registration was used to match serial scans from each individual. Voxel-level analysis of change across subject groups was performed using statistical parametric mapping. The analysis showed patterns of increased rates of volume loss (atrophy) in frontal, temporal and parietal regions in the whole FTLD group compared with controls. The different FTLD syndromes displayed different patterns of change. This technique gives an insight into disease evolution over time in these disorders and may be useful as a method of tracking change in clinical trials.     

Visual assessment of atrophy on magnetic resonance imaging in the diagnosis of pathologically confirmed young-onset dementias

OBJECTIVES: To investigate the diagnostic accuracy of visual inspection of magnetic resonance imaging (MRI) in a range of pathologically confirmed diseases causing young-onset dementia and to assess the sensitivity and specificity of atrophy patterns for Alzheimer disease (AD) and frontotemporal lobar degeneration (FTLD). DESIGN: Sixty-two patients with pathologically confirmed diseases that may present as young-onset dementia were selected from a biopsy and postmortem series. The first diagnostic T1-weighted volumetric MRI was obtained for each patient, together with images from 22 healthy control subjects. All MRIs were assessed for regional atrophy independently by 3 neuroradiologists, blinded to all clinical details except age. Observers were also asked to use their clinical judgment to form a diagnosis. RESULTS: Eighty-seven percent of dementia cases were distinguished from controls after visual inspection of MRI, and a correct pathologically confirmed diagnosis was given in 58% of cases. Hippocampal atrophy was noted in 92% of AD cases but was commonly seen in other dementias and controls. A bilateral symmetrical pattern of hippocampal atrophy discriminated AD from FTLD with 47% specificity, while posterior greater than anterior gradient of atrophy was 92% specific for AD. Atrophy of the anterior, inferior, and lateral temporal lobes was suggestive of FTLD pathology (> or =90% sensitivity), while anterior greater than posterior gradient of atrophy and hemispheric asymmetry of atrophy were each at least 85% specific for FTLD. CONCLUSION: Despite variation and overlap of atrophy patterns, visual inspection of regional atrophy on MRI may aid in discriminating AD and FTLD.     

Dysphagia in patients with frontotemporal lobar dementia

BACKGROUND: Hyperorality, compulsive eating and aspiration because of food gorging, has been described in patients with frontotemporal lobar dementia (FTLD), but swallowing function in this population has not been reported. OBJECTIVE: To identify the swallowing status in a sample of patients with FTLD. DESIGN: Case series. SETTING: Referral center, ambulatory care. PATIENTS: A consecutive series of referred patients with 3 variants of FTLD were asked to participate. Twenty-one patients were enrolled, including 9 with frontotemporal dementia, 7 with progressive nonfluent aphasia, and 5 with semantic dementia. INTERVENTION: The patients underwent a fiberoptic endoscopic examination of swallowing to assess their ability to swallow liquids and food. MAIN OUTCOME MEASURES: Presence of dysphagia and nature of impaired swallowing. RESULTS: Of the 21 patients, 4 caretakers reported swallowing difficulties. An instrumental examination revealed moderate swallowing abnormalities in 12 of the 21 patients. These abnormalities were not explained by compulsive eating behaviors, but seemed to reflect deficits in cortical and subcortical pathways connecting with the brainstem swallowing center. CONCLUSIONS: When assessed via instrumentation, swallowing abnormalities are found in many patients with FTLD. The appearance of dysphagia signals progression of FTLD to brainstem systems.     

Review: Neuropathology of non‐tau frontotemporal lobar degeneration

Frontotemporal dementia (FTD) is a heterogeneous clinical syndrome associated with frontotemporal lobar degeneration (FTLD) as a relatively consistent neuropathological hallmark feature. However, the discoveries in the past decade of many of the relevant pathological proteins aggregating in human FTD brains in addition to several new FTD causing gene mutations underlined that FTD is a diverse condition on the neuropathological and genetic basis. This resulted in a novel molecular classification of these conditions based on the predominant protein abnormality and allows most cases of FTD to be placed now into one of three broad molecular subgroups; FTLD with tau, TAR DNA‐binding protein 43 or FET protein accumulation (FTLD‐tau, FTLD‐TDP and FTLD‐FET respectively). This review will provide an overview of the molecular neuropathology of non‐tau FTLD, insights into disease mechanisms gained from the study of human post mortem tissue as well as discussion of current controversies in the field.     

Initial complaints in frontotemporal lobar degeneration

AIMS: Frontotemporal lobar degeneration (FTLD) is probably underrecognized. The goal of this study was to investigate initial complaints of both patients and their caregivers at first specialist referral. Also, we tried to assess whether misrecognition of symptoms contributed to diagnostic delay. METHODS: The case notes of all patients diagnosed with FTLD at the VU University Medical Center, Alzheimer Center of Amsterdam, The Netherlands, since 1998 were retrospectively reviewed. Only patients of whom detailed information of first specialist referral was available were included. The diagnosis of FTLD was based on the clinical diagnostic criteria of Neary and Snowden, supported by ancillary investigations. RESULTS: Forty-six patients with FTLD were included. Twenty-one patients had frontotemporal dementia (FTD), 17 semantic dementia (SD) and 8 progressive nonfluent aphasia (PA). The majority of the FTD patients presented without complaints or with somatic complaints and nearly a quarter of them expressed memory complaints. The presenting complaints of most of their caregivers differed from the patients' complaints and often consisted of cognitive complaints. In SD and PA, language problems but also forgetfulness were presented. Misrecognition of the initial symptoms in some cases seemed to have contributed to diagnostic delay. CONCLUSION: Presenting complaints in FTLD can be misleading. In our cohort, memory complaints occurred relatively often. A multidisciplinary approach, including a structured behavioral interview, is important to recognize symptoms of FTLD.     

TARDBP mutations in motoneuron disease with frontotemporal lobar degeneration

TDP‐43 (TAR‐DNA binding protein) aggregates in neuronal inclusions in motoneuron disease (MND), as well as in frontotemporal lobar degeneration (FTLD) and FTLD associated with MND (FTLD‐MND). Mutations in TARDBP gene, coding for TDP‐43, were found in patients with pure MND. We now describe TARDBP mutations in two patients with FTLD‐MND, presenting with a behavioral variant of FTLD and semantic dementia, suggesting that TDP‐43 may also have a direct pathogenic role in FTLD disorders. Ann Neurol 2009;65:470–474     

Suicide risk in frontotemporal lobe degeneration: to be considered, to be prevented

Suicide is difficult to ascertain in elderly patients, and dementia might represent a risk factor, though predictors of suicide in dementia are still unknown. We report the case of a patient recently diagnosed as having a behavioral variant of frontotemporal lobar degeneration (FTLD), apathetic syndrome, who committed suicide by hanging. His personal and family history was negative for mental disorders; a depressive syndrome was diagnosed 1 year before FTLD diagnosis, and treated unsuccessfully. To the best of our knowledge, no data are available about self-harmful events in FTLD. This case report argues for the urgent need for developing specific tools for the assessment of suicidal ideation among at-risk population.