Classification and description of frontotemporal dementias

Neuropsychological and Neuroanatomical Features of Patients with Behavioral/Dysexecutive Variant Alzheimer’s disease (AD): A Comparison to Behavioral Variant Frontotemporal Dementia and Amnestic AD Groups

Background: An understudied variant of Alzheimer’s disease (AD), the behavioral/dysexecutive variant of AD (bvAD), is associated with progressive personality, behavior, and/or executive dysfunction and frontal atrophy. Objective: This study characterizes the neuropsychological and neuroanatomical features associated with bvAD by comparing it to behavioral variant frontotemporal dementia (bvFTD), amnestic AD (aAD), and subjects with normal cognition. Methods: Subjects included 16 bvAD, 67 bvFTD, and 18 aAD patients, and 26 healthy controls. Neuropsychological assessment and MRI data were compared between these groups. Results: Compared to bvFTD, bvAD showed more significant visuospatial impairments (Rey Figure copy and recall), more irritability (Neuropsychological Inventory), and equivalent verbal memory (Philadelphia Verbal Learning Test). Compared to aAD, bvAD indicated more executive dysfunction (F-letter fluency) and better visuospatial performance. Neuroimaging analysis found that bvAD showed cortical thinning relative to bvFTD posteriorly in left temporal-occipital regions; bvFTD had cortical thinning relative to bvAD in left inferior frontal cortex. bvAD had cortical thinning relative to aAD in prefrontal and anterior temporal regions. All patient groups had lower volumes than controls in both anterior and posterior hippocampus. However, bvAD patients had higher average volume than aAD patients in posterior hippocampus and higher volume than bvFTD patients in anterior hippocampus after adjustment for age and intracranial volume. Conclusion: Findings demonstrated that underlying pathology mediates disease presentation in bvAD and bvFTD.

Frontotemporal lobar degeneration with TAR DNA-binding protein 43 (TDP-43): its journey of more than 100 years

Frontotemporal lobar degeneration (FTLD) with TDP-43-immunoreactive inclusions (FTLD-TDP) is a neurodegenerative disease associated with clinical, genetic, and neuropathological heterogeneity. An association between TDP-43, FTLD and amyotrophic lateral sclerosis (ALS) was first described in 2006. However, a century before immunohistochemistry existed, atypical dementias displaying behavioral, language and/or pyramidal symptoms and showing non-specific FTLD with superficial cortical neuronal loss, gliosis and spongiosis were often confused with Alzheimer's or Pick's disease. Initially this pathology was termed dementia lacking distinctive histopathology (DLDH), but this was later renamed when ubiquitinated inclusions originally found in ALS were also discovered in (DLDH), thus warranting a recategorization as FTLD-U (ubiquitin). Finally, the ubiquitinated protein was identified as TDP-43, which aggregates in cortical, subcortical, limbic and brainstem neurons and glial cells. The topography and morphology of TDP-43 inclusions associate with specific clinical syndromes and genetic mutations which implies different pathomechanisms that are yet to be discovered; hence, the TDP-43 journey has actually just begun. In this review, we describe how FTLD-TDP was established and defined clinically and neuropathologically throughout the past century.

Protonation-Deprotonation Switch Controls the Amyloid-like Misfolding of Nucleic-Acid-Binding Domains of TDP-43

Nutrient starvation stress acidifies the cytosol and leads to the formation of large protein assemblies and misfolded aggregates. However, how starvation stress is sensed at the molecular level and leads to protein misfolding is poorly understood. TDP-43 is a vital protein, which, under stress-like conditions, associates with stress granule proteins via its functional nucleic-acid-binding domains (TDP-43^tRRM) and misfolds to form aberrant aggregates. Here, we show that the monomeric N form of TDP-43^tRRM forms a misfolded amyloid-like protein assembly, β form, in a pH-dependent manner and identified the critical protein side-chain residue whose protonation triggers its misfolding. We systematically mutated the three buried ionizable residues, D105, H166, and H256, to neutral amino acids to block the pH-dependent protonation-deprotonation titration of their side chain and studied their effect on the N-to-β transition. We observed that D105A and H256Q resembled TDP-43^tRRM in their pH-dependent misfolding behavior. However, H166Q retains the N-like secondary structure under low-pH conditions and does not show pH-dependent misfolding to the β form. These results indicate that H166 is the critical side-chain residue whose protonation triggers the misfolding of TDP-43^tRRM and shed light on how stress-induced misfolding of proteins during neurodegeneration could begin from site-specific triggers.

Cellular and physiological functions of C9ORF72 and implications for ALS/FTD

The hexanucleotide repeat expansion (HRE) in the C9ORF72 gene is the main cause of two tightly linked neurodegenerative diseases, amyotrophic lateral sclerosis (ALS) and frontotemporal dementia (FTD). HRE leads to not only a gain of toxicity from RNA repeats and dipeptide repeats but also reduced levels of C9ORF72 protein. However, the cellular and physiological functions of C9ORF72 were unknown until recently. Through proteomic analysis, Smith-Magenis chromosome regions 8 (SMCR8) and WD repeat-containing protein (WDR41) were identified as binding partners of C9ORF72. These three proteins have been shown to form a tight complex, but the exact functions of this complex remain to be characterized. Both C9ORF72 and SMCR8 contain a DENN domain, which has been shown to regulate the activities of small GTPases. The C9ORF72 complex has been implicated in many cellular processes, including vesicle trafficking, lysosome homeostasis, mTORC1 signaling , and autophagy. C9ORF72 deficiency in mice results in exaggerated inflammatory responses and human patients with C9ORF72 mutations have neuroinflammation phenotype. Recent studies indicate that C9ORF72 regulates trafficking and lysosomal degradation of inflammatory mediators, including toll-like receptors (TLRs) and STING, to affect inflammatory outputs. Further exploration of cellular and physiological functions of C9ORF72 will help dissect the pathological mechanism of ALS/FTD caused by C9ORF72 mutations.

A Review: Mealtime Difficulties following Frontotemporal Lobar Degeneration

BACKGROUND

Frontotemporal lobar degeneration (FTLD) can result in a decline in behavior, language, and motor function. Mealtime disturbances are a common and significant outcome of FTLD. Disturbances during mealtimes can arise from dysphagia or may occur secondary to behavioral changes such as rapid eating, mealtime rigidity, and altered diet preferences.

SUMMARY

Few studies have comprehensively evaluated eating behavior or dysphagia in individuals presenting with FTLD pathology despite the potential impact on medical safety and individual quality of life. Dysphagia is reported in the late stages of frontotemporal dementia and early in the motor subtypes of FTLD. The identification of dysphagia can alert individuals and medical teams to disease progression and provide insight into the nature and spread of the underlying neuropathology. Improved understanding of eating behaviors can improve individual care and may enhance diagnostic accuracy. Key Message: Aberrant eating behavior and swallowing difficulties are reported in the conditions associated with FTLD neuropathology. The consequences of mealtime disturbances include health risks associated with an increased BMI and aspiration, reduction of an individual's independence, and an increase in caregiver stress and burden. Here we review and summarize the literature on eating behavior and swallow impairments (dysphagia) in each of the syndromes caused by FTLD.

Exploring the genetics and non-cell autonomous mechanisms underlying ALS/FTLD

Although amyotrophic lateral sclerosis (ALS), also known as Lou Gehrig's disease, was first described in 1874, a flurry of genetic discoveries in the last 10 years has markedly increased our understanding of this disease. These findings have not only enhanced our knowledge of mechanisms leading to ALS, but also have revealed that ALS shares many genetic causes with another neurodegenerative disease, frontotemporal lobar dementia (FTLD). In this review, we survey how recent genetic studies have bridged our mechanistic understanding of these two related diseases and how the genetics behind ALS and FTLD point to complex disorders, implicating non-neuronal cell types in disease pathophysiology. The involvement of non-neuronal cell types is consistent with a non-cell autonomous component in these diseases. This is further supported by studies that identified a critical role of immune-associated genes within ALS/FTLD and other neurodegenerative disorders. The molecular functions of these genes support an emerging concept that various non-autonomous functions are involved in neurodegeneration. Further insights into such a mechanism(s) will ultimately lead to a better understanding of potential routes of therapeutic intervention. Facts ALS and FTLD are severe neurodegenerative disorders on the same disease spectrum. Multiple cellular processes including dysregulation of RNA homeostasis, imbalance of proteostasis, contribute to ALS/FTLD pathogenesis. Aberrant function in non-neuronal cell types, including microglia, contributes to ALS/FTLD. Strong neuroimmune and neuroinflammatory components are associated with ALS/FTLD patients. Open Questions Why can patients with similar mutations have different disease manifestations, i.e., why do C9ORF72 mutations lead to motor neuron loss in some patients while others exhibit loss of neurons in the frontotemporal lobe? Do ALS causal mutations result in microglial dysfunction and contribute to ALS/FTLD pathology? How do microglia normally act to mitigate neurodegeneration in ALS/FTLD? To what extent do cellular signaling pathways mediate non-cell autonomous communications between distinct central nervous system (CNS) cell types during disease? Is it possible to therapeutically target specific cell types in the CNS?

Diagnosing the frontal variant of Alzheimer's disease: a clinician's yellow brick road

Background

Disruption of the frontal lobes and its associated networks are a common consequence of neurodegenerative disorders. Given the wide range of cognitive, behavioral and motor processes in which the frontal lobes are involved, there can be a great variety of manifestations depending on the pathology distribution. The most common are the behavioral variant of frontotemporal dementia (bvFTD) and the frontal variant of Alzheimer’s disease (fvAD), which are particularly challenging to disentangle. Recognizing fvAD from bvFTD-related pathologies is a diagnostic challenge and a critical need in the management and counseling of these patients.

Case presentation

Here we present three pathology-proven cases of Alzheimer’s disease initially misdiagnosed as bvFTD and discuss the distinctive or less overlapping historical, examination, and laboratory findings of fvAD and bvFTD, deriving analogies for mnemonic endurance from the Wizard of Oz worldview.

Conclusion

The Yellow Brick Road to diagnosing these disorders may be served by the metaphor of fvAD as the irritable, paranoid, and tremulous Scarecrow and bvFTD the heartless, ritualistic, and rigid Tin Man. An Oz-inspired creative license may help the clinician recognize the differential disease progression, caregiver burden, and treatment response of fvAD compared with bvFTD.

Electronic supplementary material

The online version of this article (doi:10.1186/s40734-017-0052-4) contains supplementary material, which is available to authorized users.

Midlife mental distress and risk for dementia up to 27 years later: the Nord-Trøndelag Health Study (HUNT) in linkage with a dementia registry in Norway

Background

Dementia is an increasing public health challenge, and the number of individuals affected is growing rapidly. Mental disorders and symptoms of mental distress have been reported to be risk factors for dementia. The aim of this study was to examine whether midlife mental distress is a predictor for onset of dementia later in life.

Methods

Using data from a large population-based study (The Nord-Trøndelag Health Study; HUNT1) linked to a dementia registry (The Health and Memory study; HMS) enabling a maximum 27 years of follow-up, we ascertained mental distress and subsequent dementia status for 30,902 individuals aged 30–60 years at baseline. In HUNT1, self-reported mental distress was assessed using the four-item Anxiety and Depression Index (ADI-4). Dementia status was ascertained from HMS, which included patient and caregiver history, cognitive testing and clinical and physical examinations from the hospitals and nursing homes serving the catchment area of HUNT1. In the main analysis, unadjusted and adjusted logistic regression models were computed for the prospective association between mental distress and dementia. In secondary analyses, two-way age and gender interactions with mental distress on later dementia were examined.

Results

A 50% increased odds for dementia among HUNT1-participants reporting mental distress was found (crude odds ratio (OR): 1.52; 95% CI 1.15–2.01), and a 35% increase in the fully adjusted model (OR 1.35; 95% CI 1.01-1.80). In secondary analyses, we found evidence for a two-way interaction with age on the association between mental distress and dementia (p = 0.030): the age- and gender adjusted OR was 2.44 (95% CI 1.18–5.05) in those aged 30–44 years at baseline, and 1.24 (0.91–1.69) in 45–60 year olds.

Conclusions

Our results indicate an association between midlife mental distress and increased risk of later dementia, an association that was stronger for distress measured in early compared to later midlife. Mental distress should be investigated further as a potentially modifiable risk factor for dementia.

Electronic supplementary material

The online version of this article (doi:10.1186/s12877-015-0020-5) contains supplementary material, which is available to authorized users.

Excessive TV watching in patients with frontotemporal dementia

The "environmental dependency syndrome" refers to a loss of personal autonomy such that a person's environment almost entirely controls their actions. The goal of this study is to learn if patients with frontotemporal degeneration (FTD) exhibit prolonged TV watching, a behavior which may be a symptom of environmental dependency. We recruited 40 patients with FTD and 48 patients with Alzheimer's disease (AD), and asked these participants' caregivers about TV watching behaviors including total viewing time and channel/show preference, along with other behaviors indicative of environmental dependency. Compared to AD patients, FTD patients watched TV for a longer time. In addition, the patients who watched more TV showed more signs of environmental dependency. Increased TV watching may be a sign of environmental dependency, however further research is needed to explore other hypotheses.

The clinical problem of symptomatic Alzheimer disease and mild cognitive impairment

Alzheimer disease (AD) is the most common cause of dementia in the elderly. Clinicopathological studies support the presence of a long preclinical phase of the disease, with the initial deposition of AD pathology estimated to begin approximately 10-15 years prior to the onset of clinical symptoms. The hallmark clinical phenotype of AD is a gradual and progressive decline in two or more cognitive domains, most commonly involving episodic memory and executive functions, that is sufficient to cause social or occupational impairment. Current diagnostic criteria can accurately identify AD in the majority of cases. As disease-modifying therapies are being developed, there is growing interest in the identification of individuals in the earliest symptomatic, as well as presymptomatic, stages of disease, because it is in this population that such therapies may have the greatest chance of success. The use of informant-based methods to establish cognitive and functional decline of an individual from previously attained levels of performance best allows for the identification of individuals in the very mildest stages of cognitive impairment.

Hormone replacement therapy and risk for neurodegenerative diseases

Over the past two decades, there has been a significant amount of research investigating the risks and benefits of hormone replacement therapy (HRT) with regards to neurodegenerative disease. Here, we review basic science studies, randomized clinical trials, and epidemiological studies, and discuss the putative neuroprotective effects of HRT in the context of Alzheimer's disease, Parkinson's disease, frontotemporal dementia, and HIV-associated neurocognitive disorder. Findings to date suggest a reduced risk of Alzheimer's disease and improved cognitive functioning of postmenopausal women who use 17β-estradiol. With regards to Parkinson's disease, there is consistent evidence from basic science studies for a neuroprotective effect of 17β-estradiol; however, results of clinical and epidemiological studies are inconclusive at this time, and there is a paucity of research examining the association between HRT and Parkinson's-related neurocognitive impairment. Even less understood are the effects of HRT on risk for frontotemporal dementia and HIV-associated neurocognitive disorder. Limits to the existing research are discussed, along with proposed future directions for the investigation of HRT and neurodegenerative diseases.

Let's inhibit our excitement: the relationships between Stroop, behavioral disinhibition, and the frontal lobes

OBJECTIVE

The Stroop (Stroop, 1935) is a frequently used neuropsychological test, with poor performance typically interpreted as indicative of disinhibition and frontal lobe damage. This study tested those interpretations by examining relationships between Stroop performance, behavioral disinhibition, and frontal lobe atrophy.

METHOD

Participants were 112 patients with mild cognitive impairment or dementia, recruited through UCSF's Memory and Aging Center. Participants received comprehensive dementia evaluations including structural MRI, neuropsychological testing, and informant interviews. Freesurfer, a semiautomated parcellation program, was used to analyze 1.5T MRI scans. Behavioral disinhibition was measured using the Neuropsychiatric Inventory (Cummings, 1997; Cummings et al., 1994) Disinhibition Scale. The sample (n = 112) mean age was 65.40 (SD = 8.60) years, education was 16.64 (SD = 2.54) years, and Mini-Mental State Examination (MMSE; Folstein et al., 1975) was 26.63 (SD = 3.32). Hierarchical linear regressions were used for data analysis.

RESULTS

Controlling for age, MMSE, and color naming, Stroop performance was not significantly associated with disinhibition (β = 0.01, ΔR² = 0.01, p = .29). Hierarchical regressions controlling for age, MMSE, color naming, intracranial volume, and temporal and parietal lobes, examined whether left or right hemisphere regions predict Stroop performance. Bilaterally, parietal lobe atrophy best predicted poorer Stroop (left: β = 0.0004, ΔR² = 0.02, p = .002; right: β = 0.0004, ΔR² = 0.02, p = .002). Of frontal regions, only dorsolateral prefrontal cortex atrophy predicted poorer Stroop (β = 0.001, ΔR² = 0.01, p = .03); left and right anterior cingulate cortex atrophy predicted better Stroop (left: β = -0.003, ΔR² = 0.01, p = .02; right: β = -0.004, ΔR² = 0.01, p = .02).

CONCLUSION

These findings suggest Stroop performance is a poor measure of behavioral disinhibition and frontal lobe atrophy even among a relatively high-risk population.

Aberrant septin 11 is associated with sporadic frontotemporal lobar degeneration

Background

Detergent-insoluble protein accumulation and aggregation in the brain is one of the pathological hallmarks of neurodegenerative diseases. Here, we describe the identification of septin 11 (SEPT11), an enriched component of detergent-resistant fractions in frontotemporal lobar degeneration with ubiquitin-immunoreactive inclusions (FTLD-U), using large-scale unbiased proteomics approaches.

Results

We developed and applied orthogonal quantitative proteomic strategies for the unbiased identification of disease-associated proteins in FTLD-U. Using these approaches, we proteomically profiled detergent-insoluble protein extracts prepared from frontal cortex of FTLD-U cases, unaffected controls, or neurologic controls (i.e. Alzheimer's disease; AD). Among the proteins altered specifically in FTLD-U, we identified TAR DNA binding protein-43 (TDP-43), a known component of ubiquitinated inclusions. Moreover, we identified additional proteins enriched in detergent-resistant fractions in FTLD-U, and characterized one of them, SEPT11, in detail. Using independent highly sensitive targeted proteomics approaches, we confirmed the enrichment of SEPT11 in FTLD-U extracts. We further showed that SEPT11 is proteolytically cleaved into N-terminal fragments and, in addition to its prominent glial localization in normal brain, accumulates in thread-like pathology in affected cortex of FTLD-U patients.

Conclusions

The proteomic discovery of insoluble SEPT11 accumulation in FTLD-U, along with novel pathological associations, highlights a role for this cytoskeleton-associated protein in the pathogenesis of this complex disorder.

β-amyloid triggers ALS-associated TDP-43 pathology in AD models

Amyotrophic lateral sclerosis (ALS) is a neurodegenerative disease associated with loss of motor neurons in the brain and spinal cord. ALS is occasionally diagnosed with frontotemporal lobar dementia with ubiquitin-positive inclusions (FTLD-U). Alzheimer's disease (AD) is the most common type of age-associated dementia. Abnormal levels of aggregated Tar-DNA binding protein-43 (TDP-43) are detected in the majority of patients with ALS, FTLD and AD. We observed a significant increase (200%) in the levels of TDP-43 in cortical autopsies of late stage AD patients. Lentiviral expression of Aβ(1-42) in the rat motor cortex led to an increase in TDP-43 pathology, including up-regulation of the mature ~44kDa protein, identical to the pathological changes seen in AD. Furthermore, expression of Aβ(1-42) was associated with TDP-43 phosphorylation and accumulation in the cytosol. Clearance of Aβ with parkin prevented TDP-43 pathology. TDP-43 modifications were also observed in 3xTransgenic AD (3xTg-AD) compared to wild type mice, but these changes were attenuated in parkin-injected hippocampi, even in the presence of Tau pathology, suggesting that TDP-43 pathology is triggered by Aβ, independent of Tau. Increased levels of casein kinase (CK1 and CK2), which are associated with TDP-43 phosphorylation, were also observed in Aβ(1-42) expressing brains. These data indicate an overlap in TDP-43 pathology between AD and ALS-FTLD and suggest that Aβ triggers modifications of TDP-43.

[Behavior disturbances in emergency psychiatry or fronto-temporal dementia diagnosis? A challenge for psychiatrists]

INTRODUCTION

The diagnosis of fronto-temporal dementia (FTD) represents a challenge for the psychiatrist, especially since this insidious pathology partly mimics other psychiatric diseases.

CASE-REPORT

We present a clinical case that illustrates the difficulty of FTD diagnosis particularly well. A 32 year-old woman without previous medical history presented with psychomotor agitation, logorrhea and flight of ideas. The criteria for bipolar disorder according to DSM IV were met and the patient was referred to an outpatient clinic where a mood stabilizer was initiated (lithium, 400 mg/day). An in-depth interview with her husband revealed mild but progressive modification of her personality and behavior over the course of two years. She showed signs of mild fatigue and irritability that evolved into a loss of interest for both leisure and domestic activities. In addition, she showed increasing erratic behavior and emergence of frequent episodes of verbal abuse. After the birth of her second child, the patient's clinical state worsened with the appearance of uninhibited behavior, loss of personal hygiene, sleep disturbances and nightmares. The patient was forced to stop her work as a cleaner, a steady employment that she had maintained for 10 years. The hypomanic state worsened and psychotic symptoms such as delusions and echolalia appeared within a few weeks. These events culminated in a first hospitalization in a psychiatric unit. We evoked both diagnoses of schizoaffective disorder and psychotic disorder not otherwise specified. In the following months, we conducted neurological examinations on account of the progressive deterioration of her cognitive functions. Neuroradiological results (CT scan with contrast agents, MRI, cerebral scintigraphy) coupled with her clinical evolution (neurological examination and neuropsychological testing) permitted diagnosis of fronto-temporal dementia.

DISCUSSION

Fronto-temporal dementia usually presents itself as an autosomal dominant disease in 89% of reported cases, with an insidious onset associated with thymic symptoms and behavioral disturbances. The first consultation often concludes with a suspicion of a psychiatric disorder in 33% of the cases (unipolar and bipolar depressive disorders, psychotic disorders, alcohol dependence). The clinical description of such a heterogenic and neuro-psychiatric disorder should be widely disseminated, so that psychiatrists can distinguish early symptoms and diminish the risk of misdiagnosis of FDT.

CONCLUSION

Such case reports emphasize the importance for psychiatrists to be aware of the clinical prodromal FDT symptoms, particularly since the neuro-imaging data of dementia are often delayed.

Validity and reliability of the Korean version of the AD8 informant interview (K-AD8) in dementia

The Alzheimer disease 8 (AD8) is a brief informant-based measure that distinguishes individuals with very mild dementia and mild cognitive impairment from those with normal cognition. The aim of this study was to establish the validity, reliability, and discriminative properties of the Korean version of the AD8 (K-AD8). Evaluation was made on 155 patient-informant dyads. The K-AD8 scores with the Clinical Dementia Rating (CDR) and performance on neuropsychologic tests were compared. Internal consistency of the K-AD8 was significant (Cronbach alpha=0.88). The K-AD8 had strong correlation with CDR (Spearman rho=0.76). Concurrent validity was strong with the K-AD8 scores correlating with CDR domains and performance on neuropsychologic tests. The K-AD8 was found to have excellent test-retest reliability (weighted kappa=0.81) and good interrater reliability (intraclass correlation coefficient=0.89). The area under the receiver operator characteristic curve was 0.88, suggesting good discrimination between nondemented individuals and those with cognitive impairment. To distinguish CDR 0.5 from CDR 0, in particular, the K-AD8 (cutoff score of 2) had a sensitivity of 68% and a specificity of 90%. In conclusion, the K-AD8 is a sensitive screening tool in detecting very early dementia, indicating that the AD8 could work very well in a variety of cultural entities.

The neurobiology of amyotrophic lateral sclerosis

Amyotrophic lateral sclerosis is a degenerative disease affecting the motor neurons. In spite of our growing insights into its biology, it remains a lethal condition. The identification of the cause of several of the familial forms of ALS allowed generation of models to study this disease both in vitro and in vivo. Here, we summarize what is known about the pathogenic mechanisms of ALS induced by hereditary mutations, and attempt to identify the relevance of these findings for understanding the pathogenic mechanisms of the sporadic form of this disease.

The Relationship between Parkin and Protein Aggregation in Neurodegenerative Diseases

The most prominent changes in neurodegenerative diseases are protein accumulation and inclusion formation. Several neurodegenerative diseases, including Alzheimer's, the Synucleinopathies and Tauopathies share several overlapping clinical symptoms manifest in Parkinsonism, cognitive decline and dementia. As degeneration progresses in the disease process, clinical symptoms suggest convergent pathological pathways. Biochemically, protein cleavage, ubiquitination and phosphorylation seem to play fundamental roles in protein aggregation, inclusion formation and inflammatory responses. In the following we provide a synopsis of the current knowledge about protein accumulation and astrogliosis as a common denominator in neurodegenerative diseases, and we propose insights into protein degradation and anti-inflammation. We review the E3-ubiquitin ligase and other possible functions of parkin as a suppressant of inflammatory signs and a strategy to clear amyloid proteins in neurodegenerative diseases.

Left frontal lobe contributions to concept formation: a quantitative MRI study of performance on the Delis-Kaplan Executive Function System Sorting Test

This study examined relationships between lobar volumes and performance on the Delis-Kaplan Executive Function System (D-KEFS) Sorting Test, a standardized measure of concept formation. There were 89 participants: 19 patients with probable Alzheimer's disease, 25 patients with frontotemporal dementia, 13 patients with semantic dementia, 12 patients with progressive nonfluent aphasia, 9 patients with probable progressive supranuclear palsy, 2 patients with possible progressive supranuclear palsy, and 9 healthy participants. We used BRAINS2 software to generate volumes of the right and left frontal, temporal, and parietal lobes. Multiple regression analysis indicated that, after controlling for Mini-Mental State Examination scores, intracranial volume, and demographic variables, only the left frontal lobe significantly predicted performance on the D-KEFS Sorting Test.

Driving Retirement in Older Adults with Dementia

In order to characterize the driving and mobility status of older adults with dementia, a questionnaire was mailed to 527 informants; 119 were returned. The majority of patients were diagnosed with Dementia of the Alzheimer's Type. Only 28% were actively driving at the time of survey. Informants rated 53% of current or recently retired drivers as potentially unsafe. Few informants reported using community/educational resources. Individuals with progressive dementia retire from driving for differing reasons, many subsequent to family recognition of impaired driving performance. Opportunities for education and supportive assistance exist but are underutilized.

Mimicking aspects of frontotemporal lobar degeneration and Lou Gehrig's disease in rats via TDP-43 overexpression

Since the discovery of neuropathological lesions made of TDP-43 and ubiquitin proteins in cases of frontotemporal lobar degeneration (FTLD) and amyotrophic lateral sclerosis (ALS), there is a burst of effort on finding related familial mutations and developing animal models. We used an adeno-associated virus (AAV) vector for human TDP-43 expression targeted to the substantia nigra (SN) of rats. Though TDP-43 was expressed mainly in neuronal nuclei as expected, it was also expressed in the cytoplasm, and dotted along the plasma membrane of neurons. Cytoplasmic staining was both diffuse and granular, indicative of preinclusion lesions, over 4 weeks. Ubiquitin deposited in the cytoplasm, specifically in the TDP-43 group, and staining for microglia was increased dose-dependently by 1-2 logs in the TDP-43 group, while neurons were selectively obliterated. Neuronal death induced by TDP-43 was pyknotic and apoptotic. TDP-43 gene transfer caused loss of dopaminergic neurons in the SN and their axons in the striatum. Behavioral motor dysfunction resulted after TDP-43 gene transfer that was vector dose-dependent and progressive over time. The cytoplasmic expression, ubiquitination, and neurodegeneration mimicked features of the TDP-43 diseases, and the gliosis, apoptosis, and motor impairment may also be relevant to TDP-43 disease forms involving nigrostriatal degeneration.

ALS and FTLD: two faces of TDP-43 proteinopathy

Major discoveries have been made in the recent past in the genetics, biochemistry and neuropathology of frontotemporal lobar degeneration (FTLD). TAR DNA-binding protein 43 (TDP-43), encoded by the TARDBP gene, has been identified as the major pathological protein of FTLD with ubiquitin-immunoreactive (ub-ir) inclusions (FTLD-U) with or without amyotrophic lateral sclerosis (ALS) and sporadic ALS. Recently, mutations in the TARDBP gene in familial and sporadic ALS have been reported which demonstrate that abnormal TDP-43 alone is sufficient to cause neurodegeneration. Several familial cases of FTLD-U, however, are now known to have mutations in the progranulin (GRN) gene, but granulin is not a component of the TDP-43- and ub-ir inclusions. Further, TDP-43 is found to be a component of the inclusions of an increasing number of neurodegenerative diseases. Other FTLD-U entities with TDP-43 proteinopathy include: FTLD-U with valosin-containing protein (VCP) gene mutation and FTLD with ALS linked to chromosome 9p. In contrast, chromosome 3-linked dementia, FTLD-U with chromatin modifying protein 2B (CHMP2B) mutation, has ub-ir, TDP-43-negative inclusions. In summary, recent discoveries have generated new insights into the pathogenesis of a spectrum of disorders called TDP-43 proteinopathies including: FTLD-U, FTLD-U with ALS, ALS, and a broadening spectrum of other disorders. It is anticipated that these discoveries and a revised nosology of FTLD will contribute toward an accurate diagnosis, and facilitate the development of new diagnostic tests and therapeutics.

Neuroimaging in dementia

Although dementia is a clinical diagnosis, neuroimaging often is crucial for proper assessment. Magnetic resonance imaging (MRI) and computed tomography (CT) may identify nondegenerative and potentially treatable causes of dementia. Recent neuroimaging advances, such as the Pittsburgh Compound-B (PIB) ligand for positron emission tomography imaging in Alzheimer's disease, will improve our ability to differentiate among the neurodegenerative dementias. High-resolution volumetric MRI has increased the capacity to identify the various forms of the frontotemporal lobar degeneration spectrum and some forms of parkinsonism or cerebellar neurodegenerative disorders, such as corticobasal degeneration, progressive supranuclear palsy, multiple system atrophy, and spinocerebellar ataxias. In many cases, the specific pattern of cortical and subcortical abnormalities on MRI has diagnostic utility. Finally, among the new MRI methods, diffusion-weighted MRI can help in the early diagnosis of Creutzfeldt-Jakob disease. Although only clinical assessment can lead to a diagnosis of dementia, neuroimaging is clearly an invaluable tool for the clinician in the differential diagnosis.

TDP-43 in neurodegenerative disorders

BACKGROUND

The number of neurodegenerative diseases associated with pathological aggregates of transactivation response element (TAR)-DNA-binding protein 43 (TDP-43) has increased, leading to the new designation 'TDP-43 proteinopathy.' Biochemically, TDP-43 proteinopathies are characterized by decreased solubility, hyperphosphorylation, and cleavage of TDP-43 into 25- and 35-kDa fragments, and by altered cellular localization.

OBJECTIVE

This review summarizes research characterizing the distribution of TDP-43 pathology in human postmortem brain tissue and discusses possible therapeutic strategies based on genetic and in vitro studies.

METHODS

We reviewed recent studies of TDP-43 proteinopathy.

RESULTS/CONCLUSION

Given that several different mutations can lead to TDP-43 proteinopathies, including mutations in progranulin and valosin-containing protein, research is needed to decipher and potentially exploit the link between these mutations and TDP-43 pathology.

Discriminant validity and neuroanatomical correlates of rule monitoring in frontotemporal dementia and Alzheimer's disease

Despite the predominant frontal neuropathology of frontotemporal dementia (FTD), traditional measures of executive functioning do not reliably distinguish FTD from Alzheimer's disease (AD). Performance monitoring is an executive function that is associated with frontal lobe integrity and may be disrupted in FTD. The current study adopted a component process approach to evaluate the discriminant validity and neuroanatomical correlates of performance monitoring (i.e., rule monitoring) during an executive spatial planning task. Forty-four participants with FTD, 30 with AD, and 27 healthy comparison (HC) subjects completed the Delis-Kaplan Executive Function System (D-KEFS) Tower task. A subset of patients underwent structural magnetic resonance imaging to obtain regional measures of cortical volumes. FTD and AD groups demonstrated significantly poorer overall achievement scores on the Tower test relative to the HC sample, but did not differ from one another. In contrast, the FTD group committed significantly more rule violation errors than both HC and AD groups, indicating poorer performance monitoring. In addition, poorer overall achievement correlated with smaller brain volumes in several regions, including bilateral frontal and parietal regions, whereas an increased number of rule violations correlated specifically with decreased bilateral frontal volume. Both left and right frontal volumes remained significant predictors of rule violation errors after controlling for the contribution of overall achievement on the task and all other brain regions. Findings are consistent with literature implicating the frontal lobes in performance monitoring and highlight the importance of characterizing the component processes of performance failures in the cognitive assessment of FTD and AD.

The genetics of frontotemporal dementia

This article describes the remarkable progress that has been made over the past decade in identifying the genetic contribution to frontotemporal dementia. The clinical and neuropathologic features of frontotemporal dementia with parkinsonism linked to chromosome 17 and the nature of the mutations in the progranulin and microtubule-associated protein tau genes are emphasized.

Evidence of an inferior total-order planning strategy in patients with frontotemporal dementia

We investigated planning abilities in patients with frontal temporal dementia (FTD) and normal controls (NC) using a chore location planning task. Planning tasks with increasing complexity could be either solved by constructing a linear total plan (total-order planning) or partially ordered sub-plans (partial-order planning). The NC group appeared to use partial-order planning, while the FTD group appeared to use total-order planning based on error pattern in performance, task-solution, and planning time. Our results are a reminder that besides social impairments, FTD patients also demonstrate higher-order cognitive impairment in domains such as planning and that these impairments may also have a profound effect upon the patients' day-to-day functioning.

TDP-43 in familial and sporadic frontotemporal lobar degeneration with ubiquitin inclusions

TAR DNA-binding protein 43 (TDP-43) is a major pathological protein of sporadic and familial frontotemporal lobar degeneration with ubiquitin-positive, tau-negative inclusions (FTLD-U) with or without motor neuron disease (MND). Thus, TDP-43 defines a novel class of neurodegenerative diseases called TDP-43 proteinopathies. We performed ubiquitin and TDP-43 immunohistochemistry on 193 cases of familial and sporadic FTLD with or without MND. On selected cases, immunoelectron microscopy and biochemistry were performed. Clinically defined frontotemporal dementias (FTDs) included four groups: 1) familial FTD with mutations in progranulin (n = 36), valosin-containing protein (n = 5), charged multivesicular body protein 2B (n = 4), and linked to chromosome 9p (n = 7); 2) familial cases of FTD with unknown gene association (n = 29); 3) sporadic FTD (n = 72); and 4) familial and sporadic FTD with MND (n = 40). Our studies confirm that the spectrum of TDP-43 proteinopathies includes most cases of sporadic and familial FTLD-U with and without MND and expand this disease spectrum to include reported families with FTD linked to chromosome 9p but not FTD with charged multivesicular body protein 2B mutations. Thus, despite significant clinical, genetic, and neuropathological heterogeneity of FTLD-U, TDP-43 is a common pathological substrate underlying a large subset of these disorders, thereby implicating TDP-43 in novel and unifying mechanisms of FTLD pathogenesis.

Progressive apraxia of speech as a sign of motor neuron disease

PURPOSE

To document and describe in detail the occurrence of apraxia of speech (AOS) in a group of individuals with a diagnosis of motor neuron disease (MND).

METHOD

Seven individuals with MND and AOS were identified from among 80 patients with a variety of neurodegenerative diseases and AOS (J. R. Duffy, 2006). The history, presenting complaints, neurological findings, and speech-language findings were documented for each case.

RESULTS

Spastic or mixed spastic-flaccid dysarthria was present in all 7 cases. The AOS was judged as worse than the dysarthria in 4 cases. Nonverbal oral apraxia was eventually present in all cases. Aphasia was present in 2 cases and equivocally present in another 2. Dementia was present in 1 case and equivocally present in 2.

CONCLUSIONS

AOS can occur in MND, typically also with dysarthria, but not invariably with aphasia or other cognitive deficits. Thus, a diagnosis of MND does not preclude the presence of AOS. More importantly, MND should be a diagnostic consideration when AOS is a prominent sign of degenerative disease.

Evaluation of Dopaminergic Function in Frontotemporal Dementia Using 123I-FP-CIT Single Photon Emission Computed Tomography

Extrapyramidal symptoms are observed in frontotemporal dementia (FTD). (123)I-FP-CIT (DaT scan) single photon emission computed tomography (SPECT) can detect loss of presynaptic dopamine transporters in the striatum. We aimed to evaluate the dopaminergic status of the striatum in patients with FTD using DaT scan. Seven patients (age range 65-76 years), who fulfilled the Neary criteria and in whom the diagnosis of FTD was confirmed by hexamethylpropyleneamine oxime SPECT, were included in the study. The severity of the extrapyramidal symptoms was evaluated by the motor part of the Unified Parkinson's Disease Rating Scale (UPDRS). SPECT using (123)I-FP-CIT was done. A (region - occipital)/occipital ratio was calculated for the striatum, putamen and caudate nucleus. The results were compared with those of the 7 age-matched normal controls. The uptake of the radiotracer in the right and left striatum was reduced to 62% (p = 0.000) and 68% (p = 0.000), respectively, compared to controls. The motor UPDRS score of the patients with FTD showed a negative correlation to the uptake of the radiotracer. The presynaptic dopamine transporter in FTD is impaired, related to the severity of the extrapyramidal symptoms. Since an effective treatment for FTD is still to be established, there is a need for evaluating the efficacy of dopaminergic drugs.

Progranulin and frontotemporal lobar degeneration

Frontotemporal lobar degeneration is the term used to describe the non-Alzheimer clinical syndromes of frontotemporal dementia, semantic dementia and progressive non-fluent aphasia, regardless of the underlying neuropathological features. Considerable progress has been made in recent years in our understanding of the aetiology of this disorder, notably the identification of mutations in tau and progranulin genes, both on chromosome 17q21. Mutations in tau appear to affect the ability of tau to bind microtubules and/or increase this protein's ability to form fibrils. In contrast, progranulin mutations cause haploinsufficiency leading to TDP-43 accumulation. These genes collectively account for 10-20% of FTLD. However, it is clear that much remains to be discovered before our knowledge of this heterogeneous condition is complete.

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.

Magnetic resonance imaging correlates of set shifting

The purpose of this study was to examine the relationships between lobar volumes and set shifting. We studied 101 subjects, including 36 normal controls, 16 patients with probable Alzheimer's disease, 30 patients with frontotemporal dementia (FTD), and 19 patients with semantic dementia (SD), using a shifting paradigm that carefully controlled for component abilities. Subjects were administered two conditions of the Delis-Kaplan Executive Function System (D-KEFS) Design Fluency Test. In the control condition (DF:Control), examinees generated as many unique designs as possible in 60 s by drawing lines connecting only unfilled dots. In the switching condition (DF:Switch), examinees generated designs by drawing lines alternating between filled and unfilled dots. We used BRAINS2 software to generate volumes of the right and left frontal, temporal, and parietal lobes. Partial correlations and multiple regressions showed that, after controlling for Mini-Mental State Examination and DF:Control, only the right and left frontal lobe volumes significantly correlated with the DF:Switch, most clearly in the FTD and SD groups. Follow-up analyses indicated that frontal contributions to shifting were not related to working memory. Results highlight the importance of carefully controlling for component cognitive processes when studying executive functioning.

The complex aetiology of frontotemporal lobar degeneration

Frontotemporal lobar degeneration (FTLD) is now a widely recognised form of dementia. This heterogeneous disease has been of particular interest to geneticists due to its high rate of heritability with up to 40% of patients reporting a family history of the disease in at least one extra family member. There have been several chromosome loci linked to this disorder and three genes have already been identified. Remarkably, it has been recently demonstrated that 2 of these are only 1.7 Mb from one another on chromosome 17q21, these being tau and progranulin. The identification of these genes has contributed greatly to our understanding of the differing neuropathologies associated with FTLD. Furthermore, the discovery that TDP-43 is a component of the neuronal inclusions seen in the most common neuropathological subtype has also helped expand the biochemical pathways that are the focus of much FTLD research. Nevertheless, other genes causing FTLD remain to be identified and their biology elucidated before we have a complete understanding of the complex aetiology of this disease.

Insight in frontotemporal dementia: Conceptual analysis and empirical evaluation of the consensus criterion “loss of insight” in frontotemporal dementia

The objective of this study was to suggest a new formulation of the core research diagnostic consensus criterion "loss of insight" in frontotemporal dementia (FTD). Eight patients with FTD (diagnoses made by interviews, medical and neuropsychological examination, CT scan, and regional cerebral glucose metabolism measured by positron emission tomography (PET) participated in the study). The results indicated that insight was present in three out of eight patients, and that insight appears to be a heterogeneous concept. Two types of insight emerged: Emotional insight associated with frontotemporal functions, and cognitive insight, related to posterior cognitive functions. These results suggest that loss of insight should not serve as a core criterion on FTD, but serves well as a supportive criterion of the disease.

Clinical and molecular aspects of frontotemporal dementia

Frontotemporal dementia (FTD) is a neurodegenerative disease and next to Alzheimer's disease and vascular dementia, the third most common cause of early-onset progressive dementia. FTD leads to neurodegeneration in the frontal and temporal neocortex and usually encompasses both sides of the frontal and anterior temporal lobes. Psychologically, FTD is characterized by personality changes such as lack of insight, inappropriate behaviour, disinhibition, apathy, executive disabilities and a decline in cognitive functions, with large clinical and neuropathological variations among cases. Neuropathological characteristics include gliosis or microvacuolation of cortical nerve cells. Inclusions staining for tau protein and/or ubiquitin are also common findings. Both sporadic and hereditary forms of FTD have been identified and 30-50% of the FTD cases have a familial background. So far, at least three genetic loci for FTD have been identified, at human chromosomes 3, 9 and 17 in familial forms of the disease. A large number of the familial forms have been linked to chromosome 17q21 and referred to as frontotemporal dementia and Parkinsonism linked to chromosome 17. In the majority of these families, pathogenic mutations in the tau gene were identified. However, tau mutations seem to be a rare cause of disease in the general FTD population. Thus, other genes and/or environmental factors are yet to be identified, which will give further clues to this complex and heterogeneous disorder.

Mutations in progranulin cause tau-negative frontotemporal dementia linked to chromosome 17

Frontotemporal dementia (FTD) is the second most common cause of dementia in people under the age of 65 years. A large proportion of FTD patients (35-50%) have a family history of dementia, consistent with a strong genetic component to the disease. In 1998, mutations in the gene encoding the microtubule-associated protein tau (MAPT) were shown to cause familial FTD with parkinsonism linked to chromosome 17q21 (FTDP-17). The neuropathology of patients with defined MAPT mutations is characterized by cytoplasmic neurofibrillary inclusions composed of hyperphosphorylated tau. However, in multiple FTD families with significant evidence for linkage to the same region on chromosome 17q21 (D17S1787-D17S806), mutations in MAPT have not been found and the patients consistently lack tau-immunoreactive inclusion pathology. In contrast, these patients have ubiquitin (ub)-immunoreactive neuronal cytoplasmic inclusions and characteristic lentiform ub-immunoreactive neuronal intranuclear inclusions. Here we demonstrate that in these families, FTD is caused by mutations in progranulin (PGRN) that are likely to create null alleles. PGRN is located 1.7 Mb centromeric of MAPT on chromosome 17q21.31 and encodes a 68.5-kDa secreted growth factor involved in the regulation of multiple processes including development, wound repair and inflammation. PGRN has also been strongly linked to tumorigenesis. Moreover, PGRN expression is increased in activated microglia in many neurodegenerative diseases including Creutzfeldt-Jakob disease, motor neuron disease and Alzheimer's disease. Our results identify mutations in PGRN as a cause of neurodegenerative disease and indicate the importance of PGRN function for neuronal survival.

Presymptomatic semantic impairment in a case of fronto-temporal lobar degeneration associated with the +16 mutation in MAPT

We describe a patient who came to neurological attention because of his at-risk status for the +16 exon 10 splice mutation in the tau gene (microtubule associated protein tau, MAPT), which had given rise to progressive behavioural disturbances in two of his siblings. The patient began to exhibit early signs of behavioural disturbance at around the age of symptom onset in both of his siblings. Although he did not spontaneously complain of difficulties in the domain of language, he met clinical, radiological and neuropsychological criteria for semantic dementia. On the assumption that his illness is mediated by the same pathological process as those of his siblings, we propose that this clinical picture represents the earliest changes of a semantic impairment - a phase of the illness that is often retrospectively described by patients and their relations, but has never previously been documented at first hand. Although typical of semantic dementia in many respects, the illness had several interesting and atypical features that emerged on detailed testing: first, he exhibited no insight into his difficulties; secondly, progression over a twelve-month interval was unusually slow; thirdly, he evinced a striking and consistent advantage for nonliving over living concepts; fourthly, a differential impairment of distinctive over shared knowledge did not emerge except when items that he could still name were compared with those for which he was anomic. Finally, the availability of post mortem pathological analysis from the brains of both of his affected siblings allowed us to attribute his illness to a specific pathological process which is considered unusual for patients with this clinical phenotype.

Caspase-cleaved tau accumulation in neurodegenerative diseases associated with tau and alpha-synuclein pathology

Alzheimer's disease (AD), Pick's disease (PiD), progressive supranuclear palsy (PSP), corticobasal degeneration (CBD) and dementia with Lewy bodies (DLB) are diseases associated with the accumulation of tau or alpha-synuclein. In AD, beta-amyloid (Abeta)-associated caspase activation and cleavage of tau at Asp421 (DeltaTau) may be an early step in neurofibrillary tangle (NFT) formation. To examine whether DeltaTau accumulates in other diseases not characterized by extracellular Abeta accumulation, we examined PiD, PSP, and CBD cases in comparison to those without extensive tau accumulation including frontotemporal lobar degeneration without Pick bodies (FTLD) and control cases. Additionally, we studied DeltaTau accumulation in DLB cases associated with intracellular alpha-synuclein. DeltaTau was observed in all disease cases except non-PiD FTLD and controls. These results demonstrate that the accumulation of DeltaTau may represent a common pathway associated with abnormal accumulation of intracellular tau or alpha-synuclein and may be relatively less dependent on the extracellular accumulation of Abeta in non-AD dementias.

Frontotemporal lobar degeneration and ubiquitin immunohistochemistry

We set out to determine the frequency of the different pathologies underlying frontotemporal degeneration (FTD) in our brain bank series, by reviewing all cases of pathologically diagnosed FTD over the last 12 years. We identified and reviewed 29 cases of FTD and classified them using the most recent consensus criteria with further histological analysis of 6 initially unclassifiable cases. Detailed histological analysis of these 6 cases revealed variable numbers of ubiquitin-positive (tau and alpha-synuclein-negative) inclusions in 5 cases, consistent with the diagnosis of frontotemporal lobar degeneration with ubiquitin-only-immunoreactive neuronal changes (FTLD-U). As a consequence of the current re-evaluation, 18 (62%) of the 29 cases with FTD have underlying pathology consistent with FTLD-U. Therefore in our brain bank series of frontotemporal degeneration, most cases were non-tauopathies with FTLD-U accounting for 62% of all the diagnoses.

A study of stereotypic behaviours in Alzheimer's disease and frontal and temporal variant frontotemporal dementia

OBJECTIVE

To document the prevalence and pattern of stereotypic behaviour in patients with Alzheimer's dementia and frontal and temporal variants of frontotemporal dementia. Secondly, to examine the relationship between stereotypic and other neuropsychiatric behaviours.

METHODS

Patients with the following were studied; Alzheimer's disease (n=28), frontal variant frontotemporal dementia (fvFTD, n=18), and semantic dementia-the temporal lobe variant of FTD (n=13). All patients were assessed using the Neuropsychiatric Inventory (NPI), the Mini-Mental State Examination, Addenbrooke's Cognitive Examination, and the Clinical Dementia Rating scale. Patients were also rated on the newly devised Stereotypic and Ritualistic Behaviour (SRB) subscale, which was designed as an addendum to the NPI.

RESULTS

There was no significant difference across diagnostic groups in terms of age, sex, or severity of cognitive deficits. The overall NPI was significantly higher in patients with fvFTD compared with the other two groups, but fvFTD and semantic dementia showed a similar, and significantly increased, prevalence of stereotypic behaviours on the SRB subscale. Within the FTD group as a whole these behaviours were more likely to be complex, whereas in Alzheimer's disease, when present, such behaviours tended to be more simple stereotypies or stimulus bound repetitive behaviours. Stereotypic behaviours were not correlated with either disease severity or the extent of cognitive impairment in the fvFTD group, but were in the other two diagnostic groups.

CONCLUSION

Complex stereotypic behaviours are a core feature of the dementing syndrome in FTD and may reflect early and specific deficits in orbitofrontal circuitry and basal ganglia involvement.

Estrogen replacement therapy and frontotemporal dementia

OBJECTIVE

To examine the relationship between estrogen replacement therapy (ERT) and frontotemporal dementia (FTD).

METHODS

We examined the files of thirty female patients diagnosed with FTD at the University of California, San Francisco (UCSF)-Alzheimer's Disease Research Center in Fresno between the years of 1994 and 1999. Twenty-one patients (70%) were found to have been taking ERT at the time of their evaluation. This was compared with an estimate of estrogen use in a similar cohort from the general population (24%).

RESULTS

Chi-square (chi(2)) analysis found this number to be significantly greater than estimates from the general population significant (chi(2)[df=1, N=30]=34.803, P<0.01).

CONCLUSIONS

Three potential explanations for the findings are put forth, including an intriguing neurobiological relationship between estradiol and tau, the complex protein implicated in the etiology of FTD.