Frontotemporal dementia

Frontotemporal Dementia

Frontotemporal dementia (FTD) is a heterogeneous disorder with distinct clinical phenotypes associated with multiple neuropathologic entities. Presently, the term FTD encompasses clinical disorders that include changes in behavior, language, executive control, and often motor symptoms. The core FTD spectrum disorders include behavioral variant FTD, nonfluent/agrammatic variant primary progressive aphasia, and semantic variant PPA. Related FTD disorders include frontotemporal dementia with motor neuron disease, progressive supranuclear palsy syndrome, and corticobasal syndrome. In this article, the authors discuss the clinical presentation, diagnostic criteria, neuropathology, genetics, and treatments of these disorders.

The Combination of Dysexecutive and Amnestic Deficits Strongly Predicts Conversion to Dementia in Young Mild Cognitive Impairment Patients: A Report from the Gothenburg-Oslo MCI Study

Background/Aims

The present study aimed to add to the knowledge of mild cognitive impairment (MCI) by studying the prognosis in a relatively young cohort of patients characterized by neuropsychological criteria.

Methods

Patients (mean age: 63 years) with cognitive complaints and MCI (n = 302) were recruited from two university clinics and followed for 2 years.

Results

Pure dysexecutive MCI occurred in 11.7% of the neuropsychologically impaired patients, while 59.3 and 29.0% were characterized as having pure amnestic MCI or multidomain MCI. During the study period, the state of 2 (10.5%) of the patients with single-domain dysexecutive MCI converted to dementia, while 28 (29.2%) of the patients with pure amnestic MCI became demented. Of the patients with both executive and amnestic deficits, 28 (59.6%) became demented.

Conclusion

The results suggest that dysexecutive symptoms in combination with amnestic symptoms constitute a strong risk factor for dementia in young MCI patients. A significant number of patients in all subgroups showed normal test results at follow-up, indicating that a neuropsychological diagnosis needs to be supported by imaging or biomarker data.

Executive Dysfunction in MCI: Subtype or Early Symptom

Mild cognitive impairment (MCI) may take several forms, and amnestic MCI (aMCI) has been recognized as an early stage of Alzheimer's Disease (AD). Impairment in executive functions including attention (eMCI) may be indicative of several neurodegenerative conditions. Executive impairment is frequently found in aMCI, it is significant for prognosis, and patients with eMCI may go on to develop AD. Recent studies have found changes in white matter integrity in patients with eMCI to be more sensitive than measures of cortical atrophy. Studies of genetic high-risk groups using sensitive cognitive neuroscience paradigms indicate that changes in executive function may be a cognitive marker useful for tracking development in an AD pathophysiological process.

Prevention of dementia

Dementia is a neurological condition that is characterized by decline in multiple cognitive domains and is accompanied by a functional impairment. It is important to identify the factors that may delay the onset, slow the progression, or prevent cognitive decline. This review highlights the protective and risk factors of dementia, suggesting that physical activity, intellectual activity, and social engagement may reduce Alzheimer disease and cognitive decline and may be also helpful for enhancing quality of life.

Sleep disorders in neurodegenerative diseases

The aim of this review is to provide data on sleep disturbances in three categories of neurodegenerative disorders: synucleinopathies, tauopathies, and other diseases (this heterogeneous group includes also spinocerebellar degeneration and amyotrophic lateral sclerosis). Analysing and knowing sleep disorders in neurodegenerative diseases may offer important insights into the pathomechanism of some of these diseases and calls attention to the still insufficiently known 'sleep neurology'. The identification of sleep disorders in some neurodegenerative conditions may make their diagnosis easier and earlier; for example, rapid eye movements sleep behaviour disorder may precede any other clinical manifestation of synucleinopathies by more than 10 years.

A case study of an emerging visual artist with frontotemporal lobar degeneration and amyotrophic lateral sclerosis

Patients presenting with left-sided FTLD syndromes sometimes develop a new preoccupation with art, greater attention to visual stimuli, and increased visual creativity. We describe the case of a 53-year-old, right-handed man with a history of bipolar disorder who presented with language and behavior impairments characteristic of FTLD, then developed motor symptoms consistent with a second diagnosis of amyotrophic lateral sclerosis. Though the patient had never created visual art before, he developed a compulsion for painting beginning at the earliest stages of his disease, and continued producing art daily until he could no longer lift a paintbrush because of his motor deficits. Upon autopsy, he was found to have ubiquitin and TDP43-positive inclusions with MND pathology. This case study details the patient's longitudinal neuropsychological, emotional, behavioral, and motor symptoms, along with structural imaging, neurologic, and neuropathologic findings. Multiple examples of the patient's art are depicted throughout all stages of his illness, and the possible cognitive, behavioral, and neurologic correlates of his new-onset visual artistry are discussed.

Rapidly progressive dementia

Rapidly progressive dementias (RPDs) are neurologic conditions that develop subacutely over weeks to months or, rarely, acutely over days. In contrast to most dementing conditions that take years to progress to death, RPD quickly can be fatal. It is critical to evaluate patients who have RPD without delay, usually in a hospital setting, as they may have a treatable condition. This review discusses a differential diagnostic approach to RPD, emphasizing neurodegenerative, toxic and metabolic, infectious, autoimmune, neoplastic, and other conditions to consider.

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.

Clinical Features of Frontotemporal Dementia

What was once called Pick's disease has three major anatomic variants. With all three, frontotemporal brain is selectively injured whereas posterior cortical regions are spared. These three clinical patterns include a bifrontal, slightly asymmetric subtype with more involvement of the right frontotemporal region called frontotemporal dementia or the frontal variant of FTD (fvFTD), a temporal-predominant subtype called the temporal variant of FTD or semantic dementia (SD), and a left frontal-predominant subtype called progressive nonfluent aphasia (PNFA). The three anatomic groups help to classify distinctive clinical syndromes with unique features. Careful study of these subtypes of frontotemporal dementia, using combinations of new quantitative neuroimaging, behavioral and physiological measures are yielding important information about the functioning of the brain's frontal and temporal regions. As we come to better understand the biologic basis for the three FTD clinical syndromes, new classification schemas may emerge, but our current clinical criteria serve as a strong guide to the diagnosis and separation of FTD from Alzheimer disease and other dementias.

Correlation of ventricular asymmetry with metabolic asymmetry in frontotemporal dementia

BACKGROUND AND PURPOSE

The clinical presentation of frontotemporal dementia (FTD) is often asymmetrical in terms of both its clinical features and atrophy on MRI. Asymmetry in the lateral ventricle size on structural neuroimaging in FTD patients may have clinical significance. However, this has not been systematically investigated yet. This study compares the ventricular asymmetry seen on MRI with that of the asymmetric glucose metabolism using FDG-PET in patients with FTD.

METHODS

Nineteen FTD patients who underwent both brain MRI and FDG-PET were retrospectively selected. As control groups, 23 and 11 age and sex-matched healthy normal subjects underwent either brain MRI or FDG-PET, respectively. The ventricular asymmetry index (VAI) was obtained in two ways: by visual rating (VAI-V) and by measuring the lateral ventricular volumes (VAI-ROI). The hemispheric asymmetry of the glucose metabolism on FDG-PET (MAI) was assessed in three ways: 1) by visual rating (MAI-V), 2) by counting the FDG activity of each hemisphere on normalized and smoothed PET images (MAI-ROI) and 3) by counting the number of voxels with significant hypometabolism based on statistical parametric mapping results (MAI-SPM).

RESULTS

The VAIs on MRI (VAI-V and VAI-ROI) were highly correlated, as were the MAIs (MAI-V, MAI-ROI, and MAI-SPM) on FDG-PET. More importantly, the VAIs on MRI and the MAIs on FDG-PET showed high correlation.

CONCLUSIONS

Ventricular asymmetry in FTD patients was common (78.9%) and there was a high correlation between the ventricular structural asymmetry and the hemispheric metabolic asymmetry. Therefore, it would be reasonable to interpret that the hemisphere with larger ventricle on MRI in FTD patients is undergoing a more active degenerative process.

Neurodegenerative memory disorders: a potential role of environmental toxins

The hypothesis that neurotoxins may play a role in neurodegenerative disorders remains an elusive one, given that epidemiologic studies often provide conflicting results. Although these conflicting results may result from methodological differences within and between studies, the complexity of chemical disruption of the central nervous system cannot be ignored in attempts to evaluate this hypothesis in different neurodegenerative disorders. Spencer provides a detailed review of the complex processes involved in defining the neurotoxic potential of naturally occurring and synthetic agents. Even concepts such as exposure and dose, as often reported in studies attempting to evaluate the risk imparted by a potential compound, can be deceptive. For example, although dose reflects "that amount of chemical transferred to the exposed subject", factors such as time and concentration in the organism, the ability to access the central nervous system, and how a compound reaches the central nervous system (routes of administration) or secondarily affects other organ systems leading to central nervous system disruption are clearly important to the concept of neurotoxic risk in neurodegenerative disorders. These factors would appear to explain the observed disagreements between studies using animal or neuronal models of neurotoxicity and population-based studies in humans. The importance of these factors and how a potential neurotoxin is investigated are clearly seen in the data on AD and aluminum. In contrast, the impact of MTPT on the central nervous system is more direct and compelling. Added complexity in the study of neurotoxins in human neurodegeneration is derived from data showing that agents may have additive, potentiating, synergistic, or antagonistic effects. Therefore, data from studies evaluating EMF risks could be readily confounded by the presence or absence of heavy metals (eg, arc welding). Other factors that may conceal neurotoxic causes for a given disorder focus on additional features such as genetic predispositions, physiologic changes that occur in aging, and even nutritional status that can support or hinder the affect of a given agent on the central nervous system. Finally, many studies that investigate exposure risk do not readily incorporate the five criteria proposed by Schaumburg for establishing causation. For example, if we apply Schaumburg's first criterion, epidemiologic studies often determines the presence of an agent through history, yet they cannot readily confirm exposure based on environmental or clinical chemical analyses to fulfill this criterion for causation. Additional limitations in research design along with the populations and methods that are sued to study neurotoxins in human neurodegenerative disorders often fail to meet other criteria such as linking the severity and onset with duration and exposure level. Therefore, although studies of agents such as MTPT provide compelling models of neurotoxins and neurodegeneration in humans, disorders such as ALS, PD, and particularly AD will require additional effort if research is to determine the contribution (presence or absence) of neurotoxins to these neurologic disorders.

Frontotemporal dementia

In this case study, we describe the symptoms, neuropsychological testing, and brain pathology of a man with frontotemporal dementia (FTD). FTD most often presents with either a change in personality or behavior, such as social withdrawal, increased gregariousness, disinhibition, or obsessive behaviors; or with impairment of language function. Memory difficulties are common, but usually are less prominent than these other symptoms in the early stages of the disease. Frequently, psychiatric diagnoses are initially the primary consideration. Cases may be either familial or sporadic. In this familial case, an autopsy was ultimately performed and revealed findings characteristic of FTD, with grossly evident focal brain degeneration in the frontal and temporal regions, microscopic signs of gliosis, and cellular abnormalities of the intracellular microtubule-associated protein tau.

Beyond phrenology, at last

Although integration is a widely acknowledged goal in neuroscience, our approach to the function of biological entities often places boundaries that defy integration. Mapping across systems - from the genome to cognitive function - will require innovative methods that can identify every contributing component to a function, and instantaneously scale numerous changes in large data sets to consequences over the entire biological hierarchy.

Presenile dementia syndromes: an update on taxonomy and diagnosis

The four major degenerative dementias that often begin in presenescence: are reviewed. These are Alzheimer's disease, frontotemporal dementia, dementia with Lewy bodies, and Creutzfeldt-Jakob disease. Their epidemiological, genetic, and clinical features are reviewed, and controversies in taxonomy arising from recent discoveries described. Particular attention is given to the pathological role of protein aggregation, which appears to be a factor in each disease.