Rehabilitation applications in caring for patients with Pick's disease and frontotemporal dementias

Dementia: A complex disease with multiple etiologies and multiple treatments

As the population of the United States ages, the rates of dementia are also likely to increase. Clinicians will, therefore, likely be asked to evaluate and treat an escalating number of patients experiencing a decline in multiple domains of cognitive function, which is the hallmark of neurocognitive disorders. It is also probable that clinicians will be confronted with management dilemmas related to the myriad of psychological and behavioral problems that often occur as a consequence of the neurocognitive impairment. In fact, these behavioral and psychological issues might be the initial symptoms that lead the patient to present to the clinician. Dementia has multiple potential etiologies, and a careful diagnostic assessment is imperative to best characterize the specific type of dementia impacting the patient. This is important, as knowing the type of dementia helps the clinician choose the most effective treatment. Potential treatments should be interdisciplinary in scope, patient/family-centered, and may include both nonpharmacologic and pharmacologic treatments.

Clinical Subtypes of Frontotemporal Dementia

Frontotemporal dementia (FTD) was one of the lesser known dementias until the recent advancements revealing its genetic and pathological foundation. This common neurodegenerative disorder has three clinical subtypes- behavioral, semantic and progressive non fluent aphasia. The behavioral variant mostly exhibits personality changes, while the other two encompass various language deficits. This review discusses the basic pathology, genetics, clinical and histological presentation and the diagnosis of the 3 subtypes. It also deliberates the different therapeutic modalities currently available for frontotemporal dementia and the challenges faced by the caregivers. Lastly it explores the scope of further research into the diagnosis and management of FTD.

Diagnosis and management of behavioral variant frontotemporal dementia

Frontotemporal dementia was documented over a century ago. The last decade, however, has seen substantial changes in our conceptions of this increasingly recognized disorder. Different clinical variants have been delineated, the most common of which is the behavioral variant (bvFTD). Updated diagnostic criteria have been established. New histopathological findings and genetic etiologies have been discovered. Research continues to uncover molecular mechanisms by which abnormal proteins accumulate in degenerating brain tissue. Novel neuroimaging techniques suggest that functional networks are diminished in bvFTD that might be relevant to empathy and social behavior. Despite rapid advances in our understanding of bvFTD, the disease is still under-recognized and commonly misdiagnosed. The result is inappropriate patient care. Recognizing the various presentations of bvFTD and its histological and genetic subtypes might further diagnosis, treatment, and research.

Enhancement of carer skills and patient function in the non-pharmacological management of frontotemporal dementia (FTD): A call for randomised controlled studies

FTD is a unique condition which manifests with a range of behavioural symptoms, marked dysfunction in activities of daily living (ADL) and increased levels of carer burden as compared to carers of other dementias. No efficacious pharmacological interventions to treat FTD currently exist, and research on pharmacological symptom management is variable. The few studies on non-pharmacological interventions in FTD focus on either the carer or the patients' symptoms, and lack methodological rigour. This paper reviews and discusses current studies utilising non-pharmacological approaches, exposing the clear need for more rigorous methodologies to be applied in this field. Finally, a successful randomised controlled trial helped reduce behaviours of concern in dementia, and through implementing participation in tailored activities, the FTD-specific Tailored Activities Program (TAP) is presented. Crucially, this protocol has scope to target both the person with FTD and their carer. This paper highlights that studies in this area would help to elucidate the potential for using activities to reduce characteristic behaviours in FTD, improving quality of life and the caregiving experience in FTD.

Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia

Based on the recent literature and collective experience, an international consortium developed revised guidelines for the diagnosis of behavioural variant frontotemporal dementia. The validation process retrospectively reviewed clinical records and compared the sensitivity of proposed and earlier criteria in a multi-site sample of patients with pathologically verified frontotemporal lobar degeneration. According to the revised criteria, 'possible' behavioural variant frontotemporal dementia requires three of six clinically discriminating features (disinhibition, apathy/inertia, loss of sympathy/empathy, perseverative/compulsive behaviours, hyperorality and dysexecutive neuropsychological profile). 'Probable' behavioural variant frontotemporal dementia adds functional disability and characteristic neuroimaging, while behavioural variant frontotemporal dementia 'with definite frontotemporal lobar degeneration' requires histopathological confirmation or a pathogenic mutation. Sixteen brain banks contributed cases meeting histopathological criteria for frontotemporal lobar degeneration and a clinical diagnosis of behavioural variant frontotemporal dementia, Alzheimer's disease, dementia with Lewy bodies or vascular dementia at presentation. Cases with predominant primary progressive aphasia or extra-pyramidal syndromes were excluded. In these autopsy-confirmed cases, an experienced neurologist or psychiatrist ascertained clinical features necessary for making a diagnosis according to previous and proposed criteria at presentation. Of 137 cases where features were available for both proposed and previously established criteria, 118 (86%) met 'possible' criteria, and 104 (76%) met criteria for 'probable' behavioural variant frontotemporal dementia. In contrast, 72 cases (53%) met previously established criteria for the syndrome (P < 0.001 for comparison with 'possible' and 'probable' criteria). Patients who failed to meet revised criteria were significantly older and most had atypical presentations with marked memory impairment. In conclusion, the revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotemporal lobar degeneration. Greater sensitivity of the proposed criteria may reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations. Future studies will be needed to establish the reliability and specificity of these revised diagnostic guidelines.

Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia

Based on the recent literature and collective experience, an international consortium developed revised guidelines for the diagnosis of behavioural variant frontotemporal dementia. The validation process retrospectively reviewed clinical records and compared the sensitivity of proposed and earlier criteria in a multi-site sample of patients with pathologically verified frontotemporal lobar degeneration. According to the revised criteria, 'possible' behavioural variant frontotemporal dementia requires three of six clinically discriminating features (disinhibition, apathy/inertia, loss of sympathy/empathy, perseverative/compulsive behaviours, hyperorality and dysexecutive neuropsychological profile). 'Probable' behavioural variant frontotemporal dementia adds functional disability and characteristic neuroimaging, while behavioural variant frontotemporal dementia 'with definite frontotemporal lobar degeneration' requires histopathological confirmation or a pathogenic mutation. Sixteen brain banks contributed cases meeting histopathological criteria for frontotemporal lobar degeneration and a clinical diagnosis of behavioural variant frontotemporal dementia, Alzheimer's disease, dementia with Lewy bodies or vascular dementia at presentation. Cases with predominant primary progressive aphasia or extra-pyramidal syndromes were excluded. In these autopsy-confirmed cases, an experienced neurologist or psychiatrist ascertained clinical features necessary for making a diagnosis according to previous and proposed criteria at presentation. Of 137 cases where features were available for both proposed and previously established criteria, 118 (86%) met 'possible' criteria, and 104 (76%) met criteria for 'probable' behavioural variant frontotemporal dementia. In contrast, 72 cases (53%) met previously established criteria for the syndrome (P < 0.001 for comparison with 'possible' and 'probable' criteria). Patients who failed to meet revised criteria were significantly older and most had atypical presentations with marked memory impairment. In conclusion, the revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotemporal lobar degeneration. Greater sensitivity of the proposed criteria may reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations. Future studies will be needed to establish the reliability and specificity of these revised diagnostic guidelines.

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

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

[Frontotemporal dementia: a review]

CLINICAL CHARACTERISTICS

Frontotemporal dementia (FTD) is a neurological disorder characterised by the progressive degeneration of the frontal and anterior temporal cortex. FTD, as well as nonfluent progressive aphasia and semantic dementia, belongs to the more generic entity of frontotemporal lobe degeneration. Considering the involvement of the frontal lobe, the initial clinical presentation of FTD may be psychiatric, such as changes in personality or behavioural disorders. Psychiatrists, therefore, have to establish the differential diagnosis with late-onset schizophrenia or affective disorders. An accurate history of the onset of symptoms, thanks to the patient and especially to his/her family, is essential to recognize this dementia. In addition to behavioural changes, memory impairment, and speech disturbances are often present from the beginning. Consensus criteria have been proposed in 1998 that help to bring this diagnosis to mind in clinical practice. The progressive occurrence of personality changes or inappropriate social conducts in the fifth or sixth decade must prompt cognitive evaluation. NEUROCOGNITIVE AND BRAIN IMAGING DATA: A brief cognitive evaluation, such as the frontal assessment battery (FAB) may help to identify a dysexecutive syndrome and to prompt a thorough neuropsychological evaluation. The pattern of neuropsychological impairment reflects the involvement of the frontal lobe and appears different from that of other degenerative diseases, such as Alzheimer's dementia, which involves hippocampal damage. Additional investigations should however be made to detect a potentially curable dementia. Cerebral imaging is essential to the differential diagnosis and also shows evidence for the positive diagnosis of FTD. Structural MRI may initially not show the bilateral atrophy of the frontal lobe, but functional imaging may be helpful in the early stages of the illness by showing evidence of abnormalities in the anterior cerebral hemisphere. PATHOPHYSIOLOGICAL FINDINGS: In recent years, significant advances in the understanding of the pathological characteristics of FTD were made with genetic contribution, especially the discovery of the tau protein involvement. In fact, neuropathological examination with immunohistochemical analysis defines Pick's disease with Pick bodies that belong to tauopathies. Ubiquitinated intraneuronal inclusions may also be found, and some types of FTD have no distinctive pathological feature. However, although a definite diagnosis would only be established after postmortem pathological examination, the clinical, neuropsychological and imaging data enable the early identification of patients with FTD and, subsequently, the appropriate management.

THERAPEUTICS

Although the prevalence of FTD reaches 1 Alzheimer's disease (AD) to 1.6 FTD in the general population between 45- and 64-year old, only few studies have focused on the treatment of FTD. Some evidence supports the positive effect of serotonergic agents, especially with regard to behavioural symptoms. Selective serotonin reuptake inhibitors or trazodone should therefore be prescribed in preference to acetylcholinesterase medications as in AD. However, no drug yet has the ability to stop or slow down the degenerative process. The management of daily life also bears specificities related to the younger age of these patients and to their behavioural disorders. Caregivers should receive some education about the characteristics of this dementia and should be helped in social management. As concerns aggressive behaviour, neuroleptics should generally be avoided because of poor tolerance. Finally, the outcome is characterized by a rapid loss of autonomy and sometimes by a premature institutionalisation.

Frontal lobe contributions to recognition and recall: linking basic research with clinical evaluation and remediation

The role of the human frontal lobes in episodic memory is becoming better understood, thanks mainly to focal lesion and neuroimaging studies. Here we review some recent findings from basic research on the frontal lobes in memory encoding, search, and decision-making at retrieval. For each of these processes, researchers have uncovered cases in which frontal memory impairments can be attenuated by various task manipulations. We suggest ways in which these findings may inform clinical evaluation and rehabilitation of memory problems following frontal damage.

Cognitive profiles differ in autopsy-confirmed frontotemporal dementia and AD

BACKGROUND

Frontotemporal dementia (FTD) is currently distinguished from AD primarily on the basis of behavioral features because studies of cognition have shown negligible or inconsistent differences. However, the poor discriminability of cognitive measures may relate to reliance on imprecise clinically diagnosed groups. Therefore, a retrospective examination of neuropsychological test performance in autopsy-confirmed patients is warranted.

OBJECTIVE

To compare the pattern of cognitive deficits exhibited by patients with autopsy-confirmed FTD and AD.

METHODS

The profiles of cognitive deficits exhibited by patients with neuropathologic diagnosis of FTD (n = 14) or AD (n = 28) were compared. The Mattis Dementia Rating Scale (MDRS), letter and category fluency tests, Wechsler Intelligence Scale for Children-Revised block design test, Boston naming test, and clock drawing test were administered.

RESULTS

Multivariate analysis of covariance controlling for age, education, and level of dementia revealed that patients with FTD performed significantly worse than patients with AD on letter and category fluency tests but significantly better on the MDRS memory subscale, block design test, and clock drawing test. A logistic regression model, validated in an independent clinical sample, used letter fluency, MDRS memory, and block design scores to correctly classify 91% of AD patients and 77% of FTD patients.

CONCLUSIONS

A double dissociation in the pattern of cognitive deficits exhibited by FTD and AD patients was demonstrated. The FTD patients were more impaired than AD patients on word generation tasks (i.e., verbal fluency) that are sensitive to frontal lobe dysfunction but less impaired on tests of memory and visuospatial abilities sensitive to dysfunction of medial temporal and parietal association cortices.