Pain and temperature processing in dementia: a clinical and neuroanatomical analysis
TL;DR: Using a semi-structured caregiver questionnaire and MRI voxel-based morphometry in patients with frontotemporal degeneration or Alzheimer’s disease, Fletcher et al. show that symptoms are underpinned by atrophy in a distributed thalamo-temporo-insular network implicated in somatosensory processing.
Abstract: Symptoms suggesting altered processing of pain and temperature have been described in dementia diseases and may contribute importantly to clinical phenotypes, particularly in the frontotemporal lobar degeneration spectrum, but the basis for these symptoms has not been characterized in detail. Here we analysed pain and temperature symptoms using a semi-structured caregiver questionnaire recording altered behavioural responsiveness to pain or temperature for a cohort of patients with frontotemporal lobar degeneration (n = 58, 25 female, aged 52-84 years, representing the major clinical syndromes and representative pathogenic mutations in the C9orf72 and MAPT genes) and a comparison cohort of patients with amnestic Alzheimer's disease (n = 20, eight female, aged 53-74 years). Neuroanatomical associations were assessed using blinded visual rating and voxel-based morphometry of patients' brain magnetic resonance images. Certain syndromic signatures were identified: pain and temperature symptoms were particularly prevalent in behavioural variant frontotemporal dementia (71% of cases) and semantic dementia (65% of cases) and in association with C9orf72 mutations (6/6 cases), but also developed in Alzheimer's disease (45% of cases) and progressive non-fluent aphasia (25% of cases). While altered temperature responsiveness was more common than altered pain responsiveness across syndromes, blunted responsiveness to pain and temperature was particularly associated with behavioural variant frontotemporal dementia (40% of symptomatic cases) and heightened responsiveness with semantic dementia (73% of symptomatic cases) and Alzheimer's disease (78% of symptomatic cases). In the voxel-based morphometry analysis of the frontotemporal lobar degeneration cohort, pain and temperature symptoms were associated with grey matter loss in a right-lateralized network including insula (P < 0.05 corrected for multiple voxel-wise comparisons within the prespecified anatomical region of interest) and anterior temporal cortex (P < 0.001 uncorrected over whole brain) previously implicated in processing homeostatic signals. Pain and temperature symptoms accompanying C9orf72 mutations were specifically associated with posterior thalamic atrophy (P < 0.05 corrected for multiple voxel-wise comparisons within the prespecified anatomical region of interest). Together the findings suggest candidate cognitive and neuroanatomical bases for these salient but under-appreciated phenotypic features of the dementias, with wider implications for the homeostatic pathophysiology and clinical management of neurodegenerative diseases.
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TL;DR: A clinical approach to the progressive aphasias is presented, based on the experience of these disorders and directed at non-specialists, and a prospect for future progress is concluded, emphasising generic information processing deficits and novel pathophysiological biomarkers.
Abstract: The primary progressive aphasias are a heterogeneous group of focal 'language-led' dementias that pose substantial challenges for diagnosis and management Here we present a clinical approach to the progressive aphasias, based on our experience of these disorders and directed at non-specialists We first outline a framework for assessing language, tailored to the common presentations of progressive aphasia We then consider the defining features of the canonical progressive nonfluent, semantic and logopenic aphasic syndromes, including 'clinical pearls' that we have found diagnostically useful and neuroanatomical and other key associations of each syndrome We review potential diagnostic pitfalls and problematic presentations not well captured by conventional classifications and propose a diagnostic 'roadmap' After outlining principles of management, we conclude with a prospect for future progress in these diseases, emphasising generic information processing deficits and novel pathophysiological biomarkers
159 citations
TL;DR: This review aims to clarify the often confusing terminology of FTD, and outline the various clinical features and diagnostic criteria of sporadic and familial FTD syndromes.
Abstract: The term frontotemporal dementia (FTD) describes a clinically, genetically and pathologically diverse group of neurodegenerative disorders. Symptoms of FTD can present in individuals in their 20s through to their 90s, but the mean age at onset is in the sixth decade. The most common presentation is with a change in personality and impaired social conduct (behavioural variant FTD). Less frequently patients present with language problems (primary progressive aphasia). Both of these groups of patients can develop motor features consistent with either motor neuron disease (usually the amyotrophic lateral sclerosis variant) or parkinsonism (most commonly a progressive supranuclear palsy or corticobasal syndrome). In about a third of cases FTD is familial, with mutations in the progranulin, microtubule-associated protein tau and chromosome 9 open reading frame 72 genes being the major causes. Mutations in a number of other genes including TANK-binding kinase 1 are rare causes of familial FTD. This review aims to clarify the often confusing terminology of FTD, and outline the various clinical features and diagnostic criteria of sporadic and familial FTD syndromes. It will also discuss the current major challenges in FTD research and clinical practice, and potential areas for future research. This review clarifies the terminology of frontotemporal dementia (FTD) and summarizes the various clinical features and most recent diagnostic criteria of sporadic and familial FTD syndromes. It also discusses the current major challenges in FTD research and clinical practice, and highlights potential areas for future research.
113 citations
TL;DR: It is possible therefore that FTLD is a reflection of dysfunction within lysosomal/proteasomal systems resulting in failure to remove potentially neurotoxic aggregates, which ultimately overwhelm capacity to function.
Abstract: Frontotemporal Lobar Degeneration (FTLD) is a clinically, pathologically and genetically heterogeneous group of disorders that affect principally the frontal and temporal lobes of the brain. There are three major associated clinical syndromes, behavioral variant frontotemporal dementia (bvFTD), semantic dementia (SD) and progressive non-fluent aphasia (PNFA); three principal histologies, involving tau, TDP-43 and FUS proteins; and mutations in three major genes, MAPT, GRN and C9orf72, along with several other less common gene mutations. All three clinical syndromes can exist separately or in combination with Amyotrophic Lateral Sclerosis (ALS). SD is exclusively a TDP-43 proteinopathy, and PNFA may be so, with both showing tight clinical, histological and genetic inter-relationships. bvFTD is more of a challenge with overlapping histological and genetic features, involvement of any of the three aggregating proteins, and changes in any of the three major genes. However, when ALS is present, all cases show a clear histological phenotype with TDP-43 aggregated proteins, and familial forms are associated with expansions in C9orf72. TDP-43 and FUS are nuclear carrier proteins involved in the regulation of RNA metabolism, whereas tau protein - the product of MAPT - is responsible for the assembly/disassembly of microtubules, which are vital for intracellular transport. Mutations in TDP-43 and FUS genes are linked to clinical ALS rather than FTLD (with or without ALS), suggesting that clinical ALS may be a disorder of RNA metabolism. Conversely, the protein products of GRN and C9orf72, along with those of the other minor genes, appear to form part of the cellular protein degradation machinery. It is possible therefore that FTLD is a reflection of dysfunction within lysosomal/proteasomal systems resulting in failure to remove potentially neurotoxic (TDP-43 and tau) aggregates, which ultimately overwhelm capacity to function. Spread of aggregates along distinct pathways may account for the different clinical phenotypes, and patterns of progression of disease.
113 citations
TL;DR: Given the multifactorial nature of pain in patients with ALS, different treatments have been suggested, ranging from non-steroidal anti-inflammatory drugs, drugs for neuropathic pain, opioids, and cannabinoids, to physical therapy strategies and preventive assistive devices.
Abstract: Pain is a largely neglected symptom in patients with amyotrophic lateral sclerosis (ALS) although it is reported by most of these patients. It occurs at all stages of the disease and can be an onset symptom preceding motor dysfunction. Pain is correlated with a deterioration in patients' quality of life and increased prevalence of depression. In the later stages of ALS, pain can be severe enough to require increased use of sedative and analgesic drugs, and is among the events that predict clinical deterioration and death. The site of pain depends on the pain type or underlying mechanism (eg, painful cramps, nociceptive pain, or neuropathic pain). Given the multifactorial nature of pain in patients with ALS, different treatments have been suggested, ranging from non-steroidal anti-inflammatory drugs, drugs for neuropathic pain, opioids, and cannabinoids, to physical therapy strategies and preventive assistive devices. Further understanding of the pathophysiology is crucial to drive assessment in clinical trials of therapeutic strategies targeted at specific mechanisms and studies of individualised therapies.
80 citations
Cites background from "Pain and temperature processing in ..."
...Using MRI voxel-based morphometry analysis pain and temperature symptoms were associated to a right-lateralized network including anterior temporal cortex, posterior thalamus and insula, indicating an altered processing of somatosensory signals.(69) Such failure to interpret pain and temperature variations can put patients at risk of injuries....
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TL;DR: A critical appraisal of common methods to access the behavioral and psychological symptoms as well as the cognitive alterations presented in the diagnostic criteria for Behavioral variant frontotemporal dementia is aimed at.
Abstract: Behavioral variant frontotemporal dementia (bvFTD) is the second leading cognitive disorder caused by neurodegeneration in patients under 65 years of age. Characterized by frontal, insular, and/or temporal brain atrophy, patients present with heterogeneous constellations of behavioral and psychological symptoms among which progressive changes in social conduct, lack of empathy, apathy, disinhibited behaviors, and cognitive impairments are frequently observed. Since the histopathology of the disease is heterogeneous and identified genetic mutations only account for ~30% of cases, there are no reliable biomarkers for the diagnosis of bvFTD available in clinical routine as yet. Early detection of bvFTD thus relies on correct application of clinical diagnostic criteria. Their evaluation however, requires expertise and in-depth assessments of cognitive functions, history taking, clinical observations as well as caregiver reports on behavioral and psychological symptoms and their respective changes. With this review, we aim for a critical appraisal of common methods to access the behavioral and psychological symptoms as well as the cognitive alterations presented in the diagnostic criteria for bvFTD. We highlight both, practical difficulties as well as current controversies regarding an overlap of symptoms and particularly cognitive impairments with other neurodegenerative and primary psychiatric diseases. We then review more recent developments and evidence on cognitive, behavioral and psychological symptoms of bvFTD beyond the diagnostic criteria which may prospectively enhance the early detection and differential diagnosis in clinical routine. In particular, evidence on specific impairments in social and emotional processing, praxis abilities as well as interoceptive processing in bvFTD is summarized and potential links with behavior and classic cognitive domains are discussed. We finally outline both, future opportunities and major challenges with regard to the role of clinical neuropsychology in detecting bvFTD and related neurocognitive disorders.
66 citations
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TL;DR: It is suggested that this framework provides a parsimonious account of insula function in neurotypical adults, and may provide novel insights into the neural basis of disorders of affective and social cognition.
Abstract: The insula is a brain structure implicated in disparate cognitive, affective, and regulatory functions, including interoceptive awareness, emotional responses, and empathic processes. While classically considered a limbic region, recent evidence from network analysis suggests a critical role for the insula, particularly the anterior division, in high-level cognitive control and attentional processes. The crucial insight and view we present here is of the anterior insula as an integral hub in mediating dynamic interactions between other large-scale brain networks involved in externally oriented attention and internally oriented or self-related cognition. The model we present postulates that the insula is sensitive to salient events, and that its core function is to mark such events for additional processing and initiate appropriate control signals. The anterior insula and the anterior cingulate cortex form a “salience network” that functions to segregate the most relevant among internal and extrapersonal stimuli in order to guide behavior. Within the framework of our network model, the disparate functions ascribed to the insula can be conceptualized by a few basic mechanisms: (1) bottom–up detection of salient events, (2) switching between other large-scale networks to facilitate access to attention and working memory resources when a salient event is detected, (3) interaction of the anterior and posterior insula to modulate autonomic reactivity to salient stimuli, and (4) strong functional coupling with the anterior cingulate cortex that facilitates rapid access to the motor system. In this manner, with the insula as its integral hub, the salience network assists target brain regions in the generation of appropriate behavioral responses to salient stimuli. We suggest that this framework provides a parsimonious account of insula function in neurotypical adults, and may provide novel insights into the neural basis of disorders of affective and social cognition.
4,322 citations
Additional excerpts
...…et al., 2000, 2002, 2009; Critchley et al., 2000, 2011; Brooks et al., 2005; Critchley, 2005; Henderson et al., 2007; Seeley et al., 2007a, b, 2009; Corbetta et al., 2008; Sridharan et al., 2008; Bjornsdotter et al., 2009; Mazzola et al., 2009, 2012; Menon and Uddin, 2010; Beissner et al., 2013)....
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Pierre-and-Marie-Curie University1, University of British Columbia2, University of Pittsburgh3, French Institute of Health and Medical Research4, University of California, Los Angeles5, University of California, San Diego6, McGill University7, University of Kentucky8, Tohoku University9, Brown University10, NewYork–Presbyterian Hospital11, VU University Medical Center12
TL;DR: The NINCDS-ADRDA and DSM-IV-TR criteria for Alzheimer's disease (AD) are the prevailing diagnostic standards in research; however, they have now fallen behind the unprecedented growth of scientific knowledge as discussed by the authors.
Abstract: The NINCDS-ADRDA and the DSM-IV-TR criteria for Alzheimer's disease (AD) are the prevailing diagnostic standards in research; however, they have now fallen behind the unprecedented growth of scientific knowledge. Distinctive and reliable biomarkers of AD are now available through structural MRI, molecular neuroimaging with PET, and cerebrospinal fluid analyses. This progress provides the impetus for our proposal of revised diagnostic criteria for AD. Our framework was developed to capture both the earliest stages, before full-blown dementia, as well as the full spectrum of the illness. These new criteria are centred on a clinical core of early and significant episodic memory impairment. They stipulate that there must also be at least one or more abnormal biomarkers among structural neuroimaging with MRI, molecular neuroimaging with PET, and cerebrospinal fluid analysis of amyloid beta or tau proteins. The timeliness of these criteria is highlighted by the many drugs in development that are directed at changing pathogenesis, particularly at the production and clearance of amyloid beta as well as at the hyperphosphorylation state of tau. Validation studies in existing and prospective cohorts are needed to advance these criteria and optimise their sensitivity, specificity, and accuracy.
3,951 citations
University of Pennsylvania1, University of New South Wales2, Mayo Clinic3, University of California, Los Angeles4, University of California, San Francisco5, Erasmus University Rotterdam6, Johns Hopkins University7, University of Western Ontario8, University of Southampton9, University Hospital Southampton NHS Foundation Trust10, University College London11, University of California, San Diego12, University of Toronto13, Northwestern University14, Harvard University15, Technische Universität München16, Lille University of Science and Technology17, VU University Amsterdam18, Favaloro University19, Kessler Foundation20, Vita-Salute San Raffaele University21
TL;DR: The revised criteria for behavioural variant frontotemporal dementia improve diagnostic accuracy compared with previously established criteria in a sample with known frontotmporal lobar degeneration and reflect the optimized diagnostic features, less restrictive exclusion features and a flexible structure that accommodates different initial clinical presentations.
Abstract: 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.
3,706 citations
"Pain and temperature processing in ..." refers methods in this paper
...All fulfilled consensus diagnostic criteria for a syndrome of FTLD (Gorno-Tempini et al., 2011; Rascovsky et al., 2011) (behavioural variant FTD, n = 21; semantic dementia, n = 17; PNFA, n = 20) or for Alzheimer’s disease led by decline in episodic memory (Dubois et al....
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...All fulfilled consensus diagnostic criteria for a syndrome of FTLD (Gorno-Tempini et al., 2011; Rascovsky et al., 2011) (behavioural variant FTD, n = 21; semantic dementia, n = 17; PNFA, n = 20) or for Alzheimer’s disease led by decline in episodic memory (Dubois et al., 2007)....
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University of Trento1, University of California, San Francisco2, Johns Hopkins University3, Northwestern University4, University of Western Ontario5, University of California, Los Angeles6, Vita-Salute San Raffaele University7, University College London8, University of Toronto9, Mayo Clinic10, University of California, Davis11, Katholieke Universiteit Leuven12, University of Cambridge13, University of New South Wales14, University of Pennsylvania15
TL;DR: This article provides a classification of primary progressive aphasia (PPA) and its 3 main variants to improve the uniformity of case reporting and the reliability of research results.
Abstract: This article provides a classification of primary progressive aphasia (PPA) and its 3 main variants to improve the uniformity of case reporting and the reliability of research results. Criteria for the 3 variants of PPA—nonfluent/agrammatic, semantic, and logopenic—were developed by an international group of PPA investigators who convened on 3 occasions to operationalize earlier published clinical descriptions for PPA subtypes. Patients are first diagnosed with PPA and are then divided into clinical variants based on specific speech and language features characteristic of each subtype. Classification can then be further specified as “imaging-supported” if the expected pattern of atrophy is found and “with definite pathology” if pathologic or genetic data are available. The working recommendations are presented in lists of features, and suggested assessment tasks are also provided. These recommendations have been widely agreed upon by a large group of experts and should be used to ensure consistency of PPA classification in future studies. Future collaborations will collect prospective data to identify relationships between each of these syndromes and specific biomarkers for a more detailed understanding of clinicopathologic correlations.
3,635 citations
"Pain and temperature processing in ..." refers methods in this paper
...All fulfilled consensus diagnostic criteria for a syndrome of FTLD (Gorno-Tempini et al., 2011; Rascovsky et al., 2011) (behavioural variant FTD, n = 21; semantic dementia, n = 17; PNFA, n = 20) or for Alzheimer’s disease led by decline in episodic memory (Dubois et al....
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...All fulfilled consensus diagnostic criteria for a syndrome of FTLD (Gorno-Tempini et al., 2011; Rascovsky et al., 2011) (behavioural variant FTD, n = 21; semantic dementia, n = 17; PNFA, n = 20) or for Alzheimer’s disease led by decline in episodic memory (Dubois et al., 2007)....
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TL;DR: Only that part of the pain network associated with its affective qualities, but not its sensory qualities, mediates empathy, suggesting that the neural substrate for empathic experience does not involve the entire "pain matrix".
Abstract: Our ability to have an experience of another's pain is characteristic of empathy. Using functional imaging, we assessed brain activity while volunteers experienced a painful stimulus and compared it to that elicited when they observed a signal indicating that their loved one--present in the same room--was receiving a similar pain stimulus. Bilateral anterior insula (AI), rostral anterior cingulate cortex (ACC), brainstem, and cerebellum were activated when subjects received pain and also by a signal that a loved one experienced pain. AI and ACC activation correlated with individual empathy scores. Activity in the posterior insula/secondary somatosensory cortex, the sensorimotor cortex (SI/MI), and the caudal ACC was specific to receiving pain. Thus, a neural response in AI and rostral ACC, activated in common for "self" and "other" conditions, suggests that the neural substrate for empathic experience does not involve the entire "pain matrix." We conclude that only that part of the pain network associated with its affective qualities, but not its sensory qualities, mediates empathy.
3,425 citations