Theory of mind ability in the behavioural variant of frontotemporal dementia: an analysis of the neural, cognitive, and social levels

The self-reference effect in dementia: Differential involvement of cortical midline structures in Alzheimer's disease and behavioural-variant frontotemporal dementia

Encoding information in reference to the self enhances subsequent memory for the source of this information. In healthy adults, self-referential processing has been proposed to be mediated by the cortical midline structures (CMS), with functional differentiation between anterior-ventral, anterior-dorsal and posterior regions. While both Alzheimer's disease (AD) and behavioural-variant frontotemporal dementia (bvFTD) patients show source memory impairment, it remains unclear whether they show a typical memory advantage for self-referenced materials. We also sought to identify the neural correlates of this so-called 'self-reference effect' (SRE) in these patient groups. The SRE paradigm was tested in AD (n = 16) and bvFTD (n = 22) patients and age-matched healthy controls (n = 17). In this task, participants studied pictures of common objects paired with one of two background scenes (sources) under self-reference or other-reference encoding instructions, followed by an item and source recognition memory test. Voxel-based morphometry was used to investigate correlations between SRE measures and regions of grey matter atrophy in the CMS. The behavioural results indicated that self-referential encoding did not ameliorate the significant source memory impairments in AD and bvFTD patients. Furthermore, the reduced benefit of self-referential relative to other-referential encoding was not related to general episodic memory deficits. Our imaging findings revealed that reductions in the SRE were associated with atrophy in the anterior-dorsal CMS across both patient groups, with additional involvement of the posterior CMS in AD and anterior-ventral CMS in bvFTD. These findings suggest that although the SRE is comparably reduced in AD and bvFTD, this arises due to impairments in different subcomponents of self-referential processing.

Microstructural Correlates of Emotional Attribution Impairment in Non-Demented Patients with Amyotrophic Lateral Sclerosis

Impairments in the ability to recognize and attribute emotional states to others have been described in amyotrophic lateral sclerosis patients and linked to the dysfunction of key nodes of the emotional empathy network. Microstructural correlates of such disorders are still unexplored. We investigated the white-matter substrates of emotional attribution deficits in a sample of amyotrophic lateral sclerosis patients without cognitive decline. Thirteen individuals with either probable or definite amyotrophic lateral sclerosis and 14 healthy controls were enrolled in a Diffusion Tensor Imaging study and administered the Story-based Empathy Task, assessing the ability to attribute mental states to others (i.e., Intention and Emotion attribution conditions). As already reported, a significant global reduction of empathic skills, mainly driven by a failure in Emotion Attribution condition, was found in amyotrophic lateral sclerosis patients compared to healthy subjects. The severity of this deficit was significantly correlated with fractional anisotropy along the forceps minor, genu of corpus callosum, right uncinate and inferior fronto-occipital fasciculi. The involvement of frontal commissural fiber tracts and right ventral associative fronto-limbic pathways is the microstructural hallmark of the impairment of high-order processing of socio-emotional stimuli in amyotrophic lateral sclerosis. These results support the notion of the neurofunctional and neuroanatomical continuum between amyotrophic lateral sclerosis and frontotemporal dementia.

Understanding the world of dementia. How do people with dementia experience the world?

BACKGROUND

There is growing awareness that the subjective experience of people with dementia is important for understanding behavior and improving quality of life. This paper reviews and reflects on the currently available theories on subjective experience in dementia and it explores the possibility of a knowledge gap on the influence of neurological deficits on experience in late stage dementia.

METHODS

A literature review on current commonly used theories on experience in dementia was supplemented with a systematic review in PubMed and Psychinfo. For the systematic review, the terms used were Perception and Dementia and Behavior; and Awareness and Dementia and Long term care.

RESULTS

Current models emphasize the psychosocial factors that influence subjective experience, but the consequences of neurological deficits are not elaborated upon. The systematic literature search on the neuropsychological functioning in dementia resulted in 631 papers, of which 94 were selected for review. The current knowledge is limited to the early stages of Alzheimer's disease. Next to memory impairments, perception of the direct environment, interpretation of the environment, and inhibition of own responses to the environment seem to be altered in people with dementia.

CONCLUSIONS

Without knowledge on how perception, interpretation and the ability for response control are altered, the behavior of people with dementia can easily be misinterpreted. Research into neuropsychological functioning of people in more severe stages and different forms of dementia is needed to be able to develop a model that is truly biopsychosocial. The proposed model can be used in such research as a starting point for developing tests and theories.

Emotion processing in Parkinson's disease: a three-level study on recognition, representation, and regulation

BACKGROUND

Parkinson's disease (PD) is characterised by well-known motor symptoms, whereas the presence of cognitive non-motor symptoms, such as emotional disturbances, is still underestimated. One of the major problems in studying emotion deficits in PD is an atomising approach that does not take into account different levels of emotion elaboration. Our study addressed the question of whether people with PD exhibit difficulties in one or more specific dimensions of emotion processing, investigating three different levels of analyses, that is, recognition, representation, and regulation.

METHODOLOGY

Thirty-two consecutive medicated patients with PD and 25 healthy controls were enrolled in the study. Participants performed a three-level analysis assessment of emotional processing using quantitative standardised emotional tasks: the Ekman 60-Faces for emotion recognition, the full 36-item version of the Reading the Mind in the Eyes (RME) for emotion representation, and the 20-item Toronto Alexithymia Scale (TAS-20) for emotion regulation.

PRINCIPAL FINDINGS

Regarding emotion recognition, patients obtained significantly worse scores than controls in the total score of Ekman 60-Faces but not in any other basic emotions. For emotion representation, patients obtained significantly worse scores than controls in the RME experimental score but no in the RME gender control task. Finally, on emotion regulation, PD and controls did not perform differently at TAS-20 and no specific differences were found on TAS-20 subscales. The PD impairments on emotion recognition and representation do not correlate with dopamine therapy, disease severity, or with the duration of illness. These results are independent from other cognitive processes, such as global cognitive status and executive function, or from psychiatric status, such as depression, anxiety or apathy.

CONCLUSIONS

These results may contribute to better understanding of the emotional problems that are often seen in patients with PD and the measures used to test these problems, in particular on the use of different versions of the RME task.

Does impaired socioemotional functioning account for behavioral dysexecutive disorders? Evidence from a transnosological study

Behavioral dysexecutive disorders are highly prevalent in patients with neurological diseases but cannot be explained by cognitive dysexecutive impairments. In fact, the underlying mechanisms are poorly understood. Given that socioemotional functioning underlies appropriate behavior, socioemotional impairments may contribute to the appearance of behavioral disorders. To investigate this issue, we performed a transnosological study. Seventy-five patients suffering from various neurological diseases (Alzheimer's disease (AD), Parkinson's disease (PD), frontotemporal lobar degeneration, and stroke) were included in the study. The patients were comprehensively assessed in terms of cognitive and behavioral dysexecutive disorders and socioemotional processes (facial emotion recognition and theory of mind). As was seen for cognitive and behavioral dysexecutive impairments, the prevalence of socioemotional impairments varied according to the diagnosis. Stepwise logistic regressions showed that (i) only cognitive executive indices predicted hypoactivity with apathy/abulia, (ii) theory of mind impairments predicted hyperactivity-distractibility-impulsivity and stereotyped/perseverative behaviors, and (iii) impaired facial emotion recognition predicted social behavior disorders. Several dysexecutive behavioral disorders are associated with an underlying impairment in socioemotional processes but not with cognitive indices of executive functioning (except for apathy). These results strongly suggest that some dysexecutive behavioral disorders are the outward signs of an underlying impairment in socioemotional processes.

Cognitive and affective theory of mind in dementia with Lewy bodies and Alzheimer's disease

Background

Theory of mind (ToM) refers to the ability to attribute mental states, thoughts (cognitive component) or feelings (affective component) to others. This function has been studied in many neurodegenerative diseases; however, to our knowledge, no studies investigating ToM in dementia with Lewy bodies (DLB) have been published. The aim of our study was to assess ToM in patients with DLB and to search for neural correlates of potential deficits.

Methods

Thirty-three patients with DLB (DLB group) and 15 patients with Alzheimer’s disease (AD group), all in the early stage of the disease, as well as 16 healthy elderly control subjects (HC group), were included in the study. After a global cognitive assessment, we used the Faux Pas Recognition (FPR) test, the Reading the Mind in the Eyes (RME) test and Ekman’s Facial Emotion Recognition test to assess cognitive and affective components of ToM. Patients underwent cerebral 3-T magnetic resonance imaging, and atrophy of grey matter was analysed using voxel-based morphometry. We performed a one-sample t test to investigate the correlation between each ToM score and grey matter volume and a two-sample t test to compare patients with DLB impaired with those non-impaired for each test.

Results

The DLB group performed significantly worse than the HC group on the FPR test (P = 0.033) and the RME test (P = 0.015). There was no significant difference between the AD group and the HC group or between the DLB group and the AD group. Some brain regions were associated with ToM impairments. The prefrontal cortex, with the inferior frontal cortex and the orbitofrontal cortex, was the main region, but we also found correlations with the temporoparietal junction, the precuneus, the fusiform gyrus and the insula.

Conclusions

This study is the first one to show early impairments of ToM in DLB. The two cognitive and affective components both appear to be affected in this disease. Among patients with ToM difficulties, we found atrophy in brain regions classically involved in ToM, which reinforces the neuronal network of ToM. Further studies are now needed to better understand the neural basis of such impairment.

Electronic supplementary material

The online version of this article (doi:10.1186/s13195-016-0179-9) contains supplementary material, which is available to authorized users.

Facial Emotion Recognition and Faux Pas Interpretation in Multiple Sclerosis

Multiple sclerosis (MS) is an inflammatory disease of the central nervous system leading to physical and cognitive disability. The impact of the disease on social cognition has only come to light quite recently. The aim of this study was to evaluate the social cognition abilities of MS patients and their links with characteristics of the disease, such as physical disability, cognitive impairment and disease duration.

The performances of a group of 64 MS patients were compared with that of 30 matched healthy individuals in facial emotion recognition and Faux Pas tasks as well as on a battery of standardized neuropsychological tests.

The MS patients performed worse than the control group in the recognition of the expressions of fear and anger and in the interpretation of faux pas. The impairment in social cognition increased with overall disease course. Executive impairment did not correlate with the performance in the social cognition tests.

Our results show that emotional impairment is observed at early stages of the disease in the absence of cognitive dysfunction, even if social cognition abilities worsen with the progression of MS. These data highlight the need to attempt to identify these impairments in clinical practice.

Processing ambiguity in a linguistic context: decision-making difficulties in non-aphasic patients with behavioral variant frontotemporal degeneration

Some extent of ambiguity is ubiquitous in everyday conversations. For example, words have multiple meaning and very common pronouns, like “he” and “she” (anaphoric pronouns), have little meaning on their own and refer to a noun that has been previously introduced in the discourse. Ambiguity triggers a decision process that is not a subroutine of language processing but rather a more general domain resource. Therefore non-aphasic patients with limited decision-making capability can encounter severe limitation in language processing due to extra linguistic limitations. In the present study, we test patients with behavioral variant frontotemporal degeneration (bvFTD), focusing on anaphora as a paradigmatic example of ambiguity resolution in the linguistic domain. bvFTD is characterized by gray matter (GM) atrophy in prefrontal cortex, but relative sparing of peri-Sylvian cortex. A group of patients with parietal disease due to corticobasal syndrome (CBS) was also tested here in order to investigate the specific role of prefrontal cortex in the task employed in the current study. Participants were presented with a pair of sentences in which the first sentence contained two nouns while the second contained a pronoun. In the experimental (ambiguous) condition, both nouns are plausible referents of the pronoun, thus requiring decision-making resources. The results revealed that bvFTD patients are significantly less accurate than healthy seniors in identifying the correct referent of a pronoun in the ambiguous condition, although CBS patients were as accurate as healthy seniors. Imaging analyses related bvFTD patients’ performance to GM atrophy in ventromedial prefrontal cortex (vmPFC). These results suggest that bvFTD patients have difficulties in decision processes that involve the resolution of an ambiguity.

Theory of Mind and social reserve: Alternative hypothesis of progressive Theory of Mind decay during different stages of Alzheimer's disease

Although Theory of Mind (ToM) is thought to be impaired in Alzheimer's disease (AD), it remains unclear whether this impairment is linked to the level of task complexity, the heterogeneity of the studied patients, or the implication of executive dysfunctions. To elucidate this point, 42 AD patients, divided into two subgroups [moderate AD (mAD) patients (n = 19) and early AD (eAD) patients (n = 23)], and 23 matched healthy older subjects (HO) were enrolled. All participants were given (1) a false-belief task (cognitive ToM), (2) a revised version of the "Reading the Mind in the Eyes" test (affective ToM), and (3) a composite task designed to assess ToM abilities with minimal cognitive demands. Participants were also given executive tasks assessing inhibition, shifting, and updating processes. We observed a significant impairment of cognitive and composite ToM abilities in eAD patients compared with mAD patients. There was no impairment of affective ToM. Stepwise regression revealed that measures of global efficiency and executive functions (EFs) were the best predictors of progressive decay of ToM scores. These results indicate that cognitive aspects of ToM are more sensitive to AD progression than affective tasks. They also show that ToM abilities are more affected by dementia severity than by task complexity. One explanation of our results is the presence of compensatory mechanisms (social reserve) in AD.

Social cognition in schizophrenia

Individuals with schizophrenia exhibit impaired social cognition, which manifests as difficulties in identifying emotions, feeing connected to others, inferring people's thoughts and reacting emotionally to others. These social cognitive impairments interfere with social connections and are strong determinants of the degree of impaired daily functioning in such individuals. Here, we review recent findings from the fields of social cognition and social neuroscience and identify the social processes that are impaired in schizophrenia. We also consider empathy as an example of a complex social cognitive function that integrates several social processes and is impaired in schizophrenia. This information may guide interventions to improve social cognition in patients with this disorder.

Beyond words: Pragmatic inference in behavioral variant of frontotemporal degeneration

When the message of a speaker goes beyond the literal or logical meaning of the sentences used, a pragmatic inference is required to understand the complete meaning of an utterance. Here we study one example of pragmatic inference, called scalar implicature. Such an inference is required when a weaker term "some" is used in a sentence like "Some of the students passed the exam" because the speaker presumably had a reason not to use a stronger term like "all". We investigated the comprehension of scalar implicatures in a group of 17 non-aphasic patients with behavioral variant frontotemporal degeneration (bvFTD) in order to test the contribution of non-linguistic decision-making ability and the role of prefrontal cortex in supporting the computation of pragmatic inferences. The results of two experiments point to a deficit in producing alternative interpretations beyond a logical reading. bvFTD patients thus prefer the narrowly literal or logical interpretation of a scalar term when they must generate a possible alternative interpretation by themselves, but patients prefer a pragmatic reading when offered a choice between the logical and the pragmatic interpretation of the same sentence. An imaging analysis links bvFTD patients' spontaneous tendency toward a narrowly logical interpretation with atrophy in ventromedial prefrontal cortex. Our findings are consistent with the pragmatic tolerance hypothesis, which proposes that difficulty generating alternative interpretations of an utterance, rather than a frank inability to compute an inference, affects the comprehension of a scalar term.

Theory of mind in behavioural-variant frontotemporal dementia and Alzheimer's disease: a meta-analysis

Current evidence suggests that neurocognitive testing has limited practical benefit in distinguishing behavioural-variant frontotemporal dementia (bvFTD) and Alzheimer's disease (AD). In this meta-analysis of 30 studies, theory of mind (ToM) performances of 784 individuals with bvFTD (n=273) and AD (n=511) were compared with 671 healthy controls. ToM performances of 227 patients with bvFTD and 229 with AD were also compared in studies matched for general cognition. ToM was impaired in both bvFTD (d=1.79) and AD (d=1.15). In bvFTD, patients were particularly impaired in advanced tasks such as recognition of faux pas and sarcasm (d>2.0). In AD, ToM deficits were relatively modest. In studies matched for general cognition, ToM was significantly impaired in bvFTD in comparision to AD (d=1.29), especially for faux pas recognition (d=1.75). ToM dysfunction is a robust and more specific feature of bvFTD. In contrast, ToM deficits are modest compared with level of general cognitive impairment in AD. In both disorders, longer duration of disease and level of general cognitive impairment are related to relatively more severe ToM deficits. Assessment of ToM can be beneficial for early identification of bvFTD.

Apraxia profile differentiates behavioural variant frontotemporal from Alzheimer's dementia in mild disease stages

OBJECTIVE

Despite refined criteria for behavioural variant frontotemporal dementia (bvFTD), its differentiation from Alzheimer's dementia (AD) remains difficult at early clinical presentation. Apraxia is not considered as a supportive feature for the diagnosis of bvFTD, but for AD. However, only few studies have quantified praxis disturbances in mild disease stages and their specificity for AD compared with bvFTD remains indistinct. We explore apraxia in bvFTD and investigate the differential validity of apraxia screening tests to distinguish between AD, bvFTD and healthy controls (HC).

METHODS

We compared composite apraxia scores assessed with standardised neuropsychological screening tests as well as performance in praxis subdomains in patients who fulfil current clinical criteria for AD (N=20), bvFTD (N=20), and in HC (N=20).

RESULTS

Composite scores of apraxia screening tests provided high diagnostic accuracy for detecting mild stages of both neurodegenerative disorders compared with HC (sensitivity: 75-95%; specificity: 70-90%). Both patient groups showed pronounced impairments in limb praxis, especially in imitation of hand and finger postures (bvFTD: 71.7%; AD: 55.5%; HC: 86.7%) and pantomime of object use (bvFTD: 88.6%; AD: 81.4%; HC: 97.5%). Beyond that, patients with bvFTD displayed a unique profile of deficits for imitating face postures (bvFTD: 69%; AD: 88%; HC: 95.5%).

CONCLUSIONS

Praxis disturbances are important but under-represented diagnostic features in mild stages of AD and bvFTD. Apraxia screening tests are easily applicable diagnostic tools, which may support clinical diagnoses of both neurodegenerative diseases. The analysis of individual apraxia profiles can effectively facilitate differential diagnosis of AD and bvFTD.

Emotion processing in Parkinson's disease: a three-level study on recognition, representation, and regulation

BACKGROUND

Parkinson's disease (PD) is characterised by well-known motor symptoms, whereas the presence of cognitive non-motor symptoms, such as emotional disturbances, is still underestimated. One of the major problems in studying emotion deficits in PD is an atomising approach that does not take into account different levels of emotion elaboration. Our study addressed the question of whether people with PD exhibit difficulties in one or more specific dimensions of emotion processing, investigating three different levels of analyses, that is, recognition, representation, and regulation.

METHODOLOGY

Thirty-two consecutive medicated patients with PD and 25 healthy controls were enrolled in the study. Participants performed a three-level analysis assessment of emotional processing using quantitative standardised emotional tasks: the Ekman 60-Faces for emotion recognition, the full 36-item version of the Reading the Mind in the Eyes (RME) for emotion representation, and the 20-item Toronto Alexithymia Scale (TAS-20) for emotion regulation.

PRINCIPAL FINDINGS

Regarding emotion recognition, patients obtained significantly worse scores than controls in the total score of Ekman 60-Faces but not in any other basic emotions. For emotion representation, patients obtained significantly worse scores than controls in the RME experimental score but no in the RME gender control task. Finally, on emotion regulation, PD and controls did not perform differently at TAS-20 and no specific differences were found on TAS-20 subscales. The PD impairments on emotion recognition and representation do not correlate with dopamine therapy, disease severity, or with the duration of illness. These results are independent from other cognitive processes, such as global cognitive status and executive function, or from psychiatric status, such as depression, anxiety or apathy.

CONCLUSIONS

These results may contribute to better understanding of the emotional problems that are often seen in patients with PD and the measures used to test these problems, in particular on the use of different versions of the RME task.

Social cognition and psychopathology: a critical overview

The philosophical and interdisciplinary debate about the nature of social cognition, and the processes involved, has important implications for psychiatry. On one account, mindreading depends on making theoretical inferences about another person's mental states based on knowledge of folk psychology, the so-called "theory theory" (TT). On a different account, "simulation theory" (ST), mindreading depends on simulating the other's mental states within one's own mental or motor system. A third approach, "interaction theory" (IT), looks to embodied processes (involving movement, gesture, facial expression, vocal intonation, etc.) and the dynamics of intersubjective interactions (joint attention, joint action, and processes not confined to an individual system) in highly contextualized situations to explain social cognition, and disruptions of these processes in some psychopathological conditions. In this paper, we present a brief summary of these three theoretical frameworks (TT, ST, IT). We then focus on impaired social abilities in autism and schizophrenia from the perspective of the three approaches. We discuss the limitations of such approaches in the scientific studies of these and other pathologies, and we close with a short reflection on the future of the field. In this regard we argue that, to the extent that TT, ST and IT offer explanations that capture different (limited) aspects of social cognition, a pluralist approach might be best.

Theory of mind and emotional functioning in fibromyalgia syndrome: an investigation of the relationship between social cognition and executive function

Background

Fibromyalgia (FM) is a syndrome primarily characterised by chronic, widespread musculoskeletal pain. In the aetiology of this syndrome a crucial role is played by complex interactions among biological, genetic, psychological, and socio-cultural factors. Recently, researchers have started to explore emotional functioning in FM, with their attention focused on alexithymia, a personality construct that affects the regulation of a person’s own emotions. On the other hand, the detection and experience of emotional signals from other people have only been sparsely investigated in FM syndrome and no studies have investigated the ability to represent other people’s mental states (i.e. Theory of Mind, ToM) in these patients. Here we present the first study investigating a large set of social-cognitive abilities, and the possible relationships between these abilities and the performance on executive-function tasks, in a homogenous sample of patients with FM.

Methodology

Forty women with FM and forty-one healthy women matched for education and age were involved in the study. Social cognition was assessed with a set of validated experimental tasks. Measures of executive function were used to test the correlations between this dimension and the social-cognitive profile of patients with FM. Relationships between social-cognitive abilities and demographic, clinical and psychological variables were also investigated.

Principal Findings

Patients with FM have impairments both in the regulation of their own affect and in the recognition of other’s emotions, as well as in representing other people’s mental states. No significant correlations were found between social cognition tasks and the subcomponents of the executive function that were analysed.

Conclusions

The results show the presence of several impairments in social cognition skills in patients with FM, which are largely independent of both executive function deficits and symptoms of psychological distress. The impairments reported highlight the importance of adequately assessing ToM and emotional functioning in clinical practice.

Theory of mind, empathy and neuropsychological functioning in X-linked spinal and bulbar muscular atrophy: a controlled study of 20 patients

Recent studies have described brain involvement, mainly at frontal level, in patients with spinal and bulbar muscular atrophy (SBMA), a rare adult-onset motor neuron disease caused by a CAG repeat in the androgen receptor (AR) gene. The aim of our research was to investigate the poorly characterized neuropsychological and psychological profile of these patients, on the basis of previous literature. We administered a neuropsychological screening and tests relating to cognitive and affective empathy, attributed to the theory of mind (ToM) framework, to 20 males with SBMA, and to age- and education-matched controls. Although patients' neuropsychological performance was unimpaired, a clear dissociation emerged between their cognitive and affective empathy. Patients had distinctive deficits in mentalizing, as assessed with the Faux Pas Test, whilst affective empathy (i.e., sharing experience), assessed with the Reading the Mind in the Eyes test, appeared to be preserved. The likely implications of subtle frontal lobe impairments on the one hand, and a protective influence of androgen insensitivity in these patients on the other, are discussed in the light of our results.

Neural correlates of the mini-SEA (Social cognition and Emotional Assessment) in behavioral variant frontotemporal dementia

Although Frontotemporal Dementia (FTD) is the second most common form of dementia after Alzheimer’s disease, its diagnosis remains particularly challenging today. This is particularly true for the behavioral variant (bvFTD), the most common phenotype of FTD, which is characterised by dramatic changes in personal and social conduct. Novel clinical cognitive tests have been recently proposed to diagnose and assess these patients. Among them, the mini-SEA (Social cognition & Emotional Assessment) has shown promising results. This quick clinical tool evaluates emotion recognition and theory of mind deficits, both recognized as hallmark features of bvFTD. In this study, we investigated the neural correlates of the mini-SEA in twenty bvFTD patients, using single photon emission computed tomography (SPECT) and focusing on the mPFC. Results showed that detection of faux pas during a theory of mind evaluation was related to rostral mPFC perfusion (BA 10) while recognition of emotion involved more dorsal regions within the mPFC (BA 9). As significant and early dysfunction of the mPFC has been extensively described in bvFTD, this study supports the use of the mini-SEA in evaluation and diagnosis purposes in bvFTD.

Conceptualizing neuropsychiatric diseases with multimodal data-driven meta-analyses - the case of behavioral variant frontotemporal dementia

INTRODUCTION

Uniform coordinate systems in neuroimaging research have enabled comprehensive systematic and quantitative meta-analyses. Such approaches are particularly relevant for neuropsychiatric diseases, the understanding of their symptoms, prediction and treatment. Behavioral variant frontotemporal dementia (bvFTD), a common neurodegenerative syndrome, is characterized by deep alterations in behavior and personality. Investigating this 'nexopathy' elucidates the healthy social and emotional brain.

METHODS

Here, we combine three multimodal meta-analyses approaches - anatomical and activation likelihood estimates and behavioral domain profiles - to identify neural correlates of bvFTD in 417 patients and 406 control subjects and to extract mental functions associated with this disease by meta-analyzing functional activation studies in the comprehensive probabilistic functional brain atlas of the BrainMap database.

RESULTS

The analyses identify the frontomedian cortex, basal ganglia, anterior insulae and thalamus as most relevant hubs, with a regional dissociation between atrophy and hypometabolism. Neural networks affected by bvFTD were associated with emotion and reward processing, empathy and executive functions (mainly inhibition), suggesting these functions as core domains affected by the disease and finally leading to its clinical symptoms. In contrast, changes in theory of mind or mentalizing abilities seem to be secondary phenomena of executive dysfunctions.

CONCLUSIONS

The study creates a novel conceptual framework to understand neuropsychiatric diseases by powerful data-driven meta-analytic approaches that shall be extended to the whole neuropsychiatric spectrum in the future.

Social influence on associative learning: double dissociation in high-functioning autism, early-stage behavioural variant frontotemporal dementia and Alzheimer's disease

INTRODUCTION

Most of our learning activity takes place in a social context. I examined how social interactions influence associative learning in neurodegenerative diseases and atypical neurodevelopmental conditions primarily characterised by social cognitive and memory dysfunctions.

METHODS

Participants were individuals with high-functioning autism (HFA, n = 18), early-stage behavioural variant frontotemporal dementia (bvFTD, n = 16) and Alzheimer's disease (AD, n = 20). The leading symptoms in HFA and bvFTD were social and behavioural dysfunctions, whereas AD was characterised by memory deficits. Participants received three versions of a paired associates learning task. In the game with boxes test, objects were hidden in six candy boxes placed in different locations on the computer screen. In the game with faces, each box was labelled by a photo of a person. In the real-life version of the game, participants played with real persons.

RESULTS

Individuals with HFA and bvFTD performed well in the computer games, but failed on the task including real persons. In contrast, in patients with early-stage AD, social interactions boosted paired associates learning up to the level of healthy control volunteers. Worse performance in the real life game was associated with less successful recognition of complex emotions and mental states in the Reading the Mind in the Eyes Test. Spatial span did not affect the results.

CONCLUSIONS

When social cognition is impaired, but memory systems are less compromised (HFA and bvFTD), real-life interactions disrupt associative learning; when disease process impairs memory systems but social cognition is relatively intact (early-stage AD), social interactions have a beneficial effect on learning and memory.

Frontotemporal lobar degeneration: current perspectives

The term frontotemporal lobar degeneration (FTLD) refers to a group of progressive brain diseases, which preferentially involve the frontal and temporal lobes. Depending on the primary site of atrophy, the clinical manifestation is dominated by behavior alterations or impairment of language. The onset of symptoms usually occurs before the age of 60 years, and the mean survival from diagnosis varies between 3 and 10 years. The prevalence is estimated at 15 per 100,000 in the population aged between 45 and 65 years, which is similar to the prevalence of Alzheimer's disease in this age group. There are two major clinical subtypes, behavioral-variant frontotemporal dementia and primary progressive aphasia. The neuropathology underlying the clinical syndromes is also heterogeneous. A common feature is the accumulation of certain neuronal proteins. Of these, the microtubule-associated protein tau (MAPT), the transactive response DNA-binding protein, and the fused in sarcoma protein are most important. Approximately 10% to 30% of FTLD shows an autosomal dominant pattern of inheritance, with mutations in the genes for MAPT, progranulin (GRN), and in the chromosome 9 open reading frame 72 (C9orf72) accounting for more than 80% of familial cases. Although significant advances have been made in recent years regarding diagnostic criteria, clinical assessment instruments, neuropsychological tests, cerebrospinal fluid biomarkers, and brain imaging techniques, the clinical diagnosis remains a challenge. To date, there is no specific pharmacological treatment for FTLD. Some evidence has been provided for serotonin reuptake inhibitors to reduce behavioral disturbances. No large-scale or high-quality studies have been conducted to determine the efficacy of non-pharmacological treatment approaches in FTLD. In view of the limited treatment options, caregiver education and support is currently the most important component of the clinical management.

Observation of social behavior in frontotemporal dementia

BACKGROUND

The most characteristic manifestations of behavioral variant frontotemporal dementia (bvFTD) are abnormalities in social behavior. However, distinguishing bvFTD based on social behavior can be difficult in structured clinical settings.

METHODS

Using a Social Observation Inventory, 10 patients with bvFTD and 10 patients with Alzheimer's disease (AD) were compared to their caregiver interlocutors on 1-hour mealtime, in-home videotaped segments.

RESULTS

Compared to caregivers and patients with AD, patients with bvFTD were significantly disturbed in social behavior. In contrast, patients with AD were indistinguishable from their caregivers. The lack of "you" comments and decreased tact and manners distinguished 92.6% of the patients with bvFTD from patients with AD and caregivers. The Social Observation Inventory scores correlated with scores on frontal-executive tests and socioemotional scales.

CONCLUSIONS

The systematic observation of social behavior during routine activities may be one of the best ways to distinguish patients with bvFTD from normal individuals and from patients with other dementias.

Clinical utility of short social cognitive tests in early differentiation of behavioral variant frontotemporal dementia from Alzheimer's disease

Background

Traditional cognitive tests used in clinical practice may not be sensitive enough for the early differentiation of behavioral variant frontotemporal dementia (bvFTD) from Alzheimer's disease (AD). A growing body of literature has shown that deficits in various aspects of social cognition can be found in bvFTD.

Aim

The objective of this study is to investigate whether short and easily administered tests of social cognition are useful in providing clinical information which might aid in the differentiation of bvFTD from AD in the early stages of bvFTD.

Methods

11 patients diagnosed with bvFTD and 10 patients diagnosed with AD completed a neuropsychological assessment comprising global, executive and social cognitive tasks.

Results

Measures of global cognitive function showed no significant difference between the two groups, whereas even the short social cognitive measures (the Reading the Mind in the Eyes Test and the Emotion Hexagon) showed significant group differences, reflecting a poorer performance by the bvFTD group.

Conclusion

Our results suggest that it may indeed be relevant to include short and easily administered measures of social cognition in the differential diagnosis of early bvFTD and AD.

Using memories to understand others: the role of episodic memory in theory of mind impairment in Alzheimer disease

Theory of mind (TOM) refers to the ability to infer one's own and other's mental states. Growing evidence highlighted the presence of impairment on the most complex TOM tasks in Alzheimer disease (AD). However, how TOM deficit is related to other cognitive dysfunctions and more specifically to episodic memory impairment - the prominent feature of this disease - is still under debate. Recent neuroanatomical findings have shown that remembering past events and inferring others' states of mind share the same cerebral network suggesting the two abilities share a common process .This paper proposes to review emergent evidence of TOM impairment in AD patients and to discuss the evidence of a relationship between TOM and episodic memory. We will discuss about AD patients' deficit in TOM being possibly related to their difficulties in recollecting memories of past social interactions.

Comparison of 2 diagnostic criteria for the behavioral variant of frontotemporal dementia

OBJECTIVES

The aim of this study was to compare the applicability of the 1998 consensus diagnostic criteria for the behavioral variant of frontotemporal dementia (bvFTD) with the recently proposed diagnostic criteria of the International bvFTD Criteria Consortium (FTDC).

METHODS

We reviewed each individual item in the 1998 and FTDC criteria in 30 patients with bvFTD followed in a memory clinic (including 2 with the C9orf72 gene repeat expansion).

RESULTS

All patients fulfilled the FTDC criteria (40% possible, 60% probable bvFTD) but only 66.7% fulfilled the 1998 criteria. One of the C9orf72 expansion carriers did not fulfill the 1998 criteria. This discordance was always due to the presence of exclusion features in the 1998 criteria, the most common being spatial disorientation and early severe amnesia.

CONCLUSION

The new FTDC criteria are less restrictive and hence more sensitive for the diagnosis of bvFTD.

Isolated theory of mind deficits and risk for frontotemporal dementia: a longitudinal pilot study

OBJECTIVE

Recent data suggest that theory of mind (ToM) deficits represent an early symptom of the behavioural variant of frontotemporal dementia (bvFTD). However, longitudinal data on the natural history of subjects presenting with isolated ToM deficits are lacking. The aim of the study was to verify if isolated ToM deficits represent an at-risk state for prefrontal dysfunction and bvFTD.

METHODS

A population of healthy subjects (n=4150, age range: 50-60 years) completed a clinical and neuropsychological evaluation including the Reading the Mind in the Eyes Test (RMET), a widely used ToM task. From this group, we recruited a low-RMET group (n=83) including subjects with RMET scores lower than 2 SDs but an otherwise normal neuropsychological evaluation and a control group. All subjects underwent evaluation at baseline and after 2 years.

RESULTS

Subjects in the low-RMET group showed decline in prefrontal functions at follow-up. Moreover, at follow-up 12 subjects in the low-RMET group presented with findings suggestive of bvFTD. Neuropsychological performance was stable in the control group.

CONCLUSIONS

Our data suggest that isolated ToM deficits could represent an at-risk situation for the development of future prefrontal dysfunction and bvFTD. ToM evaluation should be included in neuropsychological protocols aimed to evaluate the early phases of dementia.

Deficit of theory of mind after temporal lobe cerebral infarction

BACKGROUND

Previous studies have indicated that the temporal lobe is involved in theory of mind (ToM). However, little attention has been paid to ToM in patients with cerebral infarction. In this study, we investigated the ability of ToM in patients with temporal lobe cerebral infarction (TLCI) using a variety of tests.

METHODS

In the study, 19 patients with TLCI and 20 healthy controls (HC) were examined using the Recognition of faux pas and the Reading the Mind in the Eyes (RME) tasks, to assess their ability of ToM.

RESULTS

The results of the study indicated that the TLCI group performed significantly worse compared with the HC group as revealed in the total faux pas-related score and in emotion recognition (Mind Reading).

CONCLUSIONS

Our results implied that patients with TLCI had difficulty in ToM. Our data provided new evidence that the temporal lobe may be involved in processing ToM inferences.

Diagnosis and management of behavioral issues in frontotemporal dementia

Frontotemporal lobar degeneration is an umbrella term for several different disorders. In behavioral variant frontotemporal dementia (bvFTD), patients show deterioration in cognition and social behavior. New diagnostic criteria proposed by the International Behavioral Variant FTD Consortium provide greater sensitivity in diagnosing bvFTD. Current pharmacological management of symptoms relies on medications borrowed from treating Alzheimer's disease (AD) and psychiatric disorders. The evidence for using AD medications such as acetylcholinesterase inhibitors is questionable. Psychiatric medications can be helpful. Trazodone or SSRIs can have some efficacy in reducing disinhibition, repetitive behaviors, sexually inappropriate behaviors, and hyperorality. Small doses of atypical antipsychotics may be helpful in decreasing agitation and verbal outbursts. Nonpharmacological management includes caregiver education and support and behavioral interventions. While symptomatic treatments are likely to remain important behavior management tools, targeting the underlying pathology of bvFTD with disease-modifying agents will hopefully be the future of treatment.

Language, executive function and social cognition in the diagnosis of frontotemporal dementia syndromes

Frontotemporal dementia (FTD) represents a spectrum of non-Alzheimer's degenerative conditions associated with focal atrophy of the frontal and/or temporal lobes. Frontal and temporal regions of the brain have been shown to be strongly involved in executive function, social cognition and language processing and, thus, deficits in these domains are frequently seen in patients with FTD or may even be hallmarks of a specific FTD subtype (i.e. relatively selective and progressive language impairment in primary progressive aphasia). In this review we have attempted to delineate how language, executive function, and social cognition may contribute to the diagnosis of FTD syndromes, namely the behavioural variant FTD as well as the language variants of FTD including the three subtypes of primary progressive aphasia (PPA): non-fluent/agrammatic, semantic and logopenic. This review also addresses the extent to which deficits in these cognitive areas contribute to the differential diagnosis of FTD versus Alzheimer's disease (AD). Finally, early clinical determinants of pathology are briefly discussed and contemporary challenges to the diagnosis of FTD are presented.

Clinical diagnostic criteria and classification controversies in frontotemporal lobar degeneration

Frontotemporal lobar degeneration (FTLD) can manifest as a spectrum of clinical syndromes, ranging from behavioural impairment to language or motor dysfunction. Recently, revised diagnostic criteria have been proposed for the behavioural and progressive aphasia syndromes associated with frontotemporal degeneration. The present review will summarize these diagnostic guidelines and highlight some lingering controversies in the classification of FTLD clinical syndromes. We will discuss common tools and methods used to identify the insidious changes of behavioural variant frontotemporal dementia (bvFTD), the value of new, patient-based tasks of orbitofrontal function, and the issue of a benign or 'phenocopy' variant of bvFTD. With regard to primary progressive aphasia (PPA), we will discuss the scope of the semantic disorder in semantic-variant PPA, the nature of the speech disorder in non-fluent, agrammatic PPA, and the preliminary utility of a logopenic PPA classification.

Behavior matters--cognitive predictors of survival in amyotrophic lateral sclerosis

BACKGROUND

It is difficult to longitudinally characterize cognitive impairment in amyotrophic lateral sclerosis (ALS) due to motor deficits, and existing instruments aren't comparable with assessments in other dementias.

METHODS

The ALS Brief Cognitive Assessment (ALS-BCA) was validated in 70 subjects (37 with ALS) who also underwent detailed neuropsychological analysis. Cognitive predictors for poor survival were then analyzed in a longitudinal cohort of 171 ALS patients.

RESULTS

The ALS-BCA was highly sensitive (90%) and specific (85%) for ALS-dementia (ALS-D). ALS-D patients had shorter overall survival, primarily due to the poor survival among ALS-D patients with disinhibited or apathetic behaviors after adjusting for demographic variables, ALS site of onset, medications, and supportive measures. ALS-D without behavioral changes was not a predictor of poor survival.

CONCLUSION

ALS-D can present with or without prominent behavioral changes. Cognitive screening in ALS patients should focus on behavioral changes for prognosis, while non-behavioral cognitive impairments may impact quality of life without impacting survival.

Prospective evaluation of behavioral scales in the behavioral variant of frontotemporal dementia

BACKGROUND

The Neuropsychiatric Inventory (NPI) and the Frontal Behavioral Inventory (FBI) are widely used in patients with the behavioral variant of frontotemporal dementia (bvFTD). Yet, few data are available on the long-term relevance of these scales.

MATERIAL AND METHODS

Based on a bvFTD population that participated in the Memantine Clinical Trial (NCT00200538), we studied the evolution and correlation between scores obtained on behavioral scales (NPI and FBI), cognitive scales [Mini-Mental State Examination (MMSE) and Mattis Dementia Rating Scale (MDRS)] and a burden scale [Zarit Burden Inventory (ZBI)]. The assessments were performed at 1 year in 41 patients and at 2 years in 23 patients who agreed to participate in this open-label study.

RESULTS

The 2-year scores obtained on the FBI were significantly higher than the scores at inclusion while those obtained on the NPI did not change. There were significant correlations between the FBI, and the MDRS and MMSE, especially regarding the negative items. The ZBI correlated with behavioral scales at all stages for positive items.

CONCLUSIONS

This study based on a large population shows that the FBI is a better tool than the NPI for the long-term assessment of bvFTD patients. Moreover, the FBI allows a distinction to be made between behavioral disturbances that involve cognitive functions from those which have an important impact on caregiver burden.

The behavioral variant of frontotemporal dementia: linking neuropathology to social cognition

The behavioral variant of frontotemporal dementia (bvFTD) is one of the most frequent neurodegenerative disorders with a presenile onset. It is characterized by a long phase of subclinical behavioral changes and social conduct disorders, associated with a progressive modification of personality. Recently, an international consortium of experts developed revised guidelines for its clinical diagnosis, which highlight the supportive role of biomarkers in the diagnostic process. According to new criteria, bvFTD can be classified in "possible" (requiring three of six specific clinical features), "probable" (in the presence of functional disability and typical neuroimaging features), and "with definite frontotemporal lobar degeneration" (requiring the presence of a known causal mutation or a histopathological confirmation). Familial aggregation is frequently reported in bvFTD and frontotemporal lobar degeneration in general, with an autosomal dominant transmission in about 10 % cases. The aim of this paper is to review and discuss recent advances in the knowledge of clinical, neuropsychological, and imaging features of bvFTD. We also briefly summarize the available genetic information about the frontotemporal lobar degeneration spectrum.

My belief or yours? Differential theory of mind deficits in frontotemporal dementia and Alzheimer's disease

Theory of mind reasoning-the ability to understand someone else's mental states, such as beliefs, intentions and desires-is crucial in social interaction. It has been suggested that a theory of mind deficit may account for some of the abnormalities in interpersonal behaviour that characterize patients affected by behavioural variant frontotemporal dementia. However, there are conflicting reports as to whether understanding someone else's mind is a key difference between behavioural variant frontotemporal dementia and other neurodegenerative conditions such as Alzheimer's disease. Literature data on the relationship between theory of mind abilities and executive functions are also contradictory. These disparities may be due to underestimation of the fractionation within theory of mind components. A recent theoretical framework suggests that taking someone else's mental perspective requires two distinct processes: inferring someone else's belief and inhibiting one's own belief, with involvement of the temporoparietal and right frontal cortices, respectively. Therefore, we performed a neuropsychological and neuroimaging study to investigate the hypothesis whereby distinct cognitive deficits could impair theory of mind reasoning in patients with Alzheimer's disease and patients with behavioural variant frontotemporal dementia. We used a three-option false belief task to assess theory of mind components in 11 patients with behavioural variant frontotemporal dementia, 12 patients with Alzheimer's disease and 20 healthy elderly control subjects. The patients with behavioural variant frontotemporal dementia and those with Alzheimer's disease were matched for age, gender, education and global cognitive impairment. [(18)F]-fluorodeoxyglucose-positron emission tomography imaging was used to investigate neural correlates of theory of mind reasoning deficits. Performance in the three-option false belief task revealed differential impairments in the components of theory of mind reasoning; patients with Alzheimer's disease had a predominant deficit in inferring someone else's belief, whereas patients with behavioural variant frontotemporal dementia were selectively impaired in inhibiting their own mental perspective. Moreover, inhibiting one's own perspective was strongly correlated with inhibition in a Stroop task but not with other subprocesses of executive functions. This finding suggests that self-perspective inhibition may depend on cognitive processes that are not specific to the social domain. Last, the severity of the deficit in inferring someone else's beliefs correlated significantly over all subjects with hypometabolism in the left temporoparietal junction, whereas the severity of the deficit in self-perspective inhibition correlated significantly with hypometabolism in the right lateral prefrontal cortex. In conclusion, our findings provided clinical and imaging evidence to support differential deficits in two components of theory of mind reasoning (subserved by distinct brain regions) in patients with Alzheimer's disease and patients with behavioural variant frontotemporal dementia.

Sensitivity and specificity of ventromedial prefrontal cortex tests in behavioral variant frontotemporal dementia

BACKGROUND

Behavioral variant frontotemporal dementia (bvFTD) is characterized by early and substantial ventromedial prefrontal cortex (VMPFC) dysfunction. To date, however, there is no consensus regarding which tests are most sensitive and specific to assess VMPFC dysfunction in this condition.

METHODS

In this study we compared the sensitivity and specificity of four common VMPFC specific tests (Mini-SEA, Go/No-Go Subtest of the Frontal Assessment Battery, Reversal-Learning Test, and Iowa Gambling Task) at first clinic presentation in two neurodegenerative cohorts (bvFTD, Alzheimer's disease) and age-matched, healthy controls.

RESULTS

We found that the Mini-SEA, evaluating theory of mind and emotion processes, emerged as the most sensitive and specific of the VMPFC tests employed. The Mini-SEA alone successfully distinguished bvFTD and Alzheimer's disease (AD) in >82% of subjects at first presentation. Similarly, the FAB Go/No-Go and Reversal-Learning Tests also showed very good discrimination power, but to a lesser degree. The Iowa Gambling Task, one of the most common measures of VMPFC function, was the least specific of these tests.

CONCLUSION

Sensitivity to detect VMPFC dysfunction was high across all test employed, but specificity varied considerably. The Mini-SEA emerged as the most promising of the VMPFC-specific diagnostic tests. Clinicians should take into account the variable specificity of currently available VMPFC tests, which can complement current carer-based questionnaires and clinical evaluation to improve the diagnosis of behavioral dysfunctions due to VMPFC dysfunction.

Gray matter atrophy in behavioral variant frontotemporal dementia: a meta-analysis of voxel-based morphometry studies

BACKGROUND

Structural neuroimaging studies on behavioral variant frontotemporal dementia (bvFTD) using the voxel-based morphometry (VBM) method reported not entirely consistent findings.

METHODS

A systematic review of VBM studies of bvFTD patients and healthy controls (HC) published in PubMed and Embase databases from 2000 to June 2011 was conducted. Meta-analysis was performed using a newly improved voxel-based meta-analytic tool, namely, effect size signed differential mapping, to quantitatively explore the gray matter (GM) changes between bvFTD patients and HC subjects.

RESULTS

11 VBM studies involving 237 bvFTD patients and 297 HC subjects met the inclusion criteria. Considerable regional GM volume decrease was detected in the anterior medial frontal cortex (BA 9), extending to other frontal areas (BA 8, 10, 46, 24, 32), and other brain areas, such as the insula cortex, as well as the subcortical striatal regions in patients with bvFTD compared with HC subjects. The findings of the present study remain largely unchanged in the entire brain jackknife sensitivity analyses.

CONCLUSIONS

The present meta-analysis provides evidence of GM changes in the frontal-striatal-limbic brain areas in patients with bvFTD. Furthermore, GM atrophy in the fron-toinsular cortex and anterior cingulate cortex may be important anatomical changes for the diagnosis of patients with bvFTD.

The social brain in psychiatric and neurological disorders

Psychiatric and neurological disorders have historically provided key insights into the structure-function relationships that subserve human social cognition and behavior, informing the concept of the 'social brain'. In this review, we take stock of the current status of this concept, retaining a focus on disorders that impact social behavior. We discuss how the social brain, social cognition, and social behavior are interdependent, and emphasize the important role of development and compensation. We suggest that the social brain, and its dysfunction and recovery, must be understood not in terms of specific structures, but rather in terms of their interaction in large-scale networks.

Social Cognition and Emotional Assessment (SEA) is a marker of medial and orbital frontal functions: a voxel-based morphometry study in behavioral variant of frontotemporal degeneration

The aim of this study was to explore the cerebral correlates of functional deficits that occur in behavioral variant frontotemporal dementia (bvFTD). A specific neuropsychological battery, the Social cognition & Emotional Assessment (SEA; Funkiewiez et al., 2012), was used to assess impaired social and emotional functions in 20 bvFTD patients who also underwent structural MRI scanning. The SEA subscores of theory of mind, reversal-learning tests, facial emotion identification, and apathy evaluation were entered as covariates in a voxel-based morphometry analysis. The results revealed that the gray matter volume in the rostral part of the medial prefrontal cortex [mPFC, Brodmann area (BA) 10] was associated with scores on the theory of mind subtest, while gray matter volume within the orbitofrontal (OFC) and ventral mPFC (BA 11 and 47) was related to the scores observed in the reversal-learning subtest. Gray matter volume within BA 9 in the mPFC was correlated with scores on the emotion recognition subtest, and the severity of apathetic symptoms in the Apathy scale covaried with gray matter volume in the lateral PFC (BA 44/45). Among these regions, the mPFC and OFC cortices have been shown to be atrophied in the early stages of bvFTD. In addition, SEA and its abbreviated version (mini-SEA) have been demonstrated to be sensitive to early impairments in bvFTD (Bertoux et al., 2012). Taken together, these results suggest a differential involvement of orbital and medial prefrontal subregions in SEA subscores and support the use of the SEA to evaluate the integrity of these regions in the early stages of bvFTD.

Mentalising music in frontotemporal dementia

Despite considerable recent interest, the biological basis and clinical diagnosis of behavioural variant frontotemporal dementia (bvFTD) pose unresolved problems. Mentalising (the cognitive capacity to interpret the behaviour of oneself and others in terms of mental states) is impaired as a prominent feature of bvFTD, consistent with involvement of brain regions including ventro-medial prefrontal cortex (PFC), orbitofrontal cortex and anterior temporal lobes. Here, we investigated mentalising ability in a cohort of patients with bvFTD using a novel modality: music. We constructed a novel neuropsychological battery requiring attribution of affective mental or non-mental associations to musical stimuli. Mentalising performance of patients with bvFTD (n = 20) was assessed in relation to matched healthy control subjects (n = 20); patients also had a comprehensive assessment of behaviour and general neuropsychological functions. Neuroanatomical correlates of performance on the experimental tasks were investigated using voxel-based morphometry of patients' brain magnetic resonance imaging (MRI) scans. Compared to healthy control subjects, patients showed impaired ability to attribute mental states but not non-mental characteristics to music, and this deficit correlated with performance on a standard test of social inference and with carer ratings of patients' empathic capacity, but not with other potentially relevant measures of general neuropsychological function. Mentalising performance in the bvFTD group was associated with grey matter changes in anterior temporal lobe and ventro-medial PFC. These findings suggest that music can represent surrogate mental states and the ability to construct such mental representations is impaired in bvFTD, with potential implications for our understanding of the biology of bvFTD and human social cognition more broadly.