Reviews and perspectivesTheory of mind ability in the behavioural variant of frontotemporal dementia: An analysis of the neural, cognitive, and social levels
Introduction
The present work reviews convergent evidence on the ability to attribute mental states to one's self and to others (i.e., theory of mind, ToM) in patients affected by the behavioural variant of frontotemporal dementia (bv-FTD). In the early stages of this neurodegenerative disease, patients typically manifest behavioural and psychiatric problems. According to a recent proposal, the social and behavioural problems of these patients can be considered as being linked to a deficit in the domain of social cognition (Gregory et al., 2002, Kipps and Hodges, 2006, Lough and Hodges, 2002, Lough et al., 2001, Lough et al., 2006, Snowden et al., 2003). Based on this suggestion, herein we hypothesise that the neuropsychiatric profile of bv-FTD patients is associated, at least partially, with a specific deficit in the ToM ability.
The following sections illustrate the usefulness of a social cognitive neuroscience approach that takes into due account the neural, cognitive, and social levels of analysis in the study of bv-FTD. Indeed, in the early stages of bv-FTD, it is possible to observe various signs and symptoms that pertain to these different domains (e.g., neural atrophy in the frontal lobes, personality changes and breakdown in social conduct), and their combination must be carefully weighed by clinicians when making a diagnosis. We support the view that the examination of these equally important levels can provide a more in-depth perspective on bv-FTD. In keeping with this, we examined neuroimaging data on the neural correlates of ToM ability, the studies investigating the progressive cerebral atrophy in patients with bv-FTD, and all of the studies investigating the ToM domain in these patients.
Section snippets
Anterior medial frontal cortex and theory of mind
In the last decade, there has been growing interest in the neural correlates of social cognition, defined as the ability to construct mental representations of the relations that exist between one's self and others and to flexibly use these representations to function effectively in the social environment (Adolphs, 2001, Adolphs, 2003). Social cognition is a sum of different processes and depends on the exchange of specific signals such as facial expression, body movement, and eye gaze (Frith &
Anterior medial frontal cortex and the behavioural variant of frontotemporal dementia
Frontotemporal dementia (FTD) is the currently preferred term to describe non-Alzheimer type dementia affecting the frontal and/or temporal lobes (Brun et al., 1994, Hodges and Miller, 2001a, Hodges and Miller, 2001b, Knibb et al., 2006, Neary et al., 1988). FTD exists in three variants characterised by three prototypical neurobehavioural syndromes and associated with characteristic patterns of cerebral atrophy (Lindberg et al., 2009, Schroeter et al., 2007): (1) Progressive non-fluent aphasia
Theory of mind in the behavioural variant of frontotemporal dementia
In recent years, it has been proposed that the personality changes and breakdown in social conduct frequently seen in bv-FTD may be at least partially explained by impairment in the ToM domain (Gregory et al., 2002, Kipps and Hodges, 2006). We take this view herein by considering it to be a productive way to examine the typical behavioural problems of bv-FTD patients and we review all of the studies investigating ToM ability in these patients.
The investigation of ToM ability in bv-FTD patients
Discussion
The bv-FTD domain represents a particular challenge for researchers and clinicians, due to the absence of universally accepted biological markers (Robillard, 2007), its insidious onset, and ambiguous clinical features, which frequently render precise diagnosis difficult (Gregory et al., 2002, Lough and Hodges, 2002, McMurtray et al., 2006). A better comprehension of this clinical condition can be achieved by considering the neural, cognitive, and social levels as equally important and
Conclusions
The main aim of our paper was to consider the specific contribution of ToM deficits in the clinical presentation of bv-FTD, by analysing the relevant evidence that comes from neuroimaging, neuropsychological and ToM studies. We thus did not aim at highlighting that ToM problems explain all of the clinical features of bv-FTD, but more modestly we aimed at providing convergent and substantive evidence that ToM deficits invariably characterise this condition. Based on a social cognitive
Acknowledgments
This work was supported by Regione Piemonte (Bando regionale per la ricerca scientifica 2004, cod. A239) and by University of Turin (Ricerca scientifica finanziata dell’Università 2008 ‘Correlati cognitivi e neurali della cognizione sociale’). The work was published despite the effects of the Italian law 133/08 that drastically reduces founds to public Italian universities (see the article “Cut-throat savings”, Nature, 455, 16 October 2008, //www.nature.com/nature/journal/v455/n7215/full/455835b.html
References (122)
- et al.
Do triangles play tricks? Attribution of mental states to animated shapes in normal and abnormal development
Cognitive Development
(2000) The neurobiology of social cognition
Current Opinion in Neurobiology
(2001)Investigating the cognitive neuroscience of social behaviour
Neuropsychologia
(2003)- et al.
Social perception from visual cues: Role of the STS region
Trends in Cognitive Sciences
(2000) - et al.
Domain-specificity and theory of mind: Evaluating neuropsychological evidence
Trends in Cognitive Sciences
(2005) - et al.
Atrophy rates of the cingulate gyrus and hippocampus in AD and FTLD
Neurobiology of Aging
(2007) - et al.
Does the autistic child have a ‘theory of mind’?
Cognition
(1985) - et al.
How the brain understands intention: Different neural circuits identify the componential features of motor and prior intentions
Consciousness and Cognition
(2006) - et al.
Insensitivity to future consequences following damage to human prefrontal cortex
Cognition
(1994) - et al.
Two reasons to abandon the false belief task as a test of theory of mind
Cognition
(2000)