- Email: [email protected]
Emotional caricatures in frontotemporal dementia
c o r t e x x x x ( 2 0 1 5 ) 1 e3
Available online at www.sciencedirect.com
ScienceDirect Journal homepage: www.elsevier.com/locate/cortex
Clinical postcard
Emotional caricatures in frontotemporal dementia Camilla N. Clark and Jason D. Warren* Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom
Patients with frontotemporal lobar degeneration (FTLD) and in particular, the behavioural variant of frontotemporal dementia (bvFTD) develop diverse abnormalities of social and emotional behaviour that are generally characterised by loss of social skills and reduced empathy, as reflected in current consensus diagnostic criteria (Rascovsky et al., 2011). Typically, the patient with bvFTD is cold and self-absorbed; indeed, bvFTD has been regarded as a paradigm of sociopathy (Mendez & Shapira, 2009). Recently, we have been struck by several of our own patients with bvFTD who break this phenomenological mould by exhibiting excessive and inappropriate emotional responses directed towards other people. Four such cases are summarised in Table 1. From an early stage of their illness, these patients have shared a propensity to over-react to others' minor misfortunes by demonstrations of distress and unwonted attempts to comfort the victim (often barely known to the patient). In addition, they often exhibit effusive warmth towards family members (including repeated declarations of love and maudlin sentiment) that the recipients find odd and unwelcome. In each case, the patient otherwise fulfils criteria for an established, typical syndrome of probable bvFTD (Rascovsky et al., 2011) with no prior history of affective or other psychiatric disturbance. All cases have MRI evidence of relatively selective anterior temporal lobe atrophy, predominantly involving the right cerebral hemisphere (in the majority). The exaggerated emotional displays exhibited by our patients with bvFTD resemble ‘caricatures’ of normal emotional reactions. The valence of the response is more or less appropriate, but not its floridity (it is socially conventional to feel sympathy for an afflicted stranger, but not to embrace them or weep over their plight). While exaggerated emotional displays involving basic emotions such as surprise have been reported
in association with syndromes of FTLD (Snowden et al., 2001), such hyperemotionalism remains poorly characterised. Moreover, the patients we describe here exhibit an excess of complex, prosocial emotional behaviours: behaviours typically associated with empathy, warmth and altruism towards one's fellows, a dimension of inter-personal conduct that is considered largely absent in published case series of FTLD (Ahmed et al., 2015; Ikeda, Brown, Holland, Fukuhara, & Hodges, 2002; Snowden et al., 2001). We do not argue that the prosocial behaviours of our patients indicate retained social cognitive competence. On the contrary, these patients are no longer able to function in social contexts (partly on account of their excessive emotionalism) and exhibit many other hallmarks of social disintegration, such as faux pas, gluttony and loss of embarrassment. What can such cases tell us about the pathophysiology of bvFTD? Viewed alongside the typical syndromic pattern of hypoemotionality, blunted empathy and lack of awareness of others; the existence of hyperemotional caricatures suggests a dichotomisation of abnormal prosocial emotional behaviours within the bvFTD spectrum. We hypothesise that this apparent dichotomy signifies the erosion of neural templates for emotional behaviours (see Fig. 1). A candidate brain substrate has been identified in the distributed fronto-insular, anterior temporal and subcortical circuitry that links social concepts and representations with reward, cognitive evaluation and behavioural responses (Green et al., 2013; Sturm et al., 2015). A model neural architecture has previously been proposed to underpin the ‘simplified’ semantic classification responses exhibited by patients with semantic dementia (Lambon Ralph, Sage, Jones, & Mayberry, 2010). Our bedside observation raises a number of unresolved questions. To what extent are such behaviours truly dichotomous rather than bivalent extremes on a behavioural continuum? Does the primary fault lie with the representation of
* Corresponding author. Dementia Research Centre, UCL Institute of Neurology, University College London, 8 e 11 Queen Square, London WC1N 3BG, United Kingdom. E-mail address: [email protected] (J.D. Warren). http://dx.doi.org/10.1016/j.cortex.2015.07.026 0010-9452/© 2015 Elsevier Ltd. All rights reserved. Please cite this article in press as: Clark, C. N., & Warren, J. D., Emotional caricatures in frontotemporal dementia, Cortex (2015), http:// dx.doi.org/10.1016/j.cortex.2015.07.026
2
Behavioural domain
Bivalent alteration
Expression of prosocial emotions
Hyperemotionality
Est. freq (% cases) ~10
Case series Present (Case 1)
Present (Case 2) Present (Case 3)
Present (Case 4)
Ahmed et al., 2015 Humour Music Eating Sexual interest Pain awareness
Hypoemotionality Increased mirth Decreased mirth Musicophilia Music aversion Hyperphagia Food aversion Hypersexuality Hyposexuality Increased tolerance Decreased tolerance
~70 ~50 ~40 ~40 ~40 ~60 ~30 ~10 ~80 ~40 ~20
Clark et al., 2015 Fletcher et al., 2015 Ikeda et al., 2002 Ahmed et al., 2015 Snowden et al., 2001 Fletcher et al., 2014
Behavioural features
Anatomical associations
65 year old woman, MAPT mutation, hx 20 years: hugs caregiver excessively, inappropriate expressions of consolation, becomes enraged on seeing children hurt on TV, attempts to hug strangers 68 year old woman, hx 8 years: cries on seeing photos of grandchildren or saying goodbye on weekly visits 70 year old woman, hx 11 years: early exaggerated sympathy, tears in response to others' trivial misfortunes (e.g., lost pen), hugs other patients unknown to her and expresses concern 74 year old man, hx 13 years: inconsolable expressions of grief at funeral of a distant relative, regularly cries when recounting how he met his wife and to music, repeatedly tells his wife he loves her Increased liking to receive affection Reduced empathy, affection to others Inappropriate laughter, jocularity Reduced reactions to comedy Music craving, seeking, obsession with a specific repertoire of pieces Dislike, active avoidance of music (with or without other sounds) Increased appetite, gluttony, binge eating Reduced appetite, increased reports of satiety Increased or unusual sexual interest Loss or interest in/responsiveness to partner Reduced complaint, withdrawal responses to painful stimuli Exaggerated responses, complaints about trivial stimuli
Bilat ant TL atrophy
R > L ant TL atrophy L > R ant TL atrophy
R FL, TL atrophy
Uncertain Ant TL, mPFC* Uncertain Hippocampus Ant TL, insula OFC, insula* Uncertain Uncertain Insula, thalamus
c o r t e x x x x ( 2 0 1 5 ) 1 e3
Please cite this article in press as: Clark, C. N., & Warren, J. D., Emotional caricatures in frontotemporal dementia, Cortex (2015), http:// dx.doi.org/10.1016/j.cortex.2015.07.026
Table 1 e Examples of bivalent behaviours and their clinical and neuroanatomical associations reported in patients with bvFTD. *established in other work; ant TL, anterior temporal lobe; Bilat, bilateral; FL, frontal lobe; hx, history; L, left; MAPT, microtubule-associated protein tau; mPFC, medial prefrontal cortex; OFC, orbitofrontal cortex; R, right.
3
c o r t e x x x x ( 2 0 1 5 ) 1 e3
diseases (Ahmed et al., 2015; Fletcher et al., 2014; Ikeda et al., 2002; Lambon Ralph et al., 2010; Snowden et al., 2001, 2015; Table 1, Fig. 1).
Acknowledgments
Fig. 1 e A schematic substrate for bivalent behaviours in frontotemporal dementia and other neurodegenerative syndromes. The scheme we propose is a generalisation of the architecture proposed for semantic concept disintegration by Lambon Ralph et al. (2010). According to this scheme, stored neural templates are normally used to match representations of the sensory and social environment to output behavioural routines (left). A ‘template’ constitutes a specific pattern of activation within a neural network (here rendered as a grid of circles) that links representations of sensory data with output behaviours or experienced sensations (filled circles). The configuration of the template (linked red circles) determines the fidelity of the template matching algorithm. Neurodegenerative pathologies promote network disintegration, leading to eroded (simplified or ‘bevelled’) template boundaries. This in turn both limits template activation in response to appropriate sensory representations and allows loose or inappropriate matches to be achieved at a given intensity of sensory input or behavioural set (represented by black circles). In terms of output emotional behaviour, this could manifest as hypoemotionality in response to an adequate stimulus, exaggerated emotionality in response to a trivial stimulus or a mixture of these.
emotional signals per se, with the ‘gain’ of the behavioural response or with the linkage between them? Can behaviours be renormalised by manipulating external cues or behavioural set (see Fig. 1)? Are the behavioural routines ‘phoney’ or are they accompanied by the physiological markers of real emotions? There are a number of ways in which these questions might be addressed in experimental work. If the primary problem lies with sensory input processing, it may be possible to demonstrate a behavioural threshold by altering signal characteristics. If the primary problem is behavioural response gain, that might be reflected in a dissociation of emotional actions from physiological (autonomic) effector responses. If matching of sensory inputs to output behaviours is faulty, it should be possible to effect transitions between hypo- and hyper-emotional states in individual patients (as hinted already by bedside experience). We hope our observations will inspire further interest in the phenomenology and brain substrates for hyperhypoemotionalism and related, apparently paradoxical, bivalent phenomena in FTLD and other neurodegenerative
The Dementia Research Centre is supported by Alzheimer's Research UK, the Brain Research Trust and the Wolfson Foundation. This work was funded by the Wellcome Trust, the UK Medical Research Council and the NIHR Queen Square Dementia Biomedical Research Unit (Grant CBRC 161). JDW is supported by a Wellcome Trust Senior Clinical Fellowship (Grant No 091673/Z/10/Z).
references
Ahmed, R. M., Kaizik, C., Irish, M., Mioshi, E., Dermody, N., Kiernan, M. C., et al. (2015). Characterizing sexual behavior in frontotemporal dementia. Journal of Alzheimers Disease. Apr 2. (Epub ahead of print). Clark, C. N., Nicholas, J. M., Gordon, E., Golden, H. L., Cohen, M. H., Woodward, F., et al. (2015). Altered sense of humour in dementia. Journal of Alzheimer's Disease (in press). Fletcher, P. D., Downey, L. E., Golden, H. L., Clark, C. N., Slattery, C. F., Paterson, R. W., et al. (2015). Auditory hedonic phenotypes in dementia: a behavioural and neuroanatomical analysis. Cortex, 67, 95e105. Fletcher, P. D., Downey, L. E., Golden, H. L., Fox, N. C., Rossor, M. N., & Warren, J. D. (2014). Altered pain and temperature processing in frontotemporal lobar degeneration (abstract) American Journal of Neurodegenerative Disease, 3(Suppl. 1), 1e375. Green, S., Lambon Ralph, M. A., Moll, J., Zakrzewski, J., Deakin, J. F., Grafman, J., et al. (2013). The neural basis of conceptual-emotional integration and its role in major depressive disorder. Society for Neuroscience, 8, 417e433. Ikeda, M., Brown, J., Holland, A. J., Fukuhara, R., & Hodges, J. R. (2002). Changes in appetite, food preference, and eating habits in frontotemporal dementia and Alzheimer's disease. Journal of Neurology, Neurosurgery & Psychiatry, 73, 371e376. Lambon Ralph, M. A., Sage, K., Jones, R. W., & Mayberry, E. J. (2010). Coherent concepts are computed in the anterior temporal lobes. Proceedings of the National Academy of Sciences of the United States of America, 107, 2717e2722. Mendez, M. F., & Shapira, J. S. (2009). Altered emotional morality in frontotemporal dementia. Cognitive Neuropsychiatry, 14, 165e179. Rascovsky, K., Hodges, J. R., Knopman, D., Mendez, M. F., Kramer, J. H., Neuhaus, J., et al. (2011). Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia. Brain, 134, 2456e2477. Snowden, J. S., Bathgate, D., Varma, A., Blackshaw, A., Gibbons, Z. C., & Neary, D. (2001). Distinct behavioural profiles in frontotemporal dementia and semantic dementia. Journal of Neurology, Neurosurgery & Psychiatry, 70, 323e332. Sturm, V. E., Yokoyama, J. S., Eckart, J. A., Zakrzewski, J., Rosen, H. J., Miller, B. L., et al. (2015). Damage to left frontal regulatory circuits produces greater positive emotional reactivity in frontotemporal dementia. Cortex, 64, 55e67.
Received 3 June Reviewed 5 June Revised 6 July Accepted 15 July
2015 2015 2015 2015
Please cite this article in press as: Clark, C. N., & Warren, J. D., Emotional caricatures in frontotemporal dementia, Cortex (2015), http:// dx.doi.org/10.1016/j.cortex.2015.07.026
Available online at www.sciencedirect.com
ScienceDirect Journal homepage: www.elsevier.com/locate/cortex
Clinical postcard
Emotional caricatures in frontotemporal dementia Camilla N. Clark and Jason D. Warren* Dementia Research Centre, UCL Institute of Neurology, University College London, London, United Kingdom
Patients with frontotemporal lobar degeneration (FTLD) and in particular, the behavioural variant of frontotemporal dementia (bvFTD) develop diverse abnormalities of social and emotional behaviour that are generally characterised by loss of social skills and reduced empathy, as reflected in current consensus diagnostic criteria (Rascovsky et al., 2011). Typically, the patient with bvFTD is cold and self-absorbed; indeed, bvFTD has been regarded as a paradigm of sociopathy (Mendez & Shapira, 2009). Recently, we have been struck by several of our own patients with bvFTD who break this phenomenological mould by exhibiting excessive and inappropriate emotional responses directed towards other people. Four such cases are summarised in Table 1. From an early stage of their illness, these patients have shared a propensity to over-react to others' minor misfortunes by demonstrations of distress and unwonted attempts to comfort the victim (often barely known to the patient). In addition, they often exhibit effusive warmth towards family members (including repeated declarations of love and maudlin sentiment) that the recipients find odd and unwelcome. In each case, the patient otherwise fulfils criteria for an established, typical syndrome of probable bvFTD (Rascovsky et al., 2011) with no prior history of affective or other psychiatric disturbance. All cases have MRI evidence of relatively selective anterior temporal lobe atrophy, predominantly involving the right cerebral hemisphere (in the majority). The exaggerated emotional displays exhibited by our patients with bvFTD resemble ‘caricatures’ of normal emotional reactions. The valence of the response is more or less appropriate, but not its floridity (it is socially conventional to feel sympathy for an afflicted stranger, but not to embrace them or weep over their plight). While exaggerated emotional displays involving basic emotions such as surprise have been reported
in association with syndromes of FTLD (Snowden et al., 2001), such hyperemotionalism remains poorly characterised. Moreover, the patients we describe here exhibit an excess of complex, prosocial emotional behaviours: behaviours typically associated with empathy, warmth and altruism towards one's fellows, a dimension of inter-personal conduct that is considered largely absent in published case series of FTLD (Ahmed et al., 2015; Ikeda, Brown, Holland, Fukuhara, & Hodges, 2002; Snowden et al., 2001). We do not argue that the prosocial behaviours of our patients indicate retained social cognitive competence. On the contrary, these patients are no longer able to function in social contexts (partly on account of their excessive emotionalism) and exhibit many other hallmarks of social disintegration, such as faux pas, gluttony and loss of embarrassment. What can such cases tell us about the pathophysiology of bvFTD? Viewed alongside the typical syndromic pattern of hypoemotionality, blunted empathy and lack of awareness of others; the existence of hyperemotional caricatures suggests a dichotomisation of abnormal prosocial emotional behaviours within the bvFTD spectrum. We hypothesise that this apparent dichotomy signifies the erosion of neural templates for emotional behaviours (see Fig. 1). A candidate brain substrate has been identified in the distributed fronto-insular, anterior temporal and subcortical circuitry that links social concepts and representations with reward, cognitive evaluation and behavioural responses (Green et al., 2013; Sturm et al., 2015). A model neural architecture has previously been proposed to underpin the ‘simplified’ semantic classification responses exhibited by patients with semantic dementia (Lambon Ralph, Sage, Jones, & Mayberry, 2010). Our bedside observation raises a number of unresolved questions. To what extent are such behaviours truly dichotomous rather than bivalent extremes on a behavioural continuum? Does the primary fault lie with the representation of
* Corresponding author. Dementia Research Centre, UCL Institute of Neurology, University College London, 8 e 11 Queen Square, London WC1N 3BG, United Kingdom. E-mail address: [email protected] (J.D. Warren). http://dx.doi.org/10.1016/j.cortex.2015.07.026 0010-9452/© 2015 Elsevier Ltd. All rights reserved. Please cite this article in press as: Clark, C. N., & Warren, J. D., Emotional caricatures in frontotemporal dementia, Cortex (2015), http:// dx.doi.org/10.1016/j.cortex.2015.07.026
2
Behavioural domain
Bivalent alteration
Expression of prosocial emotions
Hyperemotionality
Est. freq (% cases) ~10
Case series Present (Case 1)
Present (Case 2) Present (Case 3)
Present (Case 4)
Ahmed et al., 2015 Humour Music Eating Sexual interest Pain awareness
Hypoemotionality Increased mirth Decreased mirth Musicophilia Music aversion Hyperphagia Food aversion Hypersexuality Hyposexuality Increased tolerance Decreased tolerance
~70 ~50 ~40 ~40 ~40 ~60 ~30 ~10 ~80 ~40 ~20
Clark et al., 2015 Fletcher et al., 2015 Ikeda et al., 2002 Ahmed et al., 2015 Snowden et al., 2001 Fletcher et al., 2014
Behavioural features
Anatomical associations
65 year old woman, MAPT mutation, hx 20 years: hugs caregiver excessively, inappropriate expressions of consolation, becomes enraged on seeing children hurt on TV, attempts to hug strangers 68 year old woman, hx 8 years: cries on seeing photos of grandchildren or saying goodbye on weekly visits 70 year old woman, hx 11 years: early exaggerated sympathy, tears in response to others' trivial misfortunes (e.g., lost pen), hugs other patients unknown to her and expresses concern 74 year old man, hx 13 years: inconsolable expressions of grief at funeral of a distant relative, regularly cries when recounting how he met his wife and to music, repeatedly tells his wife he loves her Increased liking to receive affection Reduced empathy, affection to others Inappropriate laughter, jocularity Reduced reactions to comedy Music craving, seeking, obsession with a specific repertoire of pieces Dislike, active avoidance of music (with or without other sounds) Increased appetite, gluttony, binge eating Reduced appetite, increased reports of satiety Increased or unusual sexual interest Loss or interest in/responsiveness to partner Reduced complaint, withdrawal responses to painful stimuli Exaggerated responses, complaints about trivial stimuli
Bilat ant TL atrophy
R > L ant TL atrophy L > R ant TL atrophy
R FL, TL atrophy
Uncertain Ant TL, mPFC* Uncertain Hippocampus Ant TL, insula OFC, insula* Uncertain Uncertain Insula, thalamus
c o r t e x x x x ( 2 0 1 5 ) 1 e3
Please cite this article in press as: Clark, C. N., & Warren, J. D., Emotional caricatures in frontotemporal dementia, Cortex (2015), http:// dx.doi.org/10.1016/j.cortex.2015.07.026
Table 1 e Examples of bivalent behaviours and their clinical and neuroanatomical associations reported in patients with bvFTD. *established in other work; ant TL, anterior temporal lobe; Bilat, bilateral; FL, frontal lobe; hx, history; L, left; MAPT, microtubule-associated protein tau; mPFC, medial prefrontal cortex; OFC, orbitofrontal cortex; R, right.
3
c o r t e x x x x ( 2 0 1 5 ) 1 e3
diseases (Ahmed et al., 2015; Fletcher et al., 2014; Ikeda et al., 2002; Lambon Ralph et al., 2010; Snowden et al., 2001, 2015; Table 1, Fig. 1).
Acknowledgments
Fig. 1 e A schematic substrate for bivalent behaviours in frontotemporal dementia and other neurodegenerative syndromes. The scheme we propose is a generalisation of the architecture proposed for semantic concept disintegration by Lambon Ralph et al. (2010). According to this scheme, stored neural templates are normally used to match representations of the sensory and social environment to output behavioural routines (left). A ‘template’ constitutes a specific pattern of activation within a neural network (here rendered as a grid of circles) that links representations of sensory data with output behaviours or experienced sensations (filled circles). The configuration of the template (linked red circles) determines the fidelity of the template matching algorithm. Neurodegenerative pathologies promote network disintegration, leading to eroded (simplified or ‘bevelled’) template boundaries. This in turn both limits template activation in response to appropriate sensory representations and allows loose or inappropriate matches to be achieved at a given intensity of sensory input or behavioural set (represented by black circles). In terms of output emotional behaviour, this could manifest as hypoemotionality in response to an adequate stimulus, exaggerated emotionality in response to a trivial stimulus or a mixture of these.
emotional signals per se, with the ‘gain’ of the behavioural response or with the linkage between them? Can behaviours be renormalised by manipulating external cues or behavioural set (see Fig. 1)? Are the behavioural routines ‘phoney’ or are they accompanied by the physiological markers of real emotions? There are a number of ways in which these questions might be addressed in experimental work. If the primary problem lies with sensory input processing, it may be possible to demonstrate a behavioural threshold by altering signal characteristics. If the primary problem is behavioural response gain, that might be reflected in a dissociation of emotional actions from physiological (autonomic) effector responses. If matching of sensory inputs to output behaviours is faulty, it should be possible to effect transitions between hypo- and hyper-emotional states in individual patients (as hinted already by bedside experience). We hope our observations will inspire further interest in the phenomenology and brain substrates for hyperhypoemotionalism and related, apparently paradoxical, bivalent phenomena in FTLD and other neurodegenerative
The Dementia Research Centre is supported by Alzheimer's Research UK, the Brain Research Trust and the Wolfson Foundation. This work was funded by the Wellcome Trust, the UK Medical Research Council and the NIHR Queen Square Dementia Biomedical Research Unit (Grant CBRC 161). JDW is supported by a Wellcome Trust Senior Clinical Fellowship (Grant No 091673/Z/10/Z).
references
Ahmed, R. M., Kaizik, C., Irish, M., Mioshi, E., Dermody, N., Kiernan, M. C., et al. (2015). Characterizing sexual behavior in frontotemporal dementia. Journal of Alzheimers Disease. Apr 2. (Epub ahead of print). Clark, C. N., Nicholas, J. M., Gordon, E., Golden, H. L., Cohen, M. H., Woodward, F., et al. (2015). Altered sense of humour in dementia. Journal of Alzheimer's Disease (in press). Fletcher, P. D., Downey, L. E., Golden, H. L., Clark, C. N., Slattery, C. F., Paterson, R. W., et al. (2015). Auditory hedonic phenotypes in dementia: a behavioural and neuroanatomical analysis. Cortex, 67, 95e105. Fletcher, P. D., Downey, L. E., Golden, H. L., Fox, N. C., Rossor, M. N., & Warren, J. D. (2014). Altered pain and temperature processing in frontotemporal lobar degeneration (abstract) American Journal of Neurodegenerative Disease, 3(Suppl. 1), 1e375. Green, S., Lambon Ralph, M. A., Moll, J., Zakrzewski, J., Deakin, J. F., Grafman, J., et al. (2013). The neural basis of conceptual-emotional integration and its role in major depressive disorder. Society for Neuroscience, 8, 417e433. Ikeda, M., Brown, J., Holland, A. J., Fukuhara, R., & Hodges, J. R. (2002). Changes in appetite, food preference, and eating habits in frontotemporal dementia and Alzheimer's disease. Journal of Neurology, Neurosurgery & Psychiatry, 73, 371e376. Lambon Ralph, M. A., Sage, K., Jones, R. W., & Mayberry, E. J. (2010). Coherent concepts are computed in the anterior temporal lobes. Proceedings of the National Academy of Sciences of the United States of America, 107, 2717e2722. Mendez, M. F., & Shapira, J. S. (2009). Altered emotional morality in frontotemporal dementia. Cognitive Neuropsychiatry, 14, 165e179. Rascovsky, K., Hodges, J. R., Knopman, D., Mendez, M. F., Kramer, J. H., Neuhaus, J., et al. (2011). Sensitivity of revised diagnostic criteria for the behavioural variant of frontotemporal dementia. Brain, 134, 2456e2477. Snowden, J. S., Bathgate, D., Varma, A., Blackshaw, A., Gibbons, Z. C., & Neary, D. (2001). Distinct behavioural profiles in frontotemporal dementia and semantic dementia. Journal of Neurology, Neurosurgery & Psychiatry, 70, 323e332. Sturm, V. E., Yokoyama, J. S., Eckart, J. A., Zakrzewski, J., Rosen, H. J., Miller, B. L., et al. (2015). Damage to left frontal regulatory circuits produces greater positive emotional reactivity in frontotemporal dementia. Cortex, 64, 55e67.
Received 3 June Reviewed 5 June Revised 6 July Accepted 15 July
2015 2015 2015 2015
Please cite this article in press as: Clark, C. N., & Warren, J. D., Emotional caricatures in frontotemporal dementia, Cortex (2015), http:// dx.doi.org/10.1016/j.cortex.2015.07.026