Social reasoning, emotion and empathy in frontotemporal dementia.

INTRODUCTION: Social cognition is crucial for human interaction, and is markedly impaired in the frontal variant of frontotemporal dementia (fvFTD). The relationship of various aspects of social functioning, however, remains controversial in this group. METHODS: Patients with fvFTD (n = 18), and matched controls (n = 13), were tested using tasks designed to assess their Theory of Mind (ToM), moral reasoning, emotion recognition and executive function. Caregivers documented changes in empathy compared to premorbid functioning. RESULTS: We found marked impairments in the abilities of fvFTD patients, relative to controls, in ability to mentalise (ToM), which was evident on a cartoon test, but not on a story-based ToM task. Knowledge of social rules was intact, but moral reasoning was defective, and was due, in part, to an inability to rate the seriousness of moral and conventional transgressions appropriately. Executive function was impaired in this group, and compromised aspects of moral reasoning, but ToM performance was independent of this. Emotion recognition was globally impaired in fvFTD, but was particularly so for anger and disgust which may partly explain the difficulty these patients have with identifying social violations. Empathy, as rated by carers, was also shown to be abnormal. CONCLUSION: It appears that social reasoning is disrupted in a number of ways in fvFTD, and the findings provide a basis for the understanding and further study of abnormal behaviour in this disease. The results are discussed in light of neuroimaging findings in studies of social cognition and the locus of pathology in fvFTD.

Measuring and modifying abnormal social cognition in frontal variant frontotemporal dementia.

We describe a 57-year-old man (MW) with frontal variant frontotemporal dementia (fv-FTD) who presented with a long history of drinking problem and marital disharmony followed by gradual changes in personality with disinhibition, stereotypic checking, overeating and a decline in self-care. Structural MRI imaging confirmed marked frontal atrophy involving particularly the ventromedial region. Performance on standard tests of frontal executive function was largely unremarkable and MW obtained a perfect score on the Mini-Mental State Examination (MMSE). In contrast, an experimental battery of tasks designed to evaluate theory of mind (ToM) revealed marked deficits. MW's challenging and disruptive behaviours, notably obsessive checking of car suspension by rocking, and wandering, responded to behavioural modification regimes adapted from the neurorehabilitation literature. In conclusion, deficits in ToM may underline the gross abnormalities in social conduct, which characterise fv-FTD; ToM appears to dissociate from frontal executive function; and behavioural modification approaches can be of benefit in this disorder.

Theory of mind in patients with frontal variant frontotemporal dementia and Alzheimer's disease: theoretical and practical implications.

A key aspect of social cognition is the ability to infer other people's mental states, thoughts and feelings; referred to as 'theory of mind' (ToM). We tested the hypothesis that the changes in personality and behaviour seen in frontal variant frontotemporal dementia (fvFTD) may reflect impairment in this cognitive domain. Tests of ToM, executive and general neuropsychological ability were given to 19 fvFTD patients, a comparison group of Alzheimer's disease patients (n = 12) and matched healthy controls (n = 16). Neuropsychiatric assessment was undertaken using the Neuropsychiatric Inventory (NPI). Patients with fvFTD were impaired on all tests of ToM (first-order false belief; second-order false belief; faux pas detection; and Reading the Mind in the Eyes), but had no difficulty with control questions designed to test general comprehension and memory. By contrast, the Alzheimer's disease group failed only one ToM task (second-order false belief), which places heavy demands on working memory. Performance on the faux pas test revealed a double dissociation, with the fvFTD group showing deficits on ToM-based questions and the Alzheimer's disease group failing memory-based questions only. Rank order of the fvFTD patients according to the magnitude of impairment on tests of ToM and their degree of frontal atrophy showed a striking concordance between ToM performances and ventromedial frontal damage. There was a significant correlation between the NPI score and more sophisticated tests of ToM in the fvFTD group. This study supports the hypothesis that patients with fvFTD, but not those with Alzheimer's disease, are impaired on tests of ToM, and may explain some of the abnormalities in interpersonal behaviour that characterize fvFTD.