Frontotemporal dementia deficit in theory of mind assessed with happe ́'s test

Abstract

Objective. search whether a specific deficit in Theory of Mind (ToM) can be found in fronto-temporal dementia (FTD) but not in Alzheimer Type dementia (AD). The search was further supported with brain neuro-images analysis. Method. Neuropsychological tests, executive function tests, Yesavage depression scale and ToM tests using Happe's strange stories tests (SST) were administered, to highlight any differences between Alzheimer and Frontotemporal dementia patients in their capacity to build inferences of other subject's mental states and interpreting a non literal or metaphoric sentence. With this purpose 20 patients with AD and 20 with FTD, age, sex, literacy and IQ matched were selected for this study. Analysis: data were analyzed with ANOVA and correlation tests Results. Patients with FTD performed worst than AD in SST but had identical outcomes in physical events control task. These results didn't show a meaningful correlation with EF tests. Discussion. Both groups offered low contextual content answers, but the percentage was greater with FTD. Those results are correlated with hypometabolism in ventromedial and dorsolateral brain areas, demonstrated with SPECT. Conclusions. FTD patients show a specific deficit in Theory of Mind which renders them incapable of building inferences on mental states.