Background The emotion recognition task (ERT) was developed to overcome shortcomings of static emotion recognition paradigms, by identifying more subtle deficits in emotion recognition across different intensity levels. In this study, we used the ERT to investigate emotion recognition deficits across the frontotemporal (FTD) and Alzheimer’s Dementia (AD) spectrum. Methods With the ERT, we assessed the recognition of facial emotional expressions (anger-disgust-fear-happiness-sadness-surprise) across four intensities (40–60–80–100%) in patients with behavioural variant FTD (bvFTD; n = 32), and AD ( n = 32), presymptomatic FTD mutation carriers ( n = 47) and controls ( n = 49). We examined group differences using multilevel linear regression with age, sex and education level as covariates, and performed post hoc analyses on presymptomatic ( MAPT , GRN and C9orf72 ) mutation carriers. Classification abilities were investigated by means of logistic regression. Results Lowest ERT total scores were found in patients with bvFTD and AD, whereas equal highest performance was found in presymptomatic mutation carriers and controls. For all emotions, significantly lower subscores were found in patients with bvFTD than in presymptomatic mutation carriers and in controls (highest p value = 0.025). Patients with bvFTD performed lower than patients with AD on anger ( p = 0.005) and a trend towards significance was found for a lower performance on happiness ( p = 0.065). Task performance increased with higher emotional intensity, and classification was better at the lowest than at the highest intensity. C9orf72 mutation carriers performed worse on recognizing anger at the lowest intensity than GRN mutation carriers ( p = 0.047) and controls ( p = 0.038). The ERT differentiated between patients with bvFTD and controls, and between patients with AD and controls (both p < 0.001). Discussion Our results demonstrate emotion recognition deficits in both bvFTD and AD, and suggest the presence of subtle emotion recognition changes in presymptomatic C9orf72 -FTD. This highlights the importance of incorporating emotion recognition paradigms into standard neuropsychological assessment for early differential diagnosis, and as clinical endpoints in upcoming therapeutic trials. Electronic supplementary material The online version of this article (10.1007/s00415-020-10096-y) contains supplementary material, which is available to authorized users.

Background An increasing amount of studies are emphasizing the importance of social cognitive assessments to improve early diagnosis between frontotemporal dementia (FTD) and Alzheimer’s Disease (AD). Traditional measures of social cognition, including emotion recognition paradigms, however seem insensitive to the subtle deficits in the earliest dementia stages. The Emotion Recognition Task (ERT) was developed to identify early deficits in the recognition of facial expressions across different levels of intensity. Method Using the ERT, we assessed the recognition of morphed facial expressions of six emotions (anger, disgust, fear, happiness, sadness and surprise) across four intensities (40, 60, 80 and 100%) in patients with behavioural variant FTD (bvFTD; n=32), patients with AD (n=32), FTD mutation carriers (presymptomatic n=47, mildly/questionably symptomatic n=5) and controls (n=49). We examined group differences using multilevel linear regression modelling, and performed post hoc analyses on presymptomatic (MAPT, GRN and C9orf72) and mildly/questionably symptomatic mutation carriers. Classification abilities were investigated with logistic regression analyses; we determined sensitivity/specificity with ROC analyses. Result The lowest ERT total scores were found in bvFTD and AD patients, whereas equally highest scores were found in mutation carriers and controls. bvFTD patients scored significantly lower than AD patients on anger (p=0.023) and happiness (p<0.001), where subjects with mild/questionable FTD had an intermediate position between patients with dementia and those without (p=0.051) (Figure). Discriminative ability was better at the lowest (40%) than at the highest intensity (100%). Presymptomatic C9orf72 mutation carriers were worse at recognizing anger at the lowest (40%) emotional intensity than controls (p=0.038) and presymptomatic GRN mutation carriers (p=0.047). The ERT classified between patients with bvFTD and controls, patients with AD and controls (both p<0.001), but not between patients with bvFTD and AD, nor the total group of mutation carriers and controls (p>0.05). Conclusion Our results demonstrate clear emotion recognition deficits in bvFTD and AD, and suggest the presence of subtle changes in facial emotion recognition in early‐stage FTD. This provides us more insight into the discrete neural substrates involved in behavioural and emotional changes in developing FTD, but also highlights the importance of incorporating emotion recognition paradigms into standard neuropsychological assessment for early differential diagnosis.