Individuals with different subtypes of primary progressive aphasia (PPA), a common clinical presentation of frontotemporal dementia characterized by language disturbances, often show overlapping...Show moreIndividuals with different subtypes of primary progressive aphasia (PPA), a common clinical presentation of frontotemporal dementia characterized by language disturbances, often show overlapping clinical symptoms, such that accurate diagnosis can be difficult. Prior studies indicate that social cognitive abilities, in particular emotion recognition, may improve the diagnostic process. Therefore, this study investigated emotion recognition deficits across different emotions and emotional intensities by means of the Emotion Recognition Task (ERT) among patients with a PPA subtype (semantic (svPPA), non-fluent (nfvPPA) or logopenic (lvPPA)), and behavioural frontotemporal dementia (bvFTD). The ERT is a neuropsychological test consisting of dynamic, naturalistic videos of the six basic facial emotional expressions (anger, disgust, fear, happiness, sadness and surprise) across different intensity levels (40, 60, 80 and 100%). In total, emotion recognition abilities were assessed in 152 participants (10 svPPA, 20 nfvPPA, 6 lvPPA, 63 bvFTD, 53 controls). Results of an ANCOVA controlling for age, sex, and education level showed emotion recognition deficits in patients with a PPA subtype and bvFTD compared to controls. Among the patient groups, patients with bvFTD were poorer in overall emotion recognition than patients with nfvPPA. Among the PPA subtypes emotion recognition did not differ. Patients with svPPA were worse in recognizing anger than patients with bvFTD, nfvPPA and lvPPA. In addition, patients with svPPA and bvFTD were worse in recognizing disgust than patients with nfvPPA. Besides, patients with svPPA and controls were better in recognizing happiness, than patients with bvFTD, nfvPPA and lvPPA. Results of a three-way mixed ANOVA showed that emotion recognition abilities improved with higher emotional intensity and group differences were not the largest at the lowest intensity. In conclusion, our findings demonstrate emotion recognition deficits in PPA and bvFTD, and hint towards specific impairments for recognizing anger and disgust in patients with svPPA. These insights can help to improve clinical distinction among the PPA subtypes and bvFTD, which could ultimately lead to better differential diagnosis.Show less
