Objective: To investigate emotion discrimination abilities in healthy comparison subjects, patients with mild cognitive impairment (MCI), early and moderate Alzheimer disease (AD).
Design: Prospective study design.
Setting: Outpatient memory clinic, Department of Psychiatry, Innsbruck, Austria.
Methods: One hundred forty-one subjects older than 60 years were included in the study. Thirty-five subjects were classified as healthy comparison subjects, 51 subjects as MCI (21 subjects with amnestic MCI single domain, 31 subjects with amnestic MCI multiple domain), 32 subjects with early AD and 23 subjects with moderate AD.
Measurements: All subjects were tested on an extensive neuropsychological test battery including the Penn Emotion Recognition Tests and depression symptoms were assessed additionally.
Results: Healthy subjects and patients with MCI, early and moderate AD differed significantly in the recognition of all emotions and neutral faces combined. When separated by emotion, the authors found significant differences in emotion recognition between the diagnostic groups for happy, sad, fearful, and neutral faces. Compared with comparison subjects, amnestic MCI patients single domain did not differ significantly in their emotion recognition abilities, but amnestic MCI multiple domain patients were already impaired in the recognition of overall emotions, sad, fearful, and neutral faces and the deficits increased with the severity of AD. Depression had a significant influence on the recognition of overall emotion and neutral faces and increased the probability of misinterpreting neutral faces as sad leading to a negative bias.
Conclusions: Diminished abilities for emotion discrimination are already present in patients with MCI and further decreased with AD progression.