Facial emotion recognition is associated with executive functions and depression scores, but not staging of dementia, in mild-to-moderate Alzheimer's disease

Background: Although deficits in facial emotion recognition (FER) significantly affect interpersonal communication and social functioning, there is no consensus on how FER affects Alzheimer's disease (AD). In this study, we aimed to investigate the clinical and neuropsychological factors affecting the possible deficits in the FER abilities of patients with AD.Methods: This cross-sectional study included 37 patients with mild [clinical dementia rating (CDR) scale score = 1] or moderate (CDR = 2) AD, in whom vascular dementia and depression were excluded, and 24 cognitively normal (CDR = 0) subjects. FER ability was determined using the facial emotion identification test (FEIT) and facial emotion discrimination test (FEDT). All participants underwent mini-mental state examination (MMSE), frontal assessment battery (FAB), and geriatric depression scale (GDS). The neuropsychiatric inventory-clinician rating scale (NPI-C), Katz index of independence in activities of daily living, and Lawton instrumental activities of daily living were also administered to patients with AD.Results: The FEIT and FEDT total scores showed that patients with mild and moderate AD had significant FER deficits compared to healthy controls. However, no significant difference was observed between patients with mild and moderate AD in the FEIT and FEDT total scores. FEIT and FEDT scores were not correlated with the MMSE and NPI-C total and subscales scores in patients with AD. Linear regression indicated that FEIT and FEDT total scores were significantly related to age and FAB scores. The GDS score negatively moderated the relationship between FAB and FEDT.Conclusions: This study demonstrated a decreased FER ability in patients with AD. The critical point in FER deficits is the presence of dementia, not the dementia stage, in AD. It has been determined that executive functions and depression (even at a subsyndromal level), which have limited knowledge, are associated with FER abilities.