Comparing patterns of impairment in social cognition between young-onset and late-onset Alzheimer's disease

Background Young-onset Alzheimer's disease (YOAD) is defined as when the disease starts before 65 years old. Compared with late-onset AD (LOAD), the progression is faster and more aggressive. However, the impact on social cognition deficits may not follow the same clear pattern. Objective The present study aims to investigate the relationship between social cognition, global cognition, and other clinical variables in people with YOAD and LOAD and their caregivers. Methods Using a cross-sectional design, we included 48 people with YOAD and 118 with LOAD, and their caregivers. We assessed social cognition, global cognition, quality of life, dementia severity, mood, functionality, neuropsychiatric symptoms, and caregiver burden. Results The YOAD group was more impaired in general cognition ( p = 0.002, d = 0.06), had a worse quality of life ( p = 0.036, d = 0.36), and presented more neuropsychiatric symptoms ( p = 0.044, d = 0.35). However, social cognition did not exhibit the same disease progression and showed no difference when compared with the reports of their caregivers or with individuals with LOAD. The multifactorial regression analyses showed that functionality was related to social cognition impairment in YOAD ( p = 0.035), and LOAD ( p = 0.001). Conclusions Our study found that people diagnosed with YOAD showed more global cognitive impairment but maintained social and emotional functioning.