Although Alzheimer's-type dementia (ATD) is characterized by global intellectual deterioration, few systematic efforts have been made to characterize overall dysfunction of ATD patients. The Sickness Impact Profile (SIP) was administered to ATD patients and family members to determine the concurrent validity of family member assessments of functional status. Using the Mini-Mental State score and modified Dementia Rating Scale as validation criteria, family member SIP scores showed consistently higher correlations with the Mini-Mental State and modified Dementia Rating Scale than did patient scores. Comparing family member SIP scores for ATD and nondemented patients revealed that ATD patients maintained high levels of psycho-social dysfunction at both initial evaluation and 1-year follow-up. By contrast, ATD patients showed high levels of physical dysfunction relative to nondemented patients only at follow-up. Physical deterioration over time is also suggested by comparison of ATD patient initial and follow-up scores. This study documents the well-known psychosocial dysfunction in ATD and emphasizes the importance of physical dysfunction as the disease progresses.