The Disability Assessment for Dementia (DAD) scale was developed and validated as a measure of functional ability in dementia. DAD results have been reported in Alzheimer disease (AD) randomized, controlled treatment trials of up to 6 months, but results beyond 6 months have yet to be described. SAB INT 12 was a randomized, double-blind, placebo-controlled, parallel-group study in mild to moderate AD that included DAD assessments at baseline, month 6, and month 12. One hundred forty-four patients with AD in the placebo arm of SAB INT 12 were followed up for 12 months. DAD scores were obtained at baseline (mean DAD = 70.1, SD = 22.2), 6 months (mean DAD = 63.7, SD = 25.2), and 12 months (mean DAD = 59.3, SD = 28.9). The rate of decline was consistent across the domains of basic activities of daily living (ADLs) and instrumental ADLs, as well as the scoring of initiation, planning, and organization. The decline in DAD total scores in mild to moderate AD averages about one point per month, which equates to the loss of one item on the DAD scale every 2 months.
*Division of Neurology, University of British Columbia, Clinic for Alzheimer's Disease and Related Disorders, Vancouver, Canada; †Department of Statistics, University of British Columbia, Vancouver, Canada; ‡School of Physical and Occupational Therapy, McGill University, Montreal, Canada; §McGill Center for Studies in Aging, Douglas Hospital, Montreal, Canada; and ¶CNS Clinical Research, Janssen Research Foundation, Beerse, Belgium
Received July 6, 1999.
Revised March 5, 2001.
Accepted January 20, 2000.
Address correspondence and reprint requests to Dr. Howard Feldman, S192–2211 Wesbrook Mall, Division of Neurology, UBC Hospital, Vancouver V6T 2B5, Canada.