Is functional decline necessary for a diagnosis of Alzheimer's disease?
BACKGROUND
The purpose of this study is to examine baseline differences and annualized cognitive and functional change scores in mild Alzheimer's disease (AD) patients with and without impaired activities of daily living (ADL).


METHODS
We recruited 267 mild probable AD patients with at least 1 year of follow-up (NINCDS-ADRDA criteria, MMSE>or=20). Based on initial ADL scores, they were divided into 2 groups: unimpaired (n=40) and impaired (n=227). We compared the differences in annualized change scores on MMSE, Alzheimer's Disease Assessment Scale-cognitive subscale (ADAS-cog), ADL and Clinical Dementia Rating sum of box score (CDR-SB) for patients with and without functional impairment at baseline.


RESULTS
The group with unimpaired ADL at baseline had a significantly shorter symptom duration (p=0.01) and better neuropsychological test scores at baseline (p<0.001) than those with impaired ADL. The annualized cognitive and functional change of each group from baseline to 1-year follow-up was not significantly different on the MMSE, ADAS-cog, CDR-SB, Physical Self-Maintenance Scale and Instrumental Activities of Daily Living. After 1 year, 56% of the initially unimpaired group and 6% of the initially impaired group reported no ADL impairment.


CONCLUSIONS
Our study suggests that functional decline should not be required for the diagnosis of mild AD.
Park
Kyung Won
KW
Department of Neurology, Alzheimer's Disease and Memory Disorders Center, Baylor College of Medicine, Houston, TX 77030, USA.
Pavlik
Valory N
VN
Rountree
Susan D
SD
Darby
Eveleen J
EJ
Doody
Rachelle S
RS
D000203:Activities of Daily Living; D000368:Aged; D000369:Aged, 80 and over; D000544:Alzheimer Disease / Q000150:complications / Q000175:diagnosis* / Q000503:physiopathology; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D003072:Cognition Disorders / Q000150:complications* / Q000175:diagnosis / Q000503:physiopathology; D005260:Female; D006801:Humans; D008297:Male; D008609:Mental Status Schedule; D009483:Neuropsychological Tests; D012720:Severity of Illness Index