Premium
Mild cognitive impairment in a community sample: The Sydney Memory and Ageing Study
Author(s) -
Brodaty Henry,
Heffernan Megan,
Kochan Nicole A.,
Draper Brian,
Trollor Julian N.,
Reppermund Simone,
Slavin Melissa J.,
Sachdev Perminder S.
Publication year - 2013
Publication title -
alzheimer's and dementia
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 6.713
H-Index - 118
eISSN - 1552-5279
pISSN - 1552-5260
DOI - 10.1016/j.jalz.2011.11.010
Subject(s) - dementia , incidence (geometry) , neuropsychology , confidence interval , medicine , memory impairment , cognitive impairment , gerontology , population , cognition , pediatrics , psychology , psychiatry , disease , physics , environmental health , optics
Background Mild cognitive impairment (MCI) is associated with an increased dementia risk. This study reports incidence of MCI subtypes, rates of progression to dementia, and stability of MCI classification. Methods We examined 873 community‐dwelling adults aged 70 to 90 years over 2 years as part of an ongoing population‐based longitudinal study, the Sydney Memory and Ageing Study. Neuropsychological testing assessed five cognitive domains, and a diagnosis of no cognitive impairment, MCI, or dementia (follow‐up only) was made according to published criteria. Results The incidence of MCI was 104.6 (95% confidence interval: 81.6–127.7) per 1000 person‐years, with higher incidence in men (men, 156.8; women, 70.3). Incidence rates for single‐domain amnestic, multiple‐domain amnestic, single‐domain nonamnestic, and multiple‐domain nonamnestic MCI were 47.7, 7.9, 45.0, and 3.9 per 1000 person‐years, respectively. The 2‐year rate of progression from MCI at baseline to dementia was 4.8%, being highest for multidomain amnestic MCI (9.1%). Of those with MCI at baseline, 28.2% reverted to no cognitive impairment at follow‐up. Sensitivity analyses by redefining criteria for cognitive impairment did not affect stability of diagnosis, although changing the threshold of domain impairment reduced baseline MCI prevalence from 36.7% to 5.7% and incidence to 23.5, and increased 2‐year progression rate from MCI to dementia to 14.3%. Conclusions Incidence rates for MCI are higher than previously reported, particularly in men and for single‐domain MCI; rates for amnestic and nonamnestic MCI were comparable. Multidomain amnestic MCI was the most likely subtype to progress to dementia, but overall, the diagnosis of MCI, particularly single‐domain MCI, shows considerable instability.