Mild cognitive impairment, amnestic type: an epidemiologic study

• Published in: Neurology Vol. 63; no. 1; p. 115
• Main Authors: Ganguli, Mary, Dodge, Hiroko H, Shen, Changyu, DeKosky, Steven T
• Format: Journal Article
• Language: English
• Published: United States 13.07.2004
• Subjects: Aged; Aged, 80 and over; Cohort Studies; Dementia - epidemiology; Depression - epidemiology; Disease Progression; Female; Humans; Male; Memory Disorders - epidemiology; Neuropsychological Tests; Pennsylvania - epidemiology; Predictive Value of Tests; Prevalence; Prospective Studies; Risk Factors; Socioeconomic Factors; Pennsylvania
• ISSN: 1526-632X
• DOI: 10.1212/01.WNL.0000132523.27540.81

To estimate the prevalence and examine the course of mild cognitive impairment (MCI), amnestic type, using current criteria, within a representative community sample. Retroactive application of MCI criteria to data collected during a prospective epidemiologic study was performed. The subjects were drawn from voter registration lists, composing a cohort of 1,248 individuals with mean age of 74.6 (5.3) years, who were nondemented at entry and who were assessed biennially over 10 years of follow-up. The Petersen amnestic MCI criteria were operationalized as 1) impaired memory: Word List Delayed Recall score of <1 SD below mean; 2) normal mental status: Mini-Mental State Examination score of 25+; 3) normal daily functioning: no instrumental impairments; 4) memory complaint: subjective response to standardized question; 5) not demented: Clinical Dementia Rating Scale score of <1. At the five assessments, amnestic MCI criteria were met by 2.9 to 4.0% of the cohort. Of 40 persons with MCI at the first assessment, 11 (27%) developed dementia over the next 10 years. Over each 2-year interval, MCI persons showed increased risk of dementing (odds ratio = 3.9, 95% CI = 2.1 to 7.2); 11.1 to 16.7% progressed to Alzheimer disease and 0 to 5.0% progressed to other dementias. Over the same intervals, 11.1 to 21.2% of those with MCI remained MCI; of 33.3 to 55.6% who no longer had MCI, half had reverted to normal. In this community-based sample, 3 to 4% of nondemented persons met MCI operational criteria; despite increased risk of progressing to dementia, a substantial proportion also remained stable or reverted to normal during follow-up. Amnestic MCI as currently defined is a high-risk but unstable and heterogeneous group.