Search PubMed⌕ Search

Biomedical subjects

Mary C Tierney

Publications and source records attributed to Mary C Tierney.

7 recordsLinked to original sources
PubMed2006

Mild cognitive impairment.

Mild cognitive impairment is a syndrome defined as cognitive decline greater than expected for an individual's age and education level but that does not interfere notably with activities of daily life. Prevalence in population-based epidemiological studies ranges from 3% to 19% in adults older than 65 years. Some people with mild cognitive impairment seem to remain stable or return to normal over time, but more than half progress to dementia within 5 years. Mild cognitive impairment can thus be regarded as a risk state for dementia, and its identification could lead to secondary prevention by controlling risk factors such as systolic hypertension. The amnestic subtype of mild cognitive impairment has a high risk of progression to Alzheimer's disease, and it could constitute a prodromal stage of this disorder. Other definitions and subtypes of mild cognitive impairment need to be studied as potential prodromes of Alzheimer's disease and other types of dementia.

Aged↗
PubMed2005

Neuropsychological tests accurately predict incident Alzheimer disease after 5 and 10 years.

OBJECTIVE: To determine whether neuropsychological tests accurately predict incident Alzheimer disease (AD) after 5 and 10 years in participants of the Canadian Study of Health and Aging (CSHA) who were initially nondemented. METHODS: The CSHA was conducted in three waves: CSHA-1 (1991 to 1992), CSHA-2 (1996 to 1997), and CSHA-3 (2001 to 2002). The 10-year prediction study included those who completed neuropsychological testing at CSHA-1 and received a diagnostic assessment at CSHA-3 (n = 263). The 5-year prediction study included those who completed neuropsychological testing at CSHA-2 and received a diagnostic assessment at CSHA-3 (n = 551). The diagnostic workup for dementia at CSHA-3 was formulated without knowledge of neuropsychological test performance at CSHA-1 or CSHA-2. The authors excluded cases with a baseline diagnosis of dementia or a prior history of any condition likely to affect the brain. Age and education were included in all analyses as covariates. RESULTS: In the 10-year follow-up study, only one test (short delayed verbal recall) emerged from the forward regression analyses. The model with this test and two covariates was significant, chi2 (3) = 31.61, p < 0.0001 (sensitivity = 73%, specificity = 70%). In the 5-year follow-up study, three tests (short delayed verbal recall, animal fluency, and information) emerged from the forward logistic regression analyses. The model was significant, chi2 (5) = 91.34, p < 0.0001 (sensitivity = 74%, specificity = 83%). Both models were supported with bootstrapping estimates. CONCLUSIONS: In a large epidemiologic sample of nondemented participants, neuropsychological tests accurately predicted conversion to Alzheimer disease after 5 and 10 years.

Age Factors↗
PubMed2005

Mild cognitive impairment: an operational definition and its conversion rate to Alzheimer's disease.

OBJECTIVE: Because of discrepant findings regarding the accuracy of mild cognitive impairment (MCI) in predicting Alzheimer's disease (AD), further study of this construct and conversion rates is essential before use in clinical settings. We aimed to develop an operational definition of MCI consistent with criteria proposed by the Mayo Alzheimer's Disease Center, and to examine its conversion rate to AD. METHODS: Patients were identified from an inception cohort of patients with at least a 3-month history of memory problems, and referred to a 2-year university teaching hospital investigation by primary care physicians. We classified 161 nondemented patients at baseline using MCI criteria. Diagnostic workups were completed annually, and patients were classified as meeting criteria for AD or showing no evidence of dementia after 1 and 2 years. RESULTS: Of 161 patients, 35% met MCI criteria at baseline. Conversion rates to AD were 41% after 1 year, and 64% after 2 years. Logistic regression analyses to examine predictive accuracy of MCI after 1 and 2 years, with age and education as covariates, were significant (p < 0.0001). After 1 year, MCI showed an optimal sensitivity of 91% and specificity of 79%, and after 2 years, these values were 88 and 83%, respectively. CONCLUSIONS: MCI is an accurate predictor of AD over 1 and 2 years in patients referred by their primary care physicians. Discrepancies in conversion rates may be due to the manner in which patients are recruited to studies as well as the use of different measures to operationalize the construct.

Aged↗
PubMed2004

Verbal fluency patterns in two subgroups of patients with Alzheimer's disease.

Previous research has identified two subgroups of patients with Alzheimer's disease (AD) based on performance discrepancies on semantic and visual-constructional measures: Left AD (LAD) and Right AD (RAD). In this study, verbal fluency performances (Animal Fluency [AF] and Letter Fluency [FAS]) of these two subgroups were examined. It was hypothesized that LAD patients would perform worse on AF compared to FAS, due to an underlying breakdown of left-hemisphere semantic networks. On the other hand, the RAD group, which theoretically has a relatively preserved semantic system, yet difficulties retrieving overlearned information, was not expected to differ on the two fluency tasks. These predictions were based on the notion that the AF task requires intact retrieval and semantic processes, whereas the FAS task is reliant on retrieval processes alone. Patients were classified into subgroups on the basis of performance discrepancies on the Boston Naming Test (BNT) and Copy tasks: LAD (BNT < Copy); RAD (BNT > Copy). A split-plot ANOVA using demographically corrected standard T-scores revealed a significant main effect for fluency task, and a significant subgroup x fluency task interaction. LAD patients performed poorer on AF compared to FAS; there was no fluency task difference for the RAD group. Analysis of within-subcategory response clustering on AF revealed more instances of serial subclass exemplar responses by RAD members. These results support the loss theory in explaining the semantic deficit of LAD, and suggest that retrieval difficulties underlie the fluency problems of RAD.

Aged↗
PubMed2004

Risk factors for harm in cognitively impaired seniors who live alone: a prospective study.

OBJECTIVES: To identify risk factors for harm due to self-neglect or behaviors related to disorientation in cognitively impaired seniors who live alone that can be used in primary care. DESIGN: Inception cohort followed prospectively for 18 months. SETTING: Participants were referred by their primary care physicians and community service agencies or were patients of several medical units of a large teaching hospital. PARTICIPANTS: One hundred thirty-nine community-residing participants, aged 65 and older who scored less than 131 on the Dementia Rating Scale and lived alone. MEASUREMENTS: Baseline Mini-Mental State Examination (MMSE); a social resources questionnaire; presence of chronic obstructive pulmonary disease (COPD), cerebrovascular disease, diabetes mellitus, Charlson Comorbidity Index, and medication use were examined as predictors of incident harm. Informants and primary care physicians provided information about the nature of any harm at 3-month intervals over an 18-month period. An incident of harm was included if it occurred as the result of self-neglect or behaviors related to disorientation, resulted in physical injury or property loss or damage, and required emergency community interventions. RESULTS: Based on the consensual agreement of four raters, 21.6% had an incident of harm. The proportional hazards model was highly significant (P<.001) and supported by bootstrapping estimates. Four variables were significantly predictive of time to incident harm: perception of fewer social resources, poorer performance on MMSE, presence of COPD, and presence of cerebrovascular disorders. CONCLUSION: Predictors of incident harm can be identified in the primary care setting and provide direction for the early identification of those at highest risk. Validation of findings with a new cohort is necessary.

Accidents↗
PubMed2003

Contribution of informant and patient ratings to the accuracy of the mini-mental state examination in predicting probable Alzheimer's disease.

OBJECTIVES: To determine whether the accuracy of the Mini-Mental State Examination (MMSE) in predicting future Alzheimer's disease (AD) could be improved by the addition of patient and informant ratings of cognitive difficulties. DESIGN: An inception cohort of nondemented patients followed longitudinally for 2 years. SETTING: Patients referred to a university teaching hospital research investigation by their family physicians because of concerns about memory impairment. PARTICIPANTS: One hundred sixty-five community-residing patients were included who did not have dementia or any identifiable cause for memory impairment. After 2 years, 29 met criteria for AD, and 95 were not demented. MEASUREMENTS: Baseline assessments included MMSE, an Informant Rating Scale, and a Patient Rating Scale of cognitive difficulties. After 2 years, patients were diagnosed following the reference standard for probable AD. Diagnosticians were blind to baseline scores. RESULTS: Age and education were included in all analyses as covariates. The best logistic regression model included the Informant Rating Scale and the MMSE (sensitivity = 83%, specificity = 79%). An empirically reduced six-item model that included two items each from the MMSE, the Patient Rating Scale, and the Informant Rating Scale produced a significantly better model than the one with the full test scores (sensitivity = 90%, specificity = 94%). CONCLUSION: Results indicate that inclusion of informant ratings with the MMSE significantly improved its accuracy in the prediction of probable AD. Replication in a new prospective cohort of nondemented patients is necessary to confirm these findings.

Aged↗