Biomedical subjects

G Lafleche

Publications and source records attributed to G Lafleche.

12 recordsLinked to original sources

PubMed1996

Do long tests yield a more accurate diagnosis of dementia than short tests? A comparison of 5 neuropsychological tests.

OBJECTIVE: To provide comparative evidence for a valid and practical measure of mental-status functioning that could be used in dementia clinics. DESIGN: Five mental-status neuropsychological tools for dementia screening were administered to patients in a memory disorder clinic. These included the Mini-Mental State Examination, the Dementia Rating Scale, the 6-item derivative of the Orientation-Memory-Concentration Test, a short Mental Status Questionnaire, and a composite tool we labeled the Ottawa Mental Status Examination, which assessed orientation, memory, attention, language, and visual-constructive functioning. The tools were compared using various criteria, including the statistical factors of sensitivity and reliability; effects of gender, native language, and language of testing; the utility of these tests for the differential diagnosis of Alzheimer-type and vascular dementia; and sensitivity to cognitive decline in the entire sample and among patients with severe dementia. RESULTS: All of the tests were highly intercorrelated, suggesting that they are interchangeable. CONCLUSION: The comparisons along the various criteria indicate that if the objective is to have a general index of dementia of the Alzheimer type, short tests are at least as good and sometimes better than the longer tests.

Aging↗

PubMed1996

Diagnosis of dementia. Methods for interpretation of scores of 5 neuropsychological tests.

OBJECTIVE: To provide methods to interpret and compare different neurobehavioral screening tests for the diagnosis of dementia. DESIGN: Five mental-status neuropsychological tools for dementia screening were administered to patients in a memory disorder clinic. These included the Mini-Mental State Examination, the Dementia Rating Scale, the 6-item derivative of the Orientation-memory-Concentration Test, a short Mental Status Questionnaire, and a composite tool we labeled the Ottawa Mental Status Examination, which assessed orientation, memory, attention, language, and visual-constructive functioning. RESULTS: To obtain z and percentile scores, norms are for the different tests, computed separately for patients with dementia of the Alzheimer type, vascular dementia, or no dementia. Another set of norms is reported in which a test score is translated directly into the posttest probability of dementia. Translation formulas are given to allow the estimation of the score on one test from the result on another test. CONCLUSION: The interpretation of tests used to diagnose dementia must be based on an understanding of the meaning of an individual score, which is based on the question asked and the population to which the patient is referenced.

Alzheimer Disease↗

PubMed1996

Application of a growth curve approach to modeling the progression of Alzheimer's disease.

BACKGROUND: Studies using clinical measures to track AD progression often assume linear declines over the entire course of the disease, which may not be justified. The objective of this study was to model change in measures of the clinical severity of Alzheimer's disease (AD) over time. METHODS: We developed a method to apply growth curve models to prospective data and characterize AD patients' functional change over time. Data from the modified Mini-Mental State Examination (mMMSE) and measures of basic and instrumental ADL, administered semiannually for up to 5 years to 236 patients with probable AD, were modeled. RESULTS: The rate of decline in mMMS scores per 6-month interval gradually increased as scores dropped from the maximum of 57 to 20. The rate of decline then decreased as scores approached 0, resulting in an inverse "S" curve. The rate of increase in instrumental ADL scores per interval attenuated as the scores increased, while that for basic ADL scores across intervals was constant. CONCLUSIONS: Differences in the pattern of progression of the three measures is in part a function of their psychometric properties. The progression curves may also reflect content-specific features of the instruments. Superimposition of the modeled decline in these three content areas suggests a hypothetical model of the relative timing of cognitive and functional changes in AD.

Activities of Daily Living↗

PubMed1996

Impaired awareness of deficits in Alzheimer disease.

This study examined the relation between awareness of memory and functional decline and cognitive function in patients with Alzheimer disease (AD). Twenty-six patients with early AD and 16 nondemented elderly controls were studied. Awareness of deficits was determined by using (a) a discrepancy score between subject's and caregiver's ratings on a memory questionnaire, (b) a discrepancy score between subject's and caregiver's ratings on an activities-of-daily-living scale, and (c) a clinical rating of dementia awareness for patients. Whereas self-ratings of memory and activities of daily living were not significantly different between AD patients and controls, these two measures differed significantly when AD patients' ratings were compared with those of their caregivers. Measures of awareness of deficits correlated with one another and were primarily associated with performance on tests of executive and visuospatial functions but not with depression. Early AD is characterized by a failure of self-monitoring. Deficits in self-monitoring have been proposed to occur after damage to the frontal lobes and other cerebral areas. Impaired awareness of memory and functional deficits in AD is related to cognitive impairments, which may involve frontal and right hemisphere connections.

Aged↗

PubMed1996

Quality of life in patients with Alzheimer's disease as reported by patient proxies.

OBJECTIVE: To measure behaviors indicative of quality of life (QOL) in patients with Alzheimer's disease and to examine correlates of patient QOL. DESIGN: Cross-sectional investigation. SETTING: Multi-center study. PARTICIPANTS: Sample of 130 diagnosed patients. PRINCIPAL OUTCOME MEASURES: Proxy ratings of (1) the frequency, opportunity, and enjoyment of 15 non-ADL activities potentially within the capacity of a demented person, and (2) the frequency of a series of positive and negative affects, evident in clearly demarcated facial and bodily expressions. RESULTS: QOL ratings were reliably elicited. Family and institutional caregivers differed only in reports of opportunity for patient activity. Frequency of activities declined with increasing severity of dementia. The frequency of negative affects increased and positive affects declined with increasing severity of dementia, but correlations were weak. High QOL, defined by frequent activity and positive affect, was evident in a quarter of the sample. In multivariate models, functional and cognitive status independently predicted QOL among community-resident older adults; only absence of antipsychotics was related to QOL among older people in nursing homes. Patient education, a marker of premorbid state, independently predicted some activity patterns. CONCLUSIONS: Although the subjective world of the demented patient is not directly accessible, readily observable behaviors offer a basis for assessing QOL.

Affect↗

PubMed1995

A standardized technique for establishing onset and duration of symptoms of Alzheimer's disease.

OBJECTIVES: To develop an informant-based semistructured interview to determine the onset and duration of symptoms of Alzheimer's disease, and to use this instrument with informants to characterize a cohort of mildly impaired patients with Alzheimer's disease. DESIGN: In study 1, interrater and interinformant reliability was examined for the date of onset and the order of appearance for specific symptoms that were elicited by the semistructured onset interview. In study 2, the instrument was used to characterize disease onset in a cohort of patients with Alzheimer's disease who were participating in a large multicenter study. SUBJECTS: Informants of patients with Alzheimer's disease. RESULTS: In study 1, interrater reliability for duration of illness was excellent (intraclass correlation coefficient = .99, P < .001), and interinformant reliability was good (intraclass correlation coefficient = .86, P < .001). Agreement for the presence of a given symptom was highest for those that were most commonly reported (eg, memory and performance difficulty). In study 2, 89% of the cohort had memory problems, and 63.9% had performance difficulties as the first or second symptom. Depression and language problems were less commonly reported. Psychosis and behavioral disturbances were rarely reported as the first problem. CONCLUSION: This instrument provides a reliable procedure for standardizing the estimation of duration of illness based on retrospective report.

Aged↗

PubMed1994

Assessing patient dependence in Alzheimer's disease.

BACKGROUND: While cognitive and functional deficits are the hallmark of Alzheimer's disease (AD), loss of social function (and the dependence this implies) is also critical, especially in early stages of disease. Little attention has been directed to this facet of dementing disease. We describe a scale for assessing dependency in AD and present a baseline profile of dependency in a cohort of AD patients. METHODS: In a study of the predictors of the course of AD, 233 patients in early stages of disease (modified MMS > or = 30) were assessed. Psychometric properties of the dependence scale were established. To validate the scale, dependence scores at baseline were correlated with a series of measures assessing cognition and function. The course of dependency over 18 months of follow-up was also analyzed. RESULTS: The scale shows adequate reliability (test-retest, intraclass correlation). Dependence stage was related to other measures of disease severity. Scalogram analysis shows that the dependence scale is consistent with the course of functional loss established for dementing disease. Prospective data indicate sensitivity of the scale to disease progression. CONCLUSION: Dependency is a distinct, measurable component of dementing disease and should be considered an important outcome in studies of AD.

Activities of Daily Living↗

PubMed1994

Age at onset of Alzheimer's disease: relation to pattern of cognitive dysfunction and rate of decline.

We examined the pattern of cognitive impairment and rate of cognitive and functional decline as a function of age at symptom onset in 127 patients with probable Alzheimer's disease (AD). At baseline, early-onset (before age 65) and late-onset groups were mildly and comparably impaired on the modified Mini-Mental State Examination (mMMS) and the Blessed Dementia Rating Scale-Part 1 (BDRS). Repeated-measures analysis of variance revealed significantly more rapid decline in early-onset subjects over a 2-year follow-up period. Multivariate linear regression analyses indicated that age at symptom onset strongly predicted rate of decline on the mMMS and the BDRS, even after controlling for symptom duration, gender, family history of dementia, and baseline mMMS and BDRS scores. Early- and late-onset AD subjects also differed in terms of pattern of performance on the mMMS. Early-onset subjects scored significantly lower than late-onset subjects on attentional items of the mMMS at baseline and follow-up. Conversely, late-onset subjects scored significantly lower than early-onset subjects on memory and naming items at baseline, and the two groups were comparable on these tasks at follow-up. Results provide longitudinal evidence of more rapid cognitive and functional decline in subjects with early-onset AD and suggest that early-onset AD may be characterized by predominant impairment of attentional skills.

Age of Onset↗

PubMed1993

Multicenter study of predictors of disease course in Alzheimer disease (the "predictors study"). I. Study design, cohort description, and intersite comparisons.

Clinicians should be able to provide the patient with Alzheimer disease (AD) and the family with an accurate prediction of what to expect, but the variability in the rate of disease progression precludes this. In several previous studies, specific clinical signs such as muscular rigidity, myoclonus, and hallucinations or delusions were associated with rapid progression to a more severe stage of dementia or death. The "Predictors Study," a longitudinal study at three independent sites, was designed to develop a predictor model of the natural history of Alzheimer disease. The study was conducted at three study sites, New York, Baltimore, and Boston in a cohort of 224 patients with early probable AD. This article describes the design and implementation of the Predictors Study, and compares features of the study cohort at baseline across sites. Patients were all at the mild stage of disease at entry and were relatively comparable across sites. Extrapyramidal signs and delusions were common, but myoclonus was rarely observed.

Activities of Daily Living↗

PubMed1993

Multicenter study of predictors of disease course in Alzheimer disease (the "predictors study"). II. Neurological, psychiatric, and demographic influences on baseline measures of disease severity.

The "Predictors Study" is a prospective cohort study of the natural history of Alzheimer disease (AD), the aim of which is to identify milestones in disease progression and to develop a model to predict disease course in individual patients. The empirical background to this study is based on previous reports that the presence of extrapyramidal signs (EPS), myoclonus, and psychosis in AD may signify greater disease severity at any given stage and a more rapid course of the disease over time. The present analyses were conducted to determine whether these independent "predictor" variables were associated with greater disease severity at baseline within a new cohort of 224 mild AD patients recruited from three different medical centers (in New York, Baltimore, and Boston). Measures of disease severity were provided by the modified Mini-Mental State Examination (mMMSE) and the Blessed Dementia Rating Scale (BDRS), which measures functional capacity. Independent variables were EPS, delusions, and slowing of the posterior dominant EEG rhythm. The frequency of myoclonus and hallucinations was too low to permit adequate statistical assessment of their effects at this time. EPS and EEG slowing were associated with low mMMSE scores, whereas delusions were primarily associated with impaired functional capacity. These effects were independent of the influence of age and disease duration. These results indicate that the effects of these independent variables can be detected at mild stages of AD and that these effects can be generalized across different geographical regions.

Aged↗

PubMed1991

Neuroimaging in Alzheimer's disease.

This article reviews the recent neuroimaging studies of patients with Alzheimer's disease. The neuroimaging procedures discussed include computerized tomography, magnetic resonance imaging, positron emission tomography, and single-photon emission computerized tomography.

Alzheimer Disease↗

PubMed1990

Differences in abstraction ability with age.

Three tests of abstraction were administered to 89 optimally healthy subjects aged 30-79. Performance on all 3 tasks showed significant differences with age. This was primarily, although not entirely, the result of deficits in performance by the 70-year-old subjects. These results do not appear to be related to changes in memory ability or to a differential increase in a particular type of abstraction error.

Abstracting and Indexing↗