Biomedical subjects

H Amieva

Publications and source records attributed to H Amieva.

6 recordsLinked to original sources

PubMed2005

Cognitive impairment as marker of diffuse brain abnormalities in early relapsing remitting multiple sclerosis.

OBJECTIVES: To establish the frequency of cognitive impairment in a population based sample of patients with recently diagnosed relapsing-remitting multiple sclerosis (RRMS), and to determine the relation between cognitive abnormalities and the extent of macroscopic and microscopic tissue damage revealed by magnetic resonance imaging (MRI) and magnetisation transfer (MT) imaging. METHODS: 58 patients with RRMS consecutively diagnosed in the previous six months in Aquitaine and 70 healthy controls underwent a battery of neuropsychological tests. Lesion load and atrophy indices (brain parenchymal fraction and ventricular fraction) were measured on brain MRI. MT ratio (MTR) histograms were obtained from lesions, normal appearing white matter (NAWM), and normal appearing grey matter (NAGM). Gadolinium enhanced lesions were counted. RESULTS: 44 RRMS patients could be individually matched with healthy controls for age, sex, and education. Patients performed worse in tests of verbal and spatial memory, attention, information processing speed, inhibition, and conceptualisation. Measures of attention and information processing speed were correlated with lesion load, mean NAWM MTR, and the peak location of the NAGM MTR histogram in the patients. Multivariate regression analysis showed that lesion load and mean NAWM MTR were among the MR indices that were most significantly associated with impairment of attention and information processing speed in these early RRMS cases. CONCLUSIONS: Cognitive impairment appears to be common in the early stages of RRMS, mainly affecting attention, information processing speed, memory, inhibition, and conceptualisation. The severity of these deficits reflects the extent of the lesions and the severity of tissue disorganisation outside lesions.

Adult↗

PubMed2002

Incidence and outcome of mild cognitive impairment in a population-based prospective cohort.

OBJECTIVE: To estimate the age-specific incidence rate of mild cognitive impairment (MCI) according to sex and educational level and to explore the course of MCI, particularly its progression to AD, in a population-based cohort. METHODS: A community-based cohort of nondemented elderly people (Personnes Agées QUID [PAQUID]) was followed longitudinally for 5 years. MCI was defined as memory complaints with objective memory impairment, without dementia, impairment of general cognitive functioning, or disability in activities of daily living. Incidence rates were calculated using the person-years method. A descriptive analysis at the different follow-up times was performed to study the course of MCI. RESULTS: At baseline, there were 58 prevalent cases of MCI (2.8% of the sample). During a 5-year follow-up, 40 incident cases of MCI occurred in 1,265 subjects at risk. The global incidence rate of MCI was 9.9/1,000 person-years. MCI was a good predictor of AD with an annual conversion rate of 8.3% and a good specificity, but it was very unstable over time: Within 2 to 3 years, only 6% of the subjects continued to have MCI, whereas >40% reverted to normal. CONCLUSIONS: Conventionally defined MCI has reasonable predictive value and specificity for AD. However, MCI was very unstable across time in this study. Furthermore, the definition of MCI seems to be too restrictive and should probably be extended to other categories of individuals also at high risk of developing AD.

Activities of Daily Living↗

PubMed2002

The disablement process: a conceptual framework for dementia-associated disability.

Most of the social and economic burden of dementia is attributable to its consequences in terms of disability. In this review, we describe the concepts defined in the disablement process model of Verbrugge and Jette [Soc Sci Med 1994;38:1-14] and show how they apply to dementia. The main pathway leads from pathology to impairments, functional limitations and disability. Pathologies (any cause of dementia) are expressed by impairments in specific cognitive processes. Functional limitations are limitations in generic cognitive tasks such as remembering a list of words or orientating oneself in time and space. They are responsible for disability in activities of daily living. Predisposing risk factors as well as introduced intraindividual and extraindividual factors speed up or slow down the main pathway. We show how the model can help in understanding the functional consequences of dementia, for better assessment and management of demented subjects.

Activities of Daily Living↗

PubMed1998

Analysis of error types in the trial making test evidences an inhibitory deficit in dementia of the Alzheimer type.

Several studies have reported low performances of patients with dementia of the Alzheimer Type (DAT) on the Trial Making Test (TMT), however, these studies were not designed to identify specific operations underlying this impairment. To better understand the attentional disorder in DAT, we analyzed the performances of patients with DAT and matched elderly adults on the TMT, with a detailed analysis of error types. The analysis showed that 67% of patients' errors were related to an inhibitory deficit versus only 24% in normal elderly adults. Therefore, it was suggested that inefficient inhibitory mechanisms are responsible, to a large extent, for the poor TMT performance of patients with DAT, supporting the hypothesis of an inhibitory dysfunction in DAT.

Adult↗

PubMedDate not supplied

Deterioration of controlled processes in the preclinical phase of dementia: a confirmatory analysis.

Preclinical deficits in dementia have recently been investigated in the PAQUID cohort by means of a principal component analysis (PCA) performed from various test scores. According to the interpretation of the first PCA factor, which was found to be an independent predictor of dementia 2 years later, the authors suggested that cognitive deficits occurring in the preclinical phase of dementia may reflect the deterioration of controlled processes. Because this hypothesis relies essentially on the interpretation of PCA factors, the present study was designed to test it within the same cohort. The analyses were focused on one of the tests administered to the subjects, the Wechsler Paired Associate Test (WPAT) divided into two subscores in order to provide a measure of controlled processes of memory functioning (i.e. retrieval of unrelated pairs) as well as of more automatic processes (i.e. retrieval of related pairs). The results showed that the future demented subjects, although significantly impaired compared to elderly controls, were able to increase their performance across trials. More importantly, a new PCA including the subscores of the WPAT showed that the unrelated pair scores were strongly correlated to factor 1, which remained the only factor associated with subsequent dementia, whereas the related pair scores were rather correlated to factor 2. Therefore, these results confirm our previous PCA interpretation, lending more weight to our hypothesis of a preclinical impairment of controlled processes in dementia.

Aged↗

PubMedDate not supplied

[Epidemiology of memory disorders].

To study the predictive value of memory complaints resulting in consultation with a GP as to the risk of subsequent dementia, we analysed the data from the follow-up of the Paquid cohort study carried out around Bordeaux. A sample of 1503 elderly people over 65, living at home and non-demented at the baseline screening, was considered. The risk of dementia was measured two and four years after the baseline screening: 60.8 per cent of subjects themselves perceived a memory impairment and 15.6 per cent expressed this complaint to their GP. Forty-eight developed a subsequent dementia. Taking the group without memory complaint as the reference set, three groups of elderly people could be recognized as at high risk of dementia: subjects with self-perceived memory impairment, consulting a GP with low memory performance or with normal memory performances, and subjects with memory complaints not resorting to a GP but with low memory performance. In non-demented elderly people, memory complaints expressed to the GP may be a strong predictor of dementia and should not be neglected.

Aged↗