Biomedical subjects

Amarilis Acevedo

Publications and source records attributed to Amarilis Acevedo.

8 recordsLinked to original sources

PubMed2006

Stability of neurocognitive impairment in different subtypes of mild cognitive impairment.

There has been increasing interest in delineating different cognitive subtypes of mild cognitive impairment (MCI). It remains unclear, however, the extent to which neuropsychological impairment associated with amnestic, nonamnestic, and amnestic+ subtypes of MCI remains stable over time. In this study, 70 persons meeting the criteria for MCI and 38 cognitively normal elderly subjects received a baseline neuropsychological evaluation and were reevaluated 1 year later. Our results indicated that 84.6% of the persons initially classified as amnestic, 75% of those classified as nonamnestic, and 80% of the persons classified as MCI+ evidenced stable or more pronounced neuropsychological impairment across the follow-up period. Less than 7% of the amnestic and amnestic+ cases had nonimpaired neuropsychological profiles at their reevaluation at 12 months, and 16.7% of the nonamnestic cases had nonimpaired neuropsychological test profiles at follow-up. Approximately 87% of the cognitively normal subjects at baseline continued to have unimpaired neuropsychological performance at follow-up. These results indicate that the presence of neuropsychological impairment is relatively stable over a 12-month follow-up period among different cognitive subtypes of MCI, although 15-25% of the cases did not exhibit the specific cognitive deficits that characterized their performance at baseline.

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PubMed2006

Cognitive profiles in Alzheimer's disease and in mild cognitive impairment of different etiologies.

There has been increasing interest in determining whether amnestic, nonamnestic and multiple-domain subtypes of mild cognitive impairment (MCI) reflect different disease etiologies. In this study, we examined the extent to which cognitive profiles of nondemented patients with MCI diagnosed with prodromal Alzheimer's disease (AD) differed from those MCI patients diagnosed with vascular disease. We also compared these diagnostic groups to mildly demented patients diagnosed with AD and normal elderly controls. Results indicate that a majority of both MCI-AD and MCI-vascular patients experienced amnestic features and that multiple-domain was the most common presentation. MCI-AD and MCI-vascular groups did not differ on neuropsychological measures tapping memory, language, visuospatial skills/praxis or executive function. Further both MCI groups could be distinguished from dementia patients with regards to performance on measures of memory but not on non-memory measures. Considerable variability was observed in the degree of memory impairment among MCI patients with scores as much as 6 standard deviations below expected mean values. MCI-AD and MCI-vascular patients frequently exhibit both common and overlapping amnestic and nonamnestic features. The implication of these findings for future clinical research is discussed.

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PubMed2006

Depression and risk for Alzheimer disease: systematic review, meta-analysis, and metaregression analysis.

CONTEXT: A history of depression may increase risk for developing Alzheimer disease (AD) later in life. Clarifying this relation might improve understanding of risk factors for and disease mechanisms in AD. OBJECTIVE: To systematically review and complete a meta-analysis on the relation of depression and AD. DATA SOURCES: We conducted electronic bibliographic searches of MEDLINE, PsychLit, EMBASE, and BIOSIS using search terms sensitive to studies of etiology combined with searches on terms related to depression and AD and reviewed reference lists of articles. STUDY SELECTION: Studies with data contrasting depressed vs nondepressed patients who did and did not later develop AD were included. Studies that related continuous measures of depression and cognitive status were excluded. DATA EXTRACTION: Numerical data were independently extracted by 3 reviewers. They also rated studies on a scale that assessed quality indicators for observational studies. Data on the interval between observation of depression and the diagnosis of AD were collected when available. DATA SYNTHESIS: Meta-analytic evaluation with random-effects models resulted in pooled odds ratios of 2.03 (95% confidence interval, 1.73-2.38) for case-control and of 1.90 (95% confidence interval, 1.55-2.33) for cohort studies. Findings of increased risk were robust to sensitivity analyses. Interval between diagnoses of depression and AD was positively related to increased risk of developing AD, suggesting that rather than a prodrome, depression may be a risk factor for AD. CONCLUSIONS: A history of depression may confer an increased risk for later developing AD. This relation may reflect an independent risk factor for the disease.

Alzheimer Disease↗

PubMed2006

Using different memory cutoffs to assess mild cognitive impairment.

OBJECTIVE: Although mild cognitive impairment (MCI) is characterized by performance on memory and other measures below expected normative values, neither a scientific rationale nor a consensus exists regarding which measures have the most use or the optimal cutoffs to use to establish impairment. METHODS: Different memory measures were administered to 80 normal community-dwelling subjects divided into two age groups. This provided conormed data on eight different memory indices by which to compare 23 nondemented clinically diagnosed patients with MCI who met all other criteria for Alzheimer disease (AD). RESULTS: On immediate memory for passages, delayed visual reproduction, object memory, and a measure sensitive to semantic interference, 70%-78% of patients with MCI were identified as impaired at 1.5 standard deviations or greater below expected levels. Conditional logistical regression for age-matched samples indicated that consideration of raw scores for these neuropsychologic tests in combination did not significantly change the odds of MCI diagnosis. When impairment relative to the total normal elderly sample was calculated based on one or more impairments at a 1.5 or greater cutoff, specificity fell below acceptable levels when more than three memory measures were considered. CONCLUSION: An array of widely used neuropsychologic measures demonstrated utility in distinguishing patients with MCI-AD from cognitively normal community-dwelling elders. The appropriateness of more or less stringent cutoffs was highly influenced by the number of measures considered. These findings have important implications regarding the choice of cut points for impairment used for the diagnosis of MCI in both research and clinical settings.

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PubMed2004

Assessing the cognitive abilities that differentiate patients with Alzheimer's disease from normals: single and multiple factor models.

BACKGROUND: Understanding the structure of cognitive abilities in Alzheimer's disease (AD) has considerable practical and theoretical importance. Some investigators have argued that a single cognitive process underlies the deficits seen in AD, while others have argued for multiple cognitive processes. As deficits in cognitive abilities may reflect the pathological process or processes occurring in AD, determination of the structure of abilities in AD is important. OBJECTIVES: The purpose of this study was to assess the utility of single and multiple ability factor models in differentiating patients with AD from normals. RESULTS: Findings show that although a single factor model accounts for a large part of the variability of a battery of measures used to differentiate patients and normals, a multiple factor model performed substantially better based on multiple fit criteria. CONCLUSIONS: At least in this sample, a multiple ability factor model of cognitive abilities fit data better than a single factor model in differentiating patients with AD from normals.

Activities of Daily Living↗

PubMed2004

Semantic interference deficits and the detection of mild Alzheimer's disease and mild cognitive impairment without dementia.

Impairment in delayed recall has traditionally been considered a hallmark feature of Alzheimer's disease (AD). However, vulnerability to semantic interference may reflect early manifestations of the disorder. In this study, 26 mildly demented AD patients (mild AD), 53 patients with mild cognitive impairment without dementia (MCI), and 53 normal community-dwelling elders were first presented 10 common objects that were recalled over 3 learning trials. Subjects were then presented 10 new semantically related objects followed by recall for the original targets. After controlling for the degree of overall memory impairment, mild AD patients demonstrated greater proactive but equivalent retroactive interference relative to MCI patients. Normal elderly subjects exhibited the least amount of proactive and retroactive interference effects. Recall for targets susceptible to proactive interference correctly classified 81.3% of MCI patients and 81.3% of normal elderly subjects, outperforming measures of delayed recall and rate of forgetting. Adding recognition memory scores to the model enhanced both sensitivity (84.6%) and specificity (88.5%). A combination of proactive and retroactive interference measures yielded sensitivity of 84.6% and specificity of 96.2% in differentiating mild AD patients from normal older adults. Susceptibility to proactive semantic interference may be an early cognitive feature of MCI and AD patients presenting for clinical evaluation.

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PubMedDate not supplied

Cognitive rehabilitation of mildly impaired Alzheimer disease patients on cholinesterase inhibitors.

OBJECTIVE: The authors evaluated the efficacy of a new cognitive rehabilitation program on memory and functional performance of mildly impaired Alzheimer disease (AD) patients receiving a cholinesterase inhibitor. METHODS: Twenty-five participants in the Cognitive Rehabilitation (CR) condition participated in two 45-minute sessions twice per week for 24 total sessions. CR training included face-name association tasks, object recall training, functional tasks (e.g., making change, paying bills), orientation to time and place, visuo-motor speed of processing, and the use of a memory notebook. Nineteen participants in the Mental Stimulation (MS) condition had equivalent therapist contact and number of sessions, which consisted of interactive computer games involving memory, concentration, and problem-solving skills. RESULTS: Compared with the MS condition, participants in CR demonstrated improved performance on tasks that were similar to those used in training. Gains in recall of face-name associations, orientation, cognitive processing speed, and specific functional tasks were present post-intervention and at a 3-month follow-up. CONCLUSION: A systematic program of cognitive rehabilitation can result in maintained improvement in performance on specific cognitive and functional tasks in mildly impaired AD patients.

Activities of Daily Living↗

PubMedDate not supplied

Semantic interference in mild Alzheimer disease: preliminary findings.

OBJECTIVE: The authors evaluated the usefulness and psychometric properties of the Semantic Interference Test (SIT) in patients with mild Alzheimer disease (AD). METHODS: Subjects were first presented with 10 common objects to be learned over three trials. Proactive interference was assessed by having subjects recall 10 new objects that were semantically related to the previous ones. Retroactive interference was assessed by having subjects recall the original 10 objects. RESULTS: Controlling for overall memory impairment, very mildly impaired AD patients demonstrated significantly greater proactive and retroactive interference effects than the normal, community-dwelling comparison group. The proactive score alone and the combined proactive-plus-retroactive score index were more effective than traditional neuropsychological measures of delayed recall in distinguishing between the very mildly impaired AD group and the normal-comparison group. CONCLUSION: The authors discuss the potential usefulness of the SIT in identifying vulnerability to semantic interference in early AD.

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