Biomedical subjects

David A Loewenstein

Publications and source records attributed to David A Loewenstein.

11 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

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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PubMed2005

Psychiatric aspects of mild cognitive impairment.

Mild cognitive impairment in the elderly may represent a transitional phase between normal aging and early Alzheimer's disease (AD). It recently has been recognized as a distinct clinical entity with potentially different cognitive subtypes and etiologies. Like AD, studies have shown that psychiatric symptoms are more common than in the cognitively normal geriatric population. Understanding these symptoms has been recognized as important not only because they may impair patient function and caregiver burden, but also these symptoms may be relevant to understanding the development of AD in general. This article presents current information on psychiatric symptoms in mild cognitive impairment, their suggested role in the pathophysiology of AD and future research considerations on the subject.

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PubMed2005

Caregiver appraisals of functional dependence in individuals with dementia and associated caregiver upset: psychometric properties of a new scale and response patterns by caregiver and care recipient characteristics.

UNLABELLED: To evaluate psychometric properties and response patterns of the Care-giver Assessment of Function and Upset (CAFU), a 15-item multidimensional measure of dependence in dementia patients and caregiver reaction. METHOD: 640 families were administered the CAFU (53% White, 43% African American, and 4% mixed race and ethnicity). We created a random split of the sample and conducted exploratory factor analyses on Sample 1 and confirmatory factor analyses on Sample 2. Convergent and discriminant validity were evaluated using Spearman rank correlation coefficients. RESULTS: A two-factor structure for functional items was derived, and excellent factorial validity was obtained. Convergent and discriminant validity were obtained for function and upset measures. Differential response patterns for dependence and caregiver upset were found for caregiver race, relationship, and care recipient gender but not for caregiver gender. DISCUSSION: The CAFU is easily administered, reliable, and valid for evaluating appraisals of dependencies and upsetting care areas.

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PubMed2004

Conversion to dementia among two groups with cognitive impairment. A preliminary report.

OBJECTIVE: To determine the conversion rates to dementia in patients diagnosed with mild cognitive impairment (MCI) thought to be caused by incipient Alzheimer's disease (MCI-AD) or with MCI with features of vascular disease (MCI-Vas). METHODS: On the basis of patient history, neurocognitive, neurological and MRI evaluation, 99 patients were diagnosed with MCI-AD and 35 with MCI-Vas. Conversion to dementia over an average of a 2.4 +/- 1.8-year period was determined. RESULTS: Over the follow-up period, 44% converted to dementia, 51.5% remained classified as MCI, and 4.5% were reclassified as cognitively normal. The conversion rate to dementia was significantly faster at 3 years for the MCI-AD (50.5%) than for the MCI-Vas group (25.7%). The neuropsychological test found to best differentiate converters from non-converters was the Fuld-OME, a measure of learning and recall. Age, education, gender or APOE epsilon4 allele frequency did not differentiate converters from non-converters. CONCLUSIONS: MCI-AD and MCI-Vas are clinically meaningful subtypes of MCI that may convert to dementia at different rates. Prospective studies on larger subsets of MCI patients are required to confirm these findings.

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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.

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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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PubMed2003

The effect of a family therapy and technology-based intervention on caregiver depression.

PURPOSE: The majority of persons with Alzheimer's disease (AD) are cared for at home by a family member such as a spouse or daughter. Caregiving places enormous demands on these caregivers, and the negative consequences associated with caregiving are well documented. This paper reports results from the Miami site of the REACH (Resources for Enhancing Alzheimer's Caregiver Health) program that examined the efficacy of a family therapy and technology-based intervention in reducing depressive symptoms (according to the Center for Epidemiological Studies Depression scale) among family caregivers of AD patients at 6 months and 18 months follow-up. DESIGN AND METHODS: There were 225 White American and Cuban American caregivers that were randomized into a structural ecosystems therapy, structural ecosystems therapy + computer-telephone integrated system, or minimal support control condition. RESULTS: Caregivers in the combined family therapy and technology intervention experienced a significant reduction in depressive symptoms at 6 months. The 18-month follow-up data indicated that the intervention was particularly beneficial for Cuban American husband and daughter caregivers. IMPLICATIONS: The results indicate that information technology has a promising role in alleviating distress and depression among groups of AD caregivers. The data also demonstrate that interventions have differential impacts according to ethnic group and the caregiver-patient relationship.

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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.

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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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