January 20, 2015

Alzheimer Disease & Associated Disorders - October-December 2014

Full text articles are available to fee paying members of Alzheimer’s Australia NSW by emailing NSW.Library@alzheimers.org.au




Help-Seeking for Dementia: A Systematic Review of the Literature

Background: Help-seeking (HS) for dementia presents a great challenge, especially because a timely and appropriate HS process might be associated with better outcomes for the person with dementia, their caregivers, and society. A clear understanding of the HS concept and its measurement in the area of dementia might improve the effectiveness of the process.Aims: The aims of our systematic review were: (1) to systematically obtain and evaluate the relevant literature on HS and dementia; and (2) to summarize current research findings and draw conclusions for future research and clinical care in this area.
Conclusions: Although the body of literature in the area of HS and dementia is growing, several conceptual and methodological limitations still have to be resolved to advance knowledge in the area.  p. 299-310
 

Feasibility and Validity of the Self-administered Computerized Assessment of Mild Cognitive Impairment With Older Primary Care Patients

We investigated whether a validated computerized cognitive test, the Computerized Assessment of Mild Cognitive Impairment (CAMCI), could be independently completed by older primary care patients. We also determined the optimal cut-off for the CAMCI global risk score for mild cognitive impairment against an independent neuropsychological reference standard. Lack of computer experience was the only patient characteristic that decreased the odds of independent CAMCI completion. These results support the feasibility of using self-administered computerized cognitive tests with older primary care patients, given the increasing reliance on computers by people of all ages. The optimal cut-off score had a sensitivity of 80% and specificity of 74%.  p. 311-319

Factors Associated With Primary Care Physicians’ Recognition of Cognitive Impairment in Their Older Patients
Although there are accurate screens for cognitive impairment, there is as yet no evidence that screening improves outcomes including primary care physicians’ (PCP) medical decision making. PCPs’ recognition of cognitive impairment being suboptimal, we investigated factors associated with improved recognition. Eligible patients were aged 65 years and above, without documented dementia or previous work-up for dementia, seen consecutively over 2 months by one of 13 PCPs. PCPs indicated whether they, the patient, or the family had concerns about each patient’s cognition. We enrolled 130 patients with any cognitive concerns and a matched sample of 133 without cognitive concerns, and administered standardized neuropsychological tests. PCP’s judgments of cognitive concern showed 61% sensitivity and 86% specificity against the neuropsychological standard. When combined with a Mini-Mental State Examination score ≤26, PCP recognition improved in sensitivity (82%) with some loss in specificity (74%). True positives increased when PCPs’ practices included more cognitively impaired patients and when patients reported poor memory. False positives increased when patients had diabetes, reported poor memory, or no or light alcohol consumption. Medical decision making can be improved by the Mini-Mental State Examination and greater exposure to cognitively impaired patients, but knowledge of certain risk factors for cognitive impairment negatively affected these decisions. p. 320-325

Is Bilingualism Associated With a Lower Risk of Dementia in Community-living Older Adults? Cross-sectional and Prospective Analyses
Objective: The aim of this study was to determine whether bilingualism is associated with dementia in cross-sectional or prospective analyses of older adults.
Methods: In 1991, 1616 community-living older adults were assessed and were followed 5 years later. Measures included age, sex, education, subjective memory loss (SML), and the modified Mini-mental State Examination (3MS). Dementia was determined by clinical examination in those who scored below the cut point on the 3MS. Language status was categorized based upon self-report into 3 groups: English as a first language (monolingual English, bilingual English) and English as a Second Language (ESL).C
Conclusions: We did not find any association between speaking >1 language and dementia
p. 326-332

The Effects of Spaced Retrieval Combined With Errorless Learning in Institutionalized Elders With Dementia: Recall Performance, Cognitive Status, and Food Intake
The purpose of this study was to explore the effects on recall performance, cognitive status, and food intake when using accumulating cues in a spaced retrieval (SR) paradigm. In a double-blinded experimental design, 32 participants in the SR combined with errorless learning (SR/EL) group and 29 participants in the SR-only group were trained in a variety of eating-related actions. Accumulating cues were used within each SR trial in the SR/EL group. The participants’ recall performance, the Mini-Mental State Examination (MMSE) scores, and the portion of a meal that participants had eaten were measured. After the 8-week training period, results showed significantly improved recall performances (P<0.0031) and food intake (t=2.140, P=0.038) in the SR/EL group compared with the SR-only group. MMSE scores showed no significant differences after the 8-week intervention (t=1.315, P=0.194). Results suggest that an SR/EL intervention could create optimal learning conditions for the self-regulation of common eating difficulties in people with dementia.  p. 333-339

Deficient Symbol Processing in Alzheimer Disease
Symbols and signs have been suggested to improve the orientation of patients suffering from Alzheimer disease (AD). However, there are hardly any studies that confirm whether AD patients benefit from signs or symbols and which symbol characteristics might improve or impede their symbol comprehension. To address these issues, 30 AD patients and 30 matched healthy controls performed a symbol processing task (SPT) with 4 different item categories. A repeated-measures analysis of variance was run to identify impact of different item categories on performance accuracy in both the experimental groups. Moreover, SPT scores were correlated with neuropsychological test scores in a broad range of other cognitive domains. Finally, diagnostic accuracy of the SPT was calculated by a receiver-operating characteristic curve analysis. Results revealed a global symbol processing dysfunction in AD that was associated with semantic memory and executive deficits. Moreover, AD patients showed a disproportional performance decline at SPT items with visual distraction. Finally, the SPT total score showed high sensitivity and specificity in differentiating between AD patients and healthy controls. The present findings suggest that specific symbol features impede symbol processing in AD and argue for a diagnostic benefit of the SPT in neuropsychological assessment. p. 340-346

Visit-to-Visit Blood Pressure Variability in Alzheimer Disease
The aim of this study was to evaluate visit-to-visit blood pressure (BP) variability in a cohort of patients with Alzheimer disease (AD) and healthy controls. Patients with clinically diagnosed mild or moderate AD and cognitively normal controls matched for age and sex were recruited and followed up for 6 months. To characterize the BP status of each individual, mean, maximum and minimum values, SD, and coefficient of variation were obtained for both systolic BP (SBP) and diastolic BP (DBP). Seventy AD patients and 140 controls were enrolled. No meaningful differences were found in prevalence or treatments of various vascular risk factors. AD patients had higher maximum and lower minimum values and greater SD and coefficient of variation of both SBP and DBP. Group differences in mean values were significant only for SBP. In the multiple logistic regression analysis, adjusted for confounding variables, all the indices related to BP variability were significantly associated with AD. Our results show that AD patients have a greater variability of both SBP and DBP in comparison with age-matched cognitive normal controls, suggesting potential implication in the pathogenesis or progression of the disease. p. 347-351

The Role of Cerebellar Volume in Cognition in the General Elderly Population
Background: It is unknown whether the cerebellum affects cognitive function in an aging community-dwelling population. In a population-based study on 3745 nondemented individuals aged 45 years and above, we investigated the relationship between cerebellar volume and cognitive function.
Methods: Brain volumes were obtained using automatic tissue segmentation of magnetic resonance imaging scans. Cognitive functioning was assessed using MMSE and cognitive compound scores of global cognition, executive function, information processing speed, memory, and motor speed. Linear regression modeling was used to study the associations between cerebellar volumes and cognitive measures, independent of cerebral volumes.
Results: We found a relationship between larger cerebellar volume and better global cognition, executive function, information processing speed, and motor speed. After adjustment for cerebral volume, only cerebellar gray matter volume remained borderline significantly associated with global cognition and information processing speed. After Bonferroni correction, the few associations found between cerebellar volume and cognition disappeared.
Conclusions: We only found a minor relationship between larger cerebellar volume and better cognition in healthy older adults, which further attenuated after correcting for cerebral volume. Our findings support the notion that cerebellar volume has an influence on cognition in aging, but that it is not the major leading structure. p. 352-357

Erythrocyte Membrane Stability to Hydrogen Peroxide is Decreased in Alzheimer Disease
The brain and erythrocytes have similar susceptibility toward free radicals. Therefore, erythrocyte abnormalities might indicate the progression of the oxidative damage in Alzheimer disease (AD). The aim of this study was to investigate erythrocyte membrane stability and plasma antioxidant status in AD. Fasting blood samples (from 17 patients with AD and 14 healthy controls) were obtained and erythrocyte membrane stability against hydrogen peroxide and 2,2′-azobis-(2-amidinopropane) dihydrochloride (AAPH), serum Trolox equivalent antioxidant capacity (TEAC), residual antioxidant activity or gap (GAP), erythrocyte catalase activity (CAT), erythrocyte superoxide dismutase (SOD) activity, erythrocyte nonproteic thiols, and total plasma thiols were determined. A significant decrease in erythrocyte membrane stability to hydrogen peroxide was found in AD patients when compared with controls (P<0.05). On the contrary, CAT activity (P<0.0001) and total plasma thiols (P<0.05) were increased in patients with AD compared with controls. Our results indicate that the most satisfactory measurement of the oxidative stress level in the blood of patients with AD is the erythrocyte membrane stability to hydrogen peroxide. Reduced erythrocyte membrane stability may be further evaluated as a potential peripheral marker for oxidative damage in AD.  p. 358-363

Brief Reports – p. 364-367
  • Screening Utility of the “Attended Alone” Sign for Subjective Memory Impairment
  • Retinal Vascular Dysfunction Relates to Cognitive Impairment in Alzheimer Disease

 
 
 


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