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Thursday, August 25, 2011

Sleep Apnea Doubles the Chance that an Elderly Woman Will develop Dementia Wthin Five Years



In older women, brief pauses in breathing during sleep (apnea) may cause more than daytime drowsiness, increased cardiovascular risk, and insulin resistance—it may also lead to mild cognitive impairment (MCI) or dementia. Results published in last week’s Journal of the American Medical Association showed that women with sleep-disordered breathing (SDB)—pauses in breathing or reduced ventilation quality during sleep—are more likely to develop cognitive impairment five years later.

The researchers longitudinally observed a subset of women enrolled in the large Study of Osteoporotic Fractures—a multicenter study of more than 10,000 women. First author Kristine Yaffe, MD and colleagues wanted to see if older women with SDB had a higher chance of developing MCI or dementia.

Between 2002 and 2004, the researchers conducted behavioral tests—including the Mini-Mental State Examination and a modified version of Trails B—and an at-home sleep study of 461 women (mean age 82.3 years). None of these women had dementia at baseline, or used SDB therapy, such as continuous positive airway pressure (CPAP).
At the time of follow-up about five years later, the women underwent more extensive cognitive tests than they did at baseline. Of the women who did not have SDB at baseline, 31 percent developed MCI or dementia. Of the women who did have SDB, 45 percent received either one of the diagnoses.. After adjusting for demographic and physiological factors, as well as other diseases and medication use, the researchers found that the odds of developing MCI or dementia were 85 percent higher for women with SDB.

The biology behind this finding may include hypoxia, or decreased oxygen delivery to certain parts of the brain, including the hippocampus which is critical in memory function. In addition, sleep fragmentation, which can interfere with memory consolidation which occurs during certain stages of sleep, may also lead to cognitive problems.

Because the Study of Osteoporotic Fractures cohort is composed of mostly white women, these findings may not be generalizable to men or more ethnically diverse populations. But, the results are important enough to warrant further studies looking at the link between sleep apnea and dementia.


Yaffe K, Laffan AM, Harrison SL, Redline S, Spira AP, Ensrud KE, Ancoli-Israel S, Stone KL. Sleep-disordered breathing, hypoxia, and risk of mild cognitive impairment and dementia in older women. JAMA. 2011 Aug 10.



By Michael Rafii, MD, PhD
Director, Memory Disorders Clinic
Associate Medical Core Director
Alzheimer’s Disease Cooperative Study
University of California, San Diego

 
Author: Michael Rafii MD, PhD at 3:17 PM 0 Comments

Thursday, August 18, 2011

Socio-Demographics, Health Factors and Cognitive Impairment in Elderly Taiwanese


Dear Readers,

A recent study published in BMC Public Health focused on the association between socio-demographic and health factors to cognitive impairment in the elderly in Taiwan. This study utilized data from the National Health Interview Survey conducted in Taiwan in 2005. The overall sample group was selected using a multi-stage approach, using a stratified systematic sampling design that was felt to provide a nationally representative sample of the population. The entire data set was comprised of 24726 persons, with 2727 persons comprising the study cohort aged 65 and older. Because of missing or incomplete cognitive data, the study sample was reduced to 2119; the sample size for this report.

Baseline demographic variables were obtained by self report. In addition to questions regarding history of chronic medical conditions such as hypertension, diabetes, high cholesterol/use of an anti-cholesterol agents, stroke, renal disease, cancer, osteoporosis, gout and respiratory disease; questions regarding level of difficulty in performing activities of daily living and physical function tasks were obtained. Dietary measures, smoking, alcohol intake and leisure activities also were obtained in this survey. The Mini-Mental State Examination was the test used to assess cognitive function.

Of the 2119 persons in the study, there were 1347 persons between the ages of 65-74 yrs and 772 aged 75yrs +. The mean age of the study sample was 73.3 yrs ( SD = 5.9), 48% were female and 29.4 % of the persons included were illiterate. In basic analyses, cognitive impairment rates increased with older age and decreased with higher level of education. Women and single persons were more likely to have cognitive impairment as were those with low social support.

In cross sectional analyses, some general themes emerged: a gradient relationship between decline of physical function and impaired cognitive function was evident along with worse cognitive performance in those with depressive symptoms and poor self rated health. Non smokers had higher rates of cognitive impairment than smokers, whereas "exercisers" had lower proportion of cognitive impairment than sedentary individuals. Individuals who were coffee drinkers, took a multivitamin, or had a higher BMI had lower percentages of having cognitive problems.

The main finding from this study, was that risk factors identified for cognitive impairment or decline in western cultures, appear to be the same for elderly Taiwanese. Although the analyses in this study were cross sectional, the data were derived from a larger population based sample, thus increasing the confidence in these findings. As with many population based studies examining cognitive decline in the elderly, most of the risk factors identified here, were modifiable, and thus employing similar strategies for prevention and modification in both the aging Western and Asian populations, could prevent or decrease the risk of cognitive impairment on a global level.

To learn more about this study or related research in Taiwan please refer to:

Wu M-S, Lan T-H, Chen C-M et al. Socio-demographic and health-related factors associated with cognitive impairment in the elderly in Taiwan. BMC Public Health 2011, 11:22

Yen YC, Yang MJ, Shih CH et al. Cognitive impairment and associated risk factors among aged community members. Int J Geriatr Psychiatry 2004, 19 (6): 564-569

Thanks for reading.

Neelum T. Aggarwal, MD
Steering Committee Member, ADCS
Rush Alzheimer’s Disease Center
Rush Institute for Aging
Chicago, IL
 
Author: Neelum Aggarwal MD at 3:22 PM 0 Comments

Thursday, August 11, 2011

Promising Research on Blood Test for Alzheimer’s Disease


Researchers the University of Medicine and Dentistry of New Jersey (UMDNJ) and Durin Technologies, Inc., have developed a blood test that shows promise as a method to diagnose Alzheimer’s disease with unprecedented accuracy.

The test has a diagnostic sensitivity of 96 percent and a specificity of 92.5 percent and has the potential to diagnose Alzheimer’s disease in its earliest stages, years before symptoms of dementia appear. The same test also demonstrated the ability to distinguish Alzheimer’s from Parkinson’s disease, a closely related neurodegenerative disorder. The research team’s findings appear in the August 3rd issue of the journal PLoS ONE.*

The researchers screened for antibodies against some 9,500 proteins from human blood samples from 50 AD (early- and late-stage) and 40 non-demented controls (young and old). Half of the AD and control samples served as the training set, from which 451 antibodies came up more frequently in the AD group. The researchers chose the ten antibodies showing the greatest difference between AD and controls, and verified these markers in an independent analysis with the remaining 25 AD and 20 control samples. AD blood samples were also compared against blood from Parkinson's disease and breast cancer patients, with accuracy rates of the 10 markers exceeding 90 percent in all cases.

However, there are limitations to this study. Because the blood came from commercial labs rather than controlled research cohorts, no information was given on how the samples were collected or processed, or whether the patients had brain atrophy or amyloid. In addition, the results will need to be independently confirmed by other labs, and in larger sample sizes. Another limitation in the vast majority of studies of diagnostic tests is that the “gold standard” is based on a clinical rather than autopsy diagnosis. However, this paper does give us hope that a simple blood test may soon be part of a panel of tests utilized to diagnose Alzheimer’s disease.

*Nagele E, Han M, DeMarshall C, Belinka B, Nagele R. Diagnosis of Alzheimer’s Disease Based on Disease-Specific Autoantibody Profiles in Human Sera. PLoS ONE. 3 Aug 2011.




By Michael Rafii, MD, PhD
Director
Memory Disorders Clinic
Associate Medical Core Director
Alzheimer’s Disease Cooperative Study
University of California, San Diego

 
Author: Michael Rafii MD, PhD at 8:53 AM 0 Comments

Thursday, August 04, 2011

Aboriginal Experiences of Aging and Dementia: Perspectives from Canada


Dear Readers,

Aboriginal seniors are the most rapidly growing demographic group in Canada based on data from the 2004 Canadian census. Because Alzheimer's disease is related to advancing age, one would expect that dementia and Alzheimer's disease would be common among this group. Yet, when one searches the literature for data about dementia in Aboriginals (or native Americans in the US), there are very few articles on this topic. Thus, the recent article about Aboriginal perceptions of aging, in the Journal of Cross Cultural Gerontology, is an important addition to the relatively scant literature in this area.

In this study, funded through the Canadian Institutes of Health Research: New Emerging Team (NET), a Rural and Remote Memory Clinic was established in Saskatoon, Saskatchewan, where rural dwelling older adults (Aboriginals and non Aboriginals) were evaluated. The Aboriginals were invited to participate in this study. Four participants (age 59y-73y) from the Grandmothers Group- a group of Aboriginal seniors who had experience caregiving, met regularly at the Center to discuss issues facing the community and participated in 6 informant type interviews. Members of this group represented the following tribes: Cree, Salteaux, and Métis. Participants spoke English, but also spoke a variety of dialects including Plains Cree, Mitchif Cree, French and Salteaux.

Interviews were conducted that focused on three key areas, aging, dementia and caregiving using a group facilitator/Aboriginal counselor. From the focus groups, a few prominent themes emerged: (1) Normal aging meant going "back to the baby stage", (2) a "big change in culture” was the cause of illness (including dementia) and (3) the healthcare system needed to be more culturally grounded. Cognitive tests included the CASI - "D" (Community Screening Interview for Dementia) test and the Pyramids and Palm Trees test (a test specific for semantic dementia).

With regards to perceptions of aging and dementia, the group members indicated that there was no specific Cree word or term for "dementia" and going back to the "baby stage" signified the "circle of life" [circular symbols are very important in Cree culture]. When an older person was exhibiting signs suggestive of dementia (i.e. wandering, hoarding); this was regarded as what "normal" persons in the community exhibited. Further, with regards to the topic of caregiving, changes in the community involvement of caregiving to elders, was discussed under the theme of "big change in culture". Many of the participants felt that increased pace of life, spreading out of the families had led to less support, more isolation and loneliness and more stress and more illness.

With regards to culturally grounded healthcare, participants stated that communication should have richly colored visual images to convey the information and assess functions. Many participants said that the "visual" kept their interest, and made them ask and answer questions in the assessment process. Thus, the Pyramids and Palm Trees test was modified to include color photo stimuli instead of black and white line drawings, and modified to have more culturally relevant symbols and became the Grasshoppers and Geese test. The CASI "D" was modified to remove/edit any items that required formal education or exposure to urban culture- allowing for a more "free" and relaxed assessment.

This descriptive study highlights the need for further understanding of the "bio-cultural" aspects of dementia, and how understanding the cultural contributions to perceptions of aging and dementia, will ultimately provide healthcare providers a rationale for delivering better communication and assessment tools to their patients and families. To learn more about this study or related research in Native Americans (in Canada and the United States), please refer to:

Lanting S, Crossley M, Morgan D, Cammer A. Aboriginal Experiences of Aging and Dementia in a Context of Socio-cultural Change: Qualitative Analysis of Key Informant Group Interview with Aboriginal Seniors. J Cross Cult Gerontology (2011) 26: 103-117

Henderson JN & Henderson LC. Cultural construction of disease: a supernormal construct of dementia in an American Indian Tribe. Journal of Cross Cultural Gerontology, 17, 197-212.

Thanks for reading.


Neelum T. Aggarwal, MD
Steering Committee Member, ADCS
Rush Alzheimer’s disease Center
Rush Institute for Aging
Chicago, IL
 
Author: Neelum Aggarwal MD at 2:41 PM 0 Comments

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The Alzheimer's Disease Cooperative Study (ADCS) was formed in 1991 as a cooperative agreement between the National Institute on Aging (NIA) and the University of California, San Diego. The ADCS is a major initiative for Alzheimer's disease (AD) clinical studies in the Federal government, addressing treatments for both cognitive and behavioral symptoms. This is part of the NIA Division of Neuroscience's effort to facilitate the discovery, development and testing of new drugs for the treatment of AD and also is part of the Alzheimer's Disease Prevention Initiative.

The ADCS was developed in response to a perceived need to advance research in the development of drugs that might be useful for treating patients with Alzheimer's disease (AD), particularly drugs that might not be developed by industry.