MCI: Research reports

High blood pressure associated with risk for mild cognitive impairment

A study of nearly 1000 older adults (average age 76.3) without mild cognitive impairment at the start of the study found that over the follow-up period (average: 4.7 years), 334 individuals developed mild cognitive impairment, of which 160 were amnestic (reduced memory) and 174 were non-amnestic. Hypertension (high blood pressure) was associated with an increased risk of non-amnestic mild cognitive impairment; but not with amnestic mild cognitive impairment.
The report appeared in the December issue of Archives of Neurology.  Full reference
http://www.eurekalert.org/pub_releases/2007-12/jaaj-hbp120607.php

Difficulty identifying odors may predict cognitive decline

Older adults who have difficulty identifying common odors may have a greater risk of developing mild cognitive impairment, increasingly recognized as a precursor to Alzheimer’s disease.  A study of nearly 600 older adults (average age 79.9) found that 30.1% developed mild cognitive impairment over the five-year period of the study. Risk of developing mild cognitive impairment was greater for those who scored worse on an odor identification test given at the start of the study. For example, those who scored below average (eight) were 50% more likely to develop MCI than those who scored above average (11). This association did not change when stroke, smoking habits or other factors that might influence smell or cognitive ability were considered. Impaired odor identification was also associated with lower cognitive scores at the beginning of the study and with a more rapid decline in episodic memory (memory of past experiences), semantic memory (memory of words and symbols) and perceptual speed. The odor test involved identifying 12 familiar odors given four possible alternatives to choose from.
The report appeared in the July issue of Archives of General Psychiatry. Full reference
http://www.eurekalert.org/pub_releases/2007-07/jaaj-dio062807.php

Senior’s memory complaints should be taken seriously

A study involving 120 people over 60 found those who complained of significant memory problems who still performed normally on memory tests had a 3% reduction in gray matter density in their brains. This compares to 4% in those diagnosed with mild cognitive impairment. This suggests that significant memory loss complaints may indicate a very early "pre-MCI" stage of dementia for some people.
The study was published in the September 12 issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2006-09/aaon-fym090506.htm

Risk of mild cognitive impairment increases with less education

A study of 3,957 people from the general population of Olmsted County, Minnesota is currently in train to find how many of those who did not have dementia might have mild cognitive impairment. A report on the findings so far suggests 9% of those aged 70 to 79 and nearly 18% of those 80 to 89 have MCI. Prevalence varied not only with age but also years of education: 25% in those with up to eight years of education, 14% in those with nine to 12 years, 9% in those with 13 to 16 years, and 8.5% in those with greater than 16 years.
Findings from this study were presented April 4 at the American Academy of Neurology meeting in San Diego.
http://www.eurekalert.org/pub_releases/2006-04/mc-mci033006.htm

Link between size of hippocampus and progression to Alzheimer's

A study of 20 older adults with mild cognitive impairment has found that the hippocampus was smaller in those who developed into Alzheimer's during the 3 year period.
The research appeared in the May issue of the Archives of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2006-05/uoc--rml050406.htm

Post-mortem brain studies reveal features of mild cognitive impairment

Autopsies have revealed that the brains of patients with mild cognitive impairment display pathologic features that appear to place them at an intermediate stage between normal aging and Alzheimer's disease. For instance, the patients had begun developing neurofibrillary tangles, but the number of plaques was similar to that in healthy patients. All patients with mild cognitive impairment had abnormalities in their temporal lobes, which likely caused their cognitive difficulties, and many also had abnormalities in other areas that did not relate to the features of Alzheimer's disease. In a second study, of 34 patients with mild cognitive impairment who had progressed to clinical dementia before their deaths, 24 were diagnosed (post-mortem) with Alzheimer’s, and 10 with other types of dementia. As in the other study, all patients had abnormalities in their temporal lobes.
The two studies appeared in the May issue of Archives of Neurology. Full reference 2nd
http://www.eurekalert.org/pub_releases/2006-05/jaaj-pbs050406.htm

Two pathways lead to Alzheimer's disease

Mild cognitive impairment (MCI), a transitional stage between normal cognition and Alzheimer's disease, has been categorized into two sub-types on the basis of differing symptoms. Those with the amnesic subtype (MCI-A) have memory impairments only, while those with the multiple cognitive domain subtype (MCI-MCD) have other types of mild impairments, such as in judgment or language, and mild or no memory loss. Both sub-types progress to Alzheimer's disease at the same rate. A new imaging technique has now revealed that these types do in fact have different pathologies. The hippocampus of patients with MCI-A was not significantly different from that of Alzheimer's patients (who show substantial shrinkage), but the hippocampus of those with MCI-MCD was not significantly different from that of the healthy controls.
The report appeared in the January issue of Archives of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2006-01/uopm-tpf010606.htm

Concussions increase chance of age-related cognitive impairment

A study involving retired National Football League players found that they had a 37% higher risk of Alzheimer's than other U.S. males of the same age. Some 60.8% of the retired players reported having sustained at least one concussion during their professional playing career, and 24% reported sustaining three or more concussions. Those with three or more concussions had a five-fold greater chance of having been diagnosed with mild cognitive impairment and a three-fold prevalence of reported significant memory problems compared to those players without a history of concussion. As the study was based on self-reported answers to the health questions, further studies are needed to confirm the findings, but it does seem likely that head injuries earlier in life increase the chance of developing dementia or mild cognitive impairment.
The study appeared in the October issue of Neurosurgery. Full reference
http://www.eurekalert.org/pub_releases/2005-10/uonc-nsa101005.htm

New computer program may enable early prediction of Alzheimer's risk

Researchers have developed a brain scan-based computer program that quickly and accurately measures metabolic activity in the hippocampus, a key brain region that shrinks with the development of Alzheimer’s. The study followed 53 normal subjects aged 54 to 80 for at least 9 years and in some cases for as long as 24 years, and found that hippocampal glucose metabolism was significantly reduced on the first scan of those 25 individuals who would later experience cognitive decline related to either mild cognitive impairment or to Alzheimer's. The findings bring hope of being able to predict who will develop Alzheimer’s at least 9 years ahead of symptoms.
The technical details of the program were published in the June issue of Neurology. Full reference
http://www.eurekalert.org/pub_releases/2005-06/nyum-ncp061505.htm

A study of over 700 elderly men and women has investigated the relationship between diabetes and cardiovascular disease risk factors and cognitive health. Researchers found that the presence of coronary heart disease, high cholesterol, or hypertension increased the risk of later cognitive decline, with a particularly strong effect in African Americans. They also found that although the diagnosis of diabetes increased the risk of cognitive decline by as much as two fold, the presence of high levels of fasting glucose (therefore, low insulin levels) substantially decreased the risk of cognitive decline in diabetic patients.

Data from a 24-week pilot trial of the diabetes drug rosiglitazone in patients with mild cognitive impairment (MCI) or very mild Alzheimer's disease found those who received rosiglitazone – a drug that boosts insulin activity – did not decline in their performance on memory and attention tests.

Donepezil may have short-term benefit for mild cognitive impairment

Preliminary data from a recently completed clinical trial of 769 patients with mild cognitive impairment indicates that those taking the drug donepezil were at reduced risk of progressing to Alzheimer's disease for 18 months. The reduced risk disappeared after 18 months, and by the end of the 3-year study, the probability of progressing to Alzheimer’s was the same in the two groups. The study compared donepezil, vitamin E, or placebo. There was no apparent benefit from vitamin E.
http://www.eurekalert.org/pub_releases/2004-07/nioa-dmh071504.htm
http://www.eurekalert.org/pub_releases/2004-07/mc-tcs071504.htm

Minorities hardest hit by Alzheimer's disease

A study of 119 Latinos and 55 non-Latino white Alzheimer patients suggests that Latinos in the U.S. develop Alzheimer's symptoms much earlier than their white, non-Latino peers. There are several known factors which may be responsible for this apparent vulnerability in Latinos: high rates of vascular disease, leave school earlier, and less likely to use medical services or have health insurance than other Americans.

South Carolina, as the only U.S. state that keeps a comprehensive database of people with a diagnosis of Alzheimer's disease, has found that African Americans aged 55 to 64 years were more than three times as likely to have Alzheimer's as their European American counterparts. At ages 65 to 84, African Americans were more than twice as likely to have Alzheimer's. South Carolina has greater rates of obesity, diabetes, and related health problems than the rest of the country, especially amongst African Americans.

Another study has found that, in order to avoid overestimating the number of African Americans who may have early signs of Alzheimer's disease, screening tests must be adapted to cultural differences. The study involved 635 people over the age of 60. Researchers found that, using current scoring methods, African Americans scored lower on various neuropsychological tests. Even when education was taken into account, 35% of African Americans scored low enough to warrant a diagnosis of MCI, compared to only 15% of European Americans. However, when the researchers applied new, racially sensitive scoring methods they've developed, the difference in MCI rates disappeared.
References
http://www.eurekalert.org/pub_releases/2004-07/aa-mhh070704.htm

Rate of brain volume loss predicts dementia

A new study has found that rates of total brain volume loss may help identify patients with mild cognitive impairment who are at high risk of developing dementia. The study followed 55 people over 14 years, and found that loss of volume in the hippocampus predicted which mildly cognitively impaired individuals would stay stable and which would decline to Alzheimer's with 70% accuracy, while the rate of total brain volume loss was 62% accurate in predicting cognitive outcome. Combining both variables produced the strongest model: 75% accuracy. The discovery could help doctors plan early treatment strategies and prevention studies.
The study was presented at the 56th annual meeting of the American Academy of Neurology in San Francisco.
http://www.eurekalert.org/pub_releases/2004-04/ohs-osr042804.htm

More sensitive test norms better predict who might develop Alzheimer's disease

Early diagnosis of Alzheimer's is becoming more important with new medical and psychological interventions that can slow (but not stop) the course of the disease. Given this, it is suggested that more sensitive testing may be necessary for highly intelligent people, who, on average, show clinical signs of Alzheimer's later than the general population. Once they show such signs, they decline much faster. A study of 42 older people with IQ's of 120 or more, used two different test norms to forecast problems: the standard norm, derived from a large cross-section of the population, or an adjusted high-IQ norm that measured changes against the individual's higher ability level. The raised cutoffs predicted that 11 of the 42 individuals were at risk for future decline – compared with standard cutoffs, which indicated they were normal. True to the former prediction, three and a half years later, nine of those 11 people had declined. Six of those went on to develop mild cognitive impairment (MCI), a transitional illness from normal aging to a dementia (of which one type is Alzheimer's). Five of these individuals have since received a diagnosis of Alzheimer's disease, two years after this study was submitted. It is also suggested that, at the other end of the scale, those with below-average intelligence have the potential for being misdiagnosed as 'demented' when they are not, and the norms should be adjusted downwards accordingly.
This finding is reported in the January issue of Neuropsychology. Full reference
http://www.eurekalert.org/pub_releases/2004-01/apa-mst122903.htm

Brief telephone questionnaire screens for early signs of dementia

Researchers have developed a brief telephonic questionnaire that helps distinguish between persons with early signs of dementia and persons with normal cognitive function. The questionnaire provides a way to reach out to persons with dementia whose impairment otherwise may go undetected until substantial cognitive deterioration has occurred. The questionnaire consists of a test of delayed recall and 2 questions that ask whether the person needs help with remembering to take medications or with planning a trip for errands. It is estimated that of 100 people who score positive on this test, 42 will actually have cognitive impairment. In other words, this does not provide a diagnosis of Alzheimer’s, but provides evidence that further evaluation is required. The rate of false positives compares favorably to other types of screening tests. A further study is underway to confirm the validity and reliability of the test.
The report was published in the August issue of the Journal of Clinical Outcomes Management. Full reference
http://www.eurekalert.org/pub_releases/2003-09/twc-btq091603.htm

An analysis of data from 40 participants enrolled in a long-term study at the UCSD Alzheimer’s Disease Research Center (ADRC) found that "paper-and-pencil" cognitive skills tests administered to normal subjects averaging 75 years of age contained early signs of cognitive decline in those subjects who later developed Alzheimer’s disease. All participants were symptom-free when they took the test. The differences were quite subtle - only some performance measures were affected. http://www.eurekalert.org/pub_releases/2002-04/uoc--trs040502.htm

A three-year study of 48 healthy people from 60 to 80 years old, by New York University School of Medicine researchers, predicted which healthy elderly men and women would develop memory impairment based on scans of their brains. At the beginning of the study, everyone scored within the normal range on a battery of tests typically used to detect early loss of memory and other mental skills. However, PET scans revealed a reduction in glucose metabolism in an area of the brain called the entorhinal cortex among 12 people. Three years later, 11 of these people had experienced mild cognitive impairment and one had developed Alzheimer's disease. "Our work extends the use of PET scanning to identifying in normal aging subjects the earliest metabolic abnormalities that may lead to the memory losses referred to as mild cognitive impairment (MCI). The diagnosis of MCI carries a high risk for future Alzheimer's disease."
The study is published in the September 11 issue of The Proceedings of the National Academy of Sciences.
http://www.eurekalert.org/pub_releases/2001-09/nyum-bps090701.htm