Alzheimers

Subjective cognitive impairment (SCI), marked by situations such as when a person recognizes they can't remember a name like they used to or where they recently placed important objects the way they used to, is experienced by between one-quarter and one-half of the population over the age of 65. A seven-year study involving 213 adults (mean age 67) has found that healthy older adults reporting SCI are dramatically more likely to progress to MCI or dementia than those free of SCI (54% vs 15%). Moreover, those who had SCI declined significantly faster.

A German study involving nearly 4000 older adults (55+) has found that physical activity significantly reduced the risk of developing mild cognitive impairment over a two-year period. Nearly 14% of those with no physical activity at the start of the study developed cognitive impairment, compared to 6.7% of those with moderate activity, and 5.1% of those with high activity. Moderate activity was defined as less than 3 times a week.

Rapamycin, a drug that keeps the immune system from attacking transplanted organs, was recently found to extend the life span of aged research mice. Now a study involving genetically engineered mice has found that 10 weeks of taking the drug improved learning and memory and reduced Alzheimer's-like damage in the brain.

A study involving 57 cognitively healthy older adults has found that those who showed decreased memory performance two years later (20 of the 57) had higher baseline levels of phosphorylated tau231 in the cerebrospinal fluid, and more atrophy in the medial temporal lobe. Higher levels of damaged tau protein were associated with reductions in medial temporal lobe gray matter. The finding may be useful in early diagnosis of Alzheimer’s disease.

Midlife hypertension has been confirmed as a risk factor for the development of dementia in late life, but there have been conflicting findings about the role of late-life hypertension. Now a five-year study involving 990 older adults (average age 83) with cognitive impairment but no dementia, has found that dementia developed at around the same rate among participants with and without hypertension, among those with memory dysfunction alone and those with both memory and executive dysfunction.

By following 597 Alzheimer’s patients over 15 years, researchers have determined that a simple progression rate can be calculated at the initial visit, using symptom onset and present performance, and that this can reliably identify slow, intermediate and rapid progression.

A survey of more than 100 studies involving PIB-PET, a diagnostic tool that involves injecting a radiotracer called Pittsburgh compound B into the brain via the bloodstream, and imaging the brain with positron emission tomography (PET), has confirmed its sensitivity in detecting amyloid-beta protein plaques. The tool is not yet commercially available. The study also provides strong evidence supporting the theory that accumulation of amyloid-beta protein plaques in the brain is central to the development of Alzheimer’s.

Data from 330 participants in The 90+ Study, of whom 70% were women, has revealed an overall annual incidence rate of 18.2% for dementia, rising from 12.7% per year in the 90-94 age group, to 21.2% in the 95-99 age group and 40.7% per year in the 100+ age group. 60% of the cases were attributed to Alzheimer's disease, 22% vascular dementia, 9% mixed Alzheimer’s and vascular dementia and 9% other/unknown. Unlike previous findings, rates were very similar for men and women.

A new test has been developed that measures amyloid-beta oligomers in the cerebrospinal fluid, promising a reliable means of early diagnosis. In a comparison of patients with Alzheimer’s, patients with MCI that later developed into Alzheimer’s, and controls, levels of these protein fragments directly correlated with Alzheimer’s, and was more accurate than levels of the more usual amyloid plaques.

A computerized self test (CST) has been developed that is 96% accurate in diagnosing Alzheimer’s and MCI-A (compared to 71% for the MMSE and 69% for the Mini-Cognitive — tests currently in use). Moreover, the test accurately classified 91% of the six experimental groups (control, MCI, early Alzheimer's, mild to moderate, moderate to severe, and severe) as compared to 54% for the MMSE and 48% for the Mini-Cog. The brief, interactive online test is designed to be used in the primary care setting, where physicians may not have detailed training in recognizing cognitive impairments.