Research

A survey of 7796 older adults (65+) living in three geographic areas in England has allowed us to compare dementia rates over time, with an identical survey having been taken between 1989 and 1994. The overall prevalence of dementia fell significantly, from 8.3% to 6.5%.

The finding provides further evidence that a cohort effect exists in dementia prevalence.

http://www.thelancet.com/journals/lancet/article/PIIS0140-6736%2813%2961570-6/fulltext

A large Danish study comparing two groups of nonagenarians born 10 years apart has found that not only were people born in 1915 nearly a third (32%) more likely to reach the age of 95 than those in the 1905 cohort, but members of the group born in 1915 performed significantly better on tests of cognitive ability and activities of daily living. Additionally, significantly more members of the later cohort scored maximally on the MMSE (23% vs 13% of the earlier cohort).

People with Parkinson’s disease have a six times greater risk of developing dementia than the general population. A new study points to a way of picking out those who are at risk of dementia.

A five-year study involving 525 older adults (70+) found 46 had Alzheimer’s or aMCI and a further 28 went on to develop the conditions. The blood levels of 10 specific lipids predicted with more than 90% accuracy whether an individual would go on to develop either Alzheimer’s or aMCI within 2-3 years. The researchers speculate that the lower lipid levels could be an early indication that brain cells are beginning to lose their integrity and break down.

A three-year study involving 152 adults aged 50 and older, of whom 52 had been recently diagnosed with mild cognitive impairment and 31 were diagnosed with Alzheimer's disease, has found that those with mild or no cognitive impairment who initially had amyloid-beta plaques showed greater cognitive decline than those whose brain scans were negative for plaques. Moreover, 35% of plaque-positive participants who started with MCI progressed to Alzheimer's, compared to 10% without plaque, and they were more than twice as likely to be started on cognitive-enhancing medication.

More evidence for early changes in the eye in Alzheimer’s disease comes from a study involving both rats and postmortem human retinas. Changes were found in the retinal pigment epithelial layer (which harbors the supportive cells located in the back of the eye) and in the thickness of the choroidal layer that has blood vessels providing nutrients to the retina.

The finding is consistent with growing evidence that glaucoma is a neurodegenerative disorder similar to Alzheimer’s.

Analysis of 1,821 Alzheimer’s brains has found that 11% of them actually suffered from a variant called hippocampal sparing Alzheimer’s. This subtype has been neither well recognized nor treated appropriately, but is now revealed to be relatively common.

Blocking a receptor involved in inflammation in the brains of mice with severe Alzheimer’s produced marked recovery in blood flow and vascular reactivity, a dramatic reduction in toxic amyloid-beta, and significant improvements in learning and memory.

The receptor was the bradykinin B1 receptor (B1R), and the finding confirms a role of B1R, and neuroinflammation, in the development of Alzheimer’s. It also points to a new target for therapy.

A multi-year study involving 207 healthy older adults, in which their spinal fluids were repeatedly sampled and their brains repeatedly scanned, has found that disruptions in the default mode network emerges about the same time as chemical markers of Alzheimer’s appear in the spinal fluid (decreased amyloid-beta and increased tau protein). The finding suggests not only that amyloid-beta and tau pathology affect default mode network integrity early on, but that scans of brain networks may be an equally effective and less invasive way to detect early disease.

An analysis of the anatomical connectivity in the brains of 15 people with Alzheimer's disease, 68 with mild cognitive impairment and 28 healthy older individuals, has found several measures showed disease effects: