Alzheimer’s more subtle in 80s

A new study suggests the relationship between brain shrinkage and memory loss in Alzheimer’s disease changes across the age spectrum.

The research, published in this month’s issue of Neurology, indicated age has a dramatic effect on the profile of brain atrophy and cognitive changes in Alzheimer’s disease.

The study’s author, Dr Mark Bondi of the University of California, said those who are 85 years of age make up the fastest growing population in the world and claims Alzheimer’s is most subtle in this group.

The study involved 105 people with Alzheimer’s disease and 125 people who were free from dementia and recruited through the Alzheimer’s disease Neuroimaging Initiative. Participants were grouped into those who were between 60 and 75 years of age and those aged 80 years and older. All were given tests that measured language, attention and speed of processing information, executive function, and immediate and delayed ability to recall information.

Participants also underwent brain scans to measure the thickness of the outermost tissue layers in the cerebrum, which is the largest part of the human brain, associated with higher brain function such as thought and action.

Even though the two groups had similar levels of overall cognitive impairment, researchers found the pattern of changes associated with Alzheimer’s disease appeared to be less noticeable in people over 80 years of age compared to those between the ages of 69 and 75 years. When compared to their healthy counterparts, executive function, immediate memory and attention or processing speed were less abnormal in those over 80 years of age compared to those aged 69 to 75 years old.

Those over the age of 80 years also showed less severe thinning of portions of the overall cerebrum and cerebral cortex, which plays a key role in memory, attention, perceptual awareness, thought, language, and consciousness; as compared to their healthy counterparts.

Researchers said the reasons for the thinning was because these brain areas decrease in thickness due to age, so there are fewer differences between those older participants who did not have dementia and the older participants who were suffering with the disease.