New study looks at mental aging in those at genetic risk of Alzheimer's

Reported by Susan Aldridge, PhD, medical journalist

APOE4 carriers age normally at least to mid-60s before Alzheimer's risk kicks in.
Previous research has revealed that carriers of the APOE4 gene are at genetic risk of Alzheimer's disease. Scientists at the University of Melbourne now report from the PATH Through Life Project, which compares mental aging in those who do and do not carry the APOE4 gene variant.

The study involved 6,560 people who were assessed from age 20 to 60 with mental performance tests. There was no significant difference in memory, reaction time, reading vocabulary and mental speed between those who carried the APOE4 gene variant and those who did not. All showed a decline in performance with age in all tests - except for reading vocabulary which does not tend to change with age. The researchers put this decline down to normal cognitive aging. They say the findings suggest that the genetic risk of APOE4 is one that shows itself only in old age, where it somehow accelerates the brain changes that lead to Alzheimer's disease.

Source
Neuropsychology January 2007 Volume 21 number 1