“A new study shows that having a high amount of beta amyloid or “plaques” in the brain associated with Alzheimer’s disease may cause steeper memory decline in mentally healthy older people than does having the APOE ?4 allele, also associated with the disease. “Our results show that plaques may be a more important factor in determining which people are at greater risk for cognitive impairment or other memory diseases such as Alzheimer’s disease,” said study author Yen Ying Lim, MPsych, with the University of Melbourne in Victoria, Australia. “Unfortunately, testing for the APOE genotype is easier and much less costly than conducting amyloid imaging.”
Study: Stronger effect of amyloid load than APOE genotype on cognitive decline in healthy older adults (Neurology). From the Abstract:
- Objective: Although the APOE ?4 allele is associated with more rapid decline in memory in healthy older adults, the significance of elevated cerebral ?-amyloid (A?) load for longitudinal changes in cognition is unclear.
- Conclusions: In this prospective study of healthy older adults, high cerebral A? load was associated with greater decline in episodic and working memory over 18 months. The APOE ?4 genotype was also associated with a decline in visual memory, although the effect was less than that observed for cerebral A? load.