One of these genes is thought to be the ApoE e-4 allele. Speaking of age, it too is important. The normal aging process causes a loss of neurons, synapses and the total amount of acetylcholine in the brain. As noted earlier, the incidence of AD doubles every 5 years after the age of 60 . Between the ages of 60-64 years one percent of the population is demented, while the number sky rockets to over 40 percent after the age of 85 years.
Larger studies are ongoing, so stay tuned.
It is not unusual for a lawsuit to allege that because someone has a head injury after a car accident that they will become demented at an earlier age and therefore deserve more money. Some studies do suggest that individuals with the genetic predisposition of the ApoE-4 genotype may be predisposed to develop AD after a severe diffuse brain injury. Others have suggested that the overall loss of brain cells in a traumatic brain injury may exaggerate the loses seen in the normal aging process. Larger brains have more nerve cells and more synaptic connections, thus affording greater protection as we start to lose some. We don't know.