This revealing reference talks about the dogma behind science research concerning Senile Dementia (SD). Is the scientific community open to new theory development? or closed?
The accepted theory concerning Alzheimer's is that it is a disease and Science is looking for a cure. (Look what they are up to now) Plaques and Tangles in brain cells could be a large part of the dementia process since they are always present. Another known fact is that calcium builds up in brain cells of those who exhibit Senile Dementia and this action results in the increasing speed of death for brain cells. Calcium channels to remove cellular calcium are either reduced or oxidative stress is interfering with calcium transport. The issue is why and How? Giving calcium channel blockers should help slow down or prevent calcium build up if this theory is correct, but this has adverse side effects. And another possibility also exists, that calcium channel blockers could have the exact opposite effect and speed up the brain cell death process. 
The authors of the referenced article explore a new theory about this calcium build up that just might fit more of the overall observed facts. They believe it is a slowing down of the frequency and amplitude of calcium energy waves that is the real underlying cause of calcium build up, and that this is a natural process of aging. Calcium does not leave cells as quickly as it came in because it simply does not have the needed energy. Increasing cell energy production should help prevent this slow down. ref of interest on waves
Of note is that this calcium movement in and out of cells, that requires lots of energy, is necessary to allow the cell action potential to perform it's function, i.e. nerve impulse, muscle contraction, enzyme and chemcial reactions, and mineral channel transfer in and out of the cell, etc. Aging typically slows down these functions, but the rate can be controlled by certain lifestyle factors. Future research will settle this issue of calcium wave action versus a "diseased" state for increased calcium levels from old channel transport. Should be soon.
The dilemma is that while the end functions are the same, higher calcium in brain cells, there are different treatment methods to deal with the conditions between these two theories. Depending upon which theory is right, the treatments are opposed to each other, meaning if the wrong theory is chosen for treatment, it would have a disastrous result and could increase damage.
Is SD a disease or just the result of aging plus lifestyle factors, which would explain why there are exceptions, people who exhibit the same conditions but do not have any SD symptoms. article
SUPPORT: Read this on calcium induced cell death and mitochondrial dysfunction (cell energy blockage).
"Apoptosis (programmed cell death) can be induced by a variety of stimuli. Apoptosis occurs when a cell activates an internally encoded suicide programme as a response to either intrinsic or extrinsic signals. One of the better characterized apoptotic cascade pathways has mitochondrial dysfunction as its initiator. Mitochondrial dysfunction initiated by the opening of the mitochondrial transition pore leads to mitochondrial depolarization, release of cytochrome C, activation of a variety of caspases and cleavage of downstream death effector proteins, and ultimately results in apoptotic cell death. While a variety of stimuli can trigger opening of the mitochondrial transition pore and cause apoptosis, a sustained intracellular increase in Ca2+ (CALCIUM with a charge) is one of the better‐known triggers; accumulation of lead is another...." ref