You are absolutely spot on.

There are so many factors in how each individual brain ages that an accurate and reliable test is nearly impossible until a dementia is so far advanced, everyone knows the person for more than a once a year visit to the doctor, what is going on. Those closest to the person will pick up on some issue; or the person themselves will first notice it and compensate - which is usually the case, until the person can no longer think up ways to compensate.

Add on top of that the fact there are so many reasons for onset of memory loss...many which can be fixed, such as medications that cause slow thinking, not enough sleep, diet, STRESS, exercise.

My theory is that the longer we live the MORE files of information input (data) our brains have to process and go through to come up with a thought.

I believe each human brain has a limited capacity to process and wade through all that data and that capacity is very individualized.

Some dementias are related to blood flow to the brain; some dementias are related to a disease process of neurons and neuron chemical connection capabilities; and I truly believe some "dementias" are simply an individual's brain reaching the limits of that individual's data processing speed and accuracy.

A person can not think clearly even when one's blood sugar is too high or low; or they haven't had enough sleep; or don't have the right combination of vitamins and minerals on board due to a poor diet.

Dementia is far from being simple and one size fits all.

Your husband is blessed.