Ok I'll try to explain what might be happening. When you have a scan it shows the physical make-up of the brain. So you can tell for example if there are things like shrinkage and then make a diagnosis that this shrinkage is what is causing the symptoms you are having. The brain is however a very complex organ which connects to and controls all the functions of the body. All it needs is for the disease to spread a little and break the 'wiring' that, say controls speech, and you find that the person starts having problems with this. Then you can find that the 'wiring' in the part of the brain that covers comprehension and logic, has some breaks in it. Then you will see that the person has problems in understanding and rationalising things. Then, add that to the bad wiring in the speech area and you then see someone no longer being able to explain things and their ability to communicate becomes veer jumbled. Given that some of the wiring in the brain can be as fine as a few strands of hair, then you will understand why a scan doesn't pick these things on an individual basis. Over time, depending which part of the brain becomes affected, there can be more physical symptoms that start to develop. Did you know for example that the area of the brain that sends signals to the bladder when it becomes full and keeps you continent, is also the area of the brain that covers such things as swallowing and the vocal chords? One you develop symptoms like these, the doctors will then know what area of the brain that the disease has spread to.
I have heard what is happening likened to a computer. You are having problems with sending something to the printer. So you look around the computer (Scan) and everything looks fine. You sneak a look inside, all the wires are connected and it all looks like new, except it is a little dusty (you need an air duster!!!). You reboot the system and still no printer. Then, wow, the blue screen if death comes up. Never had that happen before. You switch off, let it rest for a while then try again. Oh great, must have been a glitch. Still no printer though and now I can't get my DVD player to work. You check again, everything looks fine. Nothing changed since last time you looked. However, something has changed. On the motherboard some of the tiny bits of solder have broken. No signal being sent to the printer! Then another bit pings on another part of the board. Then one major area partially breaks and this is why you got the blue screen of death. It is only temporary THIS TIME because you gave the outer a thump and the wires are connecting again for now! And so things go on. Pinging away here and there, some permanent, others temporary for now. Eventually the damage will be so bad that you will be able to see evidence of what is happening.
The sad thing is though, that you can heal your computer, but with different types of dementia we are not able to do that, so the deterioration continues. One day they will find a cure. One day we will be able to fix it, just as we do our computers.
Hope this helps,
Fiona
