Most doctor won't do T3, T3RU, T4, and TSH for some reason, but they often do A1C test which can affect your Cognitive function. It is important to get blood test to determine what you have. Your A1C test will determine which type of diabetes you have, and the other is to determine which thyroid problem you have, there are two, Hypothyroidism and Hyperthyroidism. When you see your doctor ask him about having thyroid test.
For instance Hyperthyroidism, the Doctor need to determine if you just have hyperactive thyroid or grave disease, the test will determine what med you need to be on to help you.
Both TSH and A1C are common with seniors, or even as early as 30 years old, they will affect your cognitive ablity to live, Are you taking the right Vitamins to help you? Are you taking to much table salt?
We all excerisize, no matter what kind just as long you are doing it, this will help with your blood, muscles and brain.
Once the Doctor get the results, he can better able to help you with your situation, he may recommend someone like a dietican, or a specialist, or even an Internal specialist.
I am lucky because where we live, we have all kinds of specailist that can help you find out what your problem is and to help you to be able to deal with your everyday living.
I have been dignose with type ll diabetes for a lot of years, then last fall I been tested for thyroid problem, as it happen to be that I have hyperthyroidism, so now I have to go for a speical test to determine if I have grave diesase and yes there are medication for it.
Thyroids product hormones for your body, if you have to much of it, it will attack your antibodies, can make you anxious, depress, sick and a whole lot of other problems like bone loss. Or you can have to little of it, thus why have your thyroid tested.
There can be numerous reason through blood test that can affect your cognitive function in life. So be sure to seek medical profession to determine what you have so that you can get proper treatments for it.
Weight gain can be both from type ll and hypothyrodism if you can't loose weight but being treated for A1C, then maybe it your thyroid?
It is important to have thyroid test as it will help prevent thyroid cancer. There are lots of info on line, check it out
Here's a few links to help you learn more.