memory loss

[plh0]

My 74 yr old mother, has for several years been dealing with worsening memory loss.  Some is short-term such as not being able to remember something that just happened, but some is also long-term such as not being able to remember a major event like me having major surgery 25 yrs ago.  She also has recurring headaches, some sinus related, but not all, almost daily.  Recently, she has had several occassions of becoming dizzy and nauseated for no reason, sometimes throwing up, but no signs of an infection such as a stomach virus.  The problem is she doesn't always remember having the dizziness later on to tell her physician.  In addition to the above, she stays cold almost all the time, sleeps as much as 12+ hours a day and still complains about being tired, and just doesn't have much energy at all.
I read on another website, that sometimes hypothyroidism can cause many of the above symtoms.  40+ years ago, my mother had about half of her thyroid removed and has been on synthroid ever since.  In the last few years, she has developed a thickening in her lower neck, upper chest area, which her physician has not been able to identify a cause.  To my knowledge her synthroid prescription has not been changed for many years.
Is this something the dr should be looking at?  She is scheduled for MRI's of her brain, head, and neck/chest area tomorrow.  

[caregiver222]

I am not a big fan of synthroid. Synthroid has many undesireable side effects.  But the company has great drug salesman.  I would recommend switching to the armour product. The armour product can be taken sublingually. She probably needs a TSH level.  Dizziness and nausea are flags for many things, cardiac insufficiency being only one of those.