How would i know if my memory and expressive difficulties are more than stress related, and what can i do to rule out alzheimer? i am concerned about frequent short term memory deficit and increased difficulty trying to express myself. examples: thinking

Depression : Depression and dementia have a large number of overlapping symptoms making it sometimes difficult to distinguish between the two. A primary care provider can assess these problems with questionnaires designed to screen for each, and can also order lab tests for conditions that can mimic dementia and depression. A referral for neuropsychological testing, and new imaging techniques that allow visualization of Alzheimer's lesions in the brain (i.e. A pet scan using pittsburgh compound b), could be considered for "tough" cases.

At : At age 51 alzheimer's disease is uncommon, so first you should reduce your anxiety about this until you have been evaluated; it is unlikely to be alzheimer's. If you have a significant family history of early-onset dementia, that is a different situation, of course, but you have not mentioned this. If your difficulties prominently involve expressive language, it is possible you have one or another condition affecting specific speech areas in the brain, such as a small stroke, or one of the less common neurodegenerative diseases which are something like alzheimer's but are in other ways quite distinct....Such as the "frontotemporal dementias". I endorse the idea that you should see a neurologist to see if you are clearly depressed, or clearly have a different kind of neurological problem.