Early onset is just that .. just a few steps beyond normal forgetfulness...odd confusion, if you're watching closely... and at a typically younger age...
Late onset is usually more pronounced and at an older age...
Familial means bloodlines.

No my mother is now 85!! But it does run in the family! She was not early onset...Carolin.

This probably refers to hereditary component. My husband has dementia, Alzheimer's type, as did both his parents and one grandparent. Also his brother has this. So there is definitely a familial or heriditary component involved.

Not sure of technical terms but my husband has early onset or pre. I have noticed a huge decline in his short term memory but long term seems to be in tact

Early onset usually begins in their 40's or 50's, whereas later it may show up 60's and 70's. Also, early onset progresses more rapidly. Familial is if a family member had the same disease, like my husband's mother - he began showing symptoms late 60's, much like she did/sam