Forgetfullness.

Forgetfulness can be a normal part 
of aging. As people get older, changes 
occur in all parts of the body, including the 
brain. As a result, some people may notice 
that it takes longer to learn new things, 
they don't remember information as well 
as they did, or they lose things like their 
glasses.

Not necessarily we forget only with as
we age but also when we have some
serious health problems.