"Senior moments" are a normal part of aging. They happen to everyone. We just don’t process things as quickly as we did in younger years.
Some people develop significant memory and thinking problems, however, and are eventually unable to live safely on their own. These people have conditions that bring on a full-fledged dementia, such as Alzheimer's or Parkinson's disease.
And some people function at a level in between. They can live independently and lead normal lives. But they just aren't thinking as well as they used to. These people may have mild cognitive impairment (MCI).
Signs of MCI include greater than usual difficulty with
- remembering recent events or scheduled appointments,
- following the thread of a conversation or movie,
- making decisions or following instructions,
- finding familiar locations, or
- making well-reasoned choices.