You know those pub quizzes where they give you an unusual photo of a famous person to see if you can identify them? Failing at that doesn't just mean you don't get to win the bottle of wine, but it could be an early sign that you've got dementia.
Yes, according to the Daily Express (and therefore, probably not according to actual doctors) not being able to spot Elvis could be a symptom:
Dr Doug Brown, of the Alzheimer’s Society, said: “We all forget a face. But when ability to recognise someone as famous as Elvis or Diana becomes an issue it may be there is a deeper-rooted cause.”Possibly, although Elvis died 36 years ago, and is it fair to assume that he's still such a cultural norm that his face is useful in this way.
It's unclear if you should or shouldn't be able to recognise all the Kardashians as part of good mental health.