Can a narcissistic person fake it through the full dementia testing?

I wonder if he was tested later in the day how the tests would go. About the time they sundown. When the mind is tired.

He is not going to be able to fake forever. There will come a time when the desease progresses and they really can't fake anymore.

Full testing it might be difficult. There are brain scans that can not be "faked"
Written tests are given more than once and the tests are then compared so there can show a difference between the 2 testing phases. Questions are often asked in several different ways over the course of the testing process so it might be difficult to recall each answer and how each question is phrased.
Also the way the person responds , the affect of the person being tested, as well as just simple conversation is all taken into account for the results of the testing process.

My sister in law is a physician, she is not a geriatric specialist, nor psychiatrist. She works in hospitals and does work with many elderly patients.

When stepdad was dying we had a conversation about dementia (he had it and cancer). Her comment was that the testing is primarily qualitative, not quantitative. It is not like taking a pulse nor measuring respiration or oxygen concentration in the blood. There are no definitive tests for dementia, they are all subject to interpretation.

NPD people tend to mold reality to their point of view. It can become a he said she said situation. This is where good record keeping, video or audio recordings of 'off' behaviour can help the clinicians make a diagnosis.

It ( their personality and fluctuating mentation) change hourly. Sometimes you wonder was I too hasty? Sometimes it is where did loved one go?

Some days they are "there." An hour later, not so much. Then you have showtiming, cognitive camouflage, and a determined effort by LO to show they are not one if of " those people." My mother did this for years. She was in a geriatric behavioral unit for a week. She was worse than what we thought. She was just clever. Very.

An astute examiner can use both observation and standardized tools, plus reports by additional sources in a clients life to come up with pretty reasonable evidence of real symptoms as opposed to malingering.

I’m not sure why narcissism in particular would suggest the likelihood of attempting to “fool” an examiner? Why would there be an advantage to “faking”?

I have no scientific basis for my answer, but I'm going to vote no :)

I'm dying to see responses on this. I'd love to know too. I suppose it depends on what day it is. There are good days and not so good days.