Is there a relation between narcissism and alzheimer's disease?

Not really.: Alzheimer's is a form of dementia, with a slow subtle onset. The first sign is loss of memory which may not even be noticed. Other functional deficits, like impaired activities of daily living, disorientation, poor judgement, and poor concentration also occur. Narcissism is a personality disorder where a person has a sense of entitlement, and has little or no regard for the feelings of others.

Lack of empathy: I agree with my colleague that narcissistic personality disorder and alzheimer's dementia are very different conditions. But as an alzheimer's patient sinks deeper into illness, s/he can lose empathy for others. This can be very difficult for family members or other caretakers who want appreciation. Some might call the patient "narcissistic" at that point, but this not a correct diagnostic term.