In "Memento" the main character has got anterograde amnesia, but he's aware of it. Is it even possible and how, if it is? Compare it to "50 First Dates" — the heroine is not aware of her condition.
Imagine you wake up in the morning. How would you come to awareness that you've got anterograde amnesia, if you don't remember anything since the moment you got it, including that? And even if you find this out by logical thinking, you'll forget it soon (in "Memento", what, in several minutes?)
Yes it is possible. It is very common for normal individuals to feel like they should remember something, but are then unable to actually recall the contents of that particular memory. This feeling of knowing is called metamemory.
This study by Art Shimamura and Larry Squire found that
patients with severe anterograde amnesia can produce accurate feeling-of-knowing judgments. Thus, impaired feeling-of-knowing accuracy is not an obligatory feature of amnesia
So, some of those patients may wake up each morning and soon realize that something is amiss, as they are unable to recall facts or events that they feel they should be able to recall.
A very famous neurological patient, Henry Molaison (known as H.M. in the literature until his death) had severe anterograde amnesia. I don't believe he remembered the details of his condition, but he knew that he couldn't remember things, and he knew that something was wrong with him. I have never read any solid explanation of how that might work; I have heard a conjecture that when it is the hippocampi that are primarily affected, then the patient is aware, but this theory becomes a bit doubtful when you realize that H.M. had more extensive damage than was initially thought (it was not only his hippocampus that was extracted but the entire medial temporal lobe).
