Hemispatial Neglect patients are known to have Anosognosia meaning they don't recognize their disability. These patients neglect either their left or right field of vision entirely, as if they couldn't see anything on that side of their body.
How do these patients react when directly confronted with the fact of their disability? Hemispatial Neglect can be treated as it is an issue of attention not lack of sensation. Are these patients able to focus on the neglected area (before treatment) if explicitly told to do so?
Wikipedia notes a delusional form of the disorder:
Neglect may also present as a delusional form, where the patient denies ownership of a limb or an entire side of the body. Since this delusion often occurs alone without the accompaniment of other delusions, it is often labeled as a monothematic delusion.
So some patients may outright deny that the neglected side of their body exist, but this does not seem to exist in all cases of the disorder.