This is called the Capgras delusion, and that is a patient, who's otherwise completely normal, has had a head injury, comes out of coma, otherwise completely normal, he looks at his mother and says, "This looks exactly like my mother, this woman, but she's an impostor.
Jest to zespół Capgrasa: pacjent, zdrowy w każdym innym sensie, po urazie mózgu wychodzi ze śpiączki i patrząc na matkę stwierdza: "Ta kobieta przypomina moją matkę, ale to oszustka.