Mirrored-self misidentification

Delusional misidentification syndromes can occur in patients with a wide variety of cranial dysfunctions. have also reported being affected by this delusion. The exact prevalence of patients with this delusion is relatively unknown because the typical patient has many comorbidities; this makes it difficult to separate the symptoms of mirrored-self misidentification from other existing psychological conditions. Furthermore, a standard neurological or neuropsychological workup tends to overlook the existence of this delusion because affected patients have extensive cognitive degeneration that is the main focus of medical attention. As such, it can be incumbent upon the patient's family to recognize symptoms of the delusion, mainly that the patient is unable to recognize him or herself in the mirror but has an intact ability to recognize the reflections of others. ==Neurological basis==

All patients with mirrored-self misidentification have some type of right hemisphere dysfunction. is involved in processing self-related stimuli and helps one recognize a picture or reflection of oneself. An impairment in the right hemisphere, the likely source of the "self" in the brain, can inhibit one's ability to recognize faces, especially one's own. Patients tend to experience a distortion of the right dorsolateral prefrontal cortex, which impairs the patient's belief evaluation system. Patients can no longer logically reject delusional beliefs. Patients with this delusion also tend to have larger right anterior horns than the typical person. Such extensive damage in mirrored-self misidentification patients is rare; typically patients retain the ability to recognize others’ reflections in the mirror. When such extensive neurological damage occurs, the affected patient relies on non-facial cues to identify relatives. When looking in a mirror, the patient can only use facial cues to recognize one self. Therefore, in these rare cases, despite damage to the entire facial recognition area of the brain, the patient is still able to recognize relatives but unable to recognize the self in the mirror. ==Famous studies==

There are two famous case studies of patients with mirrored-self misidentification that have contributed to the overall understanding of this delusion. Case one: patient TH Patient TH was in the early stages of dementia and was affected by mirror agnosia. While TH was looking into a mirror, the researcher held an object behind TH in such a way so it was reflected in the mirror. Due to his belief that mirrors represent a separate place, TH tried to reach into the mirror to retrieve the object rather than reaching over his shoulder. TH's mirror agnosia accounts for the development of the delusional idea. Because not all patients with mirror agnosia develop the delusion, there needs to be the presence of a second factor that explains why TH does not reject his delusional belief that the object is inside the mirror. Neuropsychological testing showed TH had an impaired right hemisphere. He displayed poor visual memory and visuoconstructional problems but still had basic visuoperceptual skills, a normal intelligence, typical vocabulary, and average semantic ability. These issues are indicative of significant right hemisphere dysfunction, specifically in the right dorsolateral prefrontal cortex. Because of such cranial impairments, TH was unable to use logic to reject his delusional beliefs based on implausibility. From this case study, researchers concluded that while not all patients with mirror agnosia develop mirrored-self misidentification, when mirror agnosia is paired with right hemisphere damage of the belief evaluation system, the delusion will develop. Case two: patient FE Patient FE was also in early stages of dementia but experienced impaired facial processing rather than mirror agnosia. His distorted perception of his reflection in the mirror made him unable to pair the reflection to a memory of the appearance of his own face. This prompted him to believe that the person in the mirror was someone other than himself. Because not all patients with impaired facial processing develop mirrored-self misidentification, such as patients with prosopagnosia, there needed to be a second factor to explain FE's delusions. Neuropsychological testing showed that FE had extensive cranial damage in his right hemisphere. He had poor visual memory and visuoconstructional problems whilst retaining basic visuoperceptual skills. These impairments made FE unable to use logic to reject his belief that the person in the mirror was someone other than him. From this case study, researchers concluded that while not all patients with impaired facial processing develop mirrored-self misidentification, when the impairment is paired with damage to the belief evaluation system in the right dorsolateral prefrontal cortex, the delusion will develop. ==Two-factor theory of delusional belief==

Mirrored-self misidentification is an example of a monothematic delusion – a delusion restricted to a single topic or theme. The two-factor theory of delusional belief explains why monothematic delusions occur. However, not all patients with impaired facial processing or mirror agnosia develop the delusion; there therefore needs to be a second factor that accounts for why some patients with impaired facial processing or mirror agnosia develop the delusion and others with the same conditions do not. Patients who experience right hemisphere dysfunction but do not have impaired facial processing or mirror agnosia will experience general sensory-motor and cognitive impairment. ==Self-recognition in patients without mirrored-self misidentification==

Viewing one's own facial reflection in the mirror causes neurological changes in the right inferior frontal gyrus, the right inferior occipital gyrus, the right inferior parietal lobe, and the right parietal area. These changes, which all occur in the right hemisphere, highlight the role of the right hemisphere in self-related cognition and processing ==Methods of study==

This delusion is usually researched through conducting clinical case studies or inducing a state of hypnosis within healthy participants. When completing a case study, researchers use descriptive observational methods. Hypnosis research is typically completed in the lab as an experiment with both control and random assignment. Clinical case studies This delusion may be studied through observing and interviewing clinical patients in the lab. A typical case presents a patient with dementia. As such, hypnosis of healthy patients is typically used to study the delusion because it can highlight the symptoms of the delusion while removing the influence of other comorbidities. Hypnotic delusions are very similar to clinical delusions, in that both subjects exhibit delusional resistance to challenge and autobiographical memory during delusions. When their beliefs are challenged, both clinical and hypnotic patients will defend their delusional beliefs, will refuse to reject their beliefs, and will provide fabricated explanations to account for them. Because hypnosis can recreate the false beliefs (accounting for factor 1 of the two-factor theory of delusional belief above) and disrupt the ability to reject a belief on implausibility (accounting for factor 2) with no lasting consequences, it is a good model to study monothematic delusions, particularly mirrored-self misidentification. Cognitive-delusory hypnosis is the most difficult type of hypnotic suggestion to enter and is required to study mirrored-self misidentification. Therefore, only those who are highly susceptible to hypnosis can participate in these studies. In a typical study, participants are placed in a hypnotic trance and are either told to see a stranger in the mirror or to see a face in the mirror that cannot be identified. Those who are told to see an unidentifiable face in the mirror do not necessarily see a stranger; the participant may perceive the face as an unrecognizable version of one's own. To determine the impact of hypnosis on a participant, the participant is asked to describe what one sees in the mirror. If a participant reports seeing a stranger, the experimenter tries to get the participant to let go of the delusion by proposing various questions and challenges. A researcher inquires about appearance (how is it possible the participant and the reflection wear the same clothes?), behavior (when the participant places one's finger on one's nose, how is it possible the reflection performs the same action simultaneously?), and vision (how does the participant see the experimenter both in real life and in the mirror if the mirror does not produce reflections?). Because the research participants were only prompted to exhibit symptoms of mirrored-self misidentification delusion, researchers can attribute their behavior strictly to the delusion, rather than having various comorbidities affect behavior as well. This typical study set-up also highlights the ways in which hypnosis can help study this delusion because it can generate false beliefs and remove the ability to reject the belief even when it is challenged. ==Comorbidities==

Patients with mirrored-self misidentification may have other delusional misidentification syndromes (DMS) as comorbidities, including Capgras delusion, Fregoli delusion, Cotard delusion, reduplicative paramnesia, unilateral neglect, and thought insertion. Phantom border delusional misidentification symptom, or the belief that someone else is living in one's home, is also common among mirrored-self misidentification patients because the patient misidentifies one's mirror reflection to be another person. Comorbidities can be hard to record because the typical patient has Alzheimer's disease or other forms of dementia that make it difficult to separate various existing conditions. ==Treatment==

There is no explicit treatment for mirrored-self misidentification. However, cognitive-behavioral therapy is typically used as a treatment for many different types of delusions. Individual therapy is best suited to treat the patient's unique delusions. Antipsychotics may be used to treat delusions; however, they have somewhat limited success. ==References==