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. Injury to the right frontal lobe is found in 35% of cases and can also inhibit one's ability to reject delusional beliefs on the basis of implausibility. Patients with this delusion also tend to have larger right anterior horns than the typical person. These cranial distortions point to right frontal atrophy and general right hemisphere dysfunction. While approximately 50% of all patients exhibit left hemisphere damage, all patients with this hemispheric dysfunction also have cranial lesions in the right hemisphere. As no patients with solely left hemisphere damage have been reported to experience this delusion, this points to the delusion being strongly associated with right hemisphere dysfunction. In a few select case studies, patients with this delusion have such extensive right-hemisphere cranial damage that one is also unable to identify close relatives and others with whom the patient has close association. 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. There are two famous case studies of patients with mirrored-self misidentification that have contributed to the overall understanding of this delusion. 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.