Neuropsychological analysis of a case of abrupt onset mirror sign following a hypotensive crisis in a patient with vascular dementia

The mirror sign is a delusional misidentification symptom (DMS) characterized by an inability to recognize one's own image in the mirror, often in the presence of an intact ability to recognize others in the mirror. The symptom has been only sparsely reported previously, and primarily within the Alzheimer's disease literature. A case is reported of an 82-year-old female with abrupt onset of mirror sign following a hypotensive crisis. Neuroradiographic studies revealed periventricular white matter change in the bifrontal and bilateral parietal occipital regions, right greater than left, as well as scattered lacunar infarcts. The patient was unable to recognize herself in the mirror and became progressively paranoid in response to the stranger in the mirror'. However, there was no evidence of prosopagnosia and she was able to recognize others in the mirror. Results from the neurobehavioral examinations replicated a previous report of mirror sign, and were consistent with those reported for other DMS. The acute onset, vascular changes on MRI, and lateralized neuropsychological findings suggested a right hemisphere-based visual associative etiology to the mirror sign.