Prosopagnosia is a neurological disorder that results in an inability to recognize familiar faces. Also called “face blindness,” the condition is most often due to brain damage in the fusiform face area (FFA). Alternatively, Capgras Syndrome, or “imposter syndrome” is associated with an intact ability to recognize familiar faces but with the accompanying delusion that familiar people have been replaced by identical imposters. Both disorders have ties to deficits in facial perception. However, there are differences between the two with regard to physiological responses to familiar faces. Patients with prosopagnosia often still experience the galvanic skin response that occurs when shown familiar faces, while patients with Capgras syndrome do not.
Corrow, S., Dalrymple, K., & Barton, J. (2016). Prosopagnosia: current perspectives. Eye And Brain, Vol Volume 8, Pp 165-175 (2016), 165.