Face Processing Impairments and Delusional Misidentification

Abstract

We report detailed investigations of the face processing abilities of four patients who had shown symptoms involving delusional misidentification. One (GG) was diagnosed as a Fregoli case, and the other three (SL, GS, andJS) by symptoms of intermetamorphosis. The face processing tasks examined their ability to recognize emotional facial expressions, identify familiar faces, match photographs of unfamiliar faces, and remember photographs of faces of unfamiliar people. The Fregoli patient (GG) was impaired at identifying familiar faces, and severely impaired at matching photographs of unfamiliar people wearing different disguises to undisguised views. Two of the intermetamorphosis patients (SL and GS) also showed impaired face processing abilities, but the third US) performed all tests at a normal level. These findings constrain conceptions of the relation between delusional misidentification, face processing impairment, and brain injury.

Reduced autonomic responses to faces in Capgras delusion

“…With this in mind, we also investigated the performance of these patients on standard face processing tasks. Results for familiar face recognition (Young et al 1995), unfamiliar face matching (Benton et al 1983;Young et al 1990), and recognition memory for faces (Warrington 1984) are summarized in table 2. For comparison, table 2 also shows SCR differences (mean amplitude to familiar faces minus mean to unfamiliar faces) from the present investigation.…”

The Capgras and Cotard Delusions

“…During the last several years, a battery of face-pro cessing tasks has been given to three patients for whom the Capgras delusion formed a prominent feature, GS [8], MC and ML [9], and two patients for whom the Cotard delusion was prominent, WI [10] and a pre viously unpublished case, JK. The same tests were also given to one further patient, KH, who experienced both the Cotard and the Capgras delusions sequential ly [11], Such cases of co-existent or sequential delu sions arc of considerable theoretical interest, but they do not address the question of parallels or differences between face-processing impairments found when only one of these delusions is experienced.…”

“…Data concerning WI's recog nition memory for words arc not presented here, how ever, because he was given the faces and words parts of the test at very' different dates. Table 1 summarises the performance of Capgras cases GS [8], MC and ML [9], and Cotard delusion cases Wl [10] and JKon face processing tasks and recognition memory for 228 Y oung/Leafhead/Szulecka Capgras and Cotard Delusions Table 1. Performance of Capgras cases GS [8], MC and ML [9], and Cotard delusion cases WI [10] and JK on face-processing tasks and recognition memory for words words.…”

Person Identification and Self-Concept in the Delusional Misidentification Syndrome

“…Many modem techniques support the hypoth esis of an organic cerebral dysfunction [5], However, detailed investigations of face processing in Delusional Misidentification patients have led to contradictory findings, although there are some exceptions. As men tioned by Young et al [6] there exist some cases in which the face recognition processes do not seem impaired, although the patient is convinced that the person in front of him/ her is the duplicated identity of someone else, or has intentionally taken the psychical or physical appearance, or both, of someone else.…”