Can we learn from the clinically significant face processing deficits, prosopagnosia and capgras delusion?

Abstract

This review describes two clinically significant face processing deficits, prosopagnosia and Capgras delusion, and provides new knowledge about the face recognition process by a convergence of empirical findings. These empirical findings are structured around two questions that are reviewed from the perspectives of the two deficits. First is the question of hemispheric specificity, which inquires into the degree of each hemisphere's contribution to the face recognition process. Second is the question of dual neural pathways, which addresses the possibility that the face recognition process proceeds along two parallel pathways in the brain. Findings from the hemispheric specificity studies reinforce the current view that right hemispheric involvement is necessary for face recognition while left hemispheric involvement is minimal. Findings from the dual neural pathways studies reinforce the plausible but yet unproven hypothesis that two neural pathways pass information from the visual association cortex in the occipital lobe toward the temporal lobes and limbic system when faces are seen and recognized. These findings, which also indicate that each of the dual neural pathways carries different, nonredundant information, could be instrumental in showing that the pathways play different roles in the manifestations of the clinically significant face processing deficits, prosopagnosia and Capgras delusion.

Capgras Syndrome and Unilateral Spatial Neglect in Nonconvulsive Status Epilepticus

“…This resulting in patients with Capgras syndrome recognizing faces normally, but they may lack the expected subjective emotional response that face should produce secondary to associated damage to the dorsal stream. Thus they recognize the face but without an appropriate affective response there is a delusion about that person's identity due to the lack of emotional recognition [24,28]. The presence of a hemi neglect plus Capers syndrome is interesting as it confirms the theory that the dysfunction is in the dorsal visual stream with maintained ventral stream function.…”

Capgras syndrome: possibly more common among the Maori of New Zealand

“…A review of the literature regarding computed tomography, magnetic resonance imaging, electroencephalogram and neuropsychological test findings in Capgras syndrome [5] suggests a preponderance of right hemisphere abnormalities. Misidentification syndromes are commonly reported after closed head injury [6] and have been reported to occur in 20–30% of patients with Alzheimer’s disease [4,7].…”

“…Since then, several psychodynamic theories have been postulated to explain the genesis of this syndrome (e.g. [5,9–11].…”

Psychiatrische Doppelgänger-phänomene unter besonderer Berücksichtigung des Capgras-Syndroms

“…¹Depersonalisations-Theorieª, dass bei Depersonalisationen erlebte eigene Veränderungen und Entfremdungserlebnisse im Sinne der Abwehrfunktion auf eine andere Person projiziert werden, wodurch es letztlich zu deren Aufspaltung in ¹Gut und Böseª kommt. Das Capgras-Syndrom ist nach dieser Theorie das Ergebnis der Projektion eigenen Depersonalisationserlebens [81], das auf eine innere Ambivalenz rückführbar ist. Auch in neueren Untersuchungen bei Capgras-Patienten wurde ein oft auftretendes Derealisations-und Depersonalisationsmuster gefunden [17].…”

“…Die ¹Reduplikative Paramnesieª gilt meist als durch hirnorganische Alterationen verursacht [15,62,85]. Bei Capgras-Patienten wurden hirnorganische Läsionen bei einem Drittel der in der Literatur erfassten Fälle beschrieben [76,81]. Andere Autoren beschreiben das Capgras-Syndrom auch bei Demenzen vom Alzheimer-Typ mit oft rechtshemisphärisch akzentuierter Degeneration oder globaler Hirnatrophie zusammen mit fokalen Läsionen [86,87].…”