Impairment of consciously controlled use of memory in schizophrenia.

Abstract

Recent studies of memory in schizophrenia have shown that explicit but not implicit memory performance is impaired. The hypothesis that schizophrenia is associated with a failure of consciously but not unconsciously (automatic) controlled influence of memory on performance was tested using a procedure providing uncontaminated estimates of consciously controlled and automatic memory processes (i.e., the process-dissociation procedure in a stem completion task). Performance of 35 patients with schizophrenia was compared with that of 35 normal participants. Consciously controlled use but not automatic influences of memory was significantly lower in patients with schizophrenia than in controls. Consciously controlled use of memory was negatively and significantly correlated with positive symptoms of schizophrenia. Schizophrenia differentially affects 2 types of memory processes: It impairs consciously controlled use of memory but spares automatic influences. Positive symptoms could reflect the lack of control from higher level conscious processes.

Conscious and subliminal conflicts in normal subjects and patients with schizophrenia: The role of the anterior cingulate

“…Interestingly, only backward masking is impaired whereas forward masking, which is thought to be based on retinal and cortical bottom-up mechanisms, remains intact (41). Patients with schizophrenia also exhibit a dissociation between impaired explicit recollection and normal implicit memory (36)(37)(38). Together with evidence for impaired awareness of self-generated action (47), those results converge to suggest that a core deficit in schizophrenia concerns a distributed cortical conscious monitoring system that involves the ACC as a crucial node (48,49).…”

“…This predicted dissociation of subliminal and conscious processing in schizophrenia has not been studied directly in the literature (but see refs. [34][35][36][37][38]. Given the evidence for multiple, distributed sites of brain dysfunction in schizophrenia, including ACC and PFC, the finding of preserved subliminal priming would provide strong evidence that ACC and PFC are not involved in automatic conflict resolution, but solely in conscious monitoring.…”

A Comparison of Implicit Memory Tests in Schizophrenic Patients and Normal Controls

“…Patients with schizophrenia usually show preserved priming (Brebion, Amador, Smith, & Gorman, 1997;Kazes et al, 1999) and impaired explicit memory (using free recall tasks).…”

Memoria automática observada en esquizofrenia mediante el procedimiennto de disociación de procesos

“…Concretamente en pruebas explícitas de memoria reciente sus rendimientos son defectuosos, ya se trate de recuerdo libre, con clave o serial, mejorándose los resultados en tareas de reconocimiento (Traupmann, 1975;Kietzman, Zubin y Steinhauer, 1984), y siendo, por último, equiparables sus rendimientos en tareas implícitas a los sujetos control (Gras-Vincendon, Danion y Grange,1994;Hurón, Danion, Giacomoni, Grange, Robert y Rizzo 1995;Bazin y Perruchet, 1996;Kazes et al, 1999;Besche-Richards, Passerieux, Hardy-Baylé, Nicolás y Laurent, 1999). Esta preservación en pruebas implícitas se ha mostrado tanto en tareas perceptivas, tales como identificación de palabras, como conceptuales en la tarea de evocación de ejemplos de categorías (Schwartz, Rosse y Deutsch, 1993).…”

“…Este procedimiento especial se ha utilizado en escasas ocasiones con pacientes esquizofrénicos, primeramente por Kazes et al (1999) y posteriormente por Besche-Richards et al (1999), existiendo hasta el momento un escaso número de estudios y réplicas. Ambos concluyen, sin embargo, que existe un déficit en los procesos controlados de recuperación, siendo las influencias automáti-cas equiparables a las de los sujetos normales.…”