Évaluation et utilisation de stratégies en mémoire par des patients schizophrènes âgés

RésuméObjectifLes perturbations des états de conscience constituent des déterminants critiques des anomalies de comportement dans la schizophrénie. L’approche de la métamémoire permet d’examiner l’évaluation et le contrôle des capacités mnésiques au cours d’un apprentissage. L’étude présentée est la première à examiner la dissociation entre évaluation et contrôle pour des patients schizophrènes âgés. L’évaluation a été étudiée par un jugement d’apprentissage et le contrôle par le processus d’allocation du temps d’étude.Matériel et méthodeTreize patients âgés de 50 à 69 ans ont été comparés à 13 témoins appariés selon l’âge, le sexe et le niveau d’études. Pour l’expérience réalisée, les participants doivent apprendre des paires de mots pendant une durée de cinq secondes. Puis ils évaluent leur jugement d’apprentissage (dans quelle mesure ils seront capables de rappeler le second mot de chaque paire sur présentation du premier ?) sur une échelle en cinq points (0 %, 25 %, 50 %, 75 %, 100 %). Juste après ce jugement, ils doivent rappeler les mots appris. Les 40 paires de mots sont ensuite présentées une seconde fois, les participants contrôlent le temps de présentation de chacune des paires pour effectuer leur apprentissage. Et enfin, ils effectuent un second rappel de l’ensemble des paires.RésultatsMalgré des performances mnésiques plus faibles, les patients sont capables d’évaluer précisément leur jugement d’apprentissage. En effet, les jugements varient selon la difficulté des paires de mots (jugement d’apprentissage plus faible pour les paires de mots plus difficiles). Pour l’allocation de temps d’étude, les patients âgés sont capables d’adapter leur temps d’étude à la difficulté des items.ConclusionPour cette première étude de la métamémoire des patients âgés, nos résultats suggèrent que les patients présentent une capacité préservée à discriminer la difficulté des paires de mots à apprendre aussi bien pour le processus d’évaluation que pour le processus de contrôle. Toutefois, leur adaptation stratégique n’est pas aussi efficace que celle des témoins.

ObjectivesSchizophrenia is often defined as a pathology of consciousness, associated with a lack of self-awareness. An interesting way of gaining a better understanding of schizophrenia patients’ cognitive behavior is to focus on metamemory, i.e. people's awareness of their own memory capacity and their control of related behavior. Two processes are involved in metamemory, monitoring and control. Monitoring denotes participants’ subjective assessment of their own cognitive processes and knowledge. At the time of encoding, it is expressed as metamemory judgments, such as the Judgment of Learning (JOL). Control denotes the processes regulating participants’ behavior and cognitive processes, including, for this study, allocation of study time. Some schizophrenia studies have reported how some monitoring abilities are impaired and others preserved, but, to the best of our knowledge, this is the first pilot study, which set out to explore metamemory in older schizophrenia patients, in particular during encoding.PatientsTwo groups of participants were recruited, all aged between 50 and 69. The first group consisted of 13 clinically stable schizophrenia outpatients from the Psychiatric Department of Clermont-Ferrand University Hospital. These 13 older patients were compared to 13 healthy controls.Materials and methodsA computerized version of the tasks was used. The items consisted of 20 non-associated word pairs (e.g. broom-brother) and 20 associated word pairs (e.g. watch-hour). The word pairs appeared on the screen one by one (for 5 s), and participants were instructed to study them. After the learning phase, they then had to perform a non-verbal distracting task during a 4-minute retention interval. Then, the first item in each word pair (cue) was displayed by itself without the second (target). Using a 5-point scale (0%, 25%, 50%, 75% and 100%), participants were asked to give their JOL ratings, immediately after which there was a recall phase when each cue was presented and they had to try to recall the target word. They were then asked to re-learn the same 40 word pairs and told that they themselves would have to control how long (max. 20 s) each pair remained on the screen. After this second learning phase, there was a second recall test, identical to the first.ResultsDespite their memory impairment, older schizophrenia patients were able to assess the material accurately. However, they were unable to adapt their learning time as efficiently as controls.ConclusionsThe results show that both groups were able to cope with the difficulty of the material they were asked to learn. We replicated the typical finding for JOL accuracy, namely that older adults predict which items they will be able to remember. First, although patients’ JOL ratings were lower overall than those of the healthy participants, they were equally as able to assign lower JOLs to the non-associated word pairs and higher JOLs to the associated word pairs. The study provided first data about metamemory in older schizophrenia patients. Their JOL monitoring is accurate, but they are unable to control their learning time efficiently. Enhancing older patients’ control capabilities would help to guide them with their learning, thus contributing to memory rehabilitation.