Preserved priming effect in individuals with schizophrenia: cues towards rehabilitation.

INTRODUCTION: Individuals with schizophrenia and affective disorders show relatively intact implicit memory as compared to declarative memory. Implicit memory is usually assessed with skill learning and priming tasks. Whereas priming is thought to involve storage changes in the posterior neocortex, skill learning is thought to rely more on the corticostriatal pathway. Since frontostriatal and frontotemporal dysfunctions are, respectively, found in schizophrenia and affective disorders, we hypothesised that individuals with schizophrenia and first-episode psychosis would exhibit disturbances in skill learning, but not priming. METHODS: Thirty-five patients (11 first-episode psychosis; 11 schizophrenia; 13 affective disorders) and 10 controls completed a procedural learning and priming task. Participants had to identify fragmented images throughout five training sessions. The improvement of the threshold at which the images could be identified between the first and last session was used as an index of procedural learning. In a final session, the identification thresholds for old and new images were compared to assess the priming effect. RESULTS: Whereas individuals with schizophrenia and first-episode psychosis showed impaired skill learning, the priming effect was similar in all groups. CONCLUSION: Even though some aspects of learning and memory are affected in schizophrenia, our results suggest that the posterior cortical pathway remains efficient at modulating the priming effect. This intact ability could be used to guide the elaboration of new rehabilitation programmes.

Congenital amusia in childhood: a case study.

Here we describe the first documented case of congenital amusia in childhood. AS is a 10-year-old girl who was referred to us by her choir director for persisting difficulties in singing. We tested her with the child version of the Montreal Battery for the Evaluation of Amusia (MBEA) which confirmed AS's severe problems with melodic and rhythmic discrimination and memory for melodies. The disorder appears to be limited to music since her audiometry as well as her intellectual and language skills are normal. Furthermore, the musical disorder is associated to a severe deficit in detecting small pitch changes. The electrical brain responses point to an anomaly in the early stages of auditory processing, such as reflected by an abnormal mismatch negativity (MMN) response to small pitch changes. In singing, AS makes more pitch than time errors. Thus, despite frequent and regular musical practice, AS's profile is similar to the adult form of congenital amusia.