Insights from the examination of verbal and spatial memory errors in relation to clinical symptoms of patients with recent-onset schizophrenia

Abstract

Introduction. Memory deficits in patients with schizophrenia (SZ) are considered as a key feature of the clinical manifestations of the disease. In order to further examine the role and nature of memory deficits in SZ, the pattern of errors in verbal and spatial serial recall tasks committed by SZ patients was compared to that of healthy controls. We also tested the relationship between these memory errors and clinical symptoms.

Methods. Twenty-seven outpatients with recent-onset SZ and 27 age and gender matched healthy controls had to remember sequences of items (digits or localisations) in a serial recall task. Clinical symptoms were assessed with the PANSS and the SAPS.

Results. The results indicate that the number of omissions, intrusions, and transpositions can differentiate patients with SZ from healthy controls. Intrusions and transpositions committed in the verbal domain were associated with the negative subscale of the PANSS. Transposition errors were associated with delusions whether the to-be-remembered information was verbal or spatial.

Conclusion. The examination of the pattern of errors, in particular that of transpositions, is a more informative cognitive index than the mere analysis of overall performance, and provides a promising target for treatment.

Keywords:

• Clinical symptoms
• Error types
• Methodological
• Recent-onset
• Schizophrenia

Acknowledgements

CC receives support from the Fonds de la recherche en santé du Québec. This work was supported by an operating grant from the Natural Sciences and Engineering Research Council of Canada to ST, and by an operating grant from Canadian Institutes of Health Research and a scientist award from the Fonds de la recherche en santé du Québec to MAR. We are also grateful to Rosée Bruneau-Bhérer and Hélène Marcaurelle for their help in collecting the data.

Notes

¹Although we limited our analyses to intralist intrusions, our data reveal that none of the participants in the current study committed extralist intrusion in the verbal task. This is not surprising as the use of a fixed set of TBR items in serial recall—that is, the same limited set, digits from 1 to 9, served as TBR stimuli throughout the experiment—prevents the apparition of extralist intrusions.