Background:
It is now agreed that cognitive deficit is an important aspect of the clinical presentation of schizophrenia. One parsimonious brain-behaviour model with good explanatory power for both animal and human models of the disorder is that of impairment of working memory (WM). Patients with schizophrenia show a reliable decrement of WM, which has been proposed to give rise to social and employment disabilities. The aim of the current study was to validate a computer-based behavioural spatial WM test in patients with schizophrenia.
Methods:
A novel spatial WM test based on the ‘n-back’ paradigm was used to compare 15 medicated patients with schizophrenia against 15 healthy volunteers. The task involved remembering the position of a target card from an arrangement of between two and four cards presented in a radial configuration, with instructions to determine whether the card that was face up at the time of presentation was in the same location as a card that had turned face up on the previous trial (1-back condition) or two previous trials (2-back condition). All subjects were retested a week later to determine the stability and reliability of the test.
Results:
Repeated-measures ANOVA showed that patients with schizophrenia performed worse than healthy controls on tests of spatial WM.
Conclusions:
The behavioural n-back task proved to be a quick and reliable measure of spatial WM in patients with schizophrenia. Our data further support previous findings of spatial WM deficits in schizophrenia.
