Is performance on probed serial recall tasks in schizophrenia related to duration of Attentional Blink?

Schizophrenia is associated with a deficit in working memory, with the degree of working memory impairment related to the level of social and occupational functioning. This study tests the hypothesis that the working memory deficits in individuals with schizophrenia can be explained by slow processing of visual stimuli, as measured by the attentional blink (AB) task. Individuals with schizophrenia (SC) and controls (HC) were recruited from an early intervention service for psychosis and the local community. Data from 16 SC (11M/5F, mean=26.4yo) and 20 age-matched HC (11M/9F, mean=25.8yo) were analyzed. Each subject performed an AB task to determine their AB duration, defined as the lag to reach their plateau performance (ltpp). As expected, mean AB duration in the SC group (575ms) was significantly slower than HC (460ms; p=0.007). Recall accuracy of the SC group on a working memory task, a 6-item probed serial recall task (PSR), was reduced compared to the HC group at a standard interstimulus interval (ISI) (p=0.002). When the individual's AB duration was then used to adjust the ISI on the PSR task to three relative ISI rates (Slow (2×ltpp), Medium (ltpp) and Fast (1/2×ltpp)), performance on the PSR task was affected by group, position and ISI and qualified by an ISI∗position (p=0.001) and a trend to a triple interaction (p=0.054). There was main effect of group at all ISIs, but group∗position interaction only at Slow ISI (p=0.01). Our interpretation of the results is that absolute ISI, rather than ISI relative to AB duration, affected performance.