Working memory in cerebral palsy: primacy, recency and consolidation

Abstract

Two experiments assessed the degree of working memory development and the nature of the rehearsal underlying consolidation. An illiterate, non-vocal 15y3m old cerebral-palsied boy, who had used a computerized alternative communication system for two years, participated. Experiment 1 used a variation of the free-recall procedure in which after listening to each of several word-series, the subject selected from the system monitor, via touch-screen, the pictures corresponding to the names spoken by the examiner. A typical serial-position curve resulted, with primacy and recency effects. Primacy indicates consolidation which was based on some sort of rehearsal. Experiment 2 analyzed the nature of the rehearsal, whether overt or covert, and whether visual or subvocal. The procedure was replicated but the monitor was shaded in half of the trials. Shading suppressed primacy and highlighted recency whereas, in the absence of shading, primacy was as strong as recency. Thus, consolidation was an artifact of overt rehearsal based on visual search. The inability to perform covered rehearsal (both visuo-spatial and subvocal) is in accordance with the literature.