Long-term perceptual priming in transient global amnesia.

This paper addresses the question as to whether long-term perceptual priming can occur during transient global amnesia. A patient who displayed the classical features of transient global amnesia was assessed during the episode and again 7 days later. During the episode, she was administered a task that required the perceptual identification of fragmented pictures over a number of learning trials. Seven days later, after recovery from the episode, she was required to identify the same fragmented pictures together with a new set of pictures that she had never seen before. She was significantly better at identifying the old pictures than the new pictures, in spite of having amnesia for the period of the attack. Matched control subjects who had never seen either set of pictures before, were also tested and performed at a similar level on the old and the new pictures. Our findings extend the clinical domain of implicit memory phenomena and parallel similar observations in chronic amnesia (Cave & Squire, 1992). We provide the first demonstration of a residual capacity for long-term perceptual priming during an acute episode of apparent total loss of memory.