Preserved semantic priming effect in alexia.

Abstract

BH, a left-handed patient with alexia and nonfluent aphasia, was presented with a lexical-decision task in which words and pronounceable pseudowords were preceded by semantically related or unrelated picture primes (Experiment 1). In Experiment 2, BH was given an explicit reading task using the word lists from Experiment 1. Performance on Experiment 2 disclosed severe reading deficits in both oral reading and semantic matching of the words to pictures. However, in Experiment 1, BH demonstrated a significant semantic priming effect, responding more accurately and more quickly to words preceded by related primes than by unrelated primes. The present results suggest that even in a patient with severe alexia, implicit access to semantic information can be preserved in the absence of explicit identification. The possibility of categorical gradient in implicit activation (living vs. nonliving) in BH was also discussed, which, however, needs to be clarified in the further investigation.