The impact of progressive semantic loss on reading aloud.

The role of semantics in reading aloud remains controversial. To explore this issue, the current study examined the impact of semantic loss on reading-aloud performance in 7 patients with semantic dementia. The results revealed a heterogenous pattern of reading difficulties. Of the patients, 2 selectively made errors on inconsistent words (i.e., surface dyslexia), 4 had a generalized reading deficit with increased errors on consistent words, inconsistent words, and nonwords, while the remaining patient had relatively intact reading-aloud accuracy. All patients had longer reading latencies on real words than controls. The relationship between the reading and semantic deficits in the patients was examined at the item-specific level. This suggested that reading-aloud errors were related to the semantic impairment for inconsistent words but not consistent words. In contrast, semantic loss was related to longer latencies for both consistent and inconsistent words. These findings support models of reading that include a role for semantics in the reading-aloud process.