The evolution of deep dyslexia: evidence for the spontaneous recovery of the semantic reading route

Abstract

Most theoretical accounts of deep dyslexia postulate at least two independent deficits which give rise to the observed pattern of reading impairment. One deficit is an inability to derive phonology from orthography sublexically and the second is an impairment in semantically mediated reading. These deficits generate a host of symptoms including an impairment in reading nonwords, a part-of-speech and imageability effect in word reading, and, importantly, the occurrence of semantic paralexias. It is possible, then, that during recovery of deep dyslexia, either one or both of these underlying deficits resolve. We describe a case, RL, with deep dyslexia who showed significant change in his reading performance in the absence of any therapeutic intervention. At 18 months post-onset, unlike at 6 months post-onset, RL no longer produced any purely semantic errors nor did he show effects of imageability or past-of-speech on his oral readings. Despite his change, RL's ability to read nonwords did not improve significantly over this time period. These findings suggest that selective and spontaneous recovery of the semantic reading route can occur independent of significant change in the sublexical reading route.