Presentation and task effects on migration errors in attentional dyslexia.
Mayall K., Humphreys GW.
We report a case study of a patient, FL, who shows symptoms of attentional dyslexia. He performs better at reading aloud single words than pairs of words, where he tends to make letter migration errors. These letter migrations are particularly prevalent from the word presented on the right into FL's response to the word presented on the left. Performance on the word pair reading task is improved if the two words are presented in different cases or the space between them is increased. Further, FL performs better at reading a target word if he is only required to name the initial letter of a distractor word rather than read the whole word. However, single letter distractors then produce more interference than whole words. These findings are consistent with FL having poor letter location coding when attention is diffuse [Cognitive Neuropsychol. 18 (2001) 551; Cognitive Neuropsychol. 13 (1996) 205]. In addition, representations on the left side of his attentional space are particularly weak, and so vulnerable to stimuli on the right when FL adopts a wide spatial window for the task. The data point to a pre-categorical deficit in reading in this case.