An eye movement based reading intervention in lexical and segmental readers with acquired dyslexia.

Due to their brain damage, aphasic patients with acquired dyslexia often rely to a greater extent on lexical or segmental reading procedures. Thus, therapy intervention is mostly targeted on the more impaired reading strategy. In the present work we introduce a novel therapy approach based on real-time measurement of patients' eye movements as they attempt to read words. More specifically, an eye movement contingent technique of stepwise letter de-masking was used to support sequential reading, whereas fixation-dependent initial masking of non-central letters stimulated a lexical (parallel) reading strategy. Four lexical and four segmental readers with acquired central dyslexia received our intensive reading intervention. All participants showed remarkable improvements as evident in reduced total reading time, a reduced number of fixations per word and improved reading accuracy. Both types of intervention led to item-specific training effects in all subjects. A generalisation to untrained items was only found in segmental readers after the lexical training. Eye movement analyses were also used to compare word processing before and after therapy, indicating that all patients, with one exclusion, maintained their preferred reading strategy. However, in several cases the balance between sequential and lexical processing became less extreme, indicating a more effective individual interplay of both word processing routes.

What letters can "learn" from Arabic digits--fMRI-controlled single case therapy study of peripheral agraphia.

Research on (hand-)writing has revealed that Exner's area subserves transferring linguistic impulses into writing programmes. We report on a patient with a lesion affecting Broca's and Exner's area suffering from severe peripheral agraphia for letters but not for Arabic digits. Analogous to semantic (magnitude) information in numbers, we developed a specifically tailored writing training: additional mental imagery based semantic information was attached to letters. The training resulted in significant improvements. Imaging data revealed stronger fronto-parietal network activity including perilesional activation around Exner's area and precuneus for writing letters to dictation than for writing letters corresponding to their mental image expressions. Follow-up testing showed not only stable training effects but also an activation shift into the left angular gyrus. Results document neuronal correlates of a successful intervention by attaching additional meanings to letters in order to retrieve their grapho-motor patterns. These findings contribute to understanding the impact of Exner's area.