Schuett S et al. (2008) Rehabilitation of hemianopic dyslexia: are words necessary for re-learning oculomotor control? Brain 131: 3156–3168

Rehabilitation of hemianopic dyslexia—an impairment of reading ability caused by loss of part of the visual field—can be achieved by compensatory oculomotor training. This training method uses text-based materials, but whether text is essential to the rehabilitation technique is unclear. A UK study has now shown that training with nontext material (specifically, Arabic numerals) is as effective as text-based training for the rehabilitation of hemianopic dyslexia.

Schuett et al. recruited 40 patients with homonymous parafoveal visual field loss and impaired reading ability, who were divided into two equal groups, one of which used words as the basis for relearning eye-movement control while the other used Arabic numerals. Both methods were found to be equally effective for improving reading performance and the eye movements associated with reading. However, practicing eye movements with numerals was reported to be less distressing, tiring and frustrating for patients than word-based practice—the authors note that the reading task itself frequently seemed to cause distress, and also point out that numeral-based training removes patients' tendency to guess at the completion of words before they fully enter the visual field. All patients reported satisfaction with the outcome of treatment.

Although both rehabilitation techniques were successful in improving reading ability, neither had any effect on patients' visual exploration performance. The authors suggest that these two abilities may be controlled by different yet overlapping neural networks and, therefore, require specific treatment for their improvement.