Anisometry of space representation in neglect dyslexia

Patients with unilateral neglect show disorders in horizontal space perception. It has been argued that these disorders may depend on a left-right relaxation of the representational medium that becomes progressively "relaxed" toward the contralesional space and progressively "compressed" toward the ipsilesional space. We tested this hypothesis in 31 right-brain-damaged patients, 17 with neglect and 14 without neglect in two different experiments. Patients were asked to read words in canonical and anisometric letter spacing. Only in neglect patients, the manipulation of letters spacing may ameliorate neglect dyslexia. These results support the idea that the abnormalities observed in typical neglect tests are due to a distorted internal representation of the outside world. In addition, the space distortion seems to depend on the degree of horizontal relaxation of the representational medium and it is unrelated to hemianopia.