New paper on neglect dyslexia

Dissociating Word-Centred Neglect Dyslexia from Spatial Attention: A Case Study

Neglect dyslexia is a group of post-stroke reading impairments in which people have trouble reading letters on one side of individual words. For example, a patient with right neglect dyslexia might read the word PLANETS as “planet”, “plan”, or “planned”. These reading impairments are all thought to be caused by neglect, a condition in which people have trouble distributing attention equally across space. However, it is not yet clear whether this is an accurate explanation of all cases of neglect dyslexia.

In this experiment, we conducted a single case study of CD, a stroke survivor with right, word-centred neglect dyslexia. CD was found to exhibit right word-centred neglect dyslexia as well as left visuospatial neglect. If CD’s reading problems were caused by his neglect, this conjunction of neglect dyslexia and neglect in opposite lateralisations would not be expected. CD was consistently able to name all individual letters within words, but still committed neglect dyslexia errors when immediately reading the same words as a whole. This behavioural pattern would not be expected if CD’s reading problem was caused by a spatial attention problem.  Finally, factors which are known to modulate the severity of neglect had no effect on the severity of CD’s neglect dyslexia. These findings strongly suggest that CD’s neglect dyslexia cannot be accurately characterised as a neglect-related impairment.

These findings are important because they suggest that we may need to change the way we think about word-centred neglect dyslexia. Current therapies which aim to help people with word-centred neglect dyslexia try to improve neglect attentional biases. If not all cases of neglect dyslexia are not actually caused by these biases, new therapies are needed to help people with neglect dyslexia. However, before these new therapies can be designed, we need to get a better understanding of what causes word-centred neglect dyslexia.