Predicting generalisation in the training of irregular word spelling: treating lexical spelling deficits in a child with mixed dysgraphia

There is only limited research on the application of cognitive neuropsychology to spelling disorders, especially in childhood. The following study was designed to evaluate whether a cognitive neuropsychological framework can successfully guide treatment of lexical spelling deficits in the case of mixed dysgraphia in childhood. KM is a nine year old girl, who sustained a severe traumatic head injury when she was four years of age. The present study was conducted in a single case research design. An initial assessment aimed at identifying intact as well as deficient components and routes based on a dual route model of spelling. Deficits along the lexical as well as the sublexical route of spelling were identified. The aim of the treatment study presented here was to improve irregular word spelling. In an initial treatment phase we found significant improvement for training words as well as generalization to untreated words. We then identified common characteristics in words that improved without treatment. In a second treatment phase, we only treated words, which we expected not to improve without treatment and left untreated those words, which were more likely to generalize. Results will be discussed within the framework of a dual route model of spelling.