The benefits and protective effects of behavioural treatment for dysgraphia in a case of primary progressive aphasia

Background: Spoken and written language difficulties are the predominant symptoms in the progressive neurodegenerative disease referred to as primary progressive aphasia (PPA). There has been very little research on the effectiveness of intervention on spoken language impairments in this context and none directed specifically at progressive written language impairment. Aims: To examine the effectiveness of behavioural intervention for dysgraphia in a case of primary progressive aphasia. Methods & Procedures: We carried out a longitudinal single-case study that allowed us to examine the effectiveness of a non-intensive spell-study-spell intervention procedure. We did so by comparing performance on four sets of words: trained, repeated, homework, and control words at five evaluations: baseline, during intervention, after the intervention, and at 6- and 12-month follow-up. Outcomes & Results: We find that: (1) at the end of the intervention, Trained words show a small but statistically significant improvement relative to baseline and an advantage in accuracy over Control, Homework, and Repeated word sets. (2) All word sets exhibited a decline in accuracy from the end of treatment to the 6-month follow-up evaluation, consistent with the degenerative nature of the illness. Nonetheless, accuracy on Trained words continued to be superior to that of Control words and not statistically different from pre-intervention baseline levels. (3) Repeated testing and practice at home yielded modest numerical advantages relative to Control words; but these differences were, for many comparisons, not statistically significant. (4) At 12 months post-intervention, all words sets had significantly declined relative to pre-intervention baselines and performance on the four sets was comparable. Conclusions: This investigation documents - for the first time - that behavioural intervention can provide both immediate and short-term benefits for dysgraphia in the context of primary progressive aphasia.