Andrea Ruzza et al.

In this paper, we describe an intervention implemented to assist a 13.2-year-old boy with
Autism Spectrum Disorder, G, without intellectual disability, aimed at improving his ability to
compose persuasive texts. There was an initial assessment (baseline), an intermediate assessment after
two weeks, a six-session intervention phase, and a post-intervention assessment. Our intervention
applied two procedures. The first aimed at enhancing general composition abilities in terms of picking
(P) ideas, organizing (O) notes, and writing (W) them down (POW), while the second specified the
steps to write a persuasive text addressing a possible reader: a topic sentence (T), reasons (R), an
explanation (E) for the reasons and the end of the sentence (E) (TREE). These procedures were termed
POW + TREE. To analyze G’s texts, three types of measures were used by two raters at baseline,
intermediate and post-test time: (a) the presence of the TREE components; (b) the quality of the
reasons and explanations for the reasons; (c) the number of mental state terms. All these measures
showed relevant quantitative improvements, as well as qualitative changes. In addition, when G’s
performance at the end of the intervention was compared to that of typically developing controls, no
statistical difference appeared. The results are discussed in light of the potentialities offered by the
type of intervention described here.