Slowness in writing numbers in words and in digits among children with a specific learning disorder (SLD) and typically developing (TD)

Instruction: Children with a Specific Learning Disorder (SLD) write linguistic material more slowly than children with typically developing (TD). However, it is not known whether the same difficulties are present when they write numbers. The goal of the present study was to fill this gap and to compare TD's and SLD's speed in writing numbers both in words and in digits. Methods: Therefore, we examined the ability to write numbers in words and digits (numerals) in a sample of sixth- to eighth-grade children diagnosed with SLD. We assessed 32 children with SLD (17 males and 15 females) and a control group of students with TD matched for sex, age, and grade with two writing speed tasks: writing numbers in words and in digits. The two tasks were administered both in normal condition (N) and in articulatory suppression condition (AS). Results: We found that 6th to 8th graders with a SLD were slower than TD children when writing numbers, both in words and in digits, and their slowness was similar in the two cases. However, when the tasks were carried out under a condition of articulatory suppression, the SLD group exhibited a conspicuous impairment, only when writing numbers in words. A similar pattern of performance was observed also in the case of writing errors. Conclusion: We concluded that children with SLD have a general speed problem that may affect writing of different materials but also a specific problem related to the processing of phonological information during writing.