ADHD and learning disabilities (LD) co-exist in many children. Many of these students have problems with working memory. Although a little crude, the best description I have for working memory is that it is a set of cognitive functions that help you keep your s@#* together while performing a complex task.
Working memory predicts parent ratings of inattentive behaviours and has been found to be below average in LD and ADHD samples in a large number of studies. It has also been shown to be a predictor of academic success. Previously it had been thought that working memory was a fixed trait. However, recent evidence (see for e.g., Klingberg, 2010; Klingberg et al., 2005) is suggesting that it can be modified via a computerised memory training program called Cogmed. Note that the claim has been that Cogmed improves working memory when all we can really conclude is that a period of training using the program leads to improved scores on tests of working memory. There is an important difference between these two claims.