Since 2000, the spread of universal screening of newborns' hearing in the United States and in Europe and the technological advancements in hearing compensation due to the development of new digital hearing aids and cochlear implants have had a tremendous impact on the prospects of children with hearing loss (Busa et al., 2007; Harris, 2015; Spencer & Marschark, 2010). Current studies document significant gains in the receptive and expressive spoken language of deaf and hard of hearing children (DHH henceforth) following early identification and intervention, as well as the use of new technologies in hearing compensation (see Geers & Hayes, 2011; Geers, Nicholas, & Sedey, 2003; Harris et al., 2013). Significant improvements are also observed in their reading and writing achievements (Geers & Hayes, 2011). Nonetheless, the development of literacy skills remains a major challenge for many DHH children (Arfe, Dockrell, & Berninger, 2014; Geers, 2003; Geers & Hayes, 2011; Harris & Moreno, 2004; Kyle & Harris, 2010). To date, we have only partially understood why.

As Harris (2015), in this issue, highlights, unpacking the components of reading and writing success (or failure) is considerably more complex in the case of DHH children than that of hearing children. A great amount of variance and individual differences in the language and literacy outcomes of DHH children remain unexplained even when the main socioeconomic, demographic, environmental, and medical predictors of speech, language, and literacy development in this population are considered (e.g., Niparko et al., 2010; Worsfold, Mahon, Yuen, & Kennedy, 2010). Identifying the factors responsible for this variability is crucial to understand what hinders the development of DHH children's literacy.

Related to this general aim are three research challenges. The first is discussed in Harris' paper (2015), which is to understand why important technological developments such as cochlear implantation, which improved access to speech and the language for DHH children, did not produce the desired effect on the literacy achievements of DHH children (see Geers & Hayes, 2011). Notably, the benefits of a cochlear implant appear to be greater during the primary school years than in secondary school. Indeed, a decline in the reading ability of these children relative to peers, occurs with advancing grade levels (Geers, Tobey, Moog, & Brenner, 2008). One of the reasons for this decline may be that reading and writing tasks become more complex as children progress in school and thus place greater demands on the deaf child's memory system (see Arfe, this issue). Another factor to consider is how deaf children are being taught to read and write. However, as Harris suggests in this issue, there is still much to learn about how DHH children learn to read and write and how to support this process.

The second challenge is related to the analysis of DHH children's language and literacy profiles and is addressed by Nelson and Crumpton's (2015), Kyle and Cain's (2015), and Sullivan and Oakhill's (2015) papers. The identification of reading and writing profiles and subtypes has been shown to be a valuable method for understanding the normal variability that is present in children's reading comprehension and written expression (see Catts, Adlof, & Weismer, 2006; Wakely, Hooper, de Kruif, & Swartz, 2006). However, to date, very little research has explored in depth the language and literacy profiles of DHH children (see Nelson & Crumpton, 2015). This research is important because it sets the stage for the design of approaches to writing and reading instruction that are tailored to the specific needs of readers and writers.

The papers by Nelson and Crumpton (2015) and Kyle and Cain (2015) suggest that a comparison between DHH children and poor readers' and writers' reading and writing profiles may cast light on what is specific to DHH children's problems with literacy (see in particular, Nelson & Crumpton, 2015). Before 2000, ability-matched control group designs have been a challenge, due to the very poor reading and writing skills of DHH children. However, in the last 20 years, the language and literacy skills of this population have improved significantly, allowing for these important comparisons.

The third research challenge is understanding how DHH children's deficits in basic cognitive processes, such as verbal short-term memory and working memory (Hamilton, 2011; Harris et al., 2013; Pisoni & Cleary, 2003), relate to their reading and writing problems. For a long time, the preoccupation of researchers and practitioners has been that poor oral language (phonological, vocabulary, and grammatical) skills would impact the literacy achievements of DHH children. Current research suggests that cognitive factors, such as verbal short-term and working memory, may also have an impact on the reading and writing processes of these children and should be considered carefully (see Arfe et al., 2014; Geers, 2003). Verbal short-term and working memory skills may account for up to 20% of unexplained variance in speech perception and 30% of variance in the spoken language skills of children with cochlear implants (e.g., Harris et al., 2013; Pisoni & Cleary, 2003). However, their role in the reading and writing processes of DHH children has been neglected. The studies by Arfe (2015) and Nelson and Crumpton (2015), reported in this special issue, highlight the importance of also considering these cognitive-linguistic skills in the evaluation of DHH children's reading and writing problems.

The five papers in this special issue identify several possible avenues through which future research may enhance our understanding of the reasons for DHH children's reading and writing problems. Reading and writing are tools of personal empowerment, which allow children to express their views and ideas, learn, interact, and understand the world. Helping DHH children develop the ability to comprehend and produce written text is crucial not only for their academic achievement but also for their social integration and individual development. Thus, understanding the nature of DHH children's problems in learning to read and write texts and their relationship with oral language development represents today a research priority (see Arfe et al., 2014; Spencer, Barker, & Tomblin, 2003). It is hoped that the papers in this special issue could contribute to make further progress in this direction.

-Barbara Arfe, PhD

Issue Editor

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