ACQ Vol 13 no 2 2011

which cannot be sounded out phonetically, written word recognition of individual whole words needs to occur before access to word meanings and spoken word production can take place. This occurs as part of the whole word procedure or lexical route (Coltheart et al., 2001). In the various subtypes of reading disorders we describe below, one or more of these different processing steps is lacking or not working to a sufficient level. We will begin by describing some of the better known subtypes before moving on to subtypes that may be less familiar.

Rowse & Wilshire, 2007). A range of off-the-shelf phonics programs may be suitable for this purpose. Broom and Doctor (1995a) found improved reading for nonwords after such training, affecting not only trained but also untrained letter-sound-correspondences. This result suggests that the treatment of letter-sound correspondences may target both specific skills, such as the learning of particular letter-sound correspondences, and general skills, such as the ability to break down words into their phonological components Children with surface dyslexia demonstrate a difficulty in reading out loud irregular words, i.e., those that do not follow letter-sound rules. In contrast to children with phonological dyslexia, those with surface dyslexia sound out nonwords and regular words to a competent level (Broom & Doctor, 1995b; Castles & Coltheart, 1996). As these children are not able to read successfully via the lexical route, they resort to the nonlexical route, which is working normally (Broom & Doctor, 1995b; Friedmann & Lukov, 2008). Typically, children with surface dyslexia “regularise” or sound-out all words, even words with irregular pronunciations. For example, the word iron may be read as [ ˈaɪ rɒn ] rather than [ ˈaɪ ərn ]. Within the dual route theory, the reading behaviour of children with surface dyslexia suggests that they have difficulties accessing sight-words using written- word recognition on the lexical route, or that they have fewer representations of written words in their memories (Broom & Doctor, 1995b). One reason why a child may demonstrate surface dyslexia is the lack of ability to form and maintain visual representations of written words (Castles & Coltheart, 1996; Di Betta & Romani, 2006). Children with surface dyslexia can be identified by asking them to read irregular words. The reading performance of children with surface dyslexia can be overestimated if assessed on tests that include a mixture of regular and irregular words, as these children will be able to successfully sound out the regularly spelled words. The Castles and Coltheart Reading Test 2 (Castles et al., 2009) allows identification of both surface and phonological dyslexia, since it contains both irregular words and nonwords. Successful treatment of surface dyslexia focuses on teaching the association between the spelling and the pronunciation of the words a child cannot read correctly. This is usually achieved by repeatedly exposing the child to the written and spoken words and can be done with flashcard training. In addition, visual-mnemonic (i.e., picture cues) and additional copying exercises have also been used successfully (e.g., Broom & Doctor, 1995b; Rowse & Wilshire, 2007). Improvements usually affect only treated irregular words, while words that are not specifically trained will not be read any better, which means that the success of treatment will depend on the number of individual words that the child can be taught and the frequency of those Poor comprehenders have difficulty understanding what they are reading (Nation & Snowling, 1998). These children often show normal reading accuracy and even fluency, yet when they are asked questions about what they have read, they are unable to answer, or answer incorrectly (Stothard & Hulme, 1992; Yuill & Oakhill, 1991). Most poor comprehenders do not have a reading problem. It is their poor oral language skills that hamper their comprehension of written text. Other (Rowse & Wilshire, 2007). Surface dyslexia words (Broom & Doctor, 1995b). Poor comprehenders

Written Input

Visual orthographic analysis

Letter identification

Letter position

Letter-word- binding

Written word recognition

Nonlexical

Lexical

Letter-sound- correspondences

Word meanings

Spoken word recognition

Spoken output

Figure 1. The dual route model Source: based on Friedmann et al., in press Phonological dyslexia Children with phonological dyslexia show difficulties reading nonwords and unfamiliar words. When sounding out, incorrect letter-sound-correspondences are used (e.g., uh for the letter A), producing an incorrect word (e.g., reading cat as cut ). Often, nonwords are misread as similar looking words (e.g., reading drick as drink ). In addition, with this subtype there can be a tendency to leave off or replace the ending of a word. The consequence of this is sometimes a morphological error, meaning the suffix of the word is said incorrectly (e.g., needed read as need ). In relation to dual route theory, reading along the nonlexical route is proposed to be impaired in children with insufficient knowledge of letter-sound correspondences. However, processing along the lexical route is functioning well (Broom & Doctor, 1995a), which explains why a reader with pure phonological dyslexia is typically able to read sight-words to a normal or high level. To identify phonological dyslexia it is best to test nonword reading because, in order to read a nonword correctly, the nonlexical route must be used. When assessing reading ability using a test that consists of real words only, the reading performance of children with phonological dyslexia may be overestimated. Children with phonological dyslexia will often also perform poorly on phonological awareness tasks such as rhyme judgement, phoneme deletion (e.g., say tiger without the /t/ sound), blending (e.g., r-u-n becomes run ) and sound categorisation (e.g., three words are read aloud and the child is asked to identify which word does not begin with the same sound as the others) (Rowse & Wilshire, 2007). To improve processing along the nonlexical route, intervention-based research has focused on the teaching of phonics, or (unknown) letter-sound-correspondences, using regular words and nonwords (e.g., Broom & Doctor, 1995a;

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ACQ Volume 13, Number 2 2011

ACQ uiring Knowledge in Speech, Language and Hearing