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ACQ
Volume 13, Number 2 2011
ACQ
uiring Knowledge in Speech, Language and Hearing
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
(Rowse & Wilshire, 2007).
Surface dyslexia
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
words (Broom & Doctor, 1995b).
Poor comprehenders
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
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.
Spoken word
recognition
Written Input
Visual orthographic analysis
Letter
identification
Letter
position
Letter-word-
binding
Written word
recognition
Letter-sound-
correspondences
Word meanings
Lexical
Nonlexical
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;