Treatment of single word oral reading in an individual with

Transcription

Treatment of single word oral reading in an individual with
APHASIOLOGY, 2002, 16 (4/5/6), 455–471
Treatment of single word oral reading in an individual with
deep dyslexia
Sasha Yampolsky and Gloria Waters
Boston University, USA
Background: Deep dyslexia is an acquired reading disorder in which the lexical and nonlexical reading routes are impaired, resulting in poor nonword reading, semantic errors in
oral reading, visual-perceptual errors in oral reading, poor reading of functors, and
imageability effects. There is evidence that individuals combine information from the lexical
(semantic system) and the non-lexical routes to read words aloud. This evidence shows that
partial phonological and semantic information combined at the level of the phonological
output lexicon reduces semantic errors in reading aloud and increases the ability to produce
the correct words.
Aims: The aim of the present study was to use a phonologically based oral reading treatment
to treat impaired single word oral reading in an individual with deep dyslexia. We
hypothesised that phonologically based treatment would improve oral reading of real words,
decreasing the amount of semantic errors.
Methods & Procedures: The Wilson Reading System was used in therapy. This phonicsbased programme focuses on the use of grapheme–phoneme correspondences, blending, and
phonological awareness. A multiple-baseline design was used to evaluate the treatment
effects in a single individual with deep dyslexia.
Outcomes & Results: Following treatment at the single word level, the individual showed a
significant improvement in single word oral reading for the targeted syllabic structure and in
nonword reading. There was also a significant reduction in semantic errors in oral reading.
One month post-treatment, the individual maintained treatment gains.
Conclusions: Results support the hypothesis that the partial use of phonological information,
combined with semantic information, results in improved accuracy of oral reading. This
suggests that treatment of oral reading in people with deep dyslexia may benefit from
attention to the non-lexical (phonological) component of reading in addition to the lexical/
semantic component.
Information-processing models of the normal reading process have been widely utilised
to study acquired reading disorders. Ellis and Young (1988) describe a model of normal
reading which begins with the visual identification of individual letters in words and their
positions within the word. Following this initial process, the model presents three
possible routes to reading single words. One route is the non-lexical route, where
individuals read words using grapheme–phoneme correspondences (GPCs). This allows
individuals to read unfamiliar words and nonwords. Three main operations take place
when using the non-lexical route to read: segmentation of the letter string into individual
units; use of grapheme–phoneme correspondence to associate graphemes with phonemes;
Address correspondence to: Sasha Yampolsky, Boston University, Sargent College of Health and
Rehabilitation Sciences, Department of Communication Disorders, room 351, 635 Commonwealth Avenue,
Boston, MA 02215, USA. Email: sashay@bu.edu
# 2002 Psychology Press Ltd
http://www.tandf.co.uk/journals/pp/02687038.html
DOI:10.1080/02687030244000068
456
YAMPOLSKY AND WATERS
blending of each phoneme to assemble the syllables and the word. Phoneme blending is
critical for the word (or nonword) to become available for spoken output.
A second route to reading is via the lexical-semantic route, where the word passes
directly from the visual analysis to the semantic system, and does not require the reader to
sound out the word. Reading via this route is also called whole-word or sight-word
reading.
In a third route, the word feeds directly from the visual analysis system to the speech
output lexicon (also referred to as the Phonological Output Lexicon), bypassing
semantics. Persons who can read aloud irregular words without comprehension provide
evidence for this route. In all three routes, the word form becomes available for verbal
production in the speech output lexicon. Researchers have used models of normal reading
to understand acquired reading disorders and to identify sub-types of acquired dyslexia in
case studies of patients with brain damage. Dyslexias that occur after the initial stages of
visual analysis have been classified into three major syndromes: surface, phonological,
and deep dyslexia (Coltheart, 1987; Ellis & Young, 1988). The single case treatment
study reported in this paper focuses on the remediation of single-word oral reading in an
individual with deep dyslexia, an acquired disorder in which both the non-lexical and
lexical reading routes are impaired, resulting in poor nonword reading, semantic errors in
oral reading, visual-perceptual errors in oral reading, poor reading of functors, and
imageability effects (Coltheart, 1987).
DePartz (1986) and Nickels (1992) studied individuals who presented with an oral
naming impairment (anomia) in addition to deep dyslexia. Both participants had better
written than spoken naming skills (they could write words they could not name, but were
then unable to read them). The goal of therapy in both cases was to improve oral naming
indirectly through reading. The authors reasoned that if the individuals could visualise
words ‘‘inside their head’’ and orally ‘‘read’’ from this image, then their naming ability
might improve. The investigators retrained the participants to use the non-lexical reading
route in two stages. First, the participants learned to associate graphemes with their
sounds, and then to blend the sounds to produce monosyllabic words and nonwords.
DePartz’s participant improved in reading aloud (reading both words and nonwords
with similar accuracy post-treatment) and in oral naming. Although Nickels’ participant
successfully mastered GPC, he was unable to accomplish blending. After deriving the
sound for every letter in a word, and uttering the sounds in the correct order as presented
in the letter string, he was unable to blend these sounds into a complete syllabic unit.
Therefore, this individual failed to improve in nonword reading. However, he did
significantly improve his ability to read words and to name pictures. Whereas DePartz’s
participant may have relied on blending to read the word or nonword, Nickels’ participant
was encouraged to use the first or second phoneme in the word while simultaneously
thinking of its meaning. This combination of the partial use of phonological and semantic
information proved to be successful in oral reading of words and in spoken naming.
However Nickels’ participant’s failure to acquire blending skill and to read via the nonlexical route impeded his ability to read novel, unfamiliar words.
Matthews (1991) and Mitchum and Berndt (1991) also conducted case studies where
the treatment goal was to first re-establish GPCs and then to help the individuals with
deep dyslexia learn the process of blending. After Matthews’ participant succeeded in relearning GPCs, Matthews trained him to sequentially sound out each phoneme. Mitchum
and Berndt (1991) also trained their participant in auditory analysis skills using
manipulatives (matching same/different colour blocks with same/different spoken
phoneme patterns). This enabled her to improve her auditory analysis skills. Mitchum
and Berndt combined the initial grapheme with word bodies (i.e., J+eep, B+eep) and
ORAL READING IN DEEP DYSLEXIA
457
required their patient to read the words aloud. Although both individuals were able to
associate graphemes with phonemes, they were unable to successfully utilise this skill in
blending.
Kendall, McNeill, & Small (1998) attempted to re-establish rule-based sound
conversion of whole-word orthography. This approach is different from the other cited
studies that sought to establish specific letter-to-sound correspondences. The participant
in Kendall et al.’s study presented with phonological dyslexia. Individuals with
phonological dyslexia are also impaired in the use of GPCs and in reading via the nonlexical route, but unlike deep dyslexic individuals they do not produce semantic errors
when reading aloud. The participant was systematically exposed to words containing the
‘‘c’’ and ‘‘g’’ rules (i.e., cent, gem) until he provided the correct response. The authors
hypothesised that the participant would internalise the rules and develop a reading
strategy for words with the same rules. He showed improvement in oral reading of words
and nonwords using both rules, and generalisation occurred with words using other GPC
rules (pseudohomophones for real words, such as: phyl, pensul, nekliss). This result raises
the question of whether this individual’s deficit was due to lack of knowledge of GPC
rules or to the inability to implement these rules. It may be that he gradually learned to
implement rules through multiple exposures, as opposed to learning the specific rules to
which he was exposed.
Conway et al. (1998) also conducted a treatment study with an individual who
presented with characteristics of mild phonological dyslexia. The individual’s use of the
non-lexical route was impaired, as evidenced by impaired nonword reading compared
with regular and irregular word reading. His oral reading deficits were, however, less
severe than participants in the previous studies. This individual also presented with
reduced phonological awareness skills, or ‘‘the ability to represent the phonemic structure
of language as well as indicate changes in the phonemic structure’’ (Conway et al., 1998,
p. 611). Conway et al. employed a treatment programme (Auditory Discrimination in
Depth) that focused on improving the individual’s phonological awareness. Conway et
al.’s participant was first trained to understand how the articulators move to produce
phonemes, to understand voicing of phonemes, and to group together phonemes produced
in a similar fashion. He was then presented with nonwords ranging from one to three
phonemes, and was required to state the number and order of phonemes using
manipulatives. After successfully completing this step, the participant blended the
phonemes, first with cueing articulatory placement, then with the cueing removed. The
same procedure was used for more complex and multisyllabic nonwords. The
phonological awareness training, together with blending training, improved nonword
reading. Reading of real words also improved, as the participant was able to blend regular
real words that he was unable to recognise via the lexical reading route.
Two main issues emerge from the phonological/deep dyslexia treatment literature.
First, the reviewed studies demonstrate the importance of blending in lexical and nonlexical reading. The participants in the studies by Matthews (1991), Mitchum and Berndt
(1991), and Nickels (1992) were able to re-learn GPCs, however they were unable to
blend. These individuals therefore remained unable to read unfamiliar words. These
studies indicate that when a person with deep dyslexia cannot blend phonemes, relearning
GPCs does not readily transfer to reading real words and to reading phoneme strings
when no lexical information is available. Conway et al.’s (1998) study suggests that when
treatment focuses on phonological awareness and incorporates blending, then blending
and non-lexical reading ability is improved.
Second, the studies demonstrate the significance of the lexical (semantic) component
of word reading. The participants in the studies by DePartz (1986), Matthews (1991),
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YAMPOLSKY AND WATERS
Mitchum and Berndt (1991), and Nickels (1992) made fewer semantic errors when they
read aloud after GPC-based treatment. Hillis and Caramazza (1995) provide evidence
from case studies that individuals combine information from the lexical (semantic
system) and the non-lexical routes to read words aloud. The investigators showed that
individuals with impairments to both the non-lexical and lexical reading routes (as is the
case in deep dyslexia), can limit possible responses, and thus reduce semantic errors in
reading by using partial phonemic and semantic information derived from the written
word.
The ability to ‘‘visualize’’ some or all of a written word improved oral naming in
DePartz’s and Nickels’ participants. Hillis and Caramazza (1995) propose that partial
phonological and semantic information combined at the level of the phonological output
lexicon increases the ability to produce the correct words. As reading aloud and naming
require access to the correct phonological representation, it should follow that semantic
errors in both reading aloud and in naming may decrease with the use of partial phonemic
and lexical information.
The aim of the present study was to target GPC and blending skills explicitly and
simultaneously to treat impaired single word oral reading in an individual with deep
dyslexia. This treatment method differs from that used in previous studies in which GPCs
and blending were taught in distinct stages (DePartz,1986; Matthews, 1991; Mitchum &
Berndt, 1991; Nickels, 1992). Based on the reviewed case studies and on the summation
theory of Hillis and Caramazza, we hypothesised that phonologically based treatment
would improve oral reading of real words, decreasing the amount of semantic errors. We
further hypothesised that simultaneously targeting GPC and blending would improve the
participant’s ability to independently blend and to read unfamiliar letter strings. The
present study was conducted to evaluate these predictions.
METHOD
Participant
MO is a 23-year-old, right-handed female who underwent a left frontoparietal craniotomy
for a ruptured arteriovenous malformation 3 years prior to the inception of this study. The
MRI indicated a large area of tissue loss involving the left temporal, frontal, and parietal
lobes. MO was 6 months pregnant at the time and underwent a successful caesarean
section. At the time of the present study, MO presented with functional conversational
comprehension and moderate expressive aphasia characterised by anomia and
agrammatism. She was most devastated by her acquired reading impairment, and her
goal was to read aloud to her daughter. MO had been an A–B student and a recent highschool graduate at the time of the rupture. No prior history of learning disabilities was
reported, and she had enjoyed reading novels.
Intellectual functioning
Neuropsychological testing indicated that her level of functioning was in the Low
Average range. Due to MO’s expressive language deficits, and her hemiparesis, only
selected subtests from the Wechsler Adult Intelligence Scale–3 (Wechsler, 1981) were
administered. Subtest scores ranged from the ‘‘Mentally Deficient’’ range on the
Arithmetic subtest, to the Low Average range on the Matrix Reasoning and Information
subtests. On the visual memory portion of the Wechsler Memory Scale, the Face Memory
Test (Wechsler, 1987), MO performed in the Average–High Average range.
ORAL READING IN DEEP DYSLEXIA
459
MO was administered a battery of speech-language and reading tests that included
subtests of the Psycholinguistic Assessment of Language (PAL; Caplan, 1992) and the
Psycholinguistic Assessment of Language Processing in Aphasia (PALPA; Kay, Lesser, &
Coltheart, 1992). For each PAL subtest MO’s performance was compared to that of 27 nonbrain-damaged controls, ages 35–50 (Waters & Caplan, 2002). Performance was
considered impaired if it fell more than 2 standard deviations below the mean. Performance
on the PALPA subtests was compared to normative data for 32 non-brain-damaged
controls (Kay et al., 1992). The same criterion for impairment was used as with the PAL.
For some PALPA subtests normative data were not available. However, MO scored
extremely low on those tasks, hence justifying the judgement of impaired performance.
Oral language
MO’s performance on tasks tapping oral language is summarised in Table 1.
Input processing. MO’s auditory comprehension was functional. However, her
comprehension of abstract words and affixed words and of syntactically complex
sentences was impaired.
Output processing. MO presented with moderate expressive aphasia. Her ability to
repeat nonwords was impaired, indicative of difficulty in utilising phonological
TABLE 1
MO’s pre-treatment performance on oral language tasks (input and output processing)
Language processing component
Input Processing
1. Acoustic-phonetic processing
2. Auditory lexical access
3. Auditory lexical access (affixed words)
4. Auditory lexical access (affixed words)
5. Lexical semantic access
6. Lexical semantic access
7. Lexical semantic access (abstract
words)
8. Lexical semantic access (affixed words)
9. Lexical semantic access
10. Sentence level processing
Parsing & syntactic comprehension
Lexico-inferential comprehension
Output Processing
1. Access to lexical phonological
representations
2. Production of lexical phonological
representations
3. Production of non-lexical phonological
representations
4. Access to and production of lexical
phonological representations
5. Sentence construction
* Impaired performance
Subtest
Number (and %)
correct
PAL Phoneme Discrimination
PAL Lexical Decision
PAL Lexical Decision–Derived words
PALPA Lexical Decision & Morphology
PAL Word–picture Matching
PAL Probe Verification
PAL Relatedness Judgment, abstract words
14/15 (93)
20/20 (100)
40/48 (83)*
27/60 (45)*
31/32 (97)
18/18 (100)
13/20 (65)*
PAL Word–picture matching–derived words
PPVT–III
PAL Sentence Comprehension
Syntactic processing
Lexico-inferential processing
18/20 (90)
5th %ile*
31/40 (77)*
12/20 (60)*
19/20 (95)
PAL Picture–Homophone Matching
22/32 (68)*
PAL Word Repetition
20/20 (100)
PAL Nonword Repetition
12/20 (60)*
PAL Picture Naming
16/32 (50)*
PAL Sentence Production
8/20 (40)*
460
YAMPOLSKY AND WATERS
information for word production planning. A significant feature of MO’s expressive
language was word-finding difficulties. On the PAL she correctly named 16/32 concrete
nouns. No phonemic paraphasias were noted, and of the 16 pictures MO could not
correctly name, 4 were semantic paraphasias. She was unable to state the number of
syllables or initial sounds of words she could not name. On 75% of trials on which she
was unable to spontaneously name a picture, she was able to produce the word when the
initial sound was provided. These observations suggest that while MO could access the
meaning of words, she had difficulty accessing their phonological form. To assess a stage
prior to that needed for production of phonological representations, we administered the
PAL Homophone Matching subtest to examine MO’s access to lexical phonological
representations. On this task MO was presented with 32 pictures of word pairs that were
homophonic (i.e., baseball bat and flying bat) and non-homophonic (i.e., cat and can),
and was asked to indicate whether their names were homophones. Non-homophone pairs
differed by a single distinctive feature. Although MO judged the non-homophone pairs
with 100% (16/16) accuracy, her score for indicating homophone pairs fell below normal,
at 37% (6/16). This shows that MO had a response bias, and basically could not do the
task. This indicates impairment in accessing phonological forms from semantics.
Observation and informal testing also showed that MO had a mild speech apraxia
characterised by de-voicing errors and an increase in articulatory errors as phonemic
sequences increase.
Written language
Input processing. MO’s performance on written language tasks tapping input
processing is summarised in Table 2. MO had no difficulty with the visual analysis stage
of reading, as seen by unimpaired performance in cross-case matching and letter
discrimination. Normal performance on written word–picture matching and on a task
testing knowledge of semantic attributes of written words indicated that she had
functional access to lexical-semantic representations of concrete written words. However,
MO’s comprehension of abstract and derived words was impaired. This translated into
impaired performance on the PAL Relatedness Judgment for Abstract Words subtest,
TABLE 2
MO’s pre-treatment performance on written language tasks (input processing only)
Language processing component
1.
2.
3.
4.
5.
6.
7.
Orthographic analysis
Orthographic analysis
Written lexical access
Written lexical access (affixed words)
Lexical semantic access
Lexical semantic access
Lexical semantic access (abstract words)
8. Lexical semantic access
9. Sentence level processing
Parsing & syntactic comprehension
Lexico-inferential comprehension
* Impaired performance
Subtest
PALPA Cross-case matching
PALPA Letter Discrimination
PAL Written Lexical Decision
PALPA Lexical Decision and Morphology
PAL Written Word–Picture Matching
PAL Written Probe Verification
PAL Relatedness Judgment, written abstract
words
PPVT-III, Written version
PAL Written Sentence Comprehension
Syntactic processing
Lexico-inferential processing
Number (and %)
correct
52/52 (100)
26/30 (87)
28/40 (70)*
27/60 (45)*
31/32 (97)
26/27 (96)
14/20 (70)*
<1st %ile*
19/40 (48)*
6/20 (30)*
13/20 (65)*
ORAL READING IN DEEP DYSLEXIA
461
where she was asked to choose one of two written abstract words to match a target written
abstract word. She performed slightly better than chance on the PAL Written Word–
Picture Matching for Derived Words subtest. Written sentence comprehension was
severely impaired, her performance falling below chance.
Oral production of written stimuli. MO’s performance on written language tasks
tapping output processing (oral production) is summarised in Table 3. Her performance is
discussed in terms of the lexical and non-lexical reading routes of the Ellis and Young
model.
Lexical route: MO’s ability to read words was assessed by a variety of single word
oral reading tasks from the PAL and PALPA. On the PAL Oral Reading task, MO
correctly read aloud 31% (10/32) of the words. She was more successful in reading highfrequency than low-frequency nouns [w2(1) = 6.8, p < .01] and high-imagery than lowimagery nouns [w 2(1) = 5.2, p < .05]. Imageability effects were also noted on the PALPA
Grammatical Class, where reading accuracy of function words was significantly lower
than that of concrete nouns [w2(1) = 4.4, p < .05]. However, this effect disappeared when
compared with more abstract nouns on the PALPA Class 6 Imageability, where MO’s
performance was at floor level. The PALPA Oral Reading Morphological Endings
subtest indicated that she was unable to read aloud any derived words, and that she often
made morphological errors (i.e., happiness ! happy, happily).
Semantic substitutions (for example, she read double as identical, music as singing,
piano as music, ivory as soap . . . body wash . . . white) constituted 34% (13/38) of MO’s
reading errors on the PAL Oral Reading and PALPA Syllable Length Reading subtests.
MO was able to independently recognise her mistakes about 50% of the time. Visual/
phonological errors were also seen. These included reading fact as face, soul as solo, and
flash as flask. With these types of errors, MO did not self-correct or recognise her errors.
Sight word reading was also assessed using the Dolch Word List (Dolch, 1950). This
list contains the most common sight and function words from pre-primer through thirdgrade level. MO correctly read 67% (27/40) of the pre-primer words and 50% (26/52) of
the primer and first-grade (20/41) level words. She made many visual substitution errors
(i.e., where for what, through for three, cold for could, her for his, he for her) as well as
some morphological errors (i.e., fun for funny, say for said).
Non-lexical route: Parsing. To assess MO’s graphemic parsing ability (a prerequisite
for using GPCs), she was asked to name letters in single-syllable consonant-vowelconsonant (CVC) nonwords. MO was able to perform this task, however, she had to state
the alphabet aloud to produce the correct letter name.
Non-lexical route: GPC. MO’s ability to produce the sound of printed letter stimuli
(association of graphemes with phonemes) was impaired, as judged by the Phonological
Awareness Test (Robertson & Salter, 1997) Graphemes subtest. The highest score was in
production of consonant sounds (14/20), and the lowest was with blends (1/10), Rcontrolled vowels (0/15), and diphthongs (0/4).
Non-lexical route: Nonword reading. Nonword reading was assessed via the Nonword
Reading subtests of the PAL and the Phonological Awareness Test. MO was not able to
read any vowel-consonant (VC) nonwords and could read only 1 out of 20 CVC
nonwords from the Phonological Awareness Test. She was unable to read any nonwords
of various syllabic structures on the PAL. Taken together, MO’s performance indicates
that her non-lexical reading was limited due to limited GPC ability.
Non-lexical route: Phonological awareness. MO’s performance on auditory tasks that
are thought to be prerequisites to reading aloud was assessed via the Phonological
TABLE 3
MO’s pre-treatment performance in oral production of written stimuli and in
phonological awareness
Language processing component
1. Recognition and oral production of
letter names
2. Grapheme–phoneme correspondences
3. Access to and production of lexical
phonology from orthography
4. Access to and production of lexical
phonology from orthography
5. Access to and production of lexical
phonology from orthography
6. Access to and production of lexical
phonology from orthography
7. Access to and production of lexical
phonology from orthography
8. Access to and production of lexical
phonology from orthography
9. Production of non-lexical phonology
from orthography
10. Production of non-lexical phonology
from orthography
11. Phonological awareness
* Impaired performance
462
Subtest
Number (and %)
correct
PALPA Letter Naming
23/26 (88)*
Phonological Awareness Test: GPC
Consonants
Long & short vowels
Blends
Consonant digraphs
r-controlled vowels
Vowel digraphs
Diphthongs
PAL Oral Reading
14/20 (70)*
4/20 (40)*
1/10 (10)*
2/14 (14)*
0/15 (0)*
3/5 (60)*
0/4 (0)*
10/32 (31)*
PALPA Syllable Length Reading
1 syllable
2 syllable
3 syllable
PALPA Oral Reading: Grammatical Class
Adjectives
Nouns
Verbs
Functors
PALPA Oral Reading: Class 6 Imageability
Abstract nouns
Functors
PALPA Oral Reading: Morphological
Endings
Regularly inflected
Regular control
Derived
Derived control
Irregularly inflected
Irregular control
PALPA Oral Reading: Regularity
Regular
Irregular
PAL Oral Reading: Nonwords
8/24 (33)*
4/8 (50)*
3/8 (38)*
1/8 (13)*
9/80 (11)*
2/20 (10)*
4/20 (20)*
3/20 (15)*
0/20 (0)*
4/40 (10)*
2/20 (10)*
2/20 (10)*
14/90 (15)*
Phonological Awareness Test: Nonword
reading (VC and CVC)
Phonological Awareness Test:
Rhyming
Segmentation
Isolation
Deletion
Substitution
Auditory Blending
1/20 (5)*
3/15 (20)*
4/15 (26)*
0/15 (0)*
2/15 (13)*
2/15 (13)*
3/15 (20)*
12/60 (20)*
4/30 (13)*
8/30 (26)*
0/25 (0)*
20/20 (100)
11/20 (55)*
21/30 (70)*
11/20 (55)*
5/20 (25)*
13/20 (65)*
ORAL READING IN DEEP DYSLEXIA
463
Awareness Test. MO’s ability to identify pairs of rhyming words and to provide a rhyme
when given a stimulus word was tested via the Rhyming subtest. Performance was 100%.
Sub-skills necessary to classify words into their phonologic constituents were assessed on
both the syllable and the phoneme levels (Segmentation subtest). MO was able to provide
the correct number of taps for each syllable in 90% of the words presented orally. This
was contrasted with her severely impaired ability to segment by phoneme (sound), where
MO was able to correctly provide individual sounds of only 20% of the orally presented
words. MO’s ability to identify initial and final phonemes in orally presented words
(Isolation subtest) was only slightly impaired (85% correct). This is contrasted with
scores on medial-position phonemes, of which she accurately identified only 40%. MO’s
ability to delete both syllables and phonemes in orally presented compound,
multisyllabic, and single-syllable words was assessed (Deletion subtest). With
compounds, MO was able to correctly repeat all words while deleting one root (i.e.,
Say ‘‘cowboy’’. Now say it again but don’t say ‘‘boy’’.). Her ability to do this while
deleting a syllable was mildly reduced (60% correct), and performance declined greatly
when she was required to delete one phoneme (30% correct). Sound manipulation in
orally presented words (Substitution subtest) was tested both with and without
manipulatives (coloured blocks to represent sounds). MO’s ability to isolate a phoneme
in a word, then change it to a new phoneme to form a new word as specified by the
examiner, was impaired. She correctly answered 30% with manipulatives and 20%
without manipulatives. MO’s ability to blend orally presented syllables and phonemes
together to form a word was assessed (Auditory Blending). The contrast between her
ability to correctly identify the syllable and phoneme levels was again apparent, as seen
by her almost perfect performance in blending syllables (90% correct) as opposed to less
than half correct (40%) in blending phonemes.
DISCUSSION OF DEFICITS
Results of oral reading tasks indicated that MO’s single-word oral reading ability was
severely impaired. MO was attempting to read via an impaired lexical route, and was
unable to apply GPC and blending to orally read unfamiliar letter strings. MO’s complete
inability to read nonwords indicated that her non-lexical route was severely damaged.
Although her word reading ability was limited, almost at floor level, an error pattern
emerged. MO demonstrated a frequency effect (read high-frequency words more
accurately than low-frequency words) and an imageability effect (read concrete words
more accurately than abstract words), which suggest impaired lexical/semantic access in
oral reading. She also made semantic and visual errors. Hillis and Caramazza (1995)
propose that semantic errors may occur because no phonological information is available
to constrain responses stemming from an impaired semantic system. MO’s impaired
access to lexical phonology, coupled with her inability to use GPC, corresponds to this
claim. An individual’s inability to rely upon phonology may also result in visual errors,
when substitution for an orthographically close word occurs. Taken together, MO’s
reading pattern and evidence of disruption of both lexical and non-lexical routes rendered
a classification of deep dyslexia.
Rationale for treatment
MO’s major deficit lies at the phonological coding level of language, and reading aloud
was her goal. The goal of treatment was improved use of GPCs, with the larger goal being
to re-establish non-lexical reading ability. Hillis and Caramazza (1995) argue that
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YAMPOLSKY AND WATERS
semantic errors in reading aloud can be avoided by using limited phonological
information. In other words, the individual does not need to possess a complete
phonological representation, but can use the first few phonemes to limit semantically
related responses and produce the correct word. Hillis and Caramazza argue that the
partial use of semantic and phonological information can improve reading aloud in
general, as was the case for the participants in the studies by Mitchum and Berndt (1991)
and Nickels (1992). Also, if the phonological (non-lexical) route is not intact, one would
need to rely on visual memory, context cues, and the semantic system. MO’s degraded
semantic system and impaired written sentence comprehension together impede
contextual facilitation for reading aloud.
Treatment programme
Re-learning GPCs and blending using real words was the focus of treatment. The Wilson
Reading System (Wilson, 1996), a commercial programme for adults and adolescents,
focuses on oral reading. It trains GPCs and blending explicitly and simultaneously, and is
based on the Orton-Gillingham model (Orton, 1964). The features of this model include
direct teaching of phonics and blending; multi-sensory presentation; and systematic,
hierarchical, step-by-step instruction with progressing difficulty. The Wilson Reading
System emphasises the six syllable types that occur in the English language. Strategies
for learning GPCs are taught only as they relate to these syllables. Due to her impaired
GPC and blending skills, MO needed to learn that words contain components rather than
merely letters.
The Wilson Reading System consists of 12 hierarchical and cumulative levels of
difficulty based on the six syllable types. Level 1 introduces closed syllables with short
vowels (CVC words). This level also places an emphasis on awareness of phoneme and
sound structure in words. As MO’s assessment profile indicated that she needed to build a
foundation to form associations between graphemes and phonemes, and to learn to blend,
the treatment focused on level 1. Only CVC words were taught. A subset of consonants
(f, l, m, n, r, s, d, g, p, t) and the vowel /a/ were introduced first. When MO was able to
read CVC words containing these phonemes with 90% accuracy, more consonants,
digraphs, and the vowel /i/ were introduced. The phonemes introduced are listed in
sequential order (groups 1–4) next. The criteria for introducing new phonemes was a
score of 90% accuracy in reading a list of CVC words from the group. Words in each
group contained consonants from that group and from the previous groups (i.e., group 3
words contained consonants and digraphs from groups 1 and 2 in addition to those
introduced in group 3). Therefore, there was an overlap of the consonants in the trained
groups of words. However, the words in each group contained only the vowel(s)
introduced in that group (i.e., only /i/ words were presented in group 2). Frequency and
duration of treatment was 3 times per week, 2 hours per session, for 12 weeks.
Group 1: The consonants (f, l, m, n, r, s, d, g, p, t ) and the vowel /a/. Group 2: The
consonants (b, h, v, z, k), digraphs (sh, th,), and the vowel /i/. Group 3: The consonants (j,
c), digraphs (ck, ch), and the vowels /u, o/. Group 4: The consonants (w, x), digraph (wh),
and the vowel /e/. All short vowels, consonants, and digraphs were introduced in the
treatment. Each session consisted of four parts, listed in sequential order next:
(1) MO was presented with cards containing a single letter and was asked to produce
the corresponding phoneme. When MO was unable to independently produce the correct
phoneme, the therapist modelled the correct response by saying: /p/ as in pig. Digraphs
ORAL READING IN DEEP DYSLEXIA
465
were taught by presenting MO with the digraph card (i.e., sh), and explaining that
although two letters were on the card, together they made one sound (i.e., sh as in ship).
One sound got one tap (see part 2).
(2) In the phonological awareness component of the treatment, the therapist used
cards from the first exercise to make CVC words. MO was asked to blend the sounds and
name the words. MO was required to tap out each sound and drag her finger under each
letter while sounding out the words to learn segmentation and blending via multi-sensory
input. The therapist manipulated the cards to create new words by changing one phoneme
only. For example, the therapist placed three letter cards together to make a word (i.e., ma-t). After MO correctly read the word (with or without cueing), the therapist changed the
last letter card to ‘‘p’’ and asked ‘‘If I just changed the last letter, what word would it be
now?’’ Changes using the middle letter card (the vowel) were incorporated in group 3.
Awareness of word structure was taught in this manner. The therapist cued MO by
helping her to provide the sound for each grapheme (as in part 1) and then to blend the
sounds into the word.
(3) An index card was made for each word presented earlier, and MO was asked to
read aloud the words by applying the skills she learned in parts 1 and 2. The therapist
encouraged MO to use multi-sensory input by dragging her finger under each phoneme
while sounding out the words. The same cueing procedures were used as in parts 1 and 2.
(4) The therapist recorded MO’s accuracy as she independently read a list of 12
words containing only the phonemes presented thus far. The word list changed with every
session, so that MO could not memorise words.
EXPERIMENTAL DESIGN
Multiple baseline behaviours (using treatment probes and control probes) were used to
evaluate treatment effects. Control probes contained the consonants that were used in
training, but differed in syllabic structure. As discussed earlier, only the CVC syllabic
structure was taught to MO during treatment. Control probes consisted of words
containing long vowels (ending in the silent –e), words ending in the consonant –le, and
words containing r-controlled and diphthong syllables. Although most of these words
differed from treatment probes in frequency, length, and abstractness, the main difference
was syllabic structure. Two across-behaviour controls (word and sentence comprehension) were also used for further experimental control. Post-test performance on word
(using the PPVT-III) and sentence comprehension (using the PAL) was not predicted to
improve.
Baseline phase
During the baseline stage, correct independent production of CVC words containing all
phonemes, digraphs, and the five vowels was assessed. MO was given a mixed list of 10
such words for seven sessions. Correct production of 10 control probes (words not trained
in therapy) was also assessed during the seven baseline sessions.
Treatment phase
At the end of each therapy session, part 4 (as summarised earlier) was used to assess
independent oral reading of 12 treatment probes. Oral reading of 10 control probes was
also assessed. We expected that accuracy for control probes would not increase during
treatment because these syllabic structures were not explicitly taught, as opposed to the
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CVC syllabic structure. One question was whether MO would generalise to the same
syllabic structure (CVC words) containing phonemes that were not yet introduced.
Because there was an overlap of the consonants in the trained groups of words, we
expected an upward drift of the baseline in groups 2–4.
Maintenance phase
Maintenance of word reading from each previously mastered group was measured during
training of subsequent groups. Independent oral reading of eight words from each group
was assessed. Follow-up data for CVC words containing all phonemes (n = 12 words per
group) were obtained 1 month after the study’s termination.
RESULTS
The data in Figure 1 indicate that prior to therapy, MO’s reading accuracy was between
25% and 35% for all groups of CVC words. Accuracy in reading control words was
below 35%. After seven sessions, MO reached 90% accuracy in oral reading of group 1
words. Oral reading of group 2 words reached 65% during training of group 1 words, an
improvement from a baseline of 30%, indicating generalisation. Oral reading of group 3
and 4 words was below 50%. Next, group 2 words were introduced. MO achieved 90%
accuracy in five sessions. Her oral reading of group 1 words remained at between 85%
and 90% accuracy, and accuracy with group 3 and 4 words increased to 60% (from
approximately 30%), again indicating generalisation. Group 3 words were introduced in
session 21, and it took MO five sessions to achieve 90% accuracy. Her reading of group 1
and 2 words remained above 90%, and for group 4 words it remained at 60%. Group 4
words were introduced in session 27, and 90% accuracy was achieved within five
sessions. These results indicate that MO successfully acquired oral reading skills for the
CVC syllabic structure targeted in treatment. Pre- and post-tests (see table 4, n = 10
words per group) indicated significant improvement for all four word groups [Group 1:
w2(1) = 4.5, p < .05; Group 2: w2(1) = 5, p < .05; Group 3: w2(1) = 5.4, p < .05; Group 4:
w2(1) = 4.5, p < .05].
In contrast to increased reading accuracy with treatment probes, no trend was observed
for the control probes in this study. Accuracy levels for control words fell below 35% in
each session. This aspect of the experimental control provides support for the claim that
MO’s acquisition of oral reading skills for CVC words was due to therapy. The treatment
effect was further supported by the finding that non-treated aspects of language did not
show improvement (5th percentile on the PPVT-III pre-treatment and 5th percentile posttreatment; 75% accuracy on the PAL Auditory Sentence Comprehension pre-treatment
and 60% post-treatment).
As MO’s treatment focused on oral reading and the phonological output lexicon, a set
of pre-treatment tests assessing these areas was re-administered at the end of treatment
(see table 4 for results). MO’s performance improved significantly on PAL Nonword
Repetition [w2(1) = 6, p < .05]; PAL Nonword Reading [w2(1) = 6, p < .05]; Phonological
Awareness Test Substitution [w2(1) = 7.36, p < .01]; and Phonological Awareness Test
Nonword Reading [w2(1) = 10, p < .005]. Semantic errors decreased significantly on the
PAL Naming subtest, from 4/16 (25%) errors to 0 errors, [w2(1) = 4, p < .05] and on the
PAL Oral Reading and PALPA Syllable Length Reading subtests combined, from 13/38
(34%) errors to 2/33 (6 %) errors, [w2(1) = 9.3, p < .005]. Improvement on PAL Picture
Homophone Matching [w2(1) = 3.57, NS] and PAL Oral Picture Naming [w2(1) = 3.57, NS]
approached significance. Follow-up of treatment effects for each group of CVC words (n
Figure 1. Percent read correctly, n = 12 words (treatment), n = 8 words (maintenance). Groups 1–4 consisted
of CVC words, and the following phonemes: Group 1 (f,l,m,n,r,s,d,g,p,t,a); Group 2 (group 1 + b,sh,h,th,v,z,k,i);
Group 3 (group 2 + j,c,ck,ch,u,o); Group 4 (group 3 + w,x,wh,e); Control Words, n = 10 (syllables types: silente; consonant –le; r controlled; diphthong).
467
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= 12 words per group) and for VC and CVC nonwords was assessed 1 month after
termination of treatment. Accuracy levels remained stable (see Table 4).
DISCUSSION AND CONCLUSIONS
The results of this single case study suggest that remediation that focuses on GPC and
blending explicitly can help individuals with deep dyslexia improve their single word oral
reading ability. The evidence for a treatment effect consists of the finding that
performance on the trained structures improved with treatment, while performance on the
untrained control words did not.
Two caveats must be kept in mind concerning this conclusion, however. One concerns
the finding that there was some improvement on word groups 2–4 during the baseline
periods. One possibility is that this generalisation occurred because there was overlap in
the consonants, although not the vowels, in the trained groups of words. The second
caveat concerns the fact that the untrained control words were not matched for frequency
to the trained words.
Nonetheless, as opposed to the participants in studies by Matthews (1991), Mitchum
and Berndt (1991), and Nickels (1992), MO was able to re-acquire blending skills for
CVC words. Generalisation did not occur to any other syllabic structures. This was
evident in tasks of oral reading that contained non-trained syllabic structures readministered at post-testing (PAL and PALPA).
TABLE 4
MO’s pre-treatment versus post-treatment (and 1 month post-treatment) performance on
selected tasks
Subtest
1. PAL Oral reading
2. PALPA Syllable Length Reading
1 syllable
2 syllables
3 syllables
3. PAL Nonword reading
4. Phonological Awareness Test:
Nonword reading
5. PAL Picture–Homophone Matching
6. PAL Nonword Repetition
7. PAL Oral Picture Naming
8. Phonological Awareness Test
Segmentation
Isolation
Deletion
Substitution
Auditory blending
9. CVC word reading (treatment probes)
Group 1
Group 2
Group 3
Group 4
Pre-treatment:
number (and %)
correct
Post-treatment:
number (and %)
correct
1 month posttreatment: number
(and %) correct
10/32 (31)
12/32 (38)
4/8 (50)
3/8 (38)
1/8 (13)
0/25 (0)
1/20 (5)
7/8 (87)
2/8 (24)
2/8 (24)
6/25 (24)*
11/20 (55)*
22/32 (68)
12/20 (60)
16/32 (50)
27/32 (85)
18/20 (90)*
21/32 (66)
11/20 (55)
21/30 (70)
11/20 (55)
5/20 (25)
13/20 (65)
14/20 (70)
26/30 (87)
11/20 (55)
14/20 (70)*
14/20 (70)
14/20 (70)
26/30 (87)
12/20 (60)
13/20 (65)
13/20 (65)
3/10
3/10
2/10
3/10
9/10 (90)*
8/10 (80)*
9/10 (90)*
9/10 (90)*
9/10 (90)
8/10 (80)
8/10 (80)
8/10 (80)
(30)
(30)
(20)
(30)
* Statistically significant improvement from pretest to posttest (p < .05)
10/20 (50)
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469
One positive side-effect of the training was a significant reduction in semantic errors
in reading. This pattern of treatment effects supports Hillis and Caramazza’s (1995)
interactive activation account of lexical retrieval. By this account, partial semantic and
partial phonological information interacts for correct oral production of a written word.
The authors assert that semantic errors in oral reading may be reduced when phonological
(GPC) information is combined with lexical information. This appears to be the case with
MO. Prior to treatment, MO relied on an impaired semantic system for reading, with no
reliance on GPC. We hypothesised that MO made semantic errors in oral reading due to
the fact that phonological information was not available to limit responses arising from
her underspecified semantic representations. After treatment, MO was able to produce the
first one or two phonemes (and to blend these phonemes) of words she could not read
aloud as a whole. Based on Hillis and Caramazza’s theory, we hypothesised that the
partial use of this phonological information, combined with semantic information, may
result in improved accuracy of oral reading. This hypothesis appears to be supported due
to MO’s significant reduction in semantic errors in single word reading after GPC-based
therapy. This suggests that treatment of oral reading in people with deep dyslexia may
benefit from attention to the non-lexical component of reading (GPC) in addition to the
lexical/semantic component.
Hillis and Caramazza (1995) also provide evidence for improved oral naming resulting
from the interaction of phonological and lexical information in the phonological output
lexicon. The PAL Oral Picture Naming task was therefore administered to MO at posttesting to investigate whether naming improved as a result of GPC training. Remediation
of oral reading to improve naming underpinned DePartz’s (1986) and Nickels’ (1992)
studies. Although MO’s improvement in verbal naming was not statistically significant,
her naming scores increased and she did not produce any semantic paraphasias at posttesting. Also, for a sub-set of pictures that MO could not name, she was able to provide
partial information such as the first phoneme or word length. She was unable to provide
any such information prior to therapy. This indicates an improvement in access to lexical
phonological information which supports the possible effectiveness of GPC-based
treatment for naming. It indicates that GPC-based therapy enabled MO to utilise
phonological information to constrain responses and to provide some phonological
information about the word. This further suggests that if MO were explicitly trained to
use this information, her naming skills could further improve. The PAL Picture
Homophone Matching task, which does not require production, was re-administered to
MO to assess whether GPC-based treatment improved her access to lexical phonological
representations. Although improvement was not statistically significant, her performance
improved after therapy. This suggests increased access to lexical phonological
representations due to GPC-based treatment.
As the treatment method used real words, it simultaneously targeted the lexical and
non-lexical routes. Because all of the stimuli were real words, we cannot rule out the
possibility that MO was using the lexical route in treatment. However, her improvement
in nonword reading supports the notion that GPC had improved. We re-assessed nonword
reading, where reliance on the lexical-semantic route was not possible. MO was
administered two tasks of nonword reading. One list (PAL Oral Reading) contained a
variety of syllabic structures and vowel combinations. Improvement was statistically
significant, but the only nonwords that she was able to read were CVCs. The other list
(Phonological Awareness Test Decoding subtest) contained only the trained syllabic
structure. Here, MO displayed greater improvement. Her performance indicates that
treatment improved her ability to read via the non-lexical route. MO’s ability to produce
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non-semantically mediated phonological structures also improved, as indicated by
significant improvement on the PAL Nonword Repetition subtest. This indicates that
GPC-based treatment increased MO’s ability to utilise the non-lexical route between
auditory input and phonological output. We hypothesise that the phonological awareness
component of the treatment, namely tapping out each sound and learning word structure
from part 2 of each treatment session, increased MO’s awareness and use of purely
phonological information.
The Phonological Awareness Test was re-administered to assess MO’s response on
each phonological metalinguistic skill to treatment. MO’s post-test performance indicated
significant improvement in her ability to auditorily isolate and manipulate phonemes
(substitution). Improvement was most likely due to part 2 of the treatment sessions,
where MO was asked to read a new word after being told that only one phoneme changed
from the last word. Although this was done in the written modality during treatment,
MO’s improved sound structure awareness generalised into the auditory modality.
The therapy improved MO’s ability to read CVC words. However, functional singleword reading and the ability to read simple children’s books (MO’s goal was to read to
her daughter) requires more than CVC word reading. After termination of the treatment
study, subsequent reading treatments combined GPC-based training and whole-word
strategies. GPC-based treatment focused on syllable types other than CVC (such as
CVCCVC and the silent-e rule). A combination of word recognition via the lexical route
and use of GPCs was used to teach MO to make an educated guess about words based on
the first and the last sound in the word. Prior to therapy, MO was unable to use any
phonological information. However after GPC-based treatment, her ability to combine
semantic and phonological information continued to improve significantly. She is now
able to read store and advertisement signs and menu items. Automatic recognition of
common sight words was also incorporated. Finally, MO was taught to use pictures and
context to read simple sentences. MO is currently trying to read simple children’s books
to her daughter.
In light of MO’s improved decoding abilities, her oral reading is negatively affected
by co-existing apraxia of speech. Treatment directed towards apraxia of speech is
therefore warranted. However, apraxia-related difficulties may continue to be mitigating
factors in MO’s oral reading skill.
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