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KJ: A developmental deep dyslexic a

Morag Stuart & David Howard

a

a

Birkbeck College, University of London , London, UK Published online: 16 Aug 2007.

To cite this article: Morag Stuart & David Howard (1995) KJ: A developmental deep dyslexic, Cognitive Neuropsychology, 12:8, 793-824, DOI: 10.1080/02643299508251402 To link to this article: http://dx.doi.org/10.1080/02643299508251402

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COGNITIVE NEUROPSYCHOLOGY, 1995,12 (8). 793-824

KJ: A Developmental Deep Dyslexic Morag Stuart and David Howard

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Birkbeck College, University of London, London, UK We describe the case of KJ, a 13-year-old girl with a reading age of 6 years 2 months, who makes semantic errors in single-word reading. In the corpus of errors collected, 24% of her substitution errors were semantically related to their targets. Like adult-acquired deep dyslexics, KJ also makes visual, morphological, and visual andor semantic errors, and is completely unable to read even the simplest nonwords. She also makes semantic errors in speech production and comprehension. Her reading processes are examined in the context of dual-route models. We also describe training experiments investigating the effects of imageabilitylword class and of orthographic transformations and mismatches between orthography and phonology on KJ’s ability to read aloud single words, and a study comparing two therapeutic interventions. We suggest that the case of KJ provides a convincing example of developmental deep dyslexia.

INTRODUCTI0N Deep dyslexia is a striking acquired reading disorder in adult patients; it is identified by the occurrence of semantic errors in single-word reading. Eight other symptoms invariably accompany the presence of these semantic errors: Deep dyslexics also make visual errors, morphological errors, and function word substitutions; they cannot derive phonology from print either lexically o r sublexically ; they read content words more easily than function words, and concrete, high-imageable words more easily than abstract, low-imageable words; and they show impairments in writing to dictation, although their copying is intact. Adult-acquired phonological dyslexics show impairment or complete abolition of the ability to derive phonology from print sublexically, but do not make semantic errors (e.g. Funnell, 1983). Adult-acquired surface Requests for reprints should be addressed to Morag Stuart, Psychology Department, Birkbeck College, Malet Street, London, WClE 7HX. UK. We would like to thank KJ, her teacher, Clare Prisk. and speech therapist, Faith Richardson, for their co-operation and hard work. Morag Stuart acknowledges the support of ESRC Grant No. R000234380. David Howard acknowledges the support of the MRC.

@ 1995 Erlbaum (UK) Taylor & Francis

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dyslexics show impairment of the whole-word routes to word recognition and reliance on sublexical translation from print to sound. They show good reading of nonwords, and make regularisation errors to irregularly spelt words (e.g. Newcombe & Marshall, 1985). There is now robust evidence for the existence of developmental analogues of phonological and surface dyslexia from both single-case studies (Campbell & Butterworth, 1985; Coltheart et al., 1983; Holmes, unpublished; Snowling & Hulme, 1989; Temple & Marshall, 1983) and group studies (Castles & Coltheart, 1993; Seymour & MacGregor, 1984). It has proved harder to find convincing cases of developmental deep dyslexia, the critical feature for assignment to this category being the production of semantic errors in single-word reading. The earliest reported case is that of CR (Johnston, 1983), an 18-year-old girl with a reading age of 6 years 2 months. In the course of investigating her reading, CR was given 382 words to read. Five of her errors were classified as semantic errors, two as visual-or-semantic errors and one as a visual-then-semantic error. These eight errors with a semantic component represent 9.4% of substitution errors. Pure semantic errors represent 5.8% of substitution errors. In 1985, Siegel reported six developmental dyslexics, all of whom made some semantic errors. These ranged from four to seven for any particular child, although a rather lax criterion for “semantic” errors seems to have been applied: for example, “big + brown” is given as a semantic error, although any possible semantic relationship escapes us here; also “gentleman + grandmother” and “more + most” are labelled semantic, despite obeying the criterion (50% of response letters present in target) frequently used to classify errors as visual. Siegel does not report total substitution errors made by the children studied, and it is therefore impossible to estimate the proportion of errors that were semantic. KS, reported by Temple (1988), made four semantic errors, two visuosemantic errors, and nine visual-then-semantic errors. It seems odd that visual-then-semantic errors, which require two successive mistakes, should outnumber the pure semantic errors. Since KS made 77 substitution errors in all, these 15 errors with a semantic component represent 20% of the corpus, although the 4 pure semantic errors represent only 5%. Ellis and Marshall (1978) have shown that entirely random pairings of stimuli with responses produce an average “semantic” error rate of about 9%. CR’s 9.4% “semantic component” error rate falls uncomfortably close to this chance range, and her 5.8% pure semantic error rate falls within it; Siegel does not supply enough data to allow a comparison to be made; and KS’s “semantic component” rate of 20% (but not her pure semantic rate of 5%) would appear to be well clear of this chance range. Temple also assessed chance rates by presenting 6 random pairings of the 75 stimuli

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that had produced substitution errors with the 33 responses KS had made to these stimuli. None of these random pairings produced a semantic error rate higher than 1%. As Coltheart, Patterson, and Marshall (1987, p. 436) comment, “the description of these children . . . evokes the wraith of adult deep dyslexic patients,” but does not provide conclusive empirical evidence. Why is it so difficult to find convincing developmental analogues of acquired deep dyslexia? In the adult patients, both the sublexical and the direct lexical route from print to sound are completely unavailable. It has been argued that any residual functioning at all of either of these routes would preclude the occurrence of semantic errors: Just knowing that “tree” begins with /t/ is enough to prevent production of “bush” as a response to “tree.” Therefore, the only children who might be expected to produce semantic errors in single-word reading are children who have no means whatsoever of accessing phonology from print, at either the whole word or the subword level. There are many five-year-old beginning readers who are completely unable to use sublexical phonological recoding processes, as evidenced by their total inability to read simple CVC nonwords (Stuart, in press) or to map speech sounds to single letters (Stuart, 1990). What is less clear-cut is the status of the direct lexical route in these children: Are we to assume that they are also completely unable to map sequences of printed letters in whole words on to the corresponding phonological word form? If it could be shown that such children never make semantic errors in singleword reading, this assumption would be untenable. However, Seymour and Elder (1986) claim that beginning readers do make semantic errors. They studied the development of word recognition in a class of 24 4%-5lh-year-old beginning readers, 11 of whom produced some semantic errors in single-word reading. Rates were low, with no child making more than three “pure” semantic errors, or more than seven errors with a semantic component. Proportions of semantic errors were low, with only one child producing a rate of more than 6%. The child with the highest rate, l6%, made few substitution errors (19 in all), and also showed some evidence of phonological processing, producing three regularisation errors and seven overt attempts at sublexical phonological recoding. That is, this child does not appear to meet the condition we are assuming is necessary for the production of semantic errors; of having no sublexical or lexical means of recoding print to sound. There remains the thorny question of whether the apparently semantic errors were simply the result of chance pairings from within a limited sight vocabulary; Seymour and Elder did not calculate chance rates. Abolition of function of both lexical and sublexical routes from print to phonology is necessary for the emergence of semantic errors in single-word

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reading, because the only surviving route necessarily involves semantic mediation between print and phonology: Recognition of the printed word activates a semantic code, which in turn activates a phonological code. These conditions are not sufficient to entail the production of semantic errors, however. In speaking, we are constantly using semantic codes to access phonological codes; if we do not make semantic errors in speech, then our reading problem cannot arise here. Another possibility is that the semantic codes themselves are impaired in their fine detail, but if this were the source of semantic errors in reading, the same problems should again be evident in speech. Only if the problem lies at the level of transmission from orthographic to semantic code could we reasonably expect to see a problem in reading and not in speech: Input from the printed word may sometimes simply activate the wrong semantic code. In the developmental cases cited earlier, little mention is made of spoken language processing. Siege1(1985) reports delayed receptive and expressive language development in one of the six children she studied (KT), whose reading difficulties came to light during a longitudinal study of pre-term and full-term children. Johnston (1983) describes CRs speech as fluent and her comprehension as apparently unimpaired. Temple (1988) examined KS’s language in more detail. She describes his speech as fluent though sometimes poorly articulated; his auditory comprehension of words was normal for his age. KS does make errors in word and nonword repetition, and semantic errors in naming objects and colours. Thus the strongest candidate for admission to the category of developmental deep dyslexia makes semantic errors in speech as well as in reading, supporting the view that the problem is not specific to written language, but arises at a central semantic level, or at the level of transmission between semantics and output phonology. KJ, whom we report here, also makes semantic errors in naming, in spontaneous speech, and in spoken language comprehension as well as in reading. With a total of 25 pure semantic errors in single-word reading, we suggest that KJ provides the strongest evidence to date for the existence of a developmental analogue of acquired deep dyslexia.

CASE HISTORY KJ is a 13-year-oldright-handed girl who attends a school for children with moderate learning difficulties. Medical records refer to a congenital deformity of the fourth and fifth fingers bilaterally (these fingers curve slightly inwards); KJ was discharged by the orthopaedic consultant at the age of two. Late walking and late language development are reported, with KJ receiving speech therapy until the age of three and a half. There is no history of epilepsy. Her hearing, vision, and fine and gross motor control are all reported to be normal.

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Her Full Scale IQ measured on the WISC-R is 54; Verbal IQ 49, Performance IQ 68. The 19-point discrepancy between Verbal and Perfonnance IQ is in line with data reported by Siege1 (1985), where 5 of the 6 putative deep dyslexic cases discussed had Performance IQs from 11 to 25 points higher than their Verbal IQs. On the British Ability Scales Test of Single Word Reading (Elliott, Murray, & Pearson, 1983) KJ achieved a reading age of 6 years 2 months. On the Vernon Graded Word Spelling Test her spelling age was 5 years 9 months. These scores cannot be explained away as an inevitable consequence of her low intellectual ability: Cossu and Marshall (1986) report two cases of Italian girls with similar IQ equivalents to KJ who were almost 100% correct on all the reading and writing tasks given them; and there is a substantial literature on the phenomenon of hyperlexia, excellent printed word recognition and production skills in children of (occasionally unmeasurably) low IQ (see, for example, Goodman, 1972; Healy, Aram, Horwitz, & Kessler, 1982; Silberberg & Silberberg, 1967). Moreover, KJ’s reading age is 1 year and her spelling age 1 year 5 months below her mean test age (7 years 2 months) across the WISC-R subtests. Her reading age is almost 2 years and her spelling age more than 2 years below her mean test age of 7 years 11 months on the Performance subtests. Both reading and spelling age are also below her vocabulary age of 7 years 4 months as measured on the British Picture Vocabulary Scales (Dunn, Dunn, Whetton, & Pintilie, 1982). KJ was brought to our attention by her teacher, who suspected that KJ was underachieving in reading. The reading material used in KJ’s class was the “Wellington Square” reading series aimed at older poor readers, a non-phonics based series. In view of KJ’s slow progress with this, her teacher had initially consulted the speech therapist attached to the school for advice on how best to teach KJ to read. A phonic programme based on Alpha to Omega (Hornsby & Shear, 1975) had then been attempted, but without success. On further investigation, the speech therapist noted the occurrence of semantic errors in KJ’s single-word reading and referred her on to us. In initial discussions, it was suggested that KJ’s reading processes might consist of mapping the visual form of the word directly on to its meaning. Her teacher immediately attempted to exploit this suggestion by getting KJ to use a computer program which mapped printed words to pictures, and rewarded her when she spelt the words correctly. “Computer vocabulary” (following) refers to words learnt in this way.

READING RESPONSES An analysis was carried out on KJ’s reading of 858 single words presented in lower case (except for proper names with an initial capital) over a number of sessions from January to May 1994. There were 371 different

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words presented; of these 202 words (561 tokens) were drawn from the Wellington Square vocabulary, 27 (81 tokens) from her computer vocabulary, and 12 words (68 tokens) were in both the Wellington Square and computer vocabularies. The other 130 words (148 tokens) were words occurring in neither of these sets: some were words which she was asked to read on the standardised reading test; others were words from the set of computer programs available in the classroom, which we asked KJ to read to find out which of the computer programs she’d worked on. We have no certain knowledge that KJ had ever been exposed to any of these “other” words. Her reading accuracy and types of errors for these three sets are shown in Table 1. These responses are a by-word analysis: Where an item had occurred on more than one occasion the scoring of response types is in proportion to the errors which occur. For example, the word COMB was presented three times; it was read twice correctly and once as “brush”; it therefore contributes 0.67 to correct responses and 0.33 to semantic errors. KJ’s overall accuracy is highest with the words that she has learned from the computer. These are, however, all concrete nouns, the type of words with which KJ achieves the highest reading accuracy. Only 24% of words from the Wellington Square books she has read are read correctly. The “other” words, however, are read extremely poorly: Only 9 different words of the 130 are ever read correctly (animal, apple, car, cup, girl, jam, pig, sun, van).

Correct Responses By tokens, 37% of KJ’s reading responses are correct. However, there are only 118 words that she ever reads correctly; 26 are from the computer vocabulary, 71 from Wellington Square, 12 from the overlap between the 2 sets, and just 9 from the other items.

Omissions The commonest reading response for KJ is “don’t know.” In these cases she is reluctant to hazard a response. These errors are elicited by words that she has not been exposed to, and to a lesser extent by words from the Wellington Square vocabulary.

Semantic Errors The occurrence of semantic errors in single-word reading is the defining symptom of “deep dyslexia” in adults (Coltheart, 1980). KJ makes 25 different single-word semantic errors, shown in Table 2 (some of these occurred more than once). There are a few predilection errors; for instance, she is very likely to read “children” or any word with the stem

TABLE 1 Proportion of Responses of Each Type in Reading Words from Different Sets

Word Set Proportion of Responses by Weighted Type

Wellington Square

In Both Sets

Computer Set

Other Words

202 0.244 0.536 0.051 0.010 0.057 0.042 0.007 0.054

12 0.948 0.038 0.014 O.Oo0

27 0.837 0.044 0.012 0.037 0.037 O.OO0 0.012 0.020

130 0.069 0.869 0.004 0.008 O.Oo0 0.038 O.OO0 0.012

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N Correct Omissions Semantic errors Visual or semantic errors Morphological errors Visual errors Visual-then-semantic errors Other errors

O.OO0 O.Oo0 O.OO0 O.Oo0

Total 371 0.249 0.601

0.030 0.011 0.034 0.036 0.004 0.035

TABLE 2 Semantic Errors in Single-word Reading

Stimulus

Response

Stimulus

Response

boy came can children children clock comb down hurt hurt jump jumped kicked

man go tin people no friends friends watch brush UP fall accident run run ball

kitten light Max mother out Play Play played played playing run window

ball radio Rocky mum in friend friends friend friends friends jump mirror

Episodic Errors like look

I I

Wellington around

Square all

Semantic Circumlocutions Fred he’s a gardener statue Miller a man - he works in a office person -a worker

Square no not Square the other thing went in the Square

Self “Corrected” I Ben milk

two no one flower no leaf Square no Wellington

my - like Matt no Ben drink milk

one leaves Wellington

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“play” as “friend(s),” although not invariably. There are examples of errors occurring both ways (e.g. run +jump and jump + run). As in adult deep dyslexics, there are errors which are antonyms (down + up), synonyms (can + tin), co-ordinates (watch + clock), and associates (hurt + accident). In addition to these 25 semantic errors, there are 4 “episodic errors” in which she substitutes a word from a sentence in the Wellington Square books (cf. Seymour & Elder, 1986), 3 semantically based circumlocutions, and 6 further semantic errors which KJ attempts to self-correct, not necessarily successfully.

Visual or Semantic Errors Errors that resemble the stimulus both visually and semantically are common in deep dyslexia (Shallice & Warrington, 1980). One might expect a rather reduced rate of these, as KJ’s restricted reading response vocabulary limits the opportunities for such errors. There are, however, seven such errors involving content word responses, one of which is followed by a self-correction: chips + crisp, chips + crisps, dinner + drink, house + home, telephone + television, up + jump, shoe + sock no shoe.

Visual-then-semantic Errors There are two such errors in KJ’s reading corpus: crisps + fish (via chips), this + can (via tin).

Visual Errors Errors were categorised as visual if at least half the letters in the response were in the stimulus. As shown in Table 3, 19 different errors (some of which occurred more than once) met this criterion, and 4 further errors, although they did not quite reach the criterion, had sufficient visual similarity to be tentatively categorised as visual.

Morphological Errors There were 24 different morphological errors, which occur almost always with multimorphemic stimuli, and which typically involve omission of an affix. There were nine deletions of a plural marker from a noun (e.g. boys + boy, men + man), and only one addition of a plural (tin + tins). There were two deletions of possessives (e.g. teacher’s + teacher), and three deletions of other morphemes from nouns (gunman’s + guns, telephone + phone, television + telly) and just one addition (police + policeman). From verbs there were four deletions of -ed (e.g. jumped + jump, ran + run), and one omission of -ing (moving + move). One adjective had the -ly derivational suffix omitted (lovely + love), and there was one

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TABLE 3 Visual Errors in Single-word Reading Stimulus

Response

Stimulus

Response

brick dig dig eyes first followed grass grabbed house like

bird big Pig Yes fish flower glasses garden horse look

meat mother ship shop sparrow stop there trampoline will

man move shop home square shop three policeman wall

Possible Visual Errors birthday bonfire bonfire birthday down drum elephant telly

deletion of a morpheme from a preposition (upstairs + up), and one substitution (upstairs + downstairs).

Function Word Substitutions One feature of adult deep dyslexia is the frequent substitution of function words by other function words, when the response often has little visual or semantic relationship to the target. KJ produces four such errors (are -+ all, over + all, through + after, at + in, on) and two self-corrected responses (over + all, no, over; up -+ in, no, up). The majority of her function word substitutions have a visual similarity to the target (3: is + in, is + I, on + no), a semantic similarity (2: down + up, out + in), o r both (2: after + over, my + me).

Other Errors There are only three unclassifiable errors: Tessa + teacher (a possible visual error), ship + church, shirt (unrelated followed by visual), broken + don’t know, bonfire (?visual).

Semantic Errors by Chance? It seems implausible that KJ’s errors are related semantically, visually, or morphologically to the stimuli by chance, as she makes almost no errors that are unrelated to the stimulus.

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To confirm that these were not chance relationships, we undertook two analyses involving random reassignment of error responses to the stimulus words that elicited them. For the first analysis we took all 156 of her incorrect reading responses excluding omissions. In the small number of cases where she produced more than one response we considered only the first response. The relationship between stimuli and their errors was then determined using stringent criteria; where we were unsure how an error should be classified, we counted it as unrelated. We collapsed all responses where the stimulus and response were both function words into the single category of function word errors, irrespective of whether there was also a visual or semantic resemblance between stimuli and responses. The errors were then randomly reassigned to the stimuli, and the resulting pseudoerrors classified. This time, in order to favour the null hypothesis, we were lax in accepting a semantic o r episodic relationship between stimulus and response-for example, we accepted “like + birthday” as a possible semantic error, and “around + move” as a possible episodic error. Results of this analysis are shown in Table 4. The results are clear. The rates of semantic, visual, morphological, function word, and visual-and-semantic errors are significantly higher in the real error corpus than in the pseudo-corpus. Only unrelated errors are significantly more common in the pseudo-corpus. The only error category on which doubt is cast by this analysis is “episodic” errors. More stringent criteria were adopted for the real errors than the pseudo-errors, and the numbers are small, so it is hard to be certain; however, we have little confidence that KJ does make true episodic errors. The second analysis followed the same procedure as the first, but was based only on the corpus of 65 errors that were not visually related to the target word (i.e. excluding visual and morphological errors, and all mixed TABLE 4 The Proportions of Errors of Different Types in KJ’s Error Corpus, and in a Pseudo-corpus from Random Reassignmentof all Explicit Errors to the Stimuli Eliciting Them ( N = 156)

Error Type Semantic Episodic Visual Morphological Function words Visual-and-semantic Unrelated Others

Real Errors

Pseudo-errors

0.24 0.04 0.17 0.30 0.11 0.06 0.06 0.02

0.06 0.05 0.03 0.01 0.04 0.00 0.79 0.01

McNemar’s Test

P P P P P P P

= 0.00000 =

0.38721

= O.ooOo5 = 0.00000

= 0.00636 = 0.00195 = 0.00000

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errors which met the visual criterion). Random reassignment of these errors to the stimuli resulted in the distribution shown in Table 5 . In this error corpus, semantic errors make up 58% of errors; with the pseudo-errors, despite the less stringent criterion adopted, only 9% are semantically related. Only 15% of KJ’s real errors are unrelated to the stimulus, but 74% of the pseudo-errors are unrelated. This analysis confirms that both semantic errors and function word substitutions are not chance occurrences in KJ’s reading, but reinforces the doubts about episodic errors.

Summary KJ has a very limited reading vocabulary: Only 118 words are ever read correctly. Her reading errors are mostly omissions, but visual errors, semantic errors, morphological errors, visual-or-semantic errors, visualthen-semantic errors, and function word substitutions all occur at above chance levels. Her pattern of reading errors is therefore effectively identical to that found in adult deep dyslexia. It is also notable that KJ’s reading responses show absolutely no evidence of any use or attempted use of a phonological strategy. All her responses are real words, and no neologisms occur; she never tries to sound out a word; and no response in any way resembles a regularisation.

INVESTIGATIONS OF KJ‘s READING PROCESSES We gave KJ a variety of tests to look at the functioning of different components of her reading system. We will describe these investigations within the theoretical framework of dual-route models of reading.

TABLE 5 The Proportions of Errors of Different Types in KJ’s Corpus of Errors with no Visual Resemblance to the Target, and in a Pseudo-corpus from Random Reassignment of Errors to Stimuli ( N = 65)

Error Type Semantic Episodic Function words Unrelated Others

Real Errors

Pseudo-errors

McNemar’s Test

0.58 0.09 0.12 0.15 0.05

0.09 0.06 0.03 0.74 0.08

P = 0.00000

P = 0.36328 P = 0.03516 P = 0.00000

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Tests of the Sublexical Route

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Non word Reading

The purest test of sublexical route functioning is to ask subjects to read nonwords, which can only be read by this route. KJ was tested on a list of 10 CVC nonwords and read 0/10 correctly. She said “Don’t know” to six, named the first letter of three, and gave the sound of the first letter of one. She was also tested on a forced-choice matching task devised for fouryear-old prereaders (Stuart, 1990). In this test, the child is shown a picture of a friendly alien and told, for example, “This is Moz. Can you say his name? That’s right, Moz.” Two printed nonwords, “moz” and “pab,” are then placed next to the picture and the child is asked “Can you show me which one says Moz?” KJ’s score of 12/20 on the task did not differ significantly from chance. It seems she has no ability to use any phonological recoding processes in reading. Phonological Awareness

In young children, sublexical route development seems to depend in part on an ability to analyse the sound structure of spoken words (see, for example, Stuart & Masterson, 1992; Treiman & Baron, 1981, 1983; Tunmer & Nesdale, 1985;Tunmer, Herriman, & Nesdale, 1988). To assess KJ’s access to phonological structure, we gave her the Snowling auditory rhyme judgement test (Snowling, Stackhouse, & Rack, 1986), which requires yes/no judgements about pairs of words. She scored 15/24correct, not significantly different from chance (Binomial distribution, P = 0.15), and outside the range for children with a reading age of 7 (0-5 errors). Prereading children who fail on rhyme judgement tasks normally will also fail on tasks that require them to give the initial phoneme of a spoken word (Stuart, 1993). However, when KJ was given the Initial Sound Segmentation and Sound to Letter Matching test (Stuart, 1990) she gave the correct first sound for 18/24 words, and the correct letter to go with 19/24 sounds. Both scores are above the mean for five-year-olds, and five-yearolds scoring above these means invariably go on to become good readers (Stuart, in press). KJ differs from these children in having had a long but hugely unsuccessful exposure to written text, and individual phonic teaching using the Alpha to Omega programme. Her relatively good performance may thus reflect her knowledge of the printed versions of the words tested, 10 of which she can read correctly, others of which are in her reading books. Her habit of reciting, for example, “T, It/, teapot” when faced with spoken stimuli suggests an orthographic strategy. To control for this, she was later given a nonword version of the segmentation task, on which she scored 1/24 correct segmentations and 23/24 correct

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letter matches. When KJ has no access to an orthographic code, she is unable to segment initial sounds. The phonic teaching received under the Alpha to Omega regime seems to have borne some fruit, in that she can correctly map a given sound to the letter that represents it in writing, but in the absence of any understanding of the sound structure of spoken words this knowledge may not be readily applied to the reading task (Stuart, unpublished; Byrne & Fielding-Barnsley, 1991, 1993).

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Knowledge of the Alphabet

As shown earlier, KJ performs well when asked to choose the correct letter to represent a given sound. However, when shown letters and asked to give their sounds, she scored only 5/26 correct. Her performance again reflected teaching received and applied parrot fashion: presented with “a” she responded “A, /a/ apple”; to “i” she responded “I, /ii, ink”; to “b,” “B, /b/, ball”; to “t,” “T, /t/, teapot”; and to “k,” “K,M.” When asked to name letters she named 4/26 correctly, but when asked to write named letters to dictation, she wrote 17/26 correctly. In both cases her worse performance when required to produce names may be a reflection of her general naming difficulties (see following). Auditory Short-term Memory

Difficulties may also arise in the sublexical route as a result of auditory short-term memory problems, which make it difficult to retain and blend together a sequence of sounds into a pronunciation. KS,the developmental deep dyslexic reported by Temple (1988), had poor auditory short-term memory. KJ’s auditory short-term memory was investigated using the digit span subtest of the British Ability Scales; a pointing test for digit sequences, which eliminated the need for naming; a test of phonemically similar and dissimilar letter sequences; and a short-term memory test (Roodenrys, Hulme, & Brown, 1993) for word and nonword sequences where stimuli vary in syllable length. On the first three tests, converging results were obtained, with no errors on three-item sequences, one error on four-item sequences, and performance rapidly worse with any further increase in sequence length, with seven items as the longest sequence she ever reproduced correctly. She showed the usual effects of phonemic similarity. Her ability score on the BAS test put her at the 24th centile for children of her chronological age. However, since the average 9-10-year-old would achieve a similar ability score, KJ’s deficit is in terms of her chronological rather than her mental age. Hulme (Roodenrys et al., 1993) argues that the familiarity of items in digit span tests can result in these over-estimating memory span in children

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with phonological difficulties. On the Roodenrys test, KJ’s memory span was: 1-syllable words, 3.5, nonwords, 2.25; 2-syllable words, 3.0, nonwords, 0.75; 3-syllable words, 2.75, nonwords, 0.0. Her performance with both words and nonwords seems rather worse than the data for six-yearolds collected by Roodenrys et al. (1993). This contrasts with her performance at a nine-year-old level on digit span, and perhaps supports Hulme’s position.

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Summary

KJ performs very poorly on phonological awareness tasks and finds it difficult to translate single letters to their sound equivalents. Both phonological awareness and alphabet knowledge feed into sublexical route development in normal readers. KJ’s poor performance in these two areas probably underlies her complete inability to read nonwords correctly. She has some weakness in auditory short-term memory, but her attempts to read nonwords aloud never got as far as blending, where this might have compounded her problems.

Tests of the Lexical Route Lexical route functioning is usually investigated by assessing subjects’ ability to read irregularly spelled words, which can only be read correctly by lexical processes. As KJ has no sublexical route function whatsoever, we assume that her reading is accomplished via the lexical route. Irregular words are much rarer than regular words in her reading vocabulary, but she does not appear to make proportionately more errors with irregular words. What is of interest in examining the functioning of her lexical route is to try to assess where this breaks down, leading to the observed pattern of visual, morphological, and semantic errors in single-word and text reading. There are two possible lexical routes: from orthographic input lexicon to semantics to phonological output lexicon, and from orthographic input lexicon to phonological output lexicon. In either case, the first stage of processing is orthographic analysis.

Tests of Orthographic Analysis Visual Perception

On visual match-to-sample tests of reversible letters and words (devised by Elaine Funnell), where the child is required to choose between, for example, “was” and “saw” as a match for the sample “was,” KJ performed quickly and confidently and made no errors.

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Cross-case Matching

Using a test devised by Stuart (unpublished) for five-year-olds, KJ scored 88.5% correct cross-case matches, above the mean for five-year-olds (70%). Her three errors were all to visually dissimilar letter pairs (Dd, Bb, and Ii). It is unlikely that this is age or mental age appropriate behaviour.

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Reading Words in Alternating Case

KJ was presented with the words from her computer vocabulary in alternating case and in lower case. She read 34/39 lower-case versions correctly, and 18/39 alternating case. This 46% correct score for alternating case is similar to the 41% correct achieved by children in their first year at school (Stuart, unpublished). Summary

KJ’s visual perception is good, but she appears to be at the level of a five-year-old beginning reader in terms of her ability to isolate abstract letter identities from different forms. In the terms of Frith’s developmental model (Frith, 1985), KJ is a logographic reader, who is creating entries in the orthographic input lexicon from salient visual features of printed words.

Tests of the Orthographic Input Lexicon Visual Lexical Decision

We presented KJ with a list of 10 regular words, 10 irregular words, and 10 nonwords (Snowling, 1985) and asked her to look down the list and tell us which were real words and which were made up words. The nonwords were made by changing the initial letter of the regular words. KJ was unwilling to accept that any of the items presented were real words, probably because the real words were not in her reading vocabulary. The task was abandoned. Several months later we presented her with a set of 64 words and nonwords printed on cards, to sort into real word and made up word groups. Half of the 32 real words were words that KJ had read correctly on 3 occasions; the other half were words to which she had responded “don’t know” 3 times. The sets were matched for mean log frequency in the Wellington Square vocabulary, and for letter length. We made 32 nonwords to match the real words in number of letters, consonant or vowel clusters, and syllables. KJ accepted 20/32 real words and rejected 29/32 nonwords, a highly significant result (Fisher’s exact, z = 4.14, P = 0.00002). However, as anticipated from the previous attempt at visual lexical decision, she accepted 15/16 real words she could read, and rejected 11/16

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words she could not read. There was no significant difference in her rejection rate for nonwords and real words she could not read (Fisher’s exact, z = 1.49, P = 0.068, 1-tailed). There was a significant difference in her acceptance rate for words she could and could not read (Fisher’s exact, P = 0.0003).

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Visual Short-term Memory

KJ was given the Goulandris Greek Letter Test (Goulandris & Snowling, 1991), which requires children to reconstruct visually presented sequences of from 2 to 4 Greek letters, either immediately or after a lOsec filled delay. KJ enjoyed this test, performed quickly and confidently, and scored 10/12 correct. Norms are only available for younger children with a spelling age of 7 (mean 4/12, range CL9 correct). KJ thus outperformed these younger children who were better spellers than she. On the British Ability Scales Visual Memory Test, KJ scored at a level appropriate to her chronological age (immediate recall, 50th centile; delayed recall, 59th centile). This suggests that she has indeed a comparative strength in visual short-term memory, in sharp contrast to the deep dyslexic case KS (Temple, 1988), who was deficient in both auditory and visual short-term memory. Word Learning Experiment

We devised an experiment to test the hypothesis that KJ recognises printed words from salient features of their visual form. These visual representations, we assume, are mapped directly to the semantics of the words. If this is so, then KJ should be equally well able to learn words written in Greek letters as in English letters. This hypothesis also assumes that a phonological form is retrieved following semantic access. Therefore we also predicted that KJ would find it as easy to associate a meaning with a phonotactically legal nonword whose phonology is unrelated to the phonology of the taught word as with a real word in either Greek or English orthography . To make sure that KJ had semantic representations of the words to be learned, she was first asked to define 28 words, all highly concrete nouns presented audibly. Good definitions were given to all 28 words, for example: bottle -+ You drink out of it and keep milk in; bridge + Water under it. Cars can go over it; carpet --* You put it on the floor so your feet don’t get cold. She was then asked to read the words aloud. A set of 12 words was made from the 17 words to which she responded “Don’t know.” Six were four letters and six were six letters long. These 12 words were randomly allocated to 3 sets in which no 2 words were from the same semantic category. There were two four-letter and two six-letter words in

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each set. One set was transcribed into the Greek alphabet; one set was written correctly in the English alphabet; and one set was turned into phonotactically legal nonwords in the English alphabet. Stimuli can be seen in the Appendix. KJ was told: “I’ve got some words here and I want to see if you can learn them. I’ll tell you what they say, and you try to remember them.” All 12 items were presented once with the experimenter pronouncing them for KJ, who was encouraged to look at each one and try to commit it to memory. Items were then shuffled and presented again until nine trials had been given. On each trial, presentation of each item was followed by a brief pause for KJ to produce a response. When her response was wrong or “Don’t know,” the item was pronounced for her and she was again encouraged to look carefully at it. She made one semantic error twice, giving “a kind of animal-tiger’’ as the response to “lion” on the first trial, and “tiger” on the eighth trial. Results are summarised in Table 6. Friedman’s Analysis of Variance by Ranks gave x2(2df) = 0.89, P = 0.63. As predicted, she was equally well able to learn all three sets. Approximately 90 minutes after the 9th trial, KJ was unexpectedly presented with all 12 items again. She read 11/12 correctly, making 1 error to 1 of the Greek set. Summary

KJ’s performance on the visual lexical decision task is influenced by her limited reading vocabulary, but otherwise accurate. TABLE 6 Paired Associate Learning of Real Words Associated with the Correct Real Word, a Nonword, and a Greek Transcriptionof the Word ( N = 4 in each cell)

Trial

Words

Nonwords

1

0

1

2 3

2

4

1

5 6

3 4

2 3 2 3 3

7

4

8 9

3

Delay“ Total

1

4

4 26

4 4 4 4

30

Greek “Words” 2 1 3

2 2 3 4 4

4 3 28

“The tenth trial was an unexpected presentation after a filled delay of W minutes.

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She has a good visual memory. Her ability to memorise visual material was tested by asking her to learn to associate symbol strings with meanings. No advantage was found for real English words over phonotactically legal nonwords or words written in Greek letters. This supports the suggestion that KJ relies on visual rather than orthographic analysis in creating entries to the orthographic input lexicon: She is a logographic reader.

Tests of Semantic and Syntactic Functioning

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Naming

One possibility is that KJ’s propensity to produce semantic errors in single-word reading represents further evidence of a general difficulty in naming. (She confidently offers us cups of tea while making us cups of coffee, and on one occasion was driven almost to distraction by a boy who came into the classroom where I was testing her on her own, to get a bag of sugar, which KJ knew was on the window-sill. The boy was approaching the window-sill as he asked KJ where the sugar was. “It’s behind you,” she said. He looked behind him, into the space of the classroom. “No, behind you! BEHIND YOU!” shouted KJ. “It’s BEHIND YOU!” I was as puzzled as he was, since there was clearly no place behind him for a bag of sugar. What she meant was “In front of you.” The sugar was eventually found.) We have three sources of data about naming. We gave KJ a test of naming 60 pictures with nouns, transitive verbs, and intransitive verbs equally represented (Davidoff & Masterson, in preparation). The highest age range for which norms are available is 5-5% years old. KJ scored 17/20 for transitive verbs and 15/20 for intransitive verbs; in the normal range of correct responses for this age group. Her score of 12/20 for nouns was almost 2SD below the mean for nouns. She made more semantic errors to intransitive verbs than inner city control children (KJ 4, mean controls 1.85, SD 1.204). These data are suggestive of a naming difficulty which is perhaps selectively worse for nouns. When asked to name the pictures in the Initial Sound Segmentation test she made several errors (tiger + lion, kitten + cat, pan + put food in it and cook, tent + sleep in it), although pictures in this test had been chosen to be within the vocabulary of four-year-olds (who are also susceptible to the tiger-lion error). On the Naming Vocabulary test from the British Ability Scales, with norms for children aged up to 7 years 11 months, her ability score was 76, the average for a child aged 4 years 3 months to 4 years 8 months. This estimate of productive vocabulary is well below the score obtained for receptive vocabulary on the BPVS. Her errors were jar + vase and scales

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+ measure (indicating functional knowledge?); chain + metal, and robin + bird (indicating category knowledge?); and compass + clock (indicating

use of visual similarity?).

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Comprehension

When tested on Biber’s Threesomes (a test devised by Carol Biber, where a spoken or written word has to be matched to one of three pictures where one distractor is semantically related to the target and one unrelated), KJ made several semantic errors in both presentation modalities. This suggests that her semantic difficulties are not confined to the production task of naming but also affect comprehension, regardless of modality of presentation. With auditory presentation, she made four errors, all semantic: sink cooker and cooker + sink; clock + watch and watch ---* clock. With visual presentation she made eight errors, four semantic: spoon 4 fork and fork + spoon; watch + clock and clock + watch; and four unrelated, reflecting her difficulty with the printed word: sink + skirt; star 3 hen; tie + fork; and cooker + duck. Spontaneous Speech

Given these naming and comprehension problems, what is KJ’s spontaneous speech like? To get a speech sample, we recorded KJ’s responses in the Bus Story test (Renfrew, 1969), in which the tester first tells the child a story from pictures about a bus racing a train, and then asks the child to retell the story from the pictures. KJ was most unwilling to tell a story, and had to be coaxed through it. Her retelling reads: Tester KJ Tester KJ Tester KJ Tester KD Tester KJ Tester KJ

Once upon a time there was a . . . Bus. And what happened? He runned away. Mmm. Anything else happened? Yes, catch him! O.K. And what happened? He started rushing with the train. Mmmm And the train went. And the man whistles and told him to stop. He never listened. H e jumped over the fence. He saw a cow. Mmmm He went into the pond. And the man had to get a thing to get him up. Don’t like doing this, don’t like doing it.

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Her score for information was at the level of a child of 4 years 7 months; for sentence length at a 3 year 9 month level, and for use of subordinate clauses at a 4 year 4 months to 5 year old level. Similar results were gained when she was asked to describe pictures in the Action Picture Test (Renfrew , 1972): both information and grammar scores were at the 4 year to 4 year 4 month level. Her dislike of storytelling was apparent when we asked her to tell us the story of Cinderella. After much coaxing, she produced: “Once upon a time there was this girl called Cinderella and she got married.”! Reading Text

After much initial reluctance, KJ was persuaded to read two pages from her reading book. She read 26/61 words correctly, giving an overall error rate of 57%. As with her single-word reading, she made mostly omission errors (54% of total errors). She showed effects of word class, making proportionately most errors to verbs (66% wrong), followed by function words (57% wrong), followed by adjectives (50% wrong), followed by nouns (40% wrong). She made 6 semantic errors, (17% of total errors): “water” for “swim”; “swimming” for “sport” (twice); “I” for “my”; “Ben” for “Rocky”; and “tin” for “can’t” (via “can”). Of these, only “Ben” for “Rocky” was a syntactically appropriate choice. In general, she gave little sign of attempting to use cues from the pictures accompanying the text, and was not able to read enough of the words to provide herself with any support from the semantic or syntactic context. Effects of lmageability and Word Class

If KJ is reading by mapping visual input directly to semantics, then there should be effects of word frequency on single-word reading, and also effects of imageability. In adult deep dyslexia, high imageability (or concrete) words are read more accurately than low imageability (or abstract) words. There is also a word class effect, with nouns read better than verbs, which are read more accurately than function words (Marshall & Newcombe, 1973), although there has been some debate on whether the word class differences are artefacts of word imageability (Allport & Funnell, 1981). In addition, small effects of word frequency and word length have sometimes been observed (e.g. Shallice & Warrington, 1975). We investigated the effects of word class and/or imageability in a training experiment in which KJ was taught 12 words on flashcards (stimuli may be seen in the Appendix). Six were highly concrete imageable nouns, which she had previously defined correctly to auditory presentation but could not read aloud. Six were function words that she had not been asked to define, but could not read aloud. All words were four letters long. Across the 8 learning trials KJ scored 28/48correct for nouns and 1/48correct for function

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words, a highly significant difference (Wilcoxon z = -2.37, P = 0.009). On trials 6 and 8 she scored 5/6 nouns correct, with 6/6 correct on trial 7. We explored the imageability/word class issue further by analysing her reading accuracy with words from Wellington Square. We found the words from this set that had imageability values in the MRC Psycholinguistic Database (Coltheart, 1981); where KJ had attempted the word on more than one occasion, we randomly selected one of her reading responses. We also counted the number of times the word occurred in the books from the Wellington Square scheme that she had read, as a measure of word frequency. This procedure yielded a corpus of 134 words. We then further restricted the set to the words that were unambiguously nouns, verbs, or function words, giving 118 items. Performance on these items is shown in Table 7. Although these data clearly show a difference between grammatical classes, the order of difference for KJ is different from that found in adult deep dyslexics. Adult deep dyslexics are typically best at nouns and worst at function words, whereas KJ is more accurate in reading function words than verbs, even though within this sample they are of similar imageability values. Simultaneous logistic regression was used to investigate the effects of length (in number of letters), log of frequency in the Wellington Square corpus, word class, and imageability on reading accuracy. When only imageability, frequency, and length were included in the regression model, all had significant effects: KJ was more accurate on higher imageability words (P = O.OOOl), on shorter words (P = 0.019, 1-tailed), and on higher frequency words (P = 0.046, 1-tailed). When word class was included as well, this had a highly significant effect (Wald = 11.43, df = 2, P = 0.003); the effects of length (P = 0.005) and frequency (P = 0.048) remained, but the effect of imageability was no longer significant (P = 0.38, ns). Thus the logistic regression shows that there are effects of word class, length, and frequency, and suggests that the effect of imageability may be an artefact of word class. Such conclusions must, however, be tentative; word class and imageability are very much confounded within this set, and it is certainly possible that KJ would be worse at low imageability items TABLE 7 The Word Sets from the Wellington Square Vocabulary Used for Logistic Regression

N ~~

Nouns Verbs Function words

Number of Letters ~

44 27 47

~~

Frequency

Imageability

Proportion Correct

6.98 18.41 29.06

595 334 303

0.61 0.07 0.30

~

4.36 3.56 3.13

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were there less homogeneity of imageability within word classes. However, our analysis is necessarily limited to the set of words to which KJ has been exposed.

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Tests of the Phonological Output Lexicon

KJ was given the Snowling Word and Nonword Repetition Test (Snowling et al., 1986). She scored 1SD below the mean of children with a reading age of 10 on the word test, and more than 3SD below the mean for this group on the nonword test. She was also more than 1SD below the mean for children with a reading age of 7 on the nonword test. These results are indicative of phonological problems. We cannot entirely rule out the possibility of a perceptual problem here; although KJ scored significantly above chance on the Hornsby Test of Auditory Discrimination, she did make five errors, all false positives: she failed to discriminate between IipAimp; g l a d clad; thedthem; sun/fun; and windring. However, testing took place in an open library area outside the classroom, and noise conditions were not ideal. Spelling

KJ’s teacher had reported that she made semantic errors in spelling, writing “car” when she’d intended to write “van.” We dictated a list of words for her to spell (see Appendix). Eight were words to which semantic errors had been made in reading; seven were function words and seven were nouns read correctly on at least two occasions. She spelt one of the semantic error set correctly, refused to attempt four, gave a neologism to “fall” (“fau”); and made two semantic errors, writing “mum” for “mother,” which she corrected to “mummy”; and “f’for “children” (usually read as “friends”), saying “I can only remember the first one.” She spelt four of the function word set and four of the noun set correctly. All errors to function words were refusals to respond. To nouns she made one morphological error (“men” for “man”); one d/b confusion (“bog” for “dog”); and one neologism (“apper” for “apples”). These results suggest that KJ is more likely to spell correctly words she can read correctly than words to which she makes semantic errorsin reading. Like KS (Temple, 1988), KJ made function word substitutions in spelling, writing “the” for “is,” and “and” for “am” in the standardised spelling test given. She was not asked to spell nonwords. Consistency

We have shown that KJ’s reading apparently uses no phonological information from the stimulus word. Her reading most plausibly reflects learned pairings between an orthographic form (which, we have shown, is

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probably a case-specific visual representation) and a word meaning. If so, her incorrect responses might represent incorrectly learned pairings, in which case we would predict that she will produce the same response consistently. Alternatively, KJ might have learned “fuzzy mappings”-an orthographic form maps to an area of meaning corresponding to a number of possible responses including, perhaps, the correct response. In this latter case we would predict less consistency of response. KJ was presented with a set of 134 words from the Wellington Square vocabulary for reading in February 1994 and again in May 1994. She had also read 88 of these words in January 1994. Table 8 shows the responses in February down the left related to reading responses in May (across the top). On these items she improves from 33% to 37% correct over the 3 months; this improvement is not reliable (McNemar’s Test, P = 0.14, ns). She shows substantial consistency in the items eliciting correct responses [X2(ldf) = 52.7; contingency coefficient, C = 0.5311. Of her morphological errors in February, 8/14 elicit exactly the same morphological error in May. In each case the error is an omission (of a plural on a noun [4], of a possessive on a noun [l], and of -ed from verbs [3]). Of these 8, only 5 had the same reading response in January. The consistency here may reflect a tendency towards producing stem forms of words rather than mispairings. Only two items elicit identical semantic errors in February and May (children + friends and playing + friends). This consistency seems to reflect predilection responses rather than necessary consistency. This is confirmed by examining the January responses to these words; in neither case were they identical (children + people, no, friends; playing + don’t know).

TABLE 8 Relationships between Responses on Two Presentations of 134 Words from the Wellington Square Vocabulary

Responses in May 1994 Responses in Feb 1994

Correct Omission

Morphological Semantic Visual Others Total

Morphological

Semantic

Visual

Others

1 41

3

0

44

7

56

1

9 0 0 1

0 1 4 1 0

0 0 1 1 3 1

4

1

14 8

14

6

6

0 0 0 3 14

Correct

Omission

36 7 2 3 1 1 50

0 1

0 44

Total

6 6 134

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Three visual errors were identical in February and May (grass + glasses, sparrow + square, stop + shop). In January sparrow had elicited the same response but both of the other two items were “don’t knows.’’ Only one other error-a mixed visual and semantic error (chips + crisps)-was identical across these two occasions. KJ’s reading therefore shows substantial consistency in that words read correctly are very much more likely to be read correctly on a subsequent occasion than those that are read incorrectly. There is, on the other hand, little consistency in her errors; very few items elicit the same incorrect response on two occasions, unless those incorrect responses are omissions. Her reading errors do not, therefore, seem to be attributable to learning incorrect stimulus response pairings. Instead KJ seems to select error responses from a pool of candidates, resulting in error inconsistency.

THERAPY STUDY KJ’s teacher and speech therapist had initially approached us for guidance as to how best to teach her to read. Once our investigations were complete, we set up a therapy study comparing two ways of teaching KJ words. Two things were by now clear: first, KJ’s word recognition was supported entirely by the lexical-semantic route, and second, she found it difficult to learn words other than concrete nouns. We decided to teach her verbs, as this was the class of words she found most difficult, and to maximise semantic support by embedding them in sentences. KJ should know every word in each sentence except the verb. We selected a set of 20 verbs from the Wellington Square vocabulary. These were split into two sets matched for letter length, and then inserted into sentences. Each set of 10 sentences consisted of 3 4-word, 2 5-word, and 1 6-word Subject-Verb-Object sentences, one 7-word Subject-Verb-Prepositional Clause sentence, and 2 3-word and 1 4-word Imperative sentences (see Appendix). Since KJ enjoyed copying, which is akin to the tracing of words to be learned advocated by proponents of multisensory teaching techniques (Fernald, 1943; Hulme, 1981), the first set of sentences was taught by getting KJ to read them aloud and copy them. To enhance links to semantics further, the second set was taught by getting KJ to read them aloud and link them to pictures illustrating the meaning of the verb. KJ’s teacher and speech therapist shared the pre-testing, training, and post-testing, according to a schedule we laid down.

Protocol Three baseline measurements were taken on 3 successive days of all 20 verbs, once written singly on cards and twice inserted in their sentences. On the fourth day, training of Set 1 sentences began and continued for six

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daily sessions. Three post-tests of all 20 verbs followed this training, on 3 successive days. To make sure the weekend break came at the same point in both kinds of training, there was then a day of rest, followed by six daily sessions of training Set 2 sentences. Three post-tests of all 20 verbs again followed, on 3 successive days; unfortunately (due to a misunderstanding), testing of isolated verbs was omitted at this point. Seven rest days were then included so that the same interval of time elapsed between the second post-test of Set 2 sentences as for Set 1 sentences. Then there were 3 final post-tests of all 20 verbs. In the copying condition (Set 1 sentences), KJ was shown a sentence and told which word the sentence would help her to learn. A small coloured acetate flag was placed over the target word as it was spoken. The sentence was read to KJ and the acetate flag was again placed over the verb as it was spoken. KJ was then asked to read the sentence, and to place her acetate flag over the target word as she said it. After this she was asked to copy the sentence, saying each word aloud as she wrote it. Each sentence was treated twice in this manner, until all 10 sentences had been done. Where KJ was unable to read any word, this was supplied for her. In the picture condition, KJ was shown a picture and told which word it would help her to learn. As the target word was spoken, a printed version of it was placed on the picture. The sentence was then read to KJ, with the teacher pointing to the word on the picture as it was spoken. Then the teacher removed this word, and asked KJ to read the sentence, placing her version of the printed target word on to the picture as she spoke it. Each sentence was treated twice in this manner until all 10 sentences had been done. Where KJ was unable to read any word, this was supplied for her. The teacher and speech therapist were surprised to find that KJ hated copying when she was required to read aloud as she copied, and concluded that her previous observed enthusiasm for copying was enthusiasm for a mindless mechanical task that she could do well. She responded much more eagerly to the picture version of the task.

Results The results of this training experiment are shown in Fig. 1. The results for verbs in sentences are the mean of the two probes of each set at each point. Consider first the verbs in sentences. Treatment of Set 1 by copying results in improvement of that set (Wilcoxon, P = 0.008),but there is no change in performance on Set 2, which is not treated during this period. In the following period, when Set 2 is being treated, there is a nonsignificant decline in performance on the Set 1 verbs, and performance is maintained at this level at the final post-test two weeks later. Treatment of Set 2 using the picture mnemonic technique in the second period results in significant improvement on this set relative to both pre-

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* Set 1 V in sentence

-+Set 1 V alone

-A-Set 2 V in sentence

-I Set -2 V

alone

Proportion correct 1.0 1

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0.9 0.8 0.7 0.6 0.5 0.4

0.3 0.2 0.1

0.0 Pre-therapy Post therapy 1 Post therapy 2

Post-test

FIG. 1. The results of two methods of training verb reading. Set 1 were treated by copying in the period between the pre-therapy test and post-therapy 1. Set 2 were treated by the picture mnemonic technique between post-therapy 1 and post-therapy 2.

treatment baselines (Wilcoxon, P = 0.031,post-therapy 2 vs. pre-test, and P = 0.016 for post-therapy 2 vs. post-therapy 1). At the final post-test the improvement in this set is maintained (and, indeed, slightly but nonsignificantly enhanced). Although there is no difference in performance between the two sets at the point when treatment of that set has just finished (Set 1 post-therapy 1 vs. Set 2 post-therapy 2), performance with Set 2 is significantlybetter than performance with Set 1 two weeks after treatment of the set has finished (Set 1 post-therapy 2 vs. Set 2 at post-test, Rank sum test, z = 2.10, P = 0.018;this difference is still significant if the two items in Set 2 that were correct at the pre-test are excluded from consideration, z = 1.77, P = 0.038). Thus the improvement with the second method of therapy, involving mnemonic picture cues, is more durable than improvement with the copying method. Given the design of the experiment (which was constrained by the approach of the long summer holidays) it is not clear

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whether the treatment of the second set interfered with retention of the first set, or whether the durability of the two treatment effects differs. The results of the probes with isolated verbs parallel the changes found with verbs in sentences. There is, once more, some indication that the second method results in more durable improvement; performance on Set 2 at the post-test is significantly better than performance on Set 1 at posttherapy 2 (Fisher exact, P = 0.035). Both types of therapy result in improvement in reading verbs in sentence contexts, and this improvement generalises to isolated verbs. Although both treatments result in equal improvement on the treated set during therapy, improvements as a result of the second method (involving mnemonic picture cues) are perhaps more durable than those resulting from the first copying method.

DISCUSSION KJ clearly has a qualitatively unusual reading disability that we suggest demonstrates all the characteristics of deep dyslexia: she makes semantic, visual, and morphological errors; she is totally unable to derive phonology from print either lexically or sublexically; she is quicker to learn nouns than matched function words; she shows word class effects that are, to a large extent, confounded with imageability; and she cannot write to dictation (she simply cannot spell) although her copying is unimpaired. That her reading vocabulary is much smaller than that of adult deep dyslexic patients is probably an inevitable consequence of this developmental form of deep dyslexia. In terms of the proportions of errors of different types that she makes, KJ falls well within the range of adult deep dyslexics (Shallice & Warrington, 1980) (see Table 9). KJ does differ from the acquired deep dyslexics in two ways. First, she produces a higher proportion of omissions than any of the adult patients. Her proportion of omissions, however, varies a great deal between word sets (cf. Table 1); unlike the adult deep dyslexics, we have tested her with words that were never part of her reading vocabulary. The second difference is more subtle: KJ’s reading performance is more affected by part of speech than word imageability. Whereas the adult patients are better at reading verbs than function words, KJ is better at function words than verbs. As with the adult patients, KJ’s reading is best with concrete nouns. KJ’s case therefore establishes the existence of a developmental form of deep dyslexia in a child who underperforms in reading and writing relative to her oral language comprehension, her auditory and visual memory skills, and her IQ score. It is implausible that this developmental form represents use of a right-hemisphere reading system. In spite of her general learning

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STUART AND HOWARD TABLE 9 The Proportion of Different Types of Error (in Percentages) Made by a Variety of Patients with Acquired Dyslexia (Table from Shallice 81Warrington, 1980), Compared to KJ

Visual Visual

4 ? 6 11 16

13 22 35 35 48

EINC”

6 11 4 23

a2 41 41 59

I

99

61

22 11(?) 32 4 10 9 19

23 6

16 25

11

30

23

33

Semantic

PW GR~

7

51

KF

54 56 23 21 19 10 4

10

KJ

24

6

ws vs PS

Morphological

Other

Patient

DE

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andlor Semantic

“The final column gives the percentage of all non-corrected responses which were not omissions. ’The ?s for G R are because the original error analysis for this patient did not differentiate between visual and/or semantic and morphological errors.

disability, KJ has shown no signs of brain damage, let alone damage localised to the left hemisphere. She is also qualitatively unlike the 38 hemiplegic children reported by Muter (unpublished), none of whom were deep dyslexic, and who, whichever hemisphere had been damaged, showed a pattern of Verbal IQ significantly higher than Performance IQ, exactly the opposite of KJ’s pattern. KJ is part of that large group of children who have general learning difficulties with no discernible medical cause. It is not clear how frequently such children show deep dyslexic reading, although the lack of published reports-and the experience of staff in special education-suggests that it is not a common disorder. KJ’s reading performance can be accounted for if we assume an inability to use both the sublexical and the direct lexical routes from print to sound, which leaves her dependent on the route from print to semantics to phonology* Theoretically it would be possible to be as phonologically impaired as KJ and yet be classified as a phonological rather than a deep dyslexic. All that is required for this pattern to emerge is for the semantic route to be unimpaired. In practice, however, developmental phonological dyslexics discussed in the literature seem to be rather less phonologically impaired than KJ. For example, Snowling et al. (1986) discuss seven cases of developmental phonological dyslexia. Unlike KJ, all seven children performed above chance on the Snowling rhyme judgement task. Five could read some one-syllable and four could read some two-syllable nonwords

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correctly; these children also showed regularity effects in word reading similar to normal controls. All seven, again unlike KJ, made some unsuccessful attempts to sound out words they could not immediately recognise. Thus these phonological dyslexics probably had sufficient access to phonology to inhibit the production of visually unrelated semantic errors. KJ does not. However, as her semantic errors appear in speech as well as reading, we suggest that an impairment of her semantic system underlies their occurrence. Plaut and Shallice (1993) presents a computational model of reading via semantics, in the absence of any nonsemantic routes for converting from print to sound. After extensive training the semantic route maps correctly from print to sound for all words in the training vocabulary. When lesioned, the model performs in a way that resembles adult deep dyslexia: Concrete words (represented by richer semantic representations) are read more accurately than abstract words (with fewer semantic units), and visual, semantic, and mixed visual a n d o r semantic errors occurred, although no responses formed the overwhelming majority of the errors. We have argued that KJ’s reading is mediated exclusively via semantics. Her performance therefore puts a lower bound on the capabilities of an isolated semantic route. However, her semantic errors in spoken word retrieval suggest that this routine is itself probably defective. Plaut and Shallice give no data on the pattern of performance of their model during training; as a result it is impossible to assess whether KJ’s reading performance is that which they would expect from a developing isolated semantic reading routine. We have presented clear evidence of KJ’s inability to use the sublexical route: she is completely unable to read aloud simple CVC nonwords; she never makes regularisation errors in reading aloud; and she is quite happy to learn to associate a spoken word with a phonotactically legal spelling pattern that is completely impossible as a representation of the word’s phonology. Our claim that the direct lexical route is also unavailable, and that KJ is therefore making associations from print to meaning and not from print to sound at the lexical level, is supported by the fact that she was easily able to learn to read aloud highly concrete noun words, but not function words; by the results of the therapy study, where an emphasis on the meaning of a verb led to more durable improvement in reading aloud than simply repeating and copying did; and by the surprising ease with which KJ was able to learn the computer vocabulary to which she was exposed, again involving associating words with pictures. It is also interesting that from the teaching received under the Alpha to Omega program, KJ has learned to associate sounds with letters by rote, but this remains totally unrelated to her reading system. This contrasts with KS (Temple, 1988), whose reading improved and whose semantic

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errors eventually disappeared once a phonic teaching programme was successfully instigated. From the results we have presented, we think that KJ provides the first conclusive evidence that deep dyslexia exists in a developmental form, and that it can be resistant to treatment aimed at improving phonological skills. Manuscript received 22 August 1994 Revised manuscript received 14 November 1994 Revised manuscript accepted 24 November 1994

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REFERENCES Allport, D.A., & Funnell, E. (1981). Components of the mental lexicon. Philosophical Transactions of the Royal Society of London, B295,397410. Byrne, B., & Fielding-Barnsley, R. (1991). Evaluation of a program to teach phonemic awareness to young children. Journal of Educational Psychology, 83, 451-455. Byrne, B.. & Fielding-Barnsley, R. (1993). Evaluation of a program to teach phonemic awareness to young children: A one-year follow up. Journal of Educational Psychology, 85, 104-111. Campbell, R., & Butterworth, B. (1985). Phonological dyslexia and dysgraphia in a highly literate subject: Deficits of phonemic processing and awareness. Quarterly Journal of Experimental Psychology, 37A, 435475. Castles, A., & Coltheart, M. (1993). Varieties of developmental dyslexia. Cognition, 47, 149-180.

Coltheart, M. (1980). Deep dyslexia: A review of the syndrome. In M. Coltheart, K. Patterson, & J.C. Marshall (Eds.), Deep dyslexia. London: Routledge & Kegan Paul. Coltheart, M. (1981). The MRC psycholinguistic database. Quarterly Journal of Experimental Psychology, 33A, 497-505. Coltheart, M. (1987). Deep dyslexia since 1980. In M. Coltheart, K. Patterson, & J.C. Marshall (Eds.), Deep dyslexia (2nd Edition). London: Routledge & Kegan Paul. Coltheart, M., Masterson, J., Byng, S.,Prior, M., & Riddoch, J. (1983). Surface dyslexia. Quarterly Journal of Experimental Psychology, 35A, 469495. Coltheart, M., Patterson, K.. & Marshall, J.C. (1987). Deep dyslexia since 1980. In M. Coltheart, K. Patterson, & J.C. Marshall (Eds.), Deep dyslexia (2nd Edition) (Chapter 18). London: Routledge & Kegan Paul. Cossu, G., & Marshall, J.C. (1986). Theoretical implications of the hyperlexia syndrome. Two new Italian cases. Cortex, 22, 579-589. Davidoff, J., & Masterson, J. (in preparation). The development of picture naming: Differences between nouns and verbs. Submitted to Language and Cognitive Processes. Dunn, L., Dunn, L., Whetton, C., & Pintilie, D. (1982). The British Picture Vocabulary Scale. Windsor, UK: NFER-Nelson. Elliott, C.D., Murray, D.J., & Pearson, L.S. (1983). British Ability Scales. Windsor, UK: NFER-Nelson. Ellis, A.W., & Marshall, J.C. (1978). Semantic errors or statistical flukes? A note on Allport’s “On knowing the meaning of words we are unable to report.” Quarterly Journal of Experimental Psychology, 30, 569-575. Fernald, G.M. (1943). Remedial techniques in basic school subjects. New York: McGrawHill. Frith, U. (1985). Beneath the surface of developmental dyslexia. In K.E. Patterson, J.C. Marshall, & M. Coltheart (Eds.), Surface dyslexia. London: Lawrence Erlbaum Associates Ltd.

DEVELOPMENTAL DEEP DYSLEXIA

823

Funnell, E. (1983). Phonological processes in reading: New evidence from acquired dyslexia. British Journal of Psychology, 74, 159-180. Goodman, J.A. (1972). A case of an “autistic savant”: Mental function in the psychotic child with markedly discrepant abilities. Journal of Child Psychology and Psychiatry, 13, 267-278.

Goulandris, N.K., & Snowling, M. (1991). Visual memory deficits: A plausible cause of developmental dyslexia? Evidence from a single case study. Cognitive Neuropsychology,

Downloaded by [University College London] at 04:28 24 July 2015

8, 127-154.

Healy, J.M., Aram, D.M. Horwitz, S.J., & Kessler, J. (1982). A study of hyperlexia. Brain and Language, 17, 1-23. Holmes, J. (unpublished). Dyslexia: A neurolinguistic study of traumatic and developmental disorders of reading. Unpublished PhD dissertation, University of Edinburgh, 1973. Hornsby, B., & Shear, F. (1975). Alpha to omega: The A - 2 of teaching reading, writing and spelling. London: Heinemann. Hulme, C. (1981). Reading retardation and multi-sensory teaching. London: Routledge & Kegan Paul. Johnston, R.S. (1983). Developmental deep dyslexia? Cortex. 19, 133-139. Marshall, J.C., & Newcombe, F. (1973). Patterns of paralexia: A psycholinguistic approach. Journal of Psycholinguistic Research, 2, 175-199. Muter, V . (unpublished). Phonology and learning to read in normal and hemiplegic children. Unpublished PhD Thesis, University of London, 1994. Newcombe, F., & Marshall, J.C. (1985). Sound-by-sound reading and writing. In K.E. Patterson, J.C. Marshall, & M. Coltheart (Eds.), Surface dyslexia: Neuropsychological and cognitive studies of phonological reading. London: Lawrence Erlbaum Associates Ltd. Plaut, D.C., & Shallice, T. (1993). Deep dyslexia: A case study of connectionist neuropsychology. Cognitive Neuropsychology , 10,377-500. Renfrew, C. (1969). The bus story: A test of continuous speech. North Place, Old Headington. Oxford: C. Renfrew. Renfrew, C. (1972). The Action Picture tesr. North Place, Old Headington, Oxford: C. Renfrew. Roodenrys, S . , Hulme, C., & Brown, G. (1993). The development of short-term memory span: Separable effects of speech rate and long-term memory. Journal of Experimental Child Psychology, 56, 4 3 1 4 2 . Seidenberg, M.S., & McClelland, J.L. (1989). A distributed, developmental model of word recognition and naming. Psychological Review, 96,523-568. Seymour, P.H.K., & Elder, L. (1986). Beginning reading without phonology. Cognitive Neuropsychology, 3, 1-37. Seymour, P.H.K., & MacGregor, C.J. (1984). Developmental dyslexia: A cognitive experimental analysis of phonological, morphemic and visual impairments. Cognitive Neuropsychology, I , 43-82. Shallice, T., & Wamngton, E.K. (1975). Word recognition in a phonemic dyslexic patient. Quarterly Journal of Experimental Psychology, 27, 187-199. Shallice, T., & Warrington, E.K. (1980). Single and multiple component central dyslexic syndromes. In M. Coltheart, K. Patterson, & J.C. Marshall (Eds.), Deep dyslexia. London: Routledge & Kegan Paul. Siegel, L.S. (1985). Deep dyslexia in childhood? Brain and Language, 26, 16-27. Silberberg, N.E., & Silberberg, M.C. (1967). Hyperlexia: Specific word recognition skills in young children. Exceptional Children, 34, 41-42. Snowling, M.J. (1985). The assessment of reading and spelling skills. In M.J. Snowling (Ed.), Children’s written language dificulties. Windsor, UK: NFER-Nelson. Snowling, M., & Hulme, C. (1989). A longitudinal case study of developmental phonological dyslexia. Cognitive Neuropsychology, 6. 379401.

Downloaded by [University College London] at 04:28 24 July 2015

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Snowling. M., Stackhouse, J., & Rack, J. (1986). Phonological dyslexia and dysgaphia: A developmental analysis. Cognitive Neuropsychology , 3 , 309-339. Stuart, K.M. (unpublished). Phonological awareness, letter-sound knowledge and learning to read. Unpublished PhD thesis, University of London, 1986. Stuart, M. (1990). Factors influencing word recognition in pre-reading children. British Journal of Psychology, 81, 135-146. Stuart, M. (1993). Learning to read: A longitudinal study. Education 3-13, 21, 1%26. Stuart, M. (in press). Prediction of qualitative assessment of 5 and 6 year old children's reading: A longitudinal study, British Journal of Educational Psychology, 65. Stuart, M.,& Masterson, J. (1992). Patterns of reading and spelling in 10-year-old children related to prereading phonological abilities. Journal of Experimental Child Psychology, 54, 168-187. Temple, C.M. (1988). Red is read but eye is blue: A case study of developmental dyslexia and follow-up report. Brain and Language, 34, 13-37. Temple, C.M.. & Marshall, J.C. (1983). A case study of developmental phonological dyslexia. British Journal of Psychology, 74, 517-533. Treiman, R., & Baron, J. (1981). Segmental analysis ability: Developmental and relation to reading ability. In T.G. Waller & G.E. McKinnon (Eds.), Reading research: Advances in theory and practice, Vol. 3. New York: Academic Press. Treiman, R.. & Baron, J. (1983). Phonemic analysis training helps children benefit from spelling-sound rules. Memory and Cognifion, 11, 382-389. Tunmer, W.E.. Herriman, M.L., & Nesdale, A.R. (1988). Metalinguistic abilities and beginning reading. Reading Research Quarterly, 23, 134158. Tunmer, W.E., & Nesdale, A.R. (1985). Phonemic segmentation skill and beginning reading. Journal of Educational Psychology, 77,417-527.

APPENDIX Stimuli for Word Learning Experiment XAPPOT (carrot); IIAPXEA (parcel); UIOT (spot); POAA (road); lion (lion); park (park); bottle (bottle); hammer (hammer); gith (neck); feam (boat); derfal (carpet); laffot (button).

Stimuli for ImageabiIityMlord Class Experiment oven, belt, snow, lion, nail, aunt, away, with, next, here, that, some.

Stimuli for Spelling Semantic error set: fall; mother; hurt; children; kicked; Max; out; play. Function word set: to; yes; a; into; and; in; all. Noun set: cat; bird; apples; dog; men; box; fish.

Stimuli for Therapy Study Set 1 The skirt was yellow. Rocky had a ball. Dad dropped the glasses. The boy wanted the ball. The man did the garden. The boy gave Rocky the radio. The man will look at the shed. see the fire. get the ball. go up to bed. Set 2 Rocky saw the church. The boy went home. The apples were red. The boy picked the flower. The man pushed the chair. The tree is in the garden. Dad put the boots in the box. have a cake. paint the shed. swim in the water.