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A Novel Vocabulary Intervention for Poor Comprehenders: A single case study
Katrina Kelso, Anne Whitworth, Suze Leitao
Curtin University
Corresponding author:
Katrina Kelso M Ed in Applied Linguistics (Honours)
Curtin School of Allied Health
Curtin University
GPO Box U1987, Perth
Western Australia, 6845
Email: katrina.kelso@postgrad.curtin.edu.au
Email addresses for all authors
Anne Whitworth PhD anne.whitworth@curtin.edu.au
Suze Leitão PhD S.Leitao@exchange.curtin.edu.au
Acknowledgements
We would like to thank the schools, children and their families, who participated in this
study.
Declaration of Conflicting Interests
The author(s) declared no potential conflicts of interest with respect to the research,
authorship, and/or publication of this article.
This paper was accepted for publication in Journal of Clinical Practice in Speech-Language
Pathology on January 14, 2022
Please cite as
Kelso, K., Whitworth, A., & Leitão, S. (2022b). A Novel Vocabulary Intervention for
Poor Comprehenders: A single case study. Journal of Clinical Practice in Speech-
Language Pathology. 24(1), 36-43. Copyright ©2022 The Speech Pathology Association
of Australia Limited.
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Abstract
Poor comprehenders have difficulty with reading comprehension despite adequate
word reading accuracy and fluency. Weaknesses have been identified with lower-level
vocabulary and grammar skills, and higher-level language skills such as inference making. It
is important that speech-language pathologists (SLPs) tailor intervention to meet the specific
needs of individuals; however, there is a lack of research on intervention for poor
comprehenders, who comprise a heterogenous group. This case study aimed to explore
whether a pilot 8-week novel vocabulary intervention was (a) effective in improving word
knowledge, and (b) if gains generalised to reading comprehension. Following intervention,
significant improvements were found on the semantic subtasks and in word knowledge for
treated words on the Word Knowledge Profile measure; improvement was also seen for
untreated words at six-month follow-up. There were also gains on the standardised word and
reading comprehension measures, providing promising preliminary evidence for the
usefulness of the intervention.
Keywords: vocabulary intervention, poor comprehenders, reading comprehension, case
study
Poor comprehenders are a subgroup of poor readers who have difficulty
understanding what they read despite being able to decode words fluently and accurately.
Prevalence rates have varied depending on the selection criteria and the age of the
participants, but more recent research, with large cohorts, has identified 5 – 7% of children as
poor comprehenders (e.g., Clarke et al., 2010; Elwér et al., 2015; Hulme & Snowling, 2011).
These children comprise a heterogenous group, as not all poor comprehenders perform well
or poorly on the same oral language tasks (Nation et al., 2010). Broadly, there are (1) those
who have difficulty with lower-level language skills (vocabulary, morphology, and grammar)
which impacts on understanding the meaning of sentences and, in turn, texts, and (2) those
who have difficulty with higher-level language skills (inferencing, understanding of text
structure, and comprehension monitoring) needed to create a mental model of a text’s
meaning (see Cain, 2010 for an overview).
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Vocabulary Skills in Poor Comprehenders
Weak vocabulary skills are widely accepted as contributing to poor reading
comprehension; however, available evidence indicates that not all poor comprehenders have
inadequate vocabulary. In many of their studies, Oakhill, Cain and colleagues used receptive
vocabulary tasks as part of the selection of their groups of poor comprehenders,
predominantly aged 7-8 years (e.g., Cain et al., 2004; Yuill & Oakhill, 1991). These children
were matched to controls with age-appropriate vocabulary and reading accuracy but differing
levels of reading comprehension on the Neale Analysis of Reading Ability – Revised British
Edition (NARA: Neale, 1989), indicating that receptive vocabulary was not weak in these
poor comprehenders.
Some studies have tested receptive vocabulary but not used these measures to select
participants. In these studies, poor comprehenders generally performed significantly below
good comprehenders, although not necessarily scoring in the below average range (e.g.,
Adlof & Catts, 2015; Cain & Oakhill, 2006). This difference has been identified in
kindergarten children in longitudinal studies and shown to persist across school years (e.g.,
Elwér et al., 2015). Tests of receptive vocabulary measure vocabulary breadth, or how many
words a person knows, in contrast to tasks measuring vocabulary depth: knowledge about the
relations or associations between words-that is how words are organised semantically in the
mental lexicon (Cain, 2010). Poor comprehenders have weaker skills, compared to controls,
at a group level on tasks assessing vocabulary depth such as semantic fluency, providing
word definitions and multiple meanings, and explaining word relationships (Adlof & Catts,
2015; Nation et al., 2004: Nation et al., 2010; Nation & Snowling, 1998). When task scores
are examined at an individual level, however, variability is seen across the groups and the
tasks, and not all children have vocabulary deficits (Colenbrander et al., 2016; Nation et al.,
2004).
Impact of Vocabulary Intervention on Reading Comprehension
The effectiveness of vocabulary interventions on increasing comprehension in
children has been investigated extensively. In a review of published experimental and quasi-
experimental studies evaluating vocabulary instruction prior to 2000, the National Reading
Panel (NRP: NICHD, 2000) concluded that instruction was generally effective in improving
comprehension. The types of instruction in the studies included in the review were varied,
however, and excluded studies involving only students with learning disabilities (Elleman et
al., 2009). Recommendations for instruction were provided based on the results, including
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providing explicit instruction and having students actively engage in learning new vocabulary
from context. Based on the findings of their review, the NRP also recommended that non-
standardised assessment instruments matched to instruction were needed for efficacy of
instruction to be measured. In relation to which words should be selected for instruction, it
was suggested that words should be those that the learner would encounter sufficiently often
and find useful in many contexts (NICHD, 2000). Beck et al. (2013) refer to these words as
Tier 2 words: words beyond the basic level that are characteristic of written text but not oral
conversation.
Meta-analyses conducted by Elleman et al. (2009) and Wright and Cervetti (2017)
both included several studies with children identified as having reading difficulties. The
meta-analyses included 37 and 36 studies, respectively, that met selection criteria. The
studies focused specifically on the effect of vocabulary instruction on passage-level
comprehension in children across grades pre-K to 12, with the majority focused on grades 3-
5. Elleman et al. (2009) found that children with and without reading difficulties made gains
from instruction on both custom and standardised vocabulary measures, but that
comprehension only increased on custom text comprehension measures containing target
words. Gains on custom measures, but a lack of transfer to improvement on standardised
comprehension measures, was also found by Wright and Cervetti (2017). Elleman et al.
(2009) were unable to identify any specific vocabulary techniques or interventions that were
more effective than others in improving comprehension. Wright and Cervetti (2017),
however, found that instruction focused on active exploration of the meaning of words
typically had greater impact on developing vocabulary to support comprehension of texts
containing target words, than treatments where students were given word definitions or
searched word meanings up in dictionaries.
Very few studies have examined the effect of vocabulary intervention on the reading
comprehension skills of poor comprehenders. In a study with 7 to 8-year-old children
identified as having poor vocabulary, although it is not clear from the data if they were poor
comprehenders, Nash and Snowling (2006) investigated the effect of two vocabulary teaching
methods on vocabulary knowledge and reading comprehension. One method involved
teaching word definitions, and the other teaching a strategy to derive meanings from context
clues in the text. Both methods resulted in significant gains in knowledge of taught words
post-intervention but, three months later, the context group were significantly better at
expressing word meanings and comprehending texts containing taught words. Clarke et al.
(2010) conducted a randomized controlled trial that examined the efficacy of three
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intervention programmes in improving the reading comprehension of poor comprehenders
aged 8 to 9 years. One programme trained oral language skills (vocabulary, listening
comprehension, figurative language, and oral narrative), the second targeted these skills in
written texts, and the third combined elements of both. All resulted in significant
improvements on a standardised reading comprehension measure post-intervention compared
with a waiting control group. These gains were maintained at 11-month follow-up, with the
oral language group making further gains compared with the other two. As these were multi-
component interventions, it was difficult to determine the essential component(s) that may
have produced the change in reading comprehension. However, the oral language and
combined programme groups also made significant gains on the vocabulary knowledge
measures post-intervention, and a mediation analysis revealed that these gains either partially
or fully accounted for the improvements in reading comprehension at the 11 month follow-up
(Clarke et al., 2010).
The current study
The case reported here was part of a larger research programme exploring the
identification, profiling, and subsequent targeted intervention with individual poor
comprehenders. As reported in Kelso et al. (2020), 24 children were identified as poor
comprehenders following a two-phase testing protocol, and 17 subsequently completed
detailed profiling of their oral and written language, and cognitive processes (Kelso et al.,
2021b). Only two of the 17 children had difficulty on multiple lower-level oral and written
vocabulary and grammar comprehension tasks; the remainder having difficulty with higher-
level discourse comprehension (intervention study reported in Kelso et al., 2022a).
We identified few studies investigating the effect of vocabulary instruction on the
reading comprehension of poor comprehenders. The study by Clarke et al. (2010) included
multiple components but suggested that the gains in vocabulary mediated subsequent
improvements in reading comprehension. We developed and evaluated a theoretically
informed and individually targeted intervention that focused on actively developing
vocabulary depth using a semantic organisation approach.
The aims of this case study were to:
i. explore whether a pilot programme utilising a novel vocabulary intervention was
effective in improving word knowledge at both an oral and reading single word level, and
ii. investigate generalisation of any therapy gains to improvement in reading comprehension.
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Table 1
Background Assessment Data
Measure
Phonological Skills/
Word Reading
Lower-level
Vocab/Grammar
Discourse-level
Comprehension
Oral
Reading
Oral
Reading
Oral
Reading
CTOPP-2 Elision a
9
CTOPP-2 PI a
9
CTOPP-2 RN Letters a
11
CTOPP-2 Total b
107
WIAT-II Pseudowords b
100
WIAT-II Word Reading b
94
TOWRE-2 Total b
88
YARC-P Accuracy b
93
PROBE-2 F Accuracy c
99
PROBE-2 NF Accuracy c
96
PPVT-4 b
85
CELF-4 WC Receptive a
8
CELF-4 WC Expressive a
10
CELF-4 Word Definition a
5
CELF-4 Associations d
F
WRMT-III Word Comp b
73
TROG-2 b
83
CELF-4 Concepts a
4
CELF-4 Sent Assembly a
6
NSSRT Sentence Comp b
95
CELF-4 USP a
5
TNL Comprehension a
5
TNL Narrative a
4
CASL Nonliteral Lang b
70
CASL Inference b
71
TOPS-3 Total b
81
YARC-P Comprehension b
75
PROBE-2 F Comp c
20
PROBE-2 NF Comp c
0
Note. CTOPP-2 = Comprehensive Test of Phonological Processing-2; PI = Phoneme
Isolation; RN = Rapid Naming; WIAT-II = Wechsler Individual Achievement Test-II –
Australian Edition; TOWRE-2 = Test of Word Reading Efficiency-2; YARC-P = York
Assessment of Reading for Comprehension-Primary - Australian Edition; F – Fiction; NF =
Nonfiction; PPVT-4 = Peabody Picture Vocabulary Test-4; CELF-4 = Clinical Evaluation of
Language Fundamentals-4 – Australian Edition; WC = Word Classes; WRMT-III =
Woodcock Reading Mastery Tests-III; Comp = Comprehension; TROG-2 = Test for
Reception of Grammar-2; Concepts = Concepts and Following Directions; Sent = Sentence;
NSSRT = New Salford Sentence Reading Test; USP = Understanding Spoken Paragraphs;
TNL = Test of Narrative Language; CASL = Comprehensive Assessment of Spoken
Language; Lang = Language; TOPS-3 = Test of Problem Solving-3.
Shaded = Outcome Measures used in this study
a = Scaled Score; b = Standard Score; c = percentage correct; d = pass/fail criterion
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Method
Two participants with lower-level language difficulties on profiling were invited to
participate and one agreed. Ethical approval was granted by Curtin University Human
Research Ethics Committee (HRE2016-0438-01) and the Government of Western Australia
Department of Education.
Participant
Danni (pseudonym) was in Year 5 (aged 10;0 years) at the time of entry into the
study, and 11;6 years in Year 6 at the commencement of the intervention. Danni was not
exposed to English until adopted at age 5; however, since then, Australian English has been
the only language spoken. Table 1 shows the profile of Danni’s oral language and reading
skills from the background assessment. Results on the nonverbal IQ and memory tasks are in
Table 2, and further details of each test can be found in Kelso et al. (2021).
Table 1
Results of Nonverbal IQ and Memory Tasks
Measure
Score
TONI-4 Nonverbal IQ a
99
CTOPP-2 Nonword Repetition b
6
CELF-4 Number Repetition-Forwards b
14
CELF-4 Number Repetition-Backwards b
9
CELF-4 Recalling Sentences b
8
Competing Language Processing Test c
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Note. TONI-4 = Test of Nonverbal Intelligence-4; CTOPP-2 and CELF-4 (see Table 1)
a = Standard Score; b = Scaled Score; c = percentage correct
Procedure
All sessions took place in the first author’s clinic. Word selection was carried out 2
months prior to the commencement of intervention, at the same time as the pre-intervention
testing on these standardised tasks: Woodcock Reading Mastery Tests–3rd edition (WRMT-
III Form B) Word Comprehension (Woodcock, 2011), York Assessment of Reading
Comprehension Primary – Australian Edition (YARC-P: Snowling et al., 2012) and Clinical
Evaluation of Language Fundamentals–4th Edition, Australian Edition (CELF-4)
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Word
Definitions (Semel et al., 2006). The first two of these tasks were readministered 2 months
after intervention and followed up 6 months later to assess maintenance of any change, and
CELF-4 Word Definitions at the 6-month follow-up only. The Word Knowledge Profile
1
CELF-4 was current at the time of data collection
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(Spencer et al., 2017) was administered immediately prior to intervention (Time1),
immediately following (Time2), and 6 months later (Time3).
Word selection. To select the words used in
the intervention, the first author read each of the Level
2 fiction texts (decoding age 10-12 years in line with
Danni’s decoding level) from KEY into inference and
KEY into evaluation (Parkin et al., 2002; 2005) to
identify Tier 2 words (Beck et al., 2013). A total of
102 words were selected from five texts. Danni was
asked to tick the category that applied for each word
using the word knowledge chart based on Beck et al. (2013) as shown in Figure 1. Twenty-
six words rated 0-2 were selected as treated words (nine nouns, eight verbs, nine adjectives/
adverbs). Each of these was matched as closely as possible with a word from the same
category and part of speech. These served as untreated control items.
Intervention. The intervention consisted of two 30-min sessions per week over 8
weeks. It was developed to contain the same overall amount of intervention time (450 min) as
the higher-level language intervention conducted as part of this research programme (Kelso et
al., 2022a), and based on the structure (length of sessions and number of words taught per
session) used by Nash and Snowling (2006).
In the initial session, the structure of the sessions was explained, followed by the
participant reading the first text and answering the comprehension questions to provide
context for the treated words. In each treatment session, two words from the text were
explored, and the participant was encouraged to complete take-home tasks using these words.
Words from the previous session were briefly reviewed at the start of each session. When all
words in a text were completed, the next text was read and the comprehension questions
answered (Session 5, 8, 11, 13) prior to the introduction of the treated words for that text. The
protocol for exploring each treated word is seen in Figure 2, with the same sequence followed
each time.
Outcome Measures
Word Knowledge Profile (WKP). This task was used as the primary outcome measure
to assess change in depth of word knowledge. This profiling tool measures a participant’s
Word Knowledge Categories
0. Do not know the word at all
1. Have seen or heard the word
2. Know something about it, can
relate it to a situation
3. Know it Well, can explain
and use it
Figure 1
Word knowledge chart based on Beck et al. (2013)
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phonological and semantic knowledge of individual words across eight subtasks: (1) repeat
word, (2) produce rhyming word, (3) spell, (4) rate own knowledge of word, (5) use word in
a spoken sentence, (6) define word meaning, (7) provide example of when/where might use
word, and (8) give example of personal context of use (not used in this study). Each item was
scored 0 or 1, apart from word knowledge which was rated 0-3 using Beck et al.’s (2013)
categories (see above).
Figure 2
Structure for Exploration of Treated Words
WRMT-III Form B Word Comprehension. This task, standardised on a large US
sample, was used as a test of reading-input vocabulary depth. It consists of three sections,
Antonyms, Synonyms, and Analogies, each requiring the reading of stimuli word/s then a
verbal response. Scores from each are summed to create a total raw score which is used to
determine the Standard Score.
YARC-P. This is an individually administered test of two texts designed to evaluate
reading accuracy, rate, and comprehension in primary school children and was used as a
standardised measure of reading comprehension.
CELF-4 Word Definitions. This task was used to check change in oral-input
vocabulary depth on a standardised measure. It requires the examinee to define words.
Target word.
1. Read sentence with target word and
discuss what meaning might be
2. Student writes word in middle of “mind
map” sheet
3. Generate child friendly definition of word
together – use dictionary, discuss. SLP
writes definition down on sheet
4. Think of example situations where word
might be used
5. Word Analysis
• Identify “Part of Speech” using
sentence
• Word Building - Investigate
prefixes/suffixes (add, take away)
• Identify if word has more than one
meaning, and discuss if it does
• Think of synonyms, opposite
meaning words
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Results
Word Knowledge Profile
Table 3 sets out Danni’s knowledge ratings for treated (n=26) and untreated words
(n=26) (nouns, verbs, adjectives/adverbs, total) at three time points: immediately prior to
intervention (Time1), immediately following intervention (Time2), and 6 months later
(Time3). A Wilcoxon two sample t-test was calculated to look for significant differences
between the total scores at Time1 and Time2, and Time1 and Time3. Knowledge ratings
improved significantly for the treated words Time1 to Time2 (z=3.81, p<.001, two tailed) and
continued to be significant Time1 to Time3 (z=2.13, p=.034, two tailed). Knowledge ratings
for untreated words did not show significant evidence of change Time1 to Time2; however,
they were significantly improved Time1 to Time3 (z=3.03, p=.003, two tailed).
Table 1
Knowledge Ratings across Word Classes and Time.
Pre (Time1)
Post (Time2)
Follow-Up (Time3)
Treated
Untreated
Treated
Untreated
Treated
Untreated
N
V
A
T
N
V
A
T
N
V
A
T
N
V
A
T
N
V
A
T
N
V
A
T
KR0
1
1
0
2
1
1
2
4
0
2
2
4
3
0
3
6
1
3
0
4
0
1
1
2
KR1
4
4
6
14
4
4
4
12
1
0
0
1
0
1
2
3
1
2
2
5
2
1
2
5
KR2
4
3
3
10
4
3
3
10
1
0
2
3
3
5
1
9
3
2
2
7
4
2
3
9
KR3
0
0
0
0
0
0
0
0
7
6
5
18
3
2
3
8
4
1
5
10
3
4
3
10
Note. KR = Knowledge Rating; N = Noun; V = Verb; A = Adjective/Adverb; T = Total
Table 4 sets out Danni’s performance for treated (n=26) and untreated words (n=26)
at each of the three time points across a range of subtasks on the Word Knowledge Profile
(WKP). McNemar’s test (two tailed) was used to explore the presence of significant change
for total words on each subtask over time, comparingTime1 to Time2 and Time1 to Time3.
While performance on each of the phonological tasks (Word Repetition, Rhyme
Production, Spelling) for treated and untreated words was at, or close to, ceiling prior to the
intervention and remained so at each time point, significant changes were seen in the
semantic subtasks for both treated and untreated words. For treated words, a significant
increase was seen Time1 to Time 2 in Use in Sentences (p=.016), Word Meaning (p=.039),
and When/Where examples (p<.001). Although raw scores continued to be higher at Time3
than at Time1 for each subtask, this only continued to be significant for use of When/Where
examples (p=.006). For untreated words, the use of When/Where examples showed
significance (p=.016) Time1 to Time2, while significant gains were seen for untreated words
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in each of Use in Sentences (p=.022), Word Meaning (p<.001) and When/Where examples
(p<.001) Time1 to Time3.
Table 2
Word Knowledge Profile across Tasks, Word Classes, Treatment Condition and Time.
Pre (Time1)
Post (Time2)
Follow-Up (Time3)
Treated
Untreated
Treated
Untreated
Treated
Untreated
N
V
A
T
N
V
A
T
N
V
A
T
N
V
A
T
N
V
A
T
N
V
A
T
WR
9
8
9
26
9
8
9
26
9
8
9
26
9
8
9
26
9
8
9
26
9
8
9
26
RP
9
8
9
26
9
8
9
26
-
-
-
-
-
-
-
-
9
8
9
26
9
7
9
25
SP
8
6
6
20
7
7
9
23
9
6
4
19
9
8
8
25
9
7
8
24
8
8
8
24
US
4
1
6
11
5
3
1
9
7
5
6
18*
6
7
2
15
5
3
6
14
7
7
3
17*
WM
4
2
4
10
2
3
1
6
6
4
7
17*
4
3
0
7
4
3
7
14
8
6
4
18**
WW
2
0
1
3
3
0
0
3
5
5
6
16**
4
4
2
10*
5
3
6
14**
7
6
5
18**
Note. WR = Word Repetition; RP = Rhyme Production; SP = Spelling; US = Use in
Sentence; WM = Word Meaning; WW = When/ Where use; N = Noun; V = Verb; A =
Adjective/Adverb; T = Total
*p<.05, **p<.01
Standardised Outcome Measures
At pre-intervention testing, Danni’s scores on the standardised oral and word reading
vocabulary knowledge tasks continued to be below average and her reading comprehension
on the YARC-P weak (see Table 5). At post-intervention testing, Danni’s scores had crossed
a clinical boundary into the low average range (Standard Score >85) on both standardised
outcome measures. Minimal further gains were evident on the WRMT-III Word
Comprehension task at follow-up 6 months later, and there was no progress on the CELF-4
Word Definitions. Further gains were evident on the YARC-P, however, with Danni’s
standard score now having moved further into the average range. This improvement is
considered clinically significant as it represents a gain of ≥1SD from pre-intervention. She
was also able to answer two of the four vocabulary dependent questions correctly at this time
having not answered any correctly at previous test times.
Table 3
Oral and Reading Vocabulary, and Reading Comprehension Outcome Measures
Measure
Pre
Post
Follow-Up
WRMT Word Comp a
85
90
92
CELF-4 Definitions b
7
6
YARC Comp a
76
86
95
Note. a = Standard Score; b = Scaled Score
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Discussion
This single case study sought to explore whether a pilot of a novel vocabulary
intervention, focused on active exploration of the meaning and semantic organisation of
words, was effective in improving word knowledge in a poor comprehender. Consistent with
the profile of poor comprehenders, Danni did not have difficulty with the phonological
subtasks on the WKP at any time point, reflecting a strength in encoding and laying down
phonological representations. As expected, based on her results on the background
assessment, her knowledge was much weaker on the semantic subtasks on the WKP prior to
the intervention (Time1). The finding of significant improvements on these semantic subtasks
post-intervention (Time2) for treated words, along with significant gains in word knowledge,
provides further support, albeit small, for previous research showing intervention can be
effective in improving vocabulary on bespoke measures for children with reading difficulties
(Clarke et al., 2010; Elleman et al., 2009; Wright & Cervetti, 2017). Additionally, this finding
supports that improvement can be made with a relatively small amount of instruction, as per
Wright and Cervetti (2017). Further, this case study provides evidence that these gains can be
maintained over time (Time3), although the gains on the Use in Sentences and Word
Meaning subtasks were no longer significant at Time3. Another feature of this study is that it
provides evidence that improvement can transfer to untreated words. Clarke et al. (2010)
found a small but significant improvement, compared with controls, on untreated words for
their oral language group post-intervention, while in this case study such gains were not
evident across subtasks and word knowledge ratings until 6 months after intervention at
Time3 follow-up. This delayed effect suggests that Danni may have needed time to apply
word learning strategies to deepen her knowledge of words that were not directly taught.
In contrast with the significant gains on the bespoke vocabulary measure,
improvement on the standardised vocabulary measures was more limited. Danni’s score on
the standardised reading-input outcome measure (WRMT-III Word Comprehension) crossed
a clinical boundary into the average range after intervention but had made minimal
improvement 6 months later at follow-up, and there was no improvement on the CELF-4
Word Definitions task. While the meta-analysis by Elleman et al. (2009) found evidence of
improvement on standardised vocabulary measures following intervention, Clarke et al.
(2010) only identified a significant improvement for the oral language group after
intervention, but this gain was not significantly different from pre-intervention levels at
follow-up 11 months later. These results support the recommendation of the NRP (2000), that
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non-standardised assessment instruments matched to instruction are needed for efficacy of
instruction to be measured.
The second aim of this case study was to investigate generalisation of any therapy
gains to reading comprehension. Consistent with Clarke et al. (2010), but contrary to most
other studies investigating the impact of vocabulary instruction on standardised reading
comprehension measures, Danni had crossed a clinical boundary into the average range on
the reading comprehension outcome measure (YARC-P) following intervention. Her reading
comprehension then improved further at follow-up, and this gain from prior to intervention
was considered clinically significant. Analysis of the question types on the YARC-P also
revealed that she was able to answer vocabulary dependent questions at follow-up, which she
had not been able to do previously.
Limitations and Future Directions
Given the exploratory nature of this novel intervention with a single participant,
further research is required to replicate the methods and examine outcomes with a larger
sample to overcome the subjectivity of the word selection and word knowledge ratings from a
single participant. Additionally, the study would be strengthened by (1) presenting the words
in the context of the passage rather than only a sentence, (2) ensuring home tasks are
completed consistently between sessions and measuring time spent on home practice, and (3)
readministering the comprehension passages from KEY into inference/evaluation, despite the
questions on these tasks being designed to test inference-making rather than vocabulary
knowledge. Finally, further rigour would be introduced through blinded pre-post assessment,
a feature that could not be addressed in the current study.
Clinical Implications
Implications for practice that arise from this case study include the need for SLPs to
be aware that, as previously identified (Elleman et al., 2009; NRP: NICHD, 2000), bespoke
measures are likely to be required to measure change following vocabulary intervention.
Standardised measures can be useful in identifying children with poor vocabulary and for
measuring growth in vocabulary over time but, typically, are not sensitive enough to measure
proximal outcomes resulting from intervention. Most research exploring the effect of
vocabulary intervention on reading comprehension has found that gains are made on custom
measures containing target words, but this improvement does not transfer to standardised
measures. The results for poor comprehenders from Clarke et al. (2010) and this case study
show a greater level of support for the benefits of vocabulary intervention for children with
14
weak reading comprehension (Duff, 2019; Elleman at al., 2009). SLPs need to remain aware,
however, that while vocabulary is important, reading comprehension is complex, such that
intervention is likely to need to go beyond improving depth of vocabulary to ensure lasting
improvements in reading comprehension. The procedure developed for this intervention
provides a framework that SLPs could adapt for use with a wider range of children. While the
words used in the case study were specific to Danni, vocabulary and texts could be tailored to
different learning situations.
2
2
The programme template will be made available during 2022 via the LaLYP website:
https://www.languageandliteracyinyoungpeople.com
15
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