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JCPSLP Volume 15, Number 1 2013 11
The negative changes observed in DSS change scores
for preschoolers in the waitlist control group on average
were indicative of unsuccessful attempts at creating
grammatically complex and correct productions and not
a regression in these skills. An examination of the per
cent error rates revealed that these children attempted
to produce accurate and complex personal pronouns,
main verbs and achieve the sentence points, but were
unsuccessful in these attempts, resulting in the higher
per cent error rates compared to cohorts in intervention.
Lee (1974) and Lee and Canter (1971) suggested that as
children‘s language skills develop, unsuccessful attempts
at more complex productions in spontaneous language
are expected. Thus, errors in syntactic productions are
a normal part of grammatical development for young
children with typically developing language skills. In fact for
5-year-olds, a 0.12-point decline in DSS scores at the 50th
percentile is expected in 6 months. Since these errors are
anticipated for typical preschoolers, errors for preschoolers
who do not have typical language skills and are not
receiving intervention would not be unexpected.
Clinical implications
The current findings expand on those reported in the
Washington et al. (2011) study by providing evidence that
grammatical language interventions were associated with
accelerated growth to “within normal limits” for grammar
development. The inclusion of computer-assisted and
table-top intervention techniques, including specific
step-by-step procedures, may be important in achieving
this growth during SLP-led interventions for this population.
Alternatively, preschoolers with SLI who do not receive
intervention are at a significantly greater risk for not
achieving good outcomes.
Limitations and future directions
Participants included in this study demonstrated specific
expressive grammar deficits, thus application of these
findings to other preschoolers with SLI with receptive
difficulties is limited. The mixed evidence regarding the
effectiveness of expressive grammar intervention for
children with concomitant receptive and expressive
grammatical deficits (cf. Law et al., 2012) suggests
additional research is needed.
Another limitation is that DSS techniques are time
consuming and scores are narrower in their representation
of language skills (Lee & Canter, 1971). The inclusion of
MLU in this study offered another measure of linguistic
gains that might not have been captured in DSS scores.
Future research with other children with SLI with receptive
language deficits should expand the measures used to
establish acceleration in expressive grammar and perhaps
also consider sampling beyond a clinical conversation with
an adult.
Conclusion
Expressive grammar intervention offers a therapeutic
advantage over no intervention for the enhanced
development of spontaneous language skills in
preschoolers with expressive language impairment.
Acknowledgments
The authors would like to thank the families, children,
speech-language pathologists, graduate SLP students and
research assistants who made this research possible. This
study was funded by the Canadian Language and Literacy
Research Network, the Ontario Graduate Scholarship, the
at the pre-set adjusted alpha level (p < .017) were
conducted. There was a significant interaction effect for
group X time for DSS per cent error rates for, personal
pronoun, F (4,62) = 7.05, p < .001, Np
2 = .31, main verb,
F(4,62) = 7.44, p < .001, Np
2 = .32 and sentence point,
F(4,62) = 8.08, p < .001, Np
2 = .34.
Simple main effect tests were completed as a follow-up
to the significant interaction for each ANOVA. Findings for
DSS per cent error rates in each grammatical category met
the set significance level (p < .006) for follow-up tests at
post-intervention and 3 months post-intervention. Pairwise
comparisons of means revealed that computer-assisted
and table-top intervention facilitated significantly lower
DSS per cent error rates in each category compared to
no-intervention. The two intervention groups did not differ
statistically (p > .05). See Figure 3.
Discussion
Preschoolers with SLI who received expressive grammar
intervention experienced significantly greater improvement
in their grammar skills that were maintained at post-
intervention and at 3 months post-intervention compared to
waitlist controls. Maintenance of gains beyond the
intervention period is considered an important intervention
outcome indicative of development (Yoder et al., 2011). The
magnitude of gain in 6 months as a result of expressive
grammar intervention was above that expected for typically
developing 4-year-olds at the 50th percentile,
demonstrating significant accelerated growth beyond the
starting point in intervention. Thus, intervention offered a
therapeutic advantage over no intervention for facilitating
the outcomes observed for grammatical complexity, use of
morphemes, and accuracy in targeted grammatical
categories. However, computer-assisted and table-top
intervention resulted in similar effects on the spontaneous
use of expressive grammar skills. Consequently, it is
important to consider the role of expressive grammar
intervention, regardless of type, for facilitating growth in
these skills.
The goals of language intervention for grammatical
deficits are to improve children’s production and
comprehension of targeted language forms (Leonard et
al., 2006). By directly targeting children’s grammatical
use of language forms, they become more aware of how
to accurately sequence morphemes and phonemes
into meaningful units. The explicit support and attention
to grammatical features included in intervention may
provide more time to process information and increase
preschoolers’ awareness and decrease language-learning
efforts during expressive grammar intervention.
During computer-assisted and table-top intervention,
the SLP made deliberate attempts to highlight sentence
components needed to produce grammatically correct
sentences. The syntactic slot-filler approach and
emphatic stress were equally effective in highlighting these
components for the sample of preschoolers. Implementing
these techniques in a drill-play format with modelling and
repetition resulted in multiple opportunities for focused
practice (3000 production opportunities for the two
interventions). Previous researchers highlight the necessity
of explicit, repeated exposures to target forms that address
grammatical productions for this population (Cleave &
Rice, 1997). Computer-assisted intervention may provide
motivation and increased tolerance for repetition in some
preschoolers with SLI and should be considered a viable
alternative to table-top intervention, where appropriate (cf.
Washington et al., 2011).