Helping older students with DLD gain language skills

12.png

Most research on language treatment looks at younger children, but we know that kids with developmental language disorder (DLD) are likely to struggle with oral language skills in middle school and beyond. This study looked at the effectiveness of narrative and vocabulary treatment for older students with DLD. 

Researchers assigned 12-year-olds (year 7 students in the UK) to one of four groups: narrative treatment, vocabulary treatment, both narrative and vocabulary treatment, or a wait-listed control group. Teaching assistants (similar to paraprofessionals in the US) led treatment sessions with small groups of 2–6 students. Sessions lasted 45–60 minutes and took place 3 times a week for 6 weeks. The assistants used lessons from commercially available narrative and vocabulary treatment programs. Narrative lessons focused on story structure, comprehension, and generation; vocabulary lessons focused on educationally-relevant words taught through categorization, mind-mapping, and word association tasks.

After the six weeks, students in all 3 treatment groups improved on standardized tests of narrative skill, and students in the narrative and combined groups improved on some of the study narrative measures. There was no difference among the groups on standardized vocabulary tests, but on researcher-developed assessments similar to the treatment activities, vocabulary skills improved with intervention too.

These findings suggest that a short period of group treatment delivered by teaching assistants has the potential to improve language skills in older children with DLD. This is a big deal because we don’t have a lot of well-designed studies showing that language therapy actually works for older kids. Even better? The intervention model used here (treatment delivered to groups by paraprofessionals) should be feasible for most school settings.

 

Joffe, V. L., Rixon, L., & Hulme, C. (2019). Improving storytelling and vocabulary in secondary school students with language disorder: A randomized controlled trial. International Journal of Language and Communication Disorders. doi:10.1111/1460-6984.12471

Girls vs. Boys: Communication differences in autism

16.png

If you work with students with autism, chances are you’ve noticed some communication differences between the boys and girls on your caseload. But how do you quantify these differences? Do they impact treatment? Are they even real?

We’ve touched on this topic before, but there isn’t loads of research on it at the moment. This preliminary study by Sturrock et al. takes a deeper dive into examining the language and communication profiles of females and males with autism.

The study explored the language and communication skills of 9–10-year-old children with ASD and IQ scores in the average range*, compared to age and gender matched peers with typical development (TD). Within both groups, female and male performance were examined separately. Note that each of the four groups was relatively small (13 children per group). Overall, though, they found some surprising (and not so surprising) differences among the groups.

The ASD group as a whole scored about the same as the TD group on measures of expressive and receptive language. However, the authors did see a subtle deficit in the ASD group when it came to narrative language tasks (an issue we’ve discussed before).

But what about those gender-related differences? Well, it turns out that within the ASD group, females outperformed males in pragmatic language and semantic language tasks. However, females with ASD still lagged behind matched females with TD. Another interesting difference? Girls in general consistently scored better than boys on “language of emotion” tasks (like listing as many feeling/emotion words as possible in one minute).

So what we do with these preliminary findings? Primarily, this study can help you consider potential areas of strength and weakness to look out for during evaluation and treatment of children with ASD. Additionally, the authors make the case that by increasing our awareness of the female ASD profile, a historically under-diagnosed and misdiagnosed condition, we may be able to help these girls get identified and get access to services sooner rather than later.

*The authors refer to this as High-Functioning Autism.

 

Sturrock, A., Yau, N., Freed, J., Adams, C. Speaking the same language? A preliminary investigation comparing the language and communication skills of females and males with High-Functioning Autism. Journal of Autism and Developmental Disorders. doi: 10.1007/s10803-019-03920-6.

An incredible inference intervention for children with DLD

So much of story comprehension depends on inferencing, or making assumptions and connections beyond what’s stated in a story. We know that children with developmental language disorder (DLD) struggle with inferencing, but we don’t have (much) good evidence for treatments to target it. Until now, that is—Dawes et al. are here to help with a fabulous, free, feasible treatment for inferential comprehension.

The researchers randomly assigned 5- to 6-year-olds with DLD to an inferential comprehension treatment condition or to a control phonological awareness treatment condition. Both groups attended 30-minute small-group treatment sessions twice a week for 8 weeks. The inferential comprehension treatment used strategies including narrative retell, dialogic reading, think-alouds, and graphic organizers (see Table 2 for full list). And, great news—the activities for all four books used in the intervention are available for free! 

8.png

Children’s inferential comprehension ability was tested before, immediately after, and 8 weeks after the treatment using different stories. (The assessments are ALSO freely available, because these researchers are amazing.) Children in the treatment group improved significantly more than the control group on inferential comprehension measures and maintained their improvement after 8 weeks. This is about as good as it gets—a scripted, free program that you can deliver in groups with strong evidence for improvement after a short period of treatment.

For more info about profiles of children who struggle with inferential comprehension, see this article by the same researchers.

 

Dawes, E., Leitão, S., Claessen, M., & Kane, R. (2018). A randomized controlled trial of an oral inferential comprehension intervention for young children with developmental language disorder. Child Language Teaching and Therapy. Advance online publication. doi: 10.1177/0265659018815736

And more...

Chester et al. enrolled school-aged children with ASD in group social skills training that included play (unstructured or semi-structured) for 8 weeks. They found that participants gained social skills (as rated by parents, teachers, and the children themselves) compared to waiting controls.  

Conlon et al. looked at narratives (via the ERNNI) produced by 8-year-old boys and girls with ASD and average nonverbal intelligence. While we know that children with ASD often struggle with narratives in general, there may be important gender-related differences. This study found that girls’ stories were more complete, included more information about characters’ intentions, and were easier to follow (i.e. they had better referencing).

Joseph used word boxes (a low-tech method using drawn rectangles and letter tiles) to teach sound segmentation, word identification, and spelling skills to three third graders with autism, and found that all children improved on sound segmentation and word ID and two children improved on spelling. 

Montallana et al. studied inter-rater reliability of the VB-MAPP Milestones and Barriers assessments. The VB-MAPP is commonly used to assess and plan intervention for children with ASD, but we haven’t known much about its psychometrics. While the milestones section had largely moderate to good reliability, agreement between raters on barriers was poor to moderate.  

Thirumanickam et al. found that a video-based modeling intervention was effective in increasing conversational turn-taking in a small number of adolescents with ASD who used AAC—BUT, only when provided with additional instruction (least-to-most prompting). They stated that for students with ASD, some level of prompting is likely required to engage in video-based interventions.

 

Chester, M., Richdale, A. L., & McGillivray, J. (2019). Group-Based Social Skills Training with Play for Children on the Autism Spectrum. Journal of Autism and Developmental Disorders. Advance online publication. doi:10.1007/s10803-019-03892-7

Conlon, O., Volden, J., Smith, I. M., Duku, E., Zwaigenbaum, L., Waddell, C., … Pathways in ASD Study Team. (2019). Gender Differences in Pragmatic Communication in School-Aged Children with Autism Spectrum Disorder (ASD). Journal of Autism and Developmental Disorders. Advance online publication. doi:10.1007/s10803-018-03873-2

Joseph, L. M. (2018). Effects of word boxes on phoneme segmentation, word identification, and spelling for a sample of children with autism. Child Language Teaching and Therapy34(3), 303–317.

Montallana, K. L., Gard, B. M., Lotfizadeh, A. D., & Poling, A. (2019). Inter-Rater Agreement for the Milestones and Barriers Assessments of the Verbal Behavior Milestones Assessment and Placement Program (VB-MAPP). Journal of Autism and Developmental Disorders. Advance online publication. doi:10.1007/s10803-019-03879-4

Thirumanickam, A., Raghavendra, P., McMillan, J. M., & van Steenbrugge, W. (2018). Effectiveness of video-based modelling to facilitate conversational turn taking of adolescents with autism spectrum disorder who use AAC. Augmentative and Alternative Communication, 34(4), 311–322.

Assessing language with diverse preschoolers? Go for dynamic assessment

2.png

Making the right call when assessing language skills of children with cultural or language backgrounds that don’t match our own is hard. Using our go-to assessment methods, we risk labeling normal language variation as signs of a disorder. Standardized test norms may over-identify children from non-mainstream language backgrounds as having language impairment.  

Enter dynamic assessment, which involves testing a child, providing teaching and support, and then retesting to see what the child can do with help. In a new study, Henderson et al. used dynamic assessment to assess language skills of Navajo preschoolers with narrative retell tasks from the Predictive Early Assessment of Reading and Language (PEARL, from the same acronym aficionados that brought us the DYMOND).

Dynamic assessment takes longer than static (one-time) assessment. The PEARL accounts for this—you give the pretest, look at the score, and then administer the teaching and retest only if it’s below a cutoff. Henderson et al. found that the reported cutoff score for the PEARL pretest didn’t work well for Navajo children; sensitivity and specificity were better with a cutoff score of 7 rather than 9. Looking at the whole test, scores on the retest (following teaching) were even better at diagnosing children, and examiners’ “modifiability” ratings (how the child responded to teaching) diagnosed children with 100% accuracy. These findings suggest that the PEARL is a valid test for assessing language in children from non-mainstream language or cultural backgrounds.   

 

Henderson, D. E., Restrepo, M. A., & Aiken, L. S. (2018). Dynamic assessment of narratives among Navajo preschoolers. Journal of Speech, Language, and Hearing Research, 61(10), 2547–2560.

Shared reading strategies to boost comprehension in children with ASD

rts.png

Reading comprehension can be a major challenge for kids with ASD, especially when we’re talking about narratives. Narratives require readers to take on a character’s perspective in order to understand the story–which isn’t easy for kids who have impairments in social interaction and communication (Hello, ASD).

One way that we often help students understand stories is through shared reading—you know, sitting with the student, defining words, asking questions, etc. Sometimes this works well, and sometimes you probably feel like you could use some guidance on how to really help the student. 

This study does just that. The authors designed a shared reading intervention and implemented a set of strategies BEFORE, DURING, and AFTER reading narrative stories (shown below) with three elementary-aged students with ASD.

aehr.png

Note that the WH- questions were aimed at getting the students to think about the characters’ narratives and how the characters felt (e.g., “No one wanted to join her team. How did Olivia feel?”). The interventionists also provided examples that were associated with the questions (e.g., “When do you feel lonely? I feel lonely when I am eating a large pizza alone.”). When the students had difficulty answering the WH- questions, they were told to focus on the highlighted key words.  

After just 6–7 sessions of intervention, all three students improved their reading comprehension scores by answering 100% of the comprehension questions correctly (from 24%). You might be thinking: That’s a lot to do in one session. How can I possibly keep students engaged? And implementing the strategies did add 20 minutes onto sessions; however, the authors found that the students either showed similar or better engagement during intervention.

If shared reading is something you often do with your students, you may want to take a closer look at this study. Since the intervention had multiple components, the authors point out that educators may select specific strategies to suit their needs (not without caution—we have to remember that students benefitted from the whole intervention package).

 

Kim, S. Y., Rispoli, M., Lory, C., Gregori, E., & Brodhead, M. T. (2018). The effects of a shared reading intervention on narrative story comprehension and task engagement of students with Autism Spectrum Disorder. Journal of Autism and Developmental Disorders, 48(10), 3608–3622.

Throwback (2015): How and when do kids learn to make inferences?

Making an inference is a pretty involved process, cognitively speaking. It requires a person to tap into language and memory skills and tie a bunch of elements together to make a reasonable guess as to what is going to happen next, or how someone is feeling, or suggest a solution to a problem. No wonder it’s a tough skill to master! 

These authors combed the literature to help us better understand the developmental trajectory of inferencing skills. As clinicians, it’s important for us to know how typical children develop skills so we know how our students compare (and what we need to address). This paper is a scoping review, which means that the authors did an extensive search of the literature looking for patterns. They specifically focused on causal inferences within story grammar, since researchers often use dialogic reading to study how children infer, and story grammar follows a causal chain (This happened, so this happened, so she felt this way, so she did this). For the super rigid EBPers out there, brace yourselves: no stats in this one. But what this study does offer is a great summary on what we know about inferencing skills in typically developing children.  

Check out the full paper for more details (especially tables 4 & 5), but here’s the part you’ll want to flag for later—the authors highlight 6 types of causal inferences in story grammar, and discuss the order in which they develop:

2.png

 The authors also offer thoughts on how to assess and target children’s inferential comprehension during reading:

  • Use both auditory and visual modalities

  • Ask inferential questions while reading, since asking them afterwards requires memory skills

  • Consider grading answers on a scale, rather than +/- (see here or here), or using the think-aloud protocol.

This is a great paper to add to your file—we bet you’ll find yourself reaching for it during an upcoming assessment, or whenever you need a refresher or some inspiration on how to look at inferences!

Filiatrault-Veilleux, P., Bouchard, C., Trudeau, N., & Desmarais, C. (2015). Inferential comprehension of 3-6 year olds within the context of story grammar: A scoping review. International Journal of Language & Communication Disorders, 50(6), 737–749.

And more...

Brinton et al. found that five elementary-age children with DLD rarely described characters’ mental states (responses, plans, emotions) when generating stories and struggled to answer direct questions about characters’ mental states. The authors suggest that children with DLD may have difficulty with social and emotional concepts. 

Chenausky et al. found that baseline phonetic inventory and ADOS scores were most predictive of speech target approximations post-speech therapy in minimally verbal children with autism (more than IQ, language, age). And that’s not terribly surprising (except the age part—cool that they made good speech gains in older elementary children!). Perhaps the more interesting thing about this study, though, is what they did in speech therapy. It’s called “auditory motor map training”, and is basically the addition of rhythm (tapping drums) and intonation (singing the speech targets) to speech therapy. The researchers are finding that adding these tactile and auditory cues is better than not having them; so worth trying! 

Cooke and Millard asked school-aged children who stutter what they considered to be the most important therapy outcomes. The children reported increased fluency, independence, and confidence, as well as others knowing how to support them and how to make communication situations feel easier. This study serves as a good reminder that stuttering is more than dysfluent speech. The cognitive (thoughts and attitudes) and affective (feelings) components should also play a role in how we evaluate therapy outcomes.  

Dyson et al. taught 20 vocabulary words to elementary-age children with low vocabulary scores using examples, games, and worksheets. After 10 weeks of 20-minute small-group sessions, children learned five new words on average; significantly more than children in a control group. (Email the authors for free materials!)

Giusto and Ehri found that third-graders with poor decoding and average listening comprehension benefitted from a partial-read aloud test accommodation with pacing (PRAP). When examiners read aloud only directions, proper nouns, and multiple choice questions, the students improved their reading comprehension of the test passages. Although you may not be directly assessing these students, these findings may be helpful if you’re ever in the position to recommend accommodations for this subset of children.

Gough Kenyon et al. found that, compared to typical peers, 10- to 11-year-olds with developmental language disorder (DLD) struggled with making elaborative inferences (drawing on background knowledge not stated) but not cohesive inferences (linking information given) after reading a passage. They suggest targeting elaborative inferencing to boost reading comprehension for children with DLD.

Millard et al. add to the evidence base for Palin Parent–Child Interaction Therapy for young children who stutter, finding a reduction in stuttering severity and improvements in both parent and child attitudes and confidence following a year of participation in the program.

Sabri & Fabiano-Smith analyzed a case study and found that, given early implantation and support in both languages, a bilingual child with cochlear implants can acquire two phonological systems, although likely at a slower rate than other bilingual children.

Using (and maybe struggling with) the Lidcombe Program with your young clients who stutter? Van Eerdenbrugh et al. studied the challenges clinicians have with implementing the program and surveyed experts to come up with solutions.

 

Brinton, B., Fujiki, M., & Asai, N. (2018). The ability of five children with developmental language disorder to describe mental states in stories. Communication Disorders Quarterly. Advance online publication. doi: 10.1177/1525740118779767.

Chenausky, K., Norton, A., Tager-Flusberg, H., & Schlaug, G. (2018). Behavioral predictors of improved speech output in minimally verbal children with autism. Autism Research. Advance Online Publication. doi: 10.1002/aur.2006.

Cooke, K., & Millard, S. K. (2018). The most important therapy outcomes for school-aged children who stutter: An exploratory study. American Journal of Speech-Language Pathology, 27(3S), 1152.

Dyson, H. , Solity, J. , Best, W. and Hulme, C. (2018), Effectiveness of a small‐group vocabulary intervention programme: evidence from a regression discontinuity design. International Journal of Language & Communication Disorders, 53: 947-958. doi:10.1111/1460-6984.12404

Giusto, M., & Ehri, L. C. (2018). Effectiveness of a partial read-aloud test accommodation to assess reading comprehension in students with a reading disability. Journal of Learning Disabilities. Advance online publication. doi:10.1177/0022219418789377

Gough Kenyon, S. M., Palikara, O., & Lucas, R. M. (2018). Explaining reading comprehension in children with developmental language disorder: The importance of elaborative inferencing. Journal of Speech, Language, and Hearing Research, 61(10), 2517–2531. 

Millard, S. K., Zebrowski, P., & Kelman, E. (2018). Palin Parent–Child Interaction Therapy: The Bigger Picture. American Journal of Speech–Language Pathology, 27(3S), 1211–1223.

Sabri, M. & Fabiano-Smith, L. (2018). Phonological Development in a Bilingual Arabic–English-Speaking Child With Bilateral Cochlear Implants: A Longitudinal Case Study. American Journal of Speech–Language Pathology. Advance online publication. doi: 10.1044/2018_AJSLP-17-0162.

Van Eerdenbrugh, S., Packman, A., O'Brian, S., & Onslow, M. (2018). Challenges and Strategies for Speech-Language Pathologists Using the Lidcombe Program for Early Stuttering. American Journal of Speech–Language Pathology, 27(3S), 1259–1272.

And more...

In case you were wondering, the theme of the month is: OMG how were there so many studies published this month?!

  • In a study of over 1200 families in poor rural regions, Burchinal et al. confirmed the presence of a large gap in school readiness skills among low SES children that emerges during the first five years of life. Specifically, children who experienced poverty before the age of two had more significant delays on their language, cognitive, social, and executive functioning skills by 2–3 years of age. Self-regulation and executive functioning skills played an important role in school readiness at age 5. Check out the original article for a more in-depth analysis of the relationship between poverty & school readiness.

  • Byrd et al. found that a 5-day intensive camp program that focused on social-emotional topics and desensitization toward stuttering (and NOT on increasing fluency), improved the attitudes of school-age children who stutter toward communication and their perceived ability to make friends.

  • Diepeveen et al. provided data to support the growing body of evidence that suggests that children with DLD (and cognitive scores within normal limits, so SLI) also frequently exhibit motor deficits. The motor skills of two groups of 253 four-to-eleven-year-olds—half with, and half without SLI—were evaluated. Results suggested that the SLI group demonstrated delays in three of the seven motor milestones, with particular deficits noted in fine motor development.

  • Denmark et al. found that deaf children with ASD produced fewer facial actions (such as widening eyes or furrowing/raising eyebrows intensely) needed to produce emotion signs like “demand” and “mischief” when retelling a story, compared to their typically-developing deaf peers. The study addresses the research gap related to how emotion processing and theory of mind affect this population’s ability to use facial actions when signing. 

  • Finestack & Satterlund surveyed over 300 pediatric SLPs about their typical grammar interventions. SLPs reported using evidence-based procedures such as modeling, recasting, requesting imitation, and explicit instruction. Their progress monitoring was evidence based as well, consisting of observation and language sampling. Many SLPs reported using TTR (type-token ratio) to measure progress, which is not evidence based and has been found to be ineffective. More research is needed to determine which goal attack strategies (the sequence in which you address goals) are evidence-based.

  • Lim and Charlop found that speaking a child’s heritage language during play-based intervention sessions seemed to help four bilingual children with ASD play in more functional and interactive ways. The experimenters followed scripts for giving play instructions, verbal praise, and making comments related to play in both English and each child’s heritage language (in this study, Korean or Spanish). None of the children played functionally or interactively before the intervention, but all of the children showed an increase in play during and after intervention sessions in both English and the heritage language, with more impressive gains seen in heritage language sessions. More research is needed, but SLPs should keep this in mind when working with bilingual children with ASD. 

  • If you’ve been wondering if standardized language assessments would ever transition to iPads, we may be heading that way. Marble-Flint et al. found that for children with ASD, there was no significant difference in performance between iPad and typical paper tests for the PPVT. This was true as long as the iPad format did not have any interactive features (sounds effects, visuals). 

  • Children who receive cochlear implants (CIs) often have morphosyntactic and vocabulary skills are somewhat delayed, but their phonological awareness skills are often significantly delayed. In a longitudinal study, Nittrouer et al. found that this pattern persists until at least 6th grade. Two intervention methods significantly predicted better language outcomes: bimodal stimulation and literacy acquisition/instruction.  

  • Swaminathan & Farquharson asked 575 school-based SLPs whether they used an RTI (“Response to Intervention”) model with children with speech sounds disorders (SSD). SLPs with smaller caseloads were more likely to use RTI, even though those with larger caseloads could potentially benefit the most from the model. They also found a lot of inconsistency in how RTI was interpreted and used. If you’re questioning using this model, the article does a nice job of RTI applied to SSD! 

  • van den Bedem et al. found that children with developmental language disorder are at high risk for depressive symptoms. The worse the child’s communication skills, the more inclined the child was to use maladaptive strategies. On a positive note, children with DLD respond just as well to emotion regulation strategies as children without DLD. Learning and utilizing adaptive emotion regulation strategies with our kids with DLD could help them cope with their everyday stress.

  • Vessoyan et al. analyzed case studies of four girls with Rett Syndrome (9–15 years old) who used eye-tracking technology to communicate. In all cases, the technology (with ongoing support) helped the girls work toward their individual communication goals, and parents reported both psychosocial benefits and satisfaction with the technology and services.

  • Werfel found that preschoolers with hearing loss 1) had lower MLUm and 2) were less accurate in using Brown’s morphemes when compared to age-matched peers with normal hearing. The author suggests monitoring the morphosyntax development of preschool children with hearing loss.

  

Burchinal, M., Carr, R.C., Vernon-Feagans, L.V., Blair, C., Cox, M. (2018). Depth, persistence, and timing of poverty and the development of school readiness skills in rural low-income regions: Results from the family life project. Early Childhood Research Quarterly, 45, 115–130.

Byrd, C. T., Gkalitsiou, Z., Werle, D., & Coalson, G. A. (2018). Exploring the Effectiveness of an Intensive Treatment Program for School-Age Children Who Stutter, Camp Dream. Speak. Live.: A Follow-up Study. Seminars in Speech and Language. Advance online publication. doi: 10.1055/s-0038-1670669

Diepeveen, F. B., van Dommelen, P., Oudesluys-Murphy, A., & Verkerk, P. (2018). Children with specific language impairment are more likely to reach motor milestones late. Child: Care, Health, and Development, 44(6), 857–862. 

Denmark, T., Atkinson, J., Campbell, R., & Swettenham, J. (2018). Signing with the face: Emotional expression in narrative production in deaf children with autism spectrum disorder. Journal of Autism and Developmental Disorders. Advance online publication. doi: 10.1007/s10803-018-3756-x

Finestack, L.H., & Satterlund, K.E. (2018). Current practice of child grammar intervention: A survey of speech-language pathologists. American Journal of Speech-Language Pathology. Advance online publication. doi: 10.1044/2018_AJSLP-17-0168

Lim, N. & Charlop, M. H. (2018). Effects of English versus heritage language on play in bilingually exposed children with autism spectrum disorder. Behavioral Interventions. Advance online publication. doi: 10.1002/bin.1644

Marble-Flint, K.J., Strattman, K.H., & Schommer-Aikins, M.A. (2018). Comparing iPad and paper assessments for children with ASD: An initial study. Communication Disorders Quarterly. Advance online publication. doi: 10.3109/07434618.2011.644579.

Nittrouer, S., Miur, M., Tietgens, K., Moberly, A.C., & Lowenstein, J.H. (2018). Development of phonological, lexical, and syntactic abilities in children with cochlear implants across the elementary grades. Journal of Speech, Language, and Hearing Research. Advance online publication. doi: 10.1044/2018_JSLHR-H-18-0047.

Swaminathan, D., & Farquharson, K. (2018). Using Response to Intervention for Speech Sound Disorders: Exploring Practice Characteristics and Geographical Differences. Perspectives of the ASHA Special Interest Groups, 3(SIG 16), 53–66.

van den Bedem, N. P., Dockrell, J.E., van Alphen, P.M., de Rooji, M., Samson, A.C., Harjunen, E.L., & Rieffe, C. (2018). Depressive symptoms and emotion regulation strategies in children with and without developmental language disorder: a longitudinal study. International Journal of Language & Communication Disorders. Advance online publication. doi: 10.1111/1460-6984.12423.

Vessoyan, K., Steckle, G., Easton, B., Nichols, M., Mok Siu, V., & McDougall, J. (2018). Using eye-tracking technology for communication in Rett syndrome: perceptions of impact. Augmentative and Alternative Communication. Advance online publication. doi: 10.1080/07434618.2018.1462848.

Werfel, K. L. (2018). Morphosyntax production of preschool children with hearing loss: An evaluation of the extended optional infinitive and surface accounts. Journal of Speech, Language, and Hearing Research, 61, 2313–2324.