Leah Kapa

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Scholarly Contributions

Chapters

• Colombo, J., Kapa, L. L., & Curtindale, L. M. (2011). Varieties of Attention in Infancy. In Infant Perception and Cognition: Recent Advances, Emerging Theories, and Future Directions. Oxford University Press. doi:10.1093/ACPROF:OSO/9780195366709.003.0001

Journals/Publications

• Kapa, L. L. (2021). Improving Dimensional Change Card Sort Performance of Preschoolers With Developmental Language Disorder: Effects of Two Task Variations.. Journal of speech, language, and hearing research : JSLHR, 64(2), 628-634. doi:10.1044/2020_jslhr-20-00382
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  Purpose This research note addresses whether task administration variations can improve Dimensional Change Card Sort (DCCS) performance in preschoolers with developmental language disorder (DLD). Method Participants included preschoolers with DLD who failed the standard DCCS, which is characterized by inability to switch from one card sorting rule to a new rule. After an approximately 2.5-month delay, participants were retested on the DCCS in one of three conditions: repeating standard administration, participants labeling relevant card dimensions, or briefly removing target cards before the switch. Results Children in both the labeling and target removal conditions scored significantly higher on the second administration relative to the first. However, comparing across conditions, participants in the target removal condition scored higher on the second DCCS compared to participants in the standard and labeling conditions, which did not differ from each other. Conclusions DCCS performance of preschoolers with DLD can be improved by changing task administration. The most effective change is increasing the salience of the switch to the new sorting rule, as opposed to directing children's attention via their own labeling behavior.
• Kapa, L., & Mettler, H. M. (2021). Language and executive function in preschoolers with DLD: The role of self-directed speech. Perspectives of the ASHA Special Interest Groups, 6, 1315-1326.
• Mettler, H. M., & Kapa, L. L. (2021). Language and Executive Function in Preschoolers With Developmental Language Disorder: The Role of Self-Directed Speech. Perspectives of the ASHA Special Interest Groups, 6(6), 1315-1326. doi:10.1044/2021_persp-21-00010
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  Purpose: Our goal was to examine the relationship between language and executive function in children with specific language impairment (SLI) and/or developmental language disorder (DLD) with a specific focus on how language in the form of self-directed speech (SDS) affects executive functioning in this population. Method: Participants included thirty-one 4- and 5-year-old children with DLD. Children completed a visual, computer-based continuous performance task (CPT) that tapped their sustained selective attention. SDS children produced during this task was coded off-line for intelligibility, task relevancy, and whether it was regulatory. Regression analyses were used to characterize the relationship between children's performance on the CPT and their SDS. Results: The majority of SDS that children produced during the CPT was task relevant and regulatory, but there was individual variability in the total amount of SDS produced. Children's percentage of regulatory SDS was a significant predictor of their CPT performance. Conclusions: Because SDS is positively associated with executive function performance but has delayed development among children with SLI and/or DLD, clinicians have an opportunity to support SDS development in children. We discuss specific approaches and clinical activities for supporting SDS development in early childhood.
• Kapa, L. L., & Erikson, J. A. (2020). The Relationship Between Word Learning and Executive Function in Preschoolers With and Without Developmental Language Disorder. Journal of speech, language, and hearing research : JSLHR, 63(7), 2293-2307.
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  Purpose The purpose of this study was to examine the relationship between executive functioning and word learning among preschoolers with and without developmental language disorder (DLD). Method Forty-one preschool-age children with DLD were matched to typically developing children on age and sex. Participants were exposed to 10 novel pseudowords, half of which referred to familiar objects and half of which referred to unfamiliar objects. Their ability to produce, recognize, and comprehend the novel words was tested, and they completed executive function tasks measuring sustained selective attention, short-term memory, working memory, inhibition, and shifting. Results Preschoolers with DLD performed worse compared to typically developing peers on all measures of executive function and novel word learning. Both groups showed a relative weakness in producing pseudowords that corresponded with familiar objects versus pseudowords for unknown objects. Executive function accounted for statistically significant variance in word learning beyond group membership, with inhibition as a significant predictor of all word learning outcomes and short-term memory as a significant predictor of novel word comprehension. Executive function explained significant variance in novel word production and recognition even after accounting for variance explained by group differences in IQ and receptive vocabulary. Conclusion Findings replicate previous research reporting deficits in word learning and executive function in children with DLD, indicate that preschoolers are disadvantaged in learning new words for familiar objects, and support a relationship between executive function and word learning for children with and without DLD. Future research should examine the directionality of the relationship between these variables.
• Kapa, L. L., Meyers-Denman, C., Plante, E., & Doubleday, K. (2020). Predictors of Treatment Response for Preschool Children With Developmental Language Disorder. American journal of speech-language pathology, 29(4), 2082-2096.
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  Purpose Enhanced Conversational Recast treatment is an effective intervention for remediating expressive grammatical deficits in preschool-age children with developmental language disorder, but not all children respond equally well. In this study, we sought to identify which child-level variables predict response to treatment of morphological deficits. Method Predictor variables of interest, including pre-intervention test scores and target morpheme production, age, and mother's level of education (proxy for socio-economic status) were included in analyses. The sample included 105 children ( = 5;1 [years;months]) with developmental language disorder who participated in 5 weeks of daily Enhanced Conversational Recast treatment. Classification and regression tree analysis was used to identify covariates that predicted children's generalization of their trained grammatical morpheme, as measured by treatment effect size . Results Our analysis indicates that the Structured Photographic Expressive Language Test-Preschool 2 (SPELT-P 2) scores and the Peabody Picture Vocabulary Test-Fourth Edition scores significantly predicted the degree of benefit a child derived from Enhanced Conversational Recast treatment. Specifically, a SPELT-P 2 score above 75 (but still in the impaired range, < 87) combined with a high Peabody Picture Vocabulary Test-Fourth Edition score (> 100) yielded the largest treatment effect size, whereas a SPELT-P 2 score below 75 predicted the smallest treatment effect size. Other variables included in the model did not significantly predict treatment outcomes. Conclusions Understanding individual differences in response to treatment will allow service providers to make evidence-based decisions regarding how likely a child is to benefit from Enhanced Conversational Recast treatment and the expected magnitude of the response based on the child's background characteristics.
• Kapa, L., & Erikson, J. (2019). Variability of Executive Function Performance in Preschoolers with Developmental Language Disorder. Seminars in Speech and Language, 40(4), 243-255. doi:10.1055/s-0039-1692723
• Kapa, L. L., Plante, E., & Doubleday, K. (2017). Applying an Integrative Framework of Executive Function to Preschoolers With Specific Language Impairment. Journal of speech, language, and hearing research : JSLHR, 60(8), 2170-2184.
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  The first goal of this research was to compare verbal and nonverbal executive function abilities between preschoolers with and without specific language impairment (SLI). The second goal was to assess the group differences on 4 executive function components in order to determine if the components may be hierarchically related as suggested within a developmental integrative framework of executive function.
• Kapa, L. L., & Plante, E. (2015). Executive Function in SLI: Recent Advances and Future Directions. Current developmental disorders reports, 2(3), 245-252.
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  This paper provides a review of recent research on executive function abilities in children with specific language impairment (SLI). Across several studies, children with SLI are reported to perform worse than typically developing peers on measures of sustained attention, working memory, inhibition, and attention shifting. However, few studies have considered multiple executive function components simultaneously and even fewer have examined the underlying relationship between executive function deficits and impaired language acquisition. We argue that in order to fully understand the nature of executive function deficits in SLI, the field must move past simply identifying weaknesses to instead test models of executive function development and explore the nature of the relationship between executive function and language. Future research directions are recommended in order to achieve these goals.
• Brady, N. C., Anderson, C. J., Hahn, L. J., Obermeier, S. M., & Kapa, L. L. (2014). Eye tracking as a measure of receptive vocabulary in children with autism spectrum disorders. Augmentative and alternative communication (Baltimore, Md. : 1985), 30(2), 147-59.
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  This study examined the utility of eye tracking research technology to measure speech comprehension in 14 young boys with autism spectrum disorders (ASD) and 15 developmentally matched boys with typical development. Using eye tracking research technology, children were tested on individualized sets of known and unknown words, identified based on their performance on the Peabody Picture Vocabulary Test. Children in both groups spent a significantly longer amount of time looking at the target picture when previous testing indicated the word was known (known condition). Children with ASD spent similar amounts of time looking at the target and non-target pictures when previous testing indicated the word was unknown (unknown condition). However, children with typical development looked longer at the target pictures in the unknown condition as well, potentially suggesting emergent vocabulary knowledge.
• Colombo, J., Zavaleta, N., Kannass, K. N., Lazarte, F., Albornoz, C., Kapa, L. L., & Caulfield, L. E. (2014). Zinc supplementation sustained normative neurodevelopment in a randomized, controlled trial of Peruvian infants aged 6-18 months. The Journal of nutrition, 144(8), 1298-305.
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  A double-blind, randomized clinical trial was conducted to determine the effects of prevention of zinc deficiency on cognitive and sensorimotor development during infancy. At 6 mo of age, infants were randomly assigned to be administered a daily liquid supplement containing 10 mg/d of zinc (zinc sulfate), 10 mg/d of iron (ferrous sulfate), and 0.5 mg/d of copper (copper oxide), or an identical daily liquid supplement containing only 10 mg/d of iron and 0.5 mg/d of copper. Various controls were implemented to ensure adherence to the supplement protocol. A battery of developmental assessments was administered from 6 to 18 mo of age that included a visual habituation/recognition memory task augmented with heart rate at 6, 9, and 12 mo of age; the Bayley Scales of Infant Development, 2nd edition (BSID2) at 6, 12, and 18 mo; the A-not-B error task at 9 and 12 mo; and free-play attention tasks at 12 and 18 mo. Only infants supplemented with zinc had the normative decline in look duration from 6 to 12 mo during habituation and a normative decline in shifting between objects on free-play multiple-object attention tasks from 12 to 18 mo of age. The 2 groups did not differ on any of the psychophysiologic indices, the BSID2, or the A-not-B error task. The findings are consistent with zinc supplementation supporting a profile of normative information processing and active attentional profiles during the first 2 y of life. This trial was registered at clinicaltrials.gov as NCT00589264.
• Kapa, L. L., & Colombo, J. (2014). Executive function predicts artificial language learning. Journal of memory and language, 76, 237-252.
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  Previous research suggests executive function (EF) advantages among bilinguals compared to monolingual peers, and these advantages are generally attributed to experience controlling two linguistic systems. However, the possibility that the relationship between bilingualism and EF might be bidirectional has not been widely considered; while experience with two languages might improve EF, better EF skills might also facilitate language learning. In the current studies, we tested whether adults' and preschool children's EF abilities predicted success in learning a novel artificial language. After controlling for working memory and English receptive vocabulary, adults' artificial language performance was predicted by their inhibitory control ability (Study 1) and children's performance was predicted by their attentional monitoring and shifting ability (Study 2). These findings provide preliminary evidence suggesting that EF processes may be employed during initial stages of language learning, particularly vocabulary acquisition, and support the possibility of a bidirectional relationship between EF and language acquisition.
• Kemper, S., & Kapa, L. L. (2014). Commentary on Baum and Titone. Applied Psycholinguistics, 35(5), 912-916. doi:10.1017/s014271641400023x
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  Baum and Titone address several issues related to bilingual advantages in executive control that are often overlooked in this literature but warrant further consideration and empirical investigation. We limit our comments to two issues: the problem of establishing the directional relationship between bilingualism and executive control and the problem of decomposing executive control.
• Kapa, L. L., & Colombo, J. (2013). Attentional Control in Early and Later Bilingual Children. Cognitive development, 28(3), 233-246.
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  This study examined differences in attentional control among school-age children who were monolingual English speakers, early childhood Spanish-English bilinguals who began speaking both languages by age 3, and later childhood Spanish-English bilingual children who began speaking English after age 3. Children's attentional control was tested using the Attention Network Test (ANT). All language groups performed equally on ANT networks; however, when controlling for age and verbal ability, groups differed significantly on reaction time. Early bilingual children responded faster on the ANT compared to both monolingual and later bilingual children, suggesting an attentional monitoring advantage for early bilinguals. These results add to mounting evidence of advantaged cognitive functioning among bilinguals, and are consistent with the possibility that children who begin speaking a second language earlier in childhood have larger advantages due either to differential effects of acquiring a second language earlier during development or due to longer duration of bilingual experience.
• Varga, K., Kapa, L. L., Frick, J. E., & Dengler, M. J. (2010). Developmental changes in inhibition of return from 3 to 6 months of age.. Infant behavior & development, 33(2), 245-9. doi:10.1016/j.infbeh.2009.12.011
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  The development of inhibition of return was examined in 3-6-month-olds using varied stimulus onset asynchronies. The 300 ms SOA condition revealed particularly interesting findings as it elicited facilitation in 4.5-month-olds, but inhibition in 6-month-olds. Implications for understanding the development of IOR are discussed.

Presentations

• Mettler, H., & Kapa, L. (2021, November). Self-directed speech produced by preschoolers with developmental language disorder during executive function tasks. American Speech-Language-Hearing Association Convention. Washington, D.C..
• Kapa, L. (2019, February-March). Executive Function and Language Intervention. Innovative Methods for Preschool Assessment, Collaboration, and TreatmentASHA.
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  Invited ASHA webinar for online conference that included live chats in Spring 2019 and Fall 2019
• Kapa, L. (2018, October). Language and executive function in children with developmental language disorder. SLHS Department Colloquium.
• Kapa, L., Erikson, J. A., Plante, E. M., & Vance, R. (2017, June). Executive function and word learning in preschool aged children with SLI. Symposium on Research in Child Language Disorders. Madison, WI.
• Vance, R., Plante, E. M., Erikson, J. A., & Kapa, L. (2017, June). Executive function and word learning in preschool aged children with SLI. Symposium on Research in Child Language Disorders. Madison, WI.
• Kapa, L., & Plante, E. M. (2015, June). Impaired cognitive flexibility in preschoolers with SLI. Symposium on Research in Child Language Disorders.
• Kapa, L., Plante, E. M., & Vance, R. (2015, November). Sustained attention and inhibitory control abilities in preschoolers with specific language impairment. American Speech-Language-Hearing Association Annual Convention.

Poster Presentations

• Kapa, L. (2019, June). Improving Card Sorting Performance among Preschoolers with Developmental Language Disorder. Symposium on Research in Child Language Disorders.
• Kapa, L., Vovakes, A., & Erikson, J. (2019, November). Phonotactic Probability and Neighborhood Density Effects on Word Learning in Preschoolers with and without DLD. ASHA Convention 2019.
• Kapa, L. (2018, June). Does executive function performance predict enrollment in therapy for preschoolers with developmental language disorder?. Symposium on Research in Child Language Disorders.
• Kapa, L. L. (2017, November). Identifying the structure of executive function in preschoolers with SLI and typical language development. American Speech-Language-Hearing Association Annual Convention.
• Kapa, L. L., Plante, E. M., & Vance, R. (2016, June). Artificial grammar learning in preschoolers with and without SLI. Symposium on Research in Child Language Disorders.
• Kapa, L., & Plante, E. M. (2016, January). Executive function abilities in preschoolers with specific language impairment. Budapest CEU Conference on Cognitive Development.
• Kapa, L. L., Plante, E. M., & Vance, R. (2013, June). The effect of exemplar variability in grammar learning among preschoolers with and without SLI. Symposium on Research in Child Language Disorders.