# Language outcomes, mechanisms, and trajectories in adults with and without Developmental Language Disorder

> **NIH NIH R01** · UNIVERSITY OF IOWA · 2022 · $581,138

## Abstract

ABSTRACT
Developmental Language Disorder (DLD) is characterized by difficulties in the ability to learn and use language
and is one of the most common neurodevelopmental disorders (prevalence 7-12%1,2). Though problems emerge
in childhood, DLD continues into adulthood3-6 and has profoundly negative effects. Adults with DLD are less likely
to seek post-secondary education7-9, may have extended bouts of unemployment9, and have higher rates of
depression10. Yet, DLD in adulthood is severely under-researched. An understanding of the language profile is
crucial as language abilities in adulthood impact well-being, income, and job performance11. Additionally, there
is a clear need to better understand the mechanisms that mediate language abilities in adults with and without
DLD. Doing so will help explain theories of DLD12-15 (speed of processing and working memory accounts) and
expose a wider range of individual differences in language ability. Examining competition – the activation of
competing linguistic representations as speech unfolds – is an ideal approach to exploring these mechanisms.
Competition is a fundamental component of language, is well-documented in typical adults16-19, and critically,
distinct aspects of competition can be linked to each theoretical account20,21. Our overall objective is to
characterize the long-term outcomes of DLD in adulthood (Aim 1) and to identify specific cognitive mechanisms
mediating these outcomes (Aim 2). To address our objectives, we utilize a large, pre-existing dataset and
participant pool from one of the most comprehensive examinations of DLD to date: the Iowa Longitudinal Study22.
We will re-recruit subjects with DLD (n=150) and with typical language (TL; n=250) from this historic cohort, who
are now adults (30–34 years old). In Aim 1, we leverage retrospective language measures from kindergarten
through 10th grade and collect new outcome measures in adulthood to characterize the long-term outcomes of
DLD. We predict that adults with DLD will diverge from adults with TL in language skills that are more complex
and higher-level language skills that are important for communication in the workplace11. Further, we predict a
fanning effect: some children with DLD will “catch up” to their TL peers in adulthood, some will show evidence of
a decline, and others will show stable trajectories. In Aim 2, we measure real-time competition across language
modality and level using eye-tracking in the Visual World Paradigm23. According to speed of processing
accounts15,20, adults with DLD may be slower than their TL peers to activate competitors and targets. According
to working memory accounts21,24, adults with DLD will show sustained competitor activation.
Further,
we predict
that measures related to the dynamics of competition (speed of activation and timing of competitor suppression)
will account for variation in language outcomes in adults across the ability spectrum. The proposed work would
represent the largest ...

## Key facts

- **NIH application ID:** 10409087
- **Project number:** 1R01DC020143-01
- **Recipient organization:** UNIVERSITY OF IOWA
- **Principal Investigator:** Kristi Hendrickson
- **Activity code:** R01 (R01, R21, SBIR, etc.)
- **Funding institute:** NIH
- **Fiscal year:** 2022
- **Award amount:** $581,138
- **Award type:** 1
- **Project period:** 2022-09-01 → 2027-08-31

## Primary source

NIH RePORTER: https://reporter.nih.gov/project-details/10409087

## Citation

> US National Institutes of Health, RePORTER application 10409087, Language outcomes, mechanisms, and trajectories in adults with and without Developmental Language Disorder (1R01DC020143-01). Retrieved via AI Analytics 2026-05-24 from https://api.ai-analytics.org/grant/nih/10409087. Licensed CC0.

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