The current study comprises a systematic review and meta-analysis aimed at evaluating the effects of digital language interventions on oral language skills among pupils with disorders of intellectual development (ID). Disorders of ID are defined by significant limitations in both intellectual functioning and adaptive behavior which often lead to challenges in communication, social interaction, and daily living skills (Schalock et al., 2021). Conditions such as Down syndrome (DS) and other disorders that cause ID are often associated with cognitive and linguistic impairments, including difficulties with working memory, executive functions, and articulation (Bakken et al., 2021; Smith et al., 2008). Addressing these challenges through effective interventions is crucial for improving oral language development, which underpins academic success, social participation, and overall quality of life (Bakken et al., 2021; Moraleda-Sepúlveda et al., 2022).

Digital language interventions encompass a range of instructional technologies, including multimedia programs, game-based learning, and augmentative and alternative communication (AAC) tools, designed to enhance expressive and receptive language skills. These interventions utilize digital devices, such as computers, tablets, and wearable technologies, to deliver engaging, tailored, and interactive learning experiences (Moreno et al., 2021). Game-based learning strategies, for instance, incorporate activities such as labeling, sorting, and sequencing to facilitate vocabulary and grammar development, while also promoting social-pragmatic skills (Moraleda-Sepúlveda et al., 2022). Naturalistic interventions, which focus on restructuring everyday interactions and settings to promote language learning, further highlight the importance of contextually appropriate, child-centered approaches (LeJeune et al., 2022). 

Existing research highlights the potential of digital interventions in improving language outcomes for individuals with ID. For example, the Digital Down Syndrome LanguagePlus (DSL+) program demonstrated significant positive effects on expressive and receptive vocabulary through a randomized controlled trial involving first graders with Down syndrome (Næss et al., 2022). However, the heterogeneity of study designs, populations, and intervention methods found in this field presents challenges in synthesizing findings and drawing broader conclusions. Furthermore, single-case experimental designs (SCED), commonly used in special education research, are often excluded from systematic reviews due to difficulties in standardizing outcome measures (Kazdin, 2020; Ledford et al., 2023).

This review addresses these gaps by systematically analyzing SCED-based studies that assess the impact of digital instructional technologies on oral language skills in pupils with ID, aged 4–21 years.  This is particularly relevant given that over 83% of intervention studies involving individuals with autism rely on SCED methodologies, underscoring their importance in special education research (Steinbrenner et al., 2020; Ledford et al., 2023). Findings may offer critical insights into evidence-based practices, highlighting the potential of digital interventions to support language development and enhance educational outcomes for pupils with ID.

In addition to synthesizing existing evidence, this review explores the characteristics of digital language interventions, such as the types of devices used and the role of intervention providers, including teachers and special educators by identifying effective practices and intervention frameworks. Despite the promising potential of digital interventions, limitations include the variability of study designs and the lack of long-term follow-up data (Moreno et al., 2021).Thus, there is a need for greater standardization of intervention methodologies and outcome measures to enhance the comparability of findings. Addressing these limitations through rigorous, well-designed studies can provide a stronger evidence base for integrating digital technologies into educational practices for individuals with ID.

This systematic review and meta-analysis adhered to the PRISMA guidelines and was preregistered on the Open Science Framework. The inclusion criteria followed the PICO (population, intervention, comparison, outcomes) framework for defining review criteria. The population was limited to individuals with diagnosed disorders of ID, such as Down syndrome, Fragile X syndrome or fetal alcohol syndrome (FAS). Interventions were limited to instructional, digital language interventions aimed at improving oral language skills, assessed through SCED methodologies, that were implemented by teachers, assistants, or other personnel at school or in preschool. With respect to comparisons, the study considers the following categories: no treatment, standard treatment, alternative interventions, or interventions without technology support. Outcomes of interest were changes in oral language skills, such as expressive and receptive language, vocabulary, grammar, and pragmatics. Databases searched included ERIC, APA PsycInfo, Scopus, and Web of Science, with queries designed to capture all studies using digital interventions to address oral language among persons with ID. Searches yielded 10,682 records, which were imported into EPPI Reviewer 6 for screening. Duplicate removal reduced the dataset to 7,536 records. Screening was conducted in two phases. The first phase involved title and abstract screening, where 50% of the studies were double-screened (inter-rater agreement = 99.3%). Seventy-eight studies were selected for inclusion in full-text screening. These studies were double screened with disagreements resolved through discussion. Ultimately, 13 studies met the inclusion criteria. Four additional studies were identified through manual searches of reference lists from included studies, previous reviews of the literature, and a selection of articles that have addressed the topics of the current study.

Seventeen studies were identified and included in the review. We are currently in the process of extracting data from these studies and conducting analyses. Data extraction will focus on participant demographics, intervention characteristics, and language outcomes. The Single-Case Design Risk of Bias Tool (Reichow et al., 2018) will be employed to assess biases related to selection, performance, detection, and other domains. Preliminary findings suggest that digital oral language interventions have been successful in improving outcomes for pupils with ID in a variety of areas. This systematic review and meta-analysis can provide valuable insights into the potential of digital language interventions to enhance oral language skills in pupils with ID. By focusing on single-case experimental design studies, the review highlights the individualized impact of these interventions, which leverage technology to address specific language challenges faced by children and adolescents with conditions such as Down syndrome, autism spectrum disorder, and Fragile X syndrome. Despite their promise, the small number of studies identified in the current review identifies significant gaps and challenges in the field. It appears that variability in intervention protocols, outcome measures, and study designs limit the generalizability of findings and complicate comparisons across studies. Furthermore, the heterogeneity of the population of pupils with disorders of ID requires interventions tailored to diverse needs, which presents a challenge for developing evidence-based approaches. In conclusion, digital language interventions hold substantial promise for addressing the language development needs of pupils with ID, offering a path toward improved academic, social, and functional outcomes. By consolidating and advancing research in this area, educators, clinicians, and policymakers can better support this underserved population, enabling them to achieve greater success in school and beyond.

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