Our research focuses on Universal Design for Learning (UDL), a comprehensive framework for designing and implementing teaching strategies across diverse educational settings, with a particular emphasis on higher education (CAST, 2018). Recognizing the positive impact of training teachers in UDL guidelines on both student skills and the overall quality of teaching (Rusconi & Squillaci, 2023), our study seeks to contribute to the existing body of knowledge.

While previous synthesis studies have explored UDL at the university level (Cumming & Rose, 2021; Roberts et al., 2011) and its application in teacher education (Rusconi & Squillaci, 2023), there is a notable gap in reviews that concurrently consider these two critical dimensions. To address this void, our proposed mapping review aims to answer the following key questions:

• What types of studies have been conducted at the university level regarding teacher professional development with Universal Design for Learning?

• What benefits emerge from these programs or training initiatives in terms of enhancing teaching skills and practices?

A mapping review is chosen as the research method to systematically identify, evaluate, and synthesize existing literature within this specific niche of interest. By adopting this approach, we aim to provide valuable insights into the predominant trends, methodological approaches, and thematic gaps in the literature related to UDL in higher education teacher professional development (Grant & Booth, 2009).

A list of eligibility criteria was adopted to select relevant studies for this mapping review: Study Design: qualitative, quantitative, mixed-method or multi-method studies; Language: studies carried out in any country, but published in English; Publication time frame: 2014-2023; Setting: studies need to present the results of a professional development programme or teacher training on UDL conducted in higher or tertiary education; Outcomes: studies investigate the impact of training or interventions on teachers’ knowledge and skills to design and implement inclusive teaching strategies. Relevant works were searched electronically through general and educational databases (SCOPUS, Web of Science, ERIC, PsycInfo) using a combination of keywords. Additional works were included through handsearching and citation chasing practices and databases of unpublished studies (ProQuest Dissertations and Theses Global). Handsearching and citation chasing are complementary methods employed in systematic reviews to retrieve potentially overlooked but pertinent records (Cooper et al., 2018). Handsearching entails two steps: 1) identifying key journals and conferences, and 2) reviewing the contents of each issue or program. Citation chasing, or snowball search, comprises backward and forward approaches. Backward citation chasing involves assessing records in the bibliography of articles, while forward citation chasing entails finding records that cite a particular article or set of articles. The title and abstract screening phase will be conducted by two independent researchers using the ASReview software, enabling the utilization of machine learning to identify relevant studies and expedite the workflow. The studies selected were coded independently by two researchers, referring to a shared table containing a list of aspects related to the setting (country, type of university context, faculty, teaching area), to the type of training intervention or programme implemented on the UDL (duration, intensity, content, etc.), to the participants in the study (university lecturers, administrative staff, etc.), to the beneficiaries of the interventions (students with disabilities, non-traditional students, all students), to the type of outcome measured or observed (e.g. improvement in teaching skills, strategies, motivation or learning outcomes) and to methodological aspects (research design, sample, information source, instruments, etc.).

The results of the review highlight certain trends in the international literature, such as the bias towards specific research designs or the over-representation of some countries. They also indicate some perspectives for the expansion of future research in the field, particularly with regard to the types of intervention that can be carried out in a university context on the subject of UDL. Finally, issues that have already been raised by other synthesis studies (Rao et al., 2011) emerged, such as fidelity in the application of UDL principles to teaching practices.

CAST (2018). Universal Design for Learning Guidelines version 2.2. Retrieved from http://udlguidelines.cast.org Cooper, C., Booth, A., Varley-Campbell, J., Britten, N., & Garside, R. (2018). Defining the process to literature searching in systematic reviews: A literature review of guidance and supporting studies. BMC Medical Research Methodology, 18(1), 85. https://doi.org/10.1186/s12874-018-0545-3 Cumming, T.M., & Rose, M.C. (2021). Exploring universal design for learning as an accessibility tool in higher education: a review of the current literature. The Australian Educational Researcher, 49, 1025-1043. https://doi.org/s13384-021-00471-7 Grant, M.J., & Booth, A. (2009). A typology of reviews: an analysis of 14 review types and associated methodologies. Health Information and Libraries Journal, 26, 91-108. Doi: 10.1111/j.1471-1842.2009.00848.x Rao, K., Ok, M. W., & Bryant, B. R. (2014). A Review of Research on Universal Design Educational Models. Remedial and Special Education, 35(3), 153-166. https://doi.org/10.1177/0741932513518980 Roberts, K.D., Park, H.J., Brown, S., & Cook, B. (2011). Universal Design for Instruction in Postsecondary Education: a systematic review of empirically based articles. Journal of Postsecondary Education and Disability, 24(1), 5-15. Rusconi, L., & Squillaci, M. (2023). Effects of a Universal Design for Learning (UDL) training course on the development of teachers' competences: a systematic review. Education Sciences, 13, 466. https://doi.org/10.3390/educsci13050366