The protocol outlines the multistep methodological approach for completing the preparatory phase in developing the ICF Core Sets for deafblindness in children and youth.26 The preparatory phase contains four studies that will synthesise and contrast the perspectives of researchers, experts and individuals with lived experience through a systematic literature review, a qualitative study, an expert survey and a multicentre empirical study.

Apart from the systematic literature review, ethical approval will be obtained for all studies of the project at the Université de Montréal’s Comité d’éthique de la recherche clinique. Additional approvals in other countries or continents will be obtained as needed based on the requirements of international collaborators and their respective local ethics committees, ensuring the protection of participant rights and confidentiality.

In the first study, empirical research involving children and youth living with deafblindness will be explored through a systematic literature review. The objective of this systematic literature review will be to summarise the types of outcome measures used in deafblindness research, describe the characteristics of deafblindness studies and explore how these measures relate to the extensive ICF framework. Based on previous work on the development of ICF Core Sets for deafblindness across all age groups, information gathered from the review will answer the following research questions21:

1. Which aspects of functioning are described or evaluated in the scientific literature on deafblindness in children and youth?

2. What are the outcome measures, study characteristics, and population details of the included studies?

Following Arksey and O’Malley’s guidelines, the review will be defined by the population, context and concept of interest.27 Specifically, the population will consist of study participants aged 17 years old or younger as per the ICF Children and Youth Manual.6 The concept of interest will be deafblindness, defined as the combination of any level of subjectively or objectively reported hearing and vision loss in the same individual or any aetiologies at the cause of the deafblindness.28 Causes can be attributed to hereditary or chromosomal syndromes and disorders, such as Usher’s syndrome, Leber’s congenital amaurosis and CHARGE syndrome; prenatal or congenital complications, including congenital rubella, microcephaly and congenital cataracts associated with other conditions; postnatal or non-congenital complications, such as stroke, encephalitis, meningitis, tumours and head injuries; complications related to prematurity, often arising from premature birth; and undiagnosed cases, where no clear aetiology has been determined or where diagnoses are mixed with other conditions.29 As recommended by the ICF Core Set Development guide, the temporal context will be defined as articles published from 2015 onwards as the scientific literature should not be older than 10 years at the time of the systematic review26 while the spatial context will not be restricted by the location of publication or where the research was conducted. Psychometric and prevention studies, studies of phase II clinical trials, studies exclusively with laboratory parameters, animal experiments, letters, comments and editorials will not be considered in the current review.26 The inclusion and exclusion criteria are provided in table 1. This comprehensive approach will ensure that the review encompasses relevant and up-to-date research, providing a thorough understanding of the daily living aspects of children and youth with deafblindness from the perspective of researchers.

In study 2, interviews and/or focus groups with parents and caregivers of children with deafblindness, as well as adolescents with deafblindness themselves, will be conducted. The discussions will be structured around six questions as per the guidelines for the creation of ICF Core Sets26 and adapted for deafblindness. These questions are available in table 2 and explore the four ICF domains (body functions, body structures, activities and participation and environmental factors). Personal factors, such as age and socio-economic status, although not coded in the ICF, will also be explored and considered. These qualitative interviews and focus groups will ensure a comprehensive understanding of the experiences and challenges faced by children and adolescents with deafblindness and their caregivers, as well as the support systems in place to assist their development and daily living. The format of the sessions, either interview or focus groups, will depend on participants’ availabilities. This approach will provide representation and insight into the diversity and complexity of congenital and early-onset deafblindness.

An international expert survey will explore perspectives from professionals and service providers working with children and youth living with deafblindness. In addition to healthcare professionals, experts in education and research settings as well as individuals in policymaking positions relevant to deafblindness will be invited to participate in this study. Responses gathered from this survey will provide specialised knowledge and practical insights on service delivery and collaboration with this clinical population. This insight can subsequently help in identifying best practices, revealing service gaps and informing the development of more effective, targeted interventions. The inclusion of diverse professional perspectives will enrich the findings and contribute to a holistic view of the current state of services and policies affecting young individuals living with deafblindness.

In this final preparatory study, an empirical multicentre study will identify the prevalent challenges encountered by children and youth living with deafblindness as documented in clinical settings. Healthcare practitioners, such as occupational therapists and/or nurses, will engage in semistructured interviews with caregiving parents and/or young individuals. This step will serve as a complement to the data collected in the first three studies.

Once all four of the studies are completed and their data analysed, the process to establish these Core Sets will be streamlined, following a two-step approach. First, a panel of a maximum of 30 people including children and youth with lived experience and their intervenors/interpreters, family members, health and social service providers, and policy decision-makers will be made aware of the resulting categories for each of the studies. Through online surveys, they will be asked to make decisions for each category presented; whether the category should be directly included, excluded or discussed further. Consensus will be considered if 75% or more of the participants vote in agreement.

Second, based on their survey responses, a virtual consensus conference will be held to establish the Core Sets. The same participants who answered the surveys will be invited to this conference. A balanced representation of participants from all six WHO regions, with a maximum of 30 voting members, depending on participants’ availability to participate in the event will be aimed for. During this conference, the categories identified as needing further discussion as well as those that did not reach consensus in the online survey will be discussed. Through a voting process, they will review each eligible category and decide on their inclusion or exclusion from the Core Sets for children and youth living with deafblindness. Categories that receive at least 75% approval will be included in the Core Sets. This cut-off score adheres to the requirements of the WHO ICF Research Branch.26

The outcome of the proposed protocol will be five ICF-CY Core Sets: (1) a comprehensive Core Set, (2) a condensed brief version of the comprehensive Core Set and (3–5) three age-specific Core Sets: under 6 years old, between 6 and 14 years old, and between 14 and 17 years old.41 During the studies, when possible, this will be achieved by disaggregating the data according to the reported age of each participating child living with deafblindness, with the relevant categories assigned to the corresponding age group. During the consensus conference, participants will also vote for categories to be included in the three age-specific Core Sets. Integrating findings from all previous studies, the consensus conference will take place in early 2027. Once established, the Core Sets will be published and freely accessible to all on the Open Science Framework,42 similar to the already available Core Sets for deafblindness across the lifespan.43–45 The three age-specific Core Sets would cater to the unique needs and developmental stages of children and youth at different ages. In Study 1, the different age groups represented in the study participants will be identified during data extraction. In Study 2, the responses to the questions will be explored across the three age groups. In Studies 3 and 4, purposive sampling will be conducted to maintain global representation while data are analysed based on age groups. During the consensus conference, discussions will focus on the perspectives and needs of the different age groups.

This project will be led by a PhD student who will benefit from the guidance of an advisory committee composed of experts in sensory and paediatric health, as well as individuals with lived experience, including parents of children with deafblindness. Furthermore, parents will play a crucial role in this project, not only by assisting in obtaining consent for their children but also by advocating on their behalf. Given the ethical considerations and communication barriers associated with deafblindness, many children and youth may be unable to share their experiences in a formal research setting. Engaging parents in participatory research will be essential, particularly in light of the increasing emphasis on including the target population in research to ensure that outcome measures are relevant, effective and aligned with their specific needs.19 46 In the expert survey, we will draw on the expertise of professionals, some of whom may themselves have lived experience with sensory impairment, providing a dual perspective that integrates both professional and personal insights. Finally, the consensus conference will serve as the final phase, bringing together international experts, individuals with lived experience of deafblindness, researchers and policymakers to review and refine the Core Sets.

The findings from this project will be disseminated through peer-reviewed scientific publications aimed at audiences interested in paediatric health and sensory care, as well as journals focusing on public health and the ICF. In addition, we will submit presentations at local, national and international conferences, and produce stakeholder reports aimed at healthcare providers, educators and policymakers. These results will inform future practices, interventions and policies to better support children and youth with deafblindness.

The development of ICF Core Sets for deafblindness specifically for children and youth will lay the groundwork to significantly enhance healthcare delivery and rehabilitation services by supporting the development of standardised assessments for this population and ensuring consistent, comprehensive evaluations across various settings and professions. The Core Sets may assist in personalised and holistic care by identifying unique needs and facilitating interdisciplinary collaboration. Addressing the unique needs of children and youth with deafblindness involves a comprehensive understanding of their sensory and cognitive challenges, including difficulties in communication, mobility and daily functioning. Tailored interventions must focus on promoting their access to education, social inclusion and independent living, while supporting development through specialised strategies such as preferred communication modalities, assistive technologies and mobility training. Interdisciplinary collaboration is therefore crucial in this context as it brings together experts from fields such as education, orientation and mobility, low-vision rehabilitation, intervention and support services, speech-language pathology and occupational therapy. By working collaboratively, professionals can create individualised, holistic care plans that integrate the perspectives of families, educators and health providers, ensuring that children and youth with deafblindness receive the most effective and coordinated support across all aspects of their development. The Core Sets may also support the monitoring and evaluation of children by allowing consistent tracking of their progress and outcomes in sensory, mobility, communication or social abilities, among others. They will also inform policy development through the standardised data collected throughout the studies. For instance, the Core Sets can help in developing legislation promoting inclusive and accessible educational settings and training programmes or develop standards for available social services. Furthermore, the Core Sets will enhance the training and education of healthcare professionals, maybe through specific pedagogical recommendations to be included in their curriculum, raise awareness for advocacy and support service eligibility determinations, thereby facilitating the development of tailored programmes and services. The detailed, standardised information from the Core Sets could potentially assist educators in developing individualised and effective education plans, tailored to the unique functional and educational needs of each child living with deafblindness. These comprehensive and individualised plans then have the potential to improve educational outcomes and support the overall development and well-being of students with deafblindness.

Developed through a rigorous research process, the Core Sets establish a standardised framework and common language, thereby enhancing the consistency, comparability and reliability of data. The creation of these Core Sets will also aid in identifying important research priorities, guiding the formulation of precise and relevant research questions, and ensuring comprehensive and systematic assessments. Furthermore, the development of Core Sets for deafblindness in children and youth may uncover significant discrepancies from the already existing Core Sets for deafblindness across the lifespan.18–22 Revealing such discrepancies will then allow for direct comparison of individuals of different life stages living with deafblindness, exploring which aspects of functioning may be different, which could greatly inform research priorities. For instance, given the extensive age range covered by the Core Sets across the lifespan (range 0–83 years old),18–22 it is possible that aspects of functioning relevant for children and youth such as education were buried in the resulting categories. The largest group of people living with deafblindness are older adults, often because of age-related sensory changes. Consequently, the effects of deafblindness in daily life may manifest differently during childhood.

The Core Sets, providing a global standardised framework for documenting functional abilities and needs, will support the needs and rights of children and youth with deafblindness at the local, national and international levels, informing inclusive policies that enhance their quality of life and opportunities. They will inform resource allocation by providing evidence-based data and strengthening advocacy efforts through detailed information that raises awareness and supports legislative changes. The Core Sets are intended to facilitate interdisciplinary collaboration among stakeholders and enhance global cooperation by sharing best practices. Given the international breadth of the Core Sets, they can more easily be adapted to the context of any entity that desires to use them. Although the implementation of the Core Sets may vary depending on the resource levels of different countries, the benefits will be consistent worldwide. The Core Sets can be used to raise recognition and awareness of deafblindness in children and youth, potentially leading to the creation of organisations that support this population and their families. Additionally, their development may inspire the establishment of social support services and programmes for individuals with complex disabilities, such as deafblindness. The Core Sets can help refine interventions, promote interdisciplinary service delivery and advance equity, diversity and inclusion initiatives. Furthermore, by incorporating different perspectives from individuals with lived experience, experts and researchers, the Core Sets offer a well-rounded perspective of the current state of services and identify areas needing more focus and improvement and will enable monitoring and evaluation of policies.

While the process established by the ICF Research Branch for creating Core Sets (28) demonstrates strong scientific rigour, the proposed studies present various limitations. First, although research on deafblindness is continuously evolving, limiting the systematic literature review to literature published in the last 10 years may result in overlooking prior articles and important sources of evidence. The rationale behind this choice is to ensure that the included studies are directly relevant to today’s children and youth, capturing a more current picture of their challenges and needs. Second, the international scope of the project aims to integrate socio-cultural factors in the analyses in all studies; however, geographical representation is limited to WHO regions. Therefore, differences among the many countries within each region cannot be accounted for due to limitations in resources and time. For instance, variations in national health policies, resources, access to healthcare and cultural factors can significantly affect the experiences and outcomes of children with deafblindness, even within the same region. Even within each country, variability in the population in terms of socio-economic status as well as geographical location (rural vs urban) is difficult to ensure. These differences may not be captured fully within a broader WHO regional classification. Finally, caution will be needed regarding the generalisability of the findings given the heterogeneity of deafblindness. Deafblindness encompasses a wide range of aetiologies and severity levels, leading to significant variability in how individuals experience the condition. The causes of deafblindness can vary greatly, with different sensory impairments, cognitive abilities and co-occurring conditions influencing each individual’s experience. However, given the population of children and youth and the prevalence of congenital and early-onset causes of deafblindness, the heterogeneity of aetiologies will pose a smaller limitation. Additionally, factors such as age, family support, cultural background, access to healthcare and educational resources can further shape outcomes and interventions. To mitigate this, a substantial effort will be made to ensure that diversity in the clinical profiles of individuals with lived experience is achieved. Incorporating qualitative research and using multiple data sources from different regions and healthcare systems will also capture nuances in experiences.

In conclusion, this project holds significant relevance as it aims to advance the understanding and support for children and youth with deafblindness. By providing comprehensive, region-specific insights and fostering global collaboration, this work has the potential to drive meaningful improvements in care, education and accessibility for those affected. The growing international support for such initiatives underscores the urgency and importance of recognising and addressing the unique needs of this population, ultimately contributing to greater equity and inclusion on a global scale.

Not applicable.