Development of core sets for deafblindness: an international expert survey on functioning and disability of individuals living with deafblindness using the International Classification of Functioning, Disability, and Health

Abstract

BACKGROUND

The development of International Classification of Functioning, Disability, and Health (ICF) Core Sets greatly enhances the global recognition of health conditions, thereby advancing research, education, and care provision. Aside from the work of researchers, and the viewpoint of persons with lived experience, the development of Core Sets for deafblindness needs to include the viewpoints of professionals with expertise unique to this condition.

AIM

To represent the perspective of health and social service expert professionals in the development of ICF Core Sets for deafblindness.

DESIGN

Cross-sectional cohort study.

SETTING

Global online survey representing all six regions of the World Health Organization.

POPULATION

One hundred and five professionals providing and health or social service to individuals living with deafblindness with a minimum of 2 years of work experience with this population.

METHODS

An online survey was distributed through professional networks and social media for individuals working with persons living with deafblindness. Demographic items were summarized using descriptive statistics. Six open-ended questions explored the perceptions of body functions and structures that influence activities and participation, as well as environmental and personal factors that facilitate functioning. Data were linked to the ICF codes using established linking rules and procedures.

RESULTS

The 2934 survey response units were linked using IFC categories. Of the 421 unique categories, 133 were used by 5% or more of respondents. Most categories within the Activities and Participation component were equally emphasized. The most frequent Environmental factors were support and relationships, services, systems, and policies, as well as and the physical environment (e.g., hearing aids or noise). Mental functions, including higher level cognitive functions, temperament and personality were frequently emphasized.

CONCLUSIONS

Almost three quarters (73.3%) of the entire ICF classification categories were included in the expert survey results. This proportion emphasizes the importance of a multidimensional tool, such as the ICF, for assessing functioning and health for persons with deafblindness.

CLINICAL REHABILITATION IMPACT

The representation of this professional perspective in Core Set development will improve standardized assessment and documentation, intervention planning, and facilitate interprofessional communication with the goal of improving person-centered care for persons living with deafblindness.

Deafblindness is defined as a combined impairment of vision and hearing at any level that interferes with an individual’s ability to participate in society, and whereby these limitations are severe enough to require services, environmental adaptations, or the use of assistive technology.¹ There are an estimated 30 million individuals living with deafblindness in the world, of whom 14.3 million are over the age of 65.^2-4 This number is likely to climb, given the importance of age-related causes of vision and hearing impairment.^5-7 The World Federation of the Deafblind⁸ and Deafblind International⁹ are both actively advancing the recognition of deafblindness as a unique and distinct sensory impairment globally (not just the combination of vision and hearing difficulties), and the European Deafblind Network managed to formalize this recognition in the European Parliament.¹⁰ One key component of raising the visibility of deafblindness is the development of a Core Sets of classification codes specific to this condition, using the World Health Organization (WHO) International Classification of Functioning, Disability, and Health (ICF).¹¹ The present study is part of the multi-step process to fill this gap.

The ICF is a framework that allows for the conceptualization of a bio-psycho-social view of health and functioning in the presence of disease and/or impairment, that also considers contextual factors rooted in the environment as well as the individual (Figure 1).¹¹

Figure 1.

—The hierarchical structure of ICF categories, using examples relevant to the deafblindness domain. Lower-level categories increase in specificity. Please note that personal factors are not currently coded within the ICF. Figure adopted from Granberg et al.¹²

To apply this framework, an extensive classification system has been developed that contains approximately 1500 alphanumerical codes, each with a specific definition. They are divided into codes for body structure (beginning with the letter s), body function (letter b), activities and participation (letter d) and environmental variables (letter e); personal factors are recognized but do not currently have a coding system. The application of these codes allows for a precise description of variables that are relevant to any disease or condition that affects health and functioning. Given the large number of available codes, it comes as no surprise that their application can be cumbersome; therefore, a process has been proposed for the development of shorter lists of codes that are uniquely relevant to any one specific health condition — the Core Sets.¹³ These Core Sets can take several forms, including brief and comprehensive formats, as well as versions specific to children and youth versus adults.¹⁴ They have been developed for musculoskeletal, cardiopulmonary, neurological, neurodevelopmental as well as psychiatric diseases, in addition to conditions such as breast cancer, sleep disorders or vocational rehabilitation.

Of specific interest in the present context are the already existing brief and comprehensive Core Sets for hearing loss that were developed following the WHO guidelines.¹³ Their development process included a systematic review of the literature providing the perspective of researchers,^{12, 15} an international expert survey offering the viewpoint of professionals,¹⁶ qualitative interviews with individuals with lived experience of hearing loss,¹⁷ and an application of existing ICF categories in the context of clinical evaluation. Finally, a consensus conference was held in Helsingör, Denmark, in the spring of 2012 to decide upon the most relevant codes that emerged from the pooled data of these studies, resulting in the brief and comprehensive core sets for hearing loss now available online through the ICF Research Branch.¹⁸ It is timely that the development of Core Sets for vision loss is currently ongoing under the leadership of a team in the Netherlands.¹⁹ Given the recognition of deafblindness as a unique sensory impairment, it is therefore important to move forward with the development of Core Sets for deafblindness.

The overview of the process has previously been published,²⁰ and the systematic literature review protocol was registered with PROSPERO.²¹ The resulting manuscripts describing the outcome measures used in deafblindness²² and the most frequent ICF codes that are linked to these outcomes are currently accepted and under review, respectively, elsewhere. Here, we present the next step in this series of studies, the analysis of data from an international expert survey with professional health and social and service providers working with persons living with deafblindness. By definition, such services that are provided to this marginalized population are interdisciplinary; therefore, a multitude of professions were involved in this study. The objective of the survey was to identify relevant aspects of functioning, disability, and contextual barriers and facilitators for persons living with deafblindness as viewed from the perspective of health and social service professionals working with this population, and to summarize these aspects using the ICF classification framework as a reference tool.

Materials and methods

The protocol was approved by the institutional review board of the University of Montréal (CERC # 2022-1710), and the results are presented here following the recommendations laid out in the Checklist for Reporting Results of Internet E-Surveys.²³

Patient and public involvement statement

This study did not directly target or involve patients or the public; however, the research team includes individuals living with sensory impairment. Their contribution meaningfully influenced the design and execution of the project, including the data analysis and interpretation. It is likely, given the niche topic, that some of the survey participants themselves also have lived experience with deafblindness, but this aspect was not included as a question during data collection.

Study design

An anonymous online cross-sectional survey was developed and distributed globally through the web.

Recruitment procedure and study population

A link to the survey was distributed through Twitter, Facebook groups and pages aimed at professionals working in the field of deafblindness, including organizations like Deafblind International and their networks. In addition, the link was sent out through the email lists of Deafblind International and its international scientific conference committee members, as well as the European Deafblind Network, and the Réseau Francophone en Déficience Sensorielle et des Troubles du Langage. The invitation encouraged recipients to freely forward the link, thereby using a snowballing approach to increase recruitment.²⁴ Because of this recruitment method, the survey was open and did not require a code for access. Participants were not compensated, nor did they receive incentives for their participation as this survey was voluntary. The target population for this expert survey consisted of a convenience sample of professionals (aged ≥ 18 years) around the world who provide direct health, rehabilitation or social services to individuals living with deafblindness. To partake in the survey, they were also required to have delivered services to these individuals within the least two years.

Survey instrument

The online survey was developed following the ICF Research Branch set of survey questions,¹³ was comprised 21 questions divided in four sections, and required between ten and fifteen minutes to complete. On the first page, participants were asked four questions to establish their eligibility to participate in the survey. If they were deemed eligible, they were directed to the second page, where we collected their informed consent. If informed consent was provided, they moved on to the third section that included ten quantitative and categorical questions about their demographic and work-related information. Finally, in the fourth sections, experts answer six open-ended qualitative questions based on the various ICF components. The survey items were not randomized and were always presented in the same order for each participant. Participants were not required to answer each question if they did not feel comfortable to do so. The length of the answers and the time to answer the survey were not limited. Although the survey was available in both English and French, participants were free to answer in their preferred language. When completing the survey, respondents were able to review and change their answers through backward navigation.

Data collection procedure

Before launch, the content and accessibility of the survey were inspected by research collaborators and team members. Any technical or content issues were flagged in this process and were subsequently addressed. The survey was made available on the LimeSurvey²⁵ platform, a software that is accessible for participants with vision impairment using screen readers or magnification software. The survey was open from November 1^st, 2022, to January 31^st, 2023, and the data were automatically collected online and stored. Survey answers that were provided in a language other than English were translated using the DeepL software²⁶ and the translations into English were proof-read by a native speaker of the languages.

Data selection and stratification

The procedure for developing an ICF Core Set requires representation in the data from across all six regions of the WHO: the African, Eastern-Mediterranean, Southeast Asian, Western-Pacific, the European regions, and the region of the Americas.¹³ We anticipated, however, that the distribution of participants may be biased towards the Global North. Therefore, we decided to adjust the selection of responses by including all participants from the African, Eastern-Mediterranean, and Southeast Asian regions. For the Western-Pacific and the European regions, and the region of the Americas, we chose at least one participant from each country represented in the response pool, tried to select as many different professions as possible when multiple individuals responded from one country, and gave preference to including data by participants where the qualitative responses were longer (e.g., exclude participants who provided one-word responses).

Data linking methodology

The process of linking the data followed the same procedure previously applied by our team during the ICF systematic literature review. Core team members (A.P., A.J., S.G., W.W.) completed the required training provided by the WHO’s ICF Research Branch and then trained two additional team members (S.B., S.D.). Using the updated rules for ICF linking,²⁷ the codes “other specified” [code 8] and “unspecified” [code 9] were applied only when the information that was not covered within the existing codes. The code “other specified” was used when the statement provided a clear explanation of the type of functioning but none of the other codes matched the specification. The code “unspecified” was used when the statement did not provide a clear explanation or specification of the type of functioning. For summary statistics, both the other specified and the unspecified codes were merged with the code level above. Based on the experience of a senior author (S.G.), a linking template was developed that guided the linking process through seven sections: Meaning Unit; Meaningful Concept; Interpretation of Underlying Meaning; Linking Unit; ICF Code; ICF Description; and Final Codes.

Data availability

The data associated with the paper are not publicly available but are available from the corresponding author on reasonable request, given the necessary ethics approvals.

Results

Expert characteristics

The participation rate for the survey (534 visitors who agreed to participate/727 unique first survey page visitors) was 73.5%, whereas the completion rate (221 users who finished the survey/534 who agreed to participate) was 41.4%. Of the 221 individuals who completed the survey, 198 provided answers in English, five in French, three in Spanish and one in German. By stratifying the sample selection, over-sampling participants from the Global South, and eliminating participants who provided one-word answers, 105 participants were selected to be included in the analysis (Table I).

Table I. —Characteristics of study participants (N.=105).

Characteristics	Value
Gender
Woman	70.48% (N.=74)
Man	27.62% (N.=29)
Other	0.95% (N.=1)
I prefer not to answer	0.95% (N.=1)
Mean age [range]	46.91±13.5 [22-74]
Profession
Teacher/Educator	20.00% (N.=21)
Intervenor	19.05% (N.=20)
Rehabilitation professional/counsellor	10.48% (N.=11)
Administrators (director/manager/coordinator)	6.66% (N.=7)
Social worker	4.76% (N.=5)
Psychologist	4.76% (N.=5)
Audiologist	4.76% (N.=5)
Physician/medical doctor	3.81% (N.=4)
Deafblindness Advisor/Consultant/Specialist	2.86% (N.=3)
Physiotherapist	2.86% (N.=3)
Speech language pathologist	2.86% (N.=3)
Low vision therapist	2.86% (N.=3)
Volunteers/Parents of a child with deafblindness	2.86% (N.=3)
Orientation and mobility therapist	1.90% (N.=2)
Occupational therapist	1.90% (N.=2)
Interpreters	1.90% (N.=2)
Optometrist	0.95% (N.=1)
Personal support worker	0.95% (N.=1)
Academician	0.95% (N.=1)
Not reported	2.86% (N.=3)
WHO Region
Americas	30.48% (N.=32)
Europe	24.76% (N.=26)
South-East Asia	20.95% (N.=22)
Western Pacific	13.33% (N.=14)
Africa	7.62% (N.=8)
Eastern Mediterranean	2.86% (N.=3)
Professional setting
Rehabilitation agency	18.10% (N.=19)
Community Support Provider	18.10% (N.=19)
Home care/community care	14.29% (N.=15)
Private practice	9.52% (N.=10)
Primary care hospitals/clinic	5.71% (N.=6)
Long-term care/Nursing home	2.86% (N.=3)
Other	44.76% (N.=47)
Time at the profession
Minimum of 2 years	7.62% (N.=8)
More than 2 years but less than 5 years	12.38% (N.=13)
More than 5 years but less than 10 years	18.10% (N.=19)
More than 10 years	59.05% (N.=62)
Not reported	2.86% (N.=3)

Value rounded to two decimal places.

The two largest groups of respondents were educators/teachers (N.=20) and intervenors (N.=19) who are professionals specifically trained to facilitate the independence of persons living with deafblindness;²⁸ the majority of intervenors (N.=10) were located in Canada and the USA, with an additional four from Europe and four from South-East Asia, and one responding from the Western Pacific region. Participants ranged in age from 22 to 74, most were women (70.5%), and 59% had more than 10 years of professional experience working in the field of deafblindness. These experts represented 27 countries across all six WHO regions and worked in a wide range of professions. Unique site visitors could not be confirmed because the LimeSurvey platform, as offered by the University of Montréal, does not track IP addresses. Therefore, we cannot confirm that a survey respondent did not provide answers to the survey more than once. Additionally, we cannot provide page view rates.

ICF categories

The team linked the content of the survey to 2934 coded responses using ICF categories (first to fourth level). These were divided into 202 for body structure, 907 for body function, 894 for activities and participation, 931 for environmental factors (and an additional 51 personal factors that were identified but not linked). Of those, 2448 were mentioned by 5% or more of respondents. These were divided into 125 for body structure, 780 for body function, 729 for activities and participation, 814 for environmental factors, and 36 that were not linked as personal factors. When focusing on unique categories, the survey content was represented using 421 items. These were divided into 61 for body structure, 117 for body function, 135 for activities and participation, 108 for environmental factors. Of these, 133 were using by 5% or more of respondents, breaking down into nine (6.8%) for Body Structure, 37 (27.8%) for Body Function, 41 (30.8%) for Activities and Participation, 39 (29.3%) for environmental factors (Supplementary Digital Material 1: Supplementary Table I and II). The overall three most frequently used code categories were Mental Functions (b1), Support and Relationships (e3) and Sensory functions and pain (b2) (Figure 2).

Figure 2.

—Proportional frequency distribution of ICF chapters utilized during the linking process of survey responses from 105 experts on deafblindness. The width of each branch represents its proportional frequency.

The top three most frequently used categories for each chapter were Communication (d3, 12.91%), Carrying out daily routine (d230, 9.62%), and Mobility (d4, 8.24) for Activities and Participation; Other professionals (e360, 8.85%), Support and relationships (e3, 8.85%), and Immediate family (e310, 6.14%) for Environmental Factors; Seeing functions (b210, 9.23%), Hearing functions (b230, 8.85%), and Higher-level cognitive functions (b164, 7.05%) for Body Functions; and Eye, ear and related structures (s2, 45.60%), Structure of hand (s7302, 14.40%) and Structure of brain (s110, 8.00%) for Body Structure.

Overall, the proportional distributions indicates that (by 5% or more of the respondents) all nine ICF Activities and Participation chapters were represented, all five of the Environmental Factors chapters were covered, five of the eight Body Functions chapters were used, and three of the eight Body Structures chapters were covered in the linking process (Figure 2). This corresponds to 73.3% of the entire classification, given that there are 30 chapters comprising the ICF. Personal factors (pf) are not currently coded within ICF categories; however, experts mentioned concepts such as ‘comorbidity,’ ‘housing,’ and ‘mental health’ as relevant.

Discussion

The purpose of the present study was to identify the priority aspects of body structure and functioning, activities, participation, as well as environmental variables that are most relevant for persons living with deafblindness, as viewed from the perspective of health and social service professionals working with this population across the globe. We summarized these aspects using the ICF classification as a reference tool, because this information was collected within the overall goal of working towards ICF Core Sets for deafblindness.²⁰ The survey dissemination and recruitment partnership were sufficiently successful to attract a large and globally representative sample of participants that represent all six regions of the World Health Organization. In addition, they provide a large interdisciplinary perspective across multiple professions involved in the care and service provision for individuals living with deafblindness. The professional perspectives represented in the data (Table I) incorporate health and social service providers from vision- and hearing-specific professions, but also include individuals that develop specialized expertise unique to deafblindness, such as intervenors, tactile sign language interpreters, and educators that specialize in working with deafblind children and youth. The scope of practice for the majority of these professionals focuses on their understanding of functional independence and social participation, which is clearly represented in the data.

The proportional distribution of codes across the three chapters on Body Functions, Activities and Participation, and Environmental Factors is relatively equal, initially indicating a balanced evaluation on priorities from the perspective of experts. This distribution is similar to the pattern observed in the distribution of codes from the systematic literature, representing the priorities of researchers. However, within each chapter, interesting differences emerge. It is not surprising that many codes within Body Functions relate to Sensory functions (b2), including seeing, hearing, touch, taste, smell, proprioception, and vestibular function. However, the overwhelming majority of codes referred to aspects of Mental functions (b1). Experts expressed the importance of cognitive functioning, both in the context of cognitive development of children with deafblindness, as well as with working-age and older adults in the context of cognitive stimulation and protection against cognitive decline. Furthermore, the codes highlight the importance of temperament, personality, motivation as well as emotional functions that are relevant to the successful management of life with deafblindness.

Within the chapter on Activities and Participation, codes across the nine sections were relatively equally distributed, with the exception of d6 (Domestic life). There may be two separate reasons for this observation. First, those respondents who are mainly involved in the professional aspects of working with children that are deafblind may not specifically consider the Acquisition of necessities (d610-d629), Household tasks (d630-d649), or Caring for household objects and assisting others (d650-d669) as part of the responsibilities that are relevant to be considered. The responsibilities of domestic life should not fall on children, but on parents. Family and culture both likely play different roles in different countries and continents in the context of disability of any kind,²⁹ which is potentially apparent in these international data sources as well. Second, it is possible that a certain bias may be present among experts, leading them to perceive that adults living with deafblindness may rely on others with tasks that relate to domestic life. Depending on the severity as well as the age of onset of deafblindness, some professionals may be under the impression that most individuals living with deafblindness either delegate such tasks to those who provide formal or informal care, or that their deafblind clients are limited in their ability to take responsibility for such tasks. The reality of this situation is complex and varied, as its intricacies have been described, for example, in the context of the dynamics of families with a deafblind parent.³⁰ Even though our data set includes the perspectives of 19 intervenors, none of these professionals were based in the Global South, pointing at education, training and service delivery needs in underfunded regions of the world.

Within the category of Environmental Factors, an interesting discrepancy emerged between the distribution of codes from the systematic literature review, compared to the data obtained from experts here. According to the experts, the most frequently acknowledged environmental barriers and facilitators were to be found among Support and relationships (e3), followed by Services, systems, and policies (e5). The responses highlight the importance of human support, formal as well as informal, in addition to the need for funding, services and regulations that can sustain and acknowledge those that provide this support. Interestingly, these findings are aligned with the results of previous work on functioning of older adults with deafblindness in Canada,³¹ and the findings of a study with working-age adults with deafblindness in India.³² Regardless of the geographical location in the Global North or South, both studies underscored the relevance of the two factors on functioning of individuals living with deafblindness. In contrast, the majority of codes representing outcome measures in the systematic literature review were linked to Products and technology (e1) followed by Natural environment & human-made changes to the environment. The content of outcome measures utilized by researchers appear to focus on the development and evaluation of assistive technology and devices, as well as adaptations to, and accessibility of, the environment in which persons with deafblindness live. This discrepancy may, in part, be rooted in funding availability and the success of researchers who may be more likely to obtain grants that focus on technology and accessibility. It may also reflect a difference in the perspective on service delivery towards persons living with deafblindness, whereby experts in the field themselves are part of the workforce that provide this support. They are integrated into these services and depend on the policies and systems within which they are employed. In addition, access to, and use of technology varies widely across the Regions of the WHO, based on variables such as Wi-Fi access and technology affordability.^{33, 34}

Much like in the expert survey that formed part of the Core Set development for hearing loss,¹⁶ the data indicate that the care and social service priorities relevant to persons living with deafblindness are spread across a wide variety of professional expertise and interests. For hearing loss, 53% of the ICF categories were used, whereas for deafblindness 73.3% were represented. This difference represents the increased complexity of variables that influence health and wellbeing in this population. It also highlights the need for assessment tools that can capture this complexity. There are few such measure available, such as the interRAI Community Health Assessment and its Deafblind Supplement.³⁵ By developing the Core Sets for deafblindness, we hope to lay the groundwork for the development of an additional multidimensional tool that can be utilized to do justice to the multifaceted needs of this vulnerable population. Hopefully, such a measure will allow for the development of additional and more refined assessment instruments for deafblindness that can be used both clinically and in research. Although the codes within the ICF can be used to assess functional status, the ICF has been proven difficult to use in that manner. A Core Set is not an instrument by itself but rather serves as a foundation to other instruments. Unfortunately, many Core Sets have not been validated, and this step is an important aspect to highlight for future studies.³⁶

Conclusions

Health and social service professionals that are experts in working with persons living with deafblindness indicate that over 73% of the WHO ICF classification codes are relevant to the description of variables that influence functioning in this population. Together with the results of a systematic literature review, and an ongoing study exploring the priorities of persons living with deafblindness, the present study builds the foundation for the development and eventual validation of ICF Core Sets for deafblindness. Next steps include the analysis of qualitative interviews of persons living with deafblindness, and a comparison of their priorities with those represented here and in the research literature. Ultimately, the Core Sets will combine the perspectives of all partners that are involved in deafblindness, and optimally leading to improved and inclusive ways to highlight, measure and describe the priorities of functioning relevant to the lives of persons with deafblindness, giving them the recognition they deserve.

Supplementary Digital Material 1

Supplementary Table I

Relative frequencies of category codes from the Activities and Participation (d) and Environmental Factors (e) components mentioned by 5% of the respondents.

Supplementary Table II

Relative frequencies of category codes from the Body Functions (b) and Body Structures (s) components mentioned by 5% of the respondents.