Comparing perspectives from experts and individuals with lived experience in the Global North versus the Global South: ICF core sets for deafblindness

Abstract

Background

Achieving equitable global health frameworks requires the intentional integration of diverse voices—both professional and lived—from across the high-resourced Global North (GN) and low-resourced South (GS). It is, however, rare that Core Set development using the International Classification of Functioning, Disability and Health (ICF) has equal data representation from both regions. Using the data from the development of Core Sets on deafblindness, we explored a unique opportunity, given the geographic distribution of data sources. We compared ICF category frequencies from the GN and GS across body structure, body function, activities and participation, and environmental factors.

Methods

We divided the data from an expert survey (n = 105) and from interviews with deafblind individuals (n = 72) by country of origin into GN and GS using the Brandt Line, representing all six regions of the WHO (28 countries). Using the ICF coding system to identify perceived categories of functioning, aggregated frequencies of unique ICF categories were compared across ICF components and chapters using chi-square statistics.

Results

Survey data showed no significant geographic differences across activities and participation or environmental factors; however, qualitative interviews revealed significant deviations. For activities and participation, GN emphasized d9205 (socializing) and d940 (human rights), while GS highlighted d760 (family relationships). For environmental factors, GN focused on e5800 (health services) and e298 (environmental adaptations), whereas GS emphasized e5550 (associations), e310 (family), and e325 (community supports). Within the GN, survey and interview data also differed. Surveys emphasized e310, e315 and e320 (supports), while interviews highlighted e410, e425, e450, and e455 (attitudes). For activities and participation, d660 (assisting others) was more frequent in interviews. The GS showed significant within-region differences for e4 (attitudes), d9 (community, social and civic life) and d2 (general tasks and demands).

Conclusions

Findings highlight the regional variations in activities and participation among individuals with deafblindness as they reflect differences in environmental factors. Rooted in cultural and resource differences, geographic region itself constitutes a key environmental factor. Expert perspectives may underrepresent differences in lived environmental realities of individuals with deafblindness. Future Core Set development will benefit from including more diverse sources.

Background

The World Health Organization’s (WHO) International Classification of Functioning, Disability and Health (ICF) is a framework that allows for the conceptualization of health from a multidimensional bio-psycho-social perspective [34]. Since its ratification by 191 WHO member states [33], it has been widely used in clinical practice for assessment of functioning, the planning of rehabilitation services, and the tracking of intervention outcomes. It has been a useful tool for health and social policy development, via policy and service delivery planning as well as establishing eligibility criteria for insurance and care access, and it is used by researchers and educators for the identification of priorities, as well as interdisciplinary communication and collaboration [16]. The ICF complements the medical diagnoses to gain a broader understanding of how individuals interact with their environment and how this interaction affects their functioning and well-being. Even though it has had a tremendous positive impact, the ICF has been criticized for being somewhat Euro-centered and specific to high-income countries of the Global North/GN [14, 15], while often lacking the opportunity and/or ability to capture the needs and context of low- and middle-income countries in the Global South/GS [22].

In the context of the ICF, this discrepancy is specifically apparent in the development of Core Sets, condensed sets of ICF categories that are developed to identify the functioning priorities of a specific disease or health condition [11]. The ICF Research Branch has clear guidelines that the development of Core Sets needs to include data representation from each of the six WHO regions, in each of the four preparatory studies that build the foundation for a Core Set [23]. In the first of these studies, the systematic literature review, the bias towards over-representing the GN perspective most likely lies simply in the fact that economic resources allow for more peer-reviewed literature to be published in richer countries [19]. The second study, the expert survey, has more potential to reach a globally representative sample of participants because it can be conducted online, but the generally smaller number of trained professionals in subspecialties on a specific health condition or in some regions will still influence representation [3]. Both the third study, the qualitative interviews with individuals living with the condition, and the fourth study, the multi-centric clinical evaluation, become harder to balance between the GN and GS because of the resources needed to recruit and conduct data collection. In addition, many persons with certain types of disabilities may be somewhat invisible, for example due to cultural or political views on disabilities that contextualize disability as a punishment for bad deeds or divine intervention [24]. Furthermore, the voice of people with disabilities may be less prominent in the GS because of the absence of polices, such as the Americans with Disabilities Act in the GN. The COVID-19 pandemic has moved us methodologically forward because now remote interviews and assessments have become a reasonable alternative, however, internet availability remains a dividing factor for equal access [4]. The same applies to the final step, the consensus conference, which requires representation from all WHO regions, and from all stakeholder groups, because online meetings have the potential to accommodate participation across time zones and WHO regions. However, depending on the health condition, participation on-line may be problematic, depending on the effects of the condition on functioning (e.g., communication requirements). In the case of conditions that include sensory difficulties, more resources may be required for in-person meetings that can accommodate communication needs (e.g., sign language).

Closer examination of some of the existing Core Set studies reveals that, for example, the qualitative interviews on hearing loss only sampled individuals from South Africa and The Netherlands [8]. The data were only presented in merged format, and no attempt was made to compare data sources according to geographic origin. In the literature review for the Core Sets on vision loss, only 3.5% of selected studies originated from Africa and 1.6% from the Eastern Mediterranean Region [1]. Such under-representation of the GS has been reported during Core Set development of Diabetes Miletus as well [26]. A recent review of ICF Core Set validation studies indicated that none of the validations were based in the African Region [14], further contributing to what has been termed the ‘information paradox’ whereby the least information is available for regions with the highest health burden [13]. Finally, when data from the GS are analyzed separately, a content validity study to assess and confirm the relevance of specific Core Sets conducted in Nepal indicated that less than half of the categories proposed based on data from the GN applied to common disabling conditions in the context of the GS [21]. Opportunities to explore ICF coding difference among WHO regions remain elusive, but the recent development of the ICF Core Sets for deafblindness [27–29] provides a rare occasion where global collaboration with strong community partners allowed for representation of all six WHO regions, with a total of 58 countries contributing to the overall data across the four preparatory studies. The data sets from qualitative interviews with individuals with lived experience of deafblindness and their family members [31] and the expert survey [30] were available and coded in such a way that our team was able to address the following research question: Does the frequency distribution of unique categories across the four ICF components (body structure, body function, activities and participation, environmental factors) differ as a function of data collected from the GN versus the GS?

Methods

We conducted a secondary, cross-sectional comparative analysis, using descriptive statistics, frequency comparisons and chi squared statistics of aggregated frequencies of unique ICF categories as coded during the development of the Core Sets for deafblindness. Analyses were conducted at both the component and chapter levels using chi-square tests on aggregated frequencies of unique ICF categories. Ethical approval was obtained from the Institutional Review Board of the Université de Montréal (CERC # 2022–1710, CERC 2023–4150, respectively). The multi-site qualitative study was also approved by the Institutional Review Boards of the Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain (MP-50–2023-1749) in Canada, the Instituto del Salud Carlos III (#CEI PI 44_2021-v3) in Spain, and the University of Melbourne (#2023–25708–42888–3) in Australia. For both studies, detailed information on the sample, recruitment, procedure, materials, and data analysis is available elsewhere [30, 31], whereas sample demographics are displayed in Table 1.

Table 1.

Demographic Information of Participants in the Expert Survey and Qualitative Study

Variable		Expert survey (n = 105)	Qualitative study (n = 72)
Sex (n)	Male	··	23
	Female	··	30
	Unknown	··	19
Gender (n)	Man	29	··
	Woman	74	··
	Other (e.g., gender fluid, non-binary)	1	··
	Prefer not to answer	1	··
Age: Mean (SD) [Range]		46.91 (13.5) [22–74]	41.69 (19.56) [1–83]
WHO Region (n)	Global North
	Region of the Americas	26	10
	– Canada	12	10
	– United States	14	–
	Western Pacific Region	14	13
	– Australia	13	13
	– New Zealand	1	–
	European Region	25	10
	– Spain	2	7
	– United Kingdom	8	2
	– France	2	1
	– Germany	3	··
	– Denmark	3	··
	– The Netherlands	2	··
	– Sweden	2	··
	– Ireland	1	··
	– Norway	1	··
	– Switzerland	1	··
WHO Region (n)	Global South
	Region of the Americas	6	10
	– Mexico	1	10
	– Brazil	2	··
	– Bolivia	1	··
	– Colombia	1	··
	– Peru	1	··
	European Region	1	9
	– Turkey	1	9
	African Region	8	9
	– Zambia	··	9
	– Tanzania	4	··
	– Kenya	2	··
	– Uganda	1	··
	– Unknown	1	··
	Eastern Mediterranean	1	9
	– Egypt	3	9
	South-East Asia	22	11
	– India	17	7
	– Nepal	3	4
	– Bangladesh	2	··

Qualitative study

For this study, 26 interviews and nine focus groups were conducted online or in person with 72 individuals living with deafblindness and/or informal caregivers who were recruited through convenience sampling. To better understand their lived experiences, the standard open-ended interview questions mandated by the ICF Research Branch [23] explored how they perceive the physical and emotional effects of deafblindness, the specific bodily areas affected, daily challenges, environmental factors that support or hinder their daily routines, and personal qualities that help them cope with their daily lives.

Expert survey

For this study, 105 experts from across the world answered an anonymous online qualitative cross-sectional survey containing the same open-ended interview questions [23]. The two largest groups of survey respondents were educators/teachers (n = 20) and intervenors (n = 19), professionals specifically trained to facilitate the independence of individuals living with deafblindness. Survey respondents were asked about their experiences working with individuals with deafblindness, specifically regarding the impact on their body and mind, the most affected body parts, daily limitations of functioning, supportive and challenging environmental factors, and personal characteristics that support daily functioning Table 2.

Table 2.

Frequency distribution of unique ICF categories for the activities and participation component in the expert survey and the qualitative interviews across all available category levels

					Frequency
					Expert survey		Lived experience
	Chapter	Second level category	Third level category	Description	GN	GS	GN	GS
	d1			Learning and applying knowledge	27	22
		d115		Listening	.	.	.	17
		d120		Other purposeful sensing	.	.	.	2
		d129		Purposeful sensory experiences, other specified and unspecified	.	.	4	1
		d130		Copying	.	.	.	2
		d133		Acquiring an additional language	.	.	.	2
		d135		Rehearsing	.	.	2	1
		d140		Learning to read	.	.	.	4
		d145		Learning to write	.	.	.	1
		d155		Acquiring skills	9	.	1	2
			d1550	Acquiring basic skills	.		.	1
			d1551	Acquiring complex skills	3	5	1	.
			d1558	Acquiring skills, other specified	.	.	1	.
		d159		Basic learning, other specified and unspecified	.	.	.	1
		d160		Focusing attention	.	.	1	3
		d163		Thinking	.	.	1	3
		d166		Reading	6	.	2	14
		d170		Writing	.	.	1	7
		d177		Solving problems	4	1	.	.
		d198		Learning and applying knowledge, other specified	.	.	14	7
Aggregated total (d1)					49	28	28	68
	d2			General tasks and demands	5	.	.	.
		d210		Undertaking a single task	.	.	.	2
			d2100	Undertaking a simple task	.	.	2	.
			d2102	Undertaking a single task independently	.	.	1	2
		d220		Undertaking multiple tasks	.	.	1	.
			d2202	Undertaking multiple tasks independently,	3	5	4	4
		d230		Carrying out daily routine	40	30	10	4
			d2301	Managing daily routine	5	.	.	3
			d2302	Completing the daily routine	.	.	1	2
			d2303	Managing one’s own activity level	.	.	3	1
		d240		Handling stress and other psychological demands	.	.	3	3
			d2400	Handling responsibilities	.	.	.	4
			d2401	Handling stress	2	3	6	8
			d2402	Handling crisis	.	.	3	3
		d298		General tasks and demands, other specified	.	.	.	3
Aggregated total (d2)					55	38	34	39
	d3			Communication	62	32	13	21
		d310		Communicating with—receiving—spoken messages	.	.	2	1
			d3108	Communicating with—receiving—spoken messages, other specified	.	.	1	.
			d3150	Communicating with—receiving—body gestures	7	2	1	1
			d3151	Communicating with—receiving—general signs and symbols	.	.	.	3
		d320		Communicating with—receiving—formal sign language messages	5	.	1	9
		d325		Communicating with—receiving—written messages	.	.	.	7
		d329		Communicating—receiving, other specified and unspecified	.	.	.	1
		d330		Speaking	.	.	4	1
		d335		Producing nonverbal messages	.	.	1	6
			d3350	Producing body language	3	2	.	1
			d3351	Producing signs and symbols	.	.	.	2
		d340		Producing messages in formal sign language	.	.	5	5
		d349		Communication—producing, other specified and unspecified	.	.	.	2
		d350		Conversation	.	.	.	6
			d3500	Starting a conversation	.	.	1	.
			d3503	Conversing with one person	.	.	2	.
			d3504	Conversing with many people	.	.	3	2
		d360		Using communication devices and techniques	10	.	1	2
			d3600	Using telecommunication devices	.	.	.	4
			d3601	Using writing machines	.	.	1	.
			d3602	Using communication techniques	.	.	10	3
			d3608	Using communication devices and techniques, other specified	.	.	3	.
		d369		Conversation and use of communication devices and techniques, other specified and unspecified	…	.	4	.
		d398		Communication, other specified	.	.	2	10
Aggregated total (d3)					87	36	55	87
	d4			Mobility	39	21	.	14
		d410		Changing basic body position	.		.	1
			d4103	Sitting	.	.	.	1
			d4104	Standing	.	.	.	1
		d415		Maintaining a body position	.	.	.	1
			d4151	Maintaining a squatting position	.	.	.	1
			d4152	Maintaining a kneeling position		.	1	.
			d4153	Maintaining a sitting position	.	.	.	2
			d4154	Maintaining a standing position	.	.	.	1
			d4200	Transferring oneself while sitting	.	.	.	2
			d4301	Carrying in the hands	.	.	.	1
			d4302	Carrying in the arms	.	.	.	1
			d4303	Carrying on shoulders, hip and back	.	.	.	1
			d4304	Carrying on the head	.	.	1	.
			d4305	Putting down objects	.	.	1	.
		d440		Fine hand use	.	.	1	1
		d445		Hand and arm use	.	5	1	4
			d4452	Reaching	.	.	.	1
			d4453	Turning or twisting the hands or arms	.	.	.	1
			d4458	Hand and arm use, other specified	.	.	.	3
		d449		Carrying, moving and handling objects, other specified and unspecified		.	1	.
		d450		Walking	4	3	10	11
			d4502	Walking on different surfaces	.	.	1	.
			d4503	Walking around obstacles	.	.	17	9
			d4508	Walking, other specified	.	.	.	1
		d455		Moving around	6	2	3	8
			d4550	Crawling	.	.	.	1
			d4551	Climbing	.	.	.	1
			d4552	Running	.	.	.	1
			d4558	Moving around, other specified	.	.	.	1
		d460		Moving around in different locations	.	.	3	4
			d4600	Moving around within the home		.	.	1
			d4601	Moving around within buildings other than home	.	.	2	.
			d4602	Moving around outside the home and other buildings	.	.	4	7
		d469		Walking and moving, other specified and unspecified	.	.	1	.
		d470		Using transportation	10	3	1	2
			d4701	Using private motorized transportation	.	.	5	1
			d4702	Using public motorized transportation	.	.	5	9
			d4708	Using transportation, other specified	.	.	1	.
		d475		Driving	.	.	2	3
		d489		Moving around using transportation, other specified and unspecified	.	.	1	2
		d498		Mobility, other specified	.	.	.	2
Aggregated total (d4)					59	34	62	101
	d5			Self-care	12	2	2	1
		d510		Washing oneself	.	.	3	2
		d520		Caring body parts	.	.	.	2
			d5201	Caring for teeth	.	.	1	.
		d530		Toileting	.	.	1	2
			d5300	Regulating urination	.	.	1	1
			d5301	Regulating defecation	.	.	.	2
			d5302	Menstrual care	.	.	1	1
		d540		Dressing	3	.	2	2
		d550		Eating	.	2	3	5
		d560		Drinking	.	.	.	3
		d570		Looking after one’s health	19	6	.	3
			d5700	Ensuring one’s physical comfort	.	.	.	1
			d5701	Managing diet and fitness	.	.	3	.
			d5702	Maintaining one’s health	8	3	2	3
		d598		Self-care, other specified	.	.	1	2
Aggregated total (d5)					42	13	20	30
			d6100	Buying a place to live	.	.	1	.
		d620		Acquisition of goods and services	.	.	1	.
		d630		Preparing meals	4	2	6	.
			d6300	Preparing simple meals	.	.	1	.
		d640		Doing housework	.	.	2	12
			d6400	Washing and drying clothes and garments	.	.	.	1
			d6402	Cleaning living area	.	.	.	1
		d649		Household tasks, other specified and unspecified	.	.	1	.
			d6506	Taking care of animals	.	.	.	2
		d660		Assisting others	.	.	3	.
			d6600	Assisting others with self-care	.	.	.	1
			d6601	Assisting others in movement	.	.	.	2
			d6602	Assisting others in communication	.	.	2	4
			d6608	Assisting others, other specified	.	.	.	1
Aggregated total (d6)					4	2	17	24
	d7			Interpersonal interactions and relationships	11	6	4	16
		d710		Basic interpersonal interactions	20	7	1	.
			d7100	Respect and warmth in relationships	.	.	.	3
			d7101	Appreciation in relationships	.	.	.	5
			d7102	Tolerance in relationships	.	.	.	3
			d7104	Social cues in relationships	…	.	.	1
			d7105	Physical contact in relationships	.	.	.	2
		d720		Complex interpersonal interactions	5	.	2	1
			d7200	Forming relationships	.	.	4	.
			d7201	Terminating relationships	.	.	1	.
			d7202	Regulating behaviours within interactions	.	.	1	.
		d729		General interpersonal interactions, other specified and unspecified	.	.	1	.
		d730		Relating with strangers	.	.	.	1
		d740		Formal relationships	.	.	.	1
			d7400	Relating with persons in authority	.	.	.	1
			d7402	Relating with equals	.	.	.	1
			d7408	Formal relationships, other specified	.	.	.	1
		d750		Informal social relationships	.	.	3	1
			d7500	Informal relationships with friends	.	.	1	5
			d7501	Informal relationships with neighbours	.	.	.	1
			d7504	Informal relationships with peers	.	.	.	3
		d760		Family relationships	18	8	5	15
			d7600	Parent–child relationships	2	6	2	9
			d7601	Child-parent relationships	.	.	.	16
			d7602	Sibling relationships	.	.	.	6
			d7603	Extended family relationships	.	.	.	4
			d7701	Spousal relationships	.	.	4	11
		d798		Interpersonal interactions and relationships, other specified	.	.	1	.
Aggregated total (d7)					56	27	30	107
	d8			Major life areas	5	3	.	.
		d810		Informal education	.	.	.	1
		d820		School education	12	6	1	5
		d825		Vocational Training	.	.	5	.
		d830		Higher education	.	.	.	2
		d838		Education, other specified	.	.	.	1
		d839		Education, unspecified	14	6	.	6
		d845		Acquiring, keeping and terminating a job	.	.	.	1
			d8450	Seeking employment	.	.	4	2
			d8451	Maintaining a job	.	.	3	1
			d8452	Terminating a job	.	.	.	1
			d8458	Acquiring, keeping and terminating a job, other specified	.	.	.	1
		d850		Remunerative employment	4	2	2	3
			d8502	Full-time employment	.	.	.	1
			d8508	Remunerative employment, other specified	.	.	.	1
		d855		Non-remunerative employment	.	.	4	1
		d859		Work and employment, other specified and unspecified	.	4	14	5
		d860		Basic economic transactions	8	.	1	.
			d8700	Personal economic resources	.	.	2	1
Aggregated total (d8)					43	21	36	33
	d9			Community, social and civic life	9	5	2	1
		d910		Community life	21	12	5	4
			d9100	Informal associations	.	.	.	6
			d9101	Formal associations	.	.	.	2
		d920		Recreation and leisure	13	7	7	11
			d9200	Play	.	.	3	.
			d9201	Sports	.	.	5	4
			d9202	Arts and culture	.	.	5	1
			d9203	Crafts	.	.	1	1
			d9204	Hobbies	.	.	2	3
			d9205	Socializing	16	13	26	5
			d9208	Recreation and leisure, other specified	.	.	3	.
		d930		Religion and spirituality	.	.	2	.
			d9300	Organized religion	.	.	1	.
		d940		Human rights	23	8	10	.
		d950		Political life and citizenship	.	.	2	.
		d998		Community, social and civic life, other specified	.	.	3	.
Aggregated total (d9)					82	45	77	38

Data from both studies were coded by a trained team of 4 coders in our research lab at the Université de Montréal with extensive experience using the linking procedure laid out by Cieza and colleagues [5]. Please note that × 99 categories (unspecified) are merged with chapter level categories, since they do not contain content-specific information.

Results

The proportional category distributions across component and chapter levels are displayed in Fig. 1. The detailed frequencies of categories for both studies for both the GN and GS across all components, chapters and categories are provided in Tables 2 through 5 .

Table 4.

Frequency distribution of unique ICF categories for the environmental factors component in the expert survey and the qualitative interviews across all available category levels

						Frequency
						Expert survey		Lived experience
		Chapter	Second level category	Third level category	Description	GN	GS	GN	GS
		e1			Products and technology	11	··	1	··
				e1101	Drugs	··	··	2	··
			e115		Products and technology for personal use in daily living	7	1	4	1
				e1151	Assistive products and technology for personal use in daily living	11	6	10	1
			e120		Products and technology for personal indoor and outdoor mobility and transportation	5	··	1	··
				e1201	Assistive products and technology for personal indoor and outdoor mobility and transportation	··	··	16	6
			e125		Products and technology for communication	··	··	5	2
				e1250	General products and technology for communication	··	··	··	4
				e1251	Assistive products and technology for communication	12	··	21	24
			e130		Products and technology for education	··	··	1	··
				e1300	General products and technology for education	··	··	··	1
				e1301	Assistive products and technology for education	··	··	3	··
				e1308	Products and technology for education, other specified	··	··	··	1
				e1351	Assistive products and technology for employment	··	··	··	1
			e150		Design, construction and building products and technology of buildings for public use	24	20	2	··
				e1501	Design, construction and building products and technology for gaining access to facilities inside buildings for public use	··	··	1	··
			e155		Design, construction and building products and technology of buildings for private use	3	2	2	··
				e1551	Design, construction and building products and technology for gaining access to facilities in buildings for private use	··	··	1	··
			e165		Assets	··	··	1	··
				e1650	Financial assets	6	2	··	3
Aggregated total (e1)						79	31	71	44
		e2			Natural environment and human-made changes to environment	15	19	2	1
			e210		Physical geography	··	··	1	··
			e215		Population	3	2	··	··
				e2151	Population density	··	··	2	··
				e2201	Animals	··	··	··	1
			e225		Climate	··	··	··	2
				e2254	Wind	··	··	··	1
			e235		Human-caused events	14	4	··	··
			e240		Light	17	1	··	··
				e2400	Light intensity	··	··	7	··
				e2401	Light quality	··	··	2	··
			e250		Sound	13	2	1	··
				e2500	Sound intensity	··	··	··	3
				e2501	Sound quality	··	··	11	3
			e255		Vibration	··	··	··	1
			e298		Natural environment and human-made changes to environment, other specified	··	··	27	7
Aggregated total (e2)						62	28	53	19
		e3			Support and Relationships	53	19	10	14
			e310		Immediate family	29	21	18	40
			e315		Extended family	25	15	2	6
			e320		Friends	9	8	4	15
			e325		Acquaintances, peers, colleagues, neighbours and community members	5	6	3	11
			e330		People in positions of authority	··	··	2	2
			e335		People in subordinate positions	··	··	··	1
			e340		Personal care providers and personal assistants	30	11	39	13
			e350		Domesticated animals	··	··	2	··
			e355		Health professionals	22	12	10	1
			e360		Other professionals	50	22	7	11
			e398		Support and relationships, other specified	··	··	19	10
Aggregated total (e3)						223	114	116	124
		e4			Attitudes	25	11	2	1
			e410		Individual attitudes of immediate family members	8	4	19	17
			e415		Individual attitudes of extended family members	6	2	8	3
			e420		Individual attitudes of friends	··	··	5	7
			e425		Individual attitudes of acquaintances, peers, colleagues, neighbours and community members	··	··	18	15
			e430		Individual attitudes of people in positions of authority	··	··	9	3
			e435		Individual attitudes of people in subordinate positions	··	··	··	1
			e440		Individual attitudes of personal care providers and personal assistants	6	1	4	··
			e445		Individual attitudes of strangers	··	··	9	6
			e450		​​Individual attitudes of health professionals	6	3	17	··
			e455		Individual attitudes of other professionals	4	1	10	1
			e460		Societal attitudes	24	9	72	72
			e465		Social norms, practices and ideologies	··	··	1	5
			e498		Attitudes, other specified	··	··	9	8
Aggregated total (e4)						79	31	183	139
		e5			Services, systems and policies	5	1	1	··
			e515		Architecture and construction services, systems and policies	··	··	1	1
				e5151	Architecture and construction systems	··	··	··	1
			e520		Open space planning services, systems and policies	··	··	2	··
			e535		Communication services, systems and policies	14	5	1	1
				e5350	Communication services	··	··	2	1
				e5351	Communication systems	7	1	··	··
				e5358	Communication services, systems and policies, other specified	··	··	1	··
			e540		Transportation services, systems and policies	··	··	2	··
				e5401	Transportation systems	··	··	2	2
				e5408	Transportation services, systems and policies, other specified	··	··	1	··
			e555		Associations and organizational services, systems and policies	··	··	2	··
				e5550	Associations and organizational services	··	··	4	12
			e560		Media services, systems and policies	··	··	1
				e5600	Media services	··	··	1	1
			e570		Social security services, systems and policies	··	··	1
				e5700	Social security services	··	··	··	1
			e575		General social support services, systems and policies	9		2	3
				e5750	General social support services	25	7	6	··
				e5751	General social support systems	··	··	1	··
			e580		Health services, systems and policies	··	··	5	··
				e5800	Health services	20	11	15	2
				e5801	Health systems	6	2	4	··
				e5802	Health policies	21	5	7	2
				e5808	Health services, systems and policies, other specified	··	··	2	··
			e585		Education and training services, systems and policies	11	5	5	··
				e5850	Education and training services	1	4	2	1
				e5851	Education and training systems	··	··	··	1
				e5858	Education and training services, systems and policies, other specified	··	··	3	··
				e5859	Education and training services, systems and policies, unspecified	··	··	1	··
			e590		Labour and employment services, systems and policies	··	··	2	··
				e5900	Labour and employment services	··	··	··	1
			e595		Political services, systems and policies	··	··	2	··
Aggregated total (e5)						119	41	79	30

Fig. 1.

Distribution of unique ICF Categories across the four ICF components, compared horizontally between data sources from the Global North (left) and the Global South (right). The top graph displays the data distributions for ICF categories resulting from qualitative interviews/focus groups with 72 deafblind participants and their family members. The bottom graph presents categories from a survey with 105 experts in the field of deafblindness

Component level

First, we compared the frequency distribution of unique categories across the four ICF components (body structure, body function, activities and participation, environmental factors) as a function of data collected from the GN versus the GS. For data from the qualitative interviews with individuals living with deafblindness, chi squared analysis indicated a statistically significant deviation from expected values, ꭓ² (df = 3) = 13.48, p < 0.01. Using the component calculations for each contributing square towards the sum of the ꭓ², we used the largest values in each calculation to attribute which value most deviated from expected values. The results indicated a higher proportion of environmental factor categories in the GN compared to the GS. The other ICF components did not show a significant difference. The same analysis of data from the expert survey did not reveal any statistically significant deviation from the expected distribution, χ² (df = 3) = 0.50, p > 0.05.

Chapter level

Please note that statistical analyses at this level for b (body functions) and s (body structures) was not possible, given the data distribution and the resulting empty cells (details available in Tables 3 and 5, respectively). Only three body structure chapters were used during coding, referring to s1 (the nervous system), s2 (the eye and ear), and s7 (structures related to movement). This last chapter specifically contains categories for s710 (the structure of the head and neck region) and s7302 (the structure of the hand), both of which are important for tactile communication. Most categories in the chapters on body function related to b1 (mental functions) as well as b2 (sensory functions and pain).

Table 3.

Frequency distribution of unique ICF categories for the body structure component in the expert survey and the qualitative interviews across all available category levels

					Frequency
					Expert survey		Lived experience
	Chapter	Second level category	Third level category	Description	GN	GS	GN	GS
	s1	Structures of the nervous system			2	6	.	··
		s110		Structure of brain	3	7	1	1
			s1106	Structure of cranial nerves				1
		s120		Spinal cord and related structures				1
Aggregated total (s1)					5	13	1	1
	s2	The eye, ear and related structures			38	19	1	6
		s220		Eyeball	.	.	.	2
			s2201	Cornea	.	.	1	1
			s2203	Retina	.	.	.	3
			s2204	Lens of eyeball	.	.	.	3
			s2205	Vitreous body	.	.	1	2
		s230		Structures around eye	.	.	.	1
			s2301	Eyelid	.	.	.	1
		s240		Structure of external ear	.	.	.	4
		s250		Structure of middle ear	.	.	.	1
			s2600	Cochlea	.	.	.	2
Aggregated total (s2)					38	19	3	26
		s310		Structure of nose	.	.	.	1
		s320		Structure of mouth	.	.	.	1
			s3200	Teeth	.	.	.	4
			s3201	Gums	.	.	.	1
			s3202	Structure of palate	.	.	.	2
			s3204 (s32041)	Structure of mouth (Lower lip)	.	.	.	1
			s3208	Structure of mouth, other specified	.	.	.	1
		s330		Structure of pharynx	.	.	.	1
Aggregated total (s3)					0	0	0	12
		s410 (s41008)		Structure of heart (Structure of heart, other specified)	.	.	.	3
			s4101	Arteries	.	.	.	1
Aggregated total (s4)					0	0	0	4
			s6303	Structure of vagina and external genitalia	.	.	.	1
Aggregated total (s6)					0	0	0	1
	s7	Structures related to movement			7	.	1	.
		s710		Structure of head and neck region	9	··	.	1
			s7102	Bones of neck region	.	.	1	.
			s7103	Joints of head and neck region	.	.	.	1
			s7108	Structure of head and neck region, other specified	.	.	1	.
		s720		Structure of shoulder region	5	··	.	.
		s730		Structure of upper extremity	.	.	.	1
			s7300	Structure of upper arm	.	.	1
			s7302	Structure of hand	14	4
		s750		Structure of lower extremity	3	3	1	1
			s7500 (s75001)	Structure of thigh (Hip joint)	··	··	1	··
			s7501	Structure of lower leg	3	2	1	.
			s7600	Structure of vertebral column	.	.	.	1
Aggregated total (s7)					41	9	7	5

Table 5.

Frequency distribution of unique ICF categories for the body function component in the expert survey and the qualitative interviews across all available category levels

					Frequency
					Expert survey		Lived experience
	Chapter	Second level category	Third level category	Description	GN	GS	GN	GS
	b1	Mental functions			14	7	.	.
		b114		Orientation functions	12	6	8	8
			b1140	Orientation to time	.	.	2	.
			b1141	Orientation to place	9	1	8	3
			b1142	Orientation to person	.	.	4	.
		b117		Intellectual functions	29	10	4	10
		b122		Global psychosocial functions	.	.	1	2
		b126		Temperament and personality functions	40	15	27	16
			b1261	Agreeableness	.	.	.	1
			b1622	Conscientiousness	.	.	.	1
			b1263	Psychic stability	.	.	1	15
			b1264	Openness to experience	23	10	2	5
			b1265	Optimism	.	.	.	4
			b1266	Confidence	11	5	7	25
			b1267	Trustworthiness	5	1	2	3
			b1268	Temperament and personality functions, other specified	.	.	.	3
		b130		Energy and drive functions	6	2	2	.
			b1300	Energy level	.	.	.	8
			b1301	Motivation	22	7	.	11
			b1304	Impulse control	.	.	.	4
		b134		Sleep functions	6	1	3	.
			1340	Amount of sleep	.	.		1
		b140		Attention functions	.	.	7	1
			b1400	Sustaining attention	.	.	2	2
			b1401	Shifting attention	.	.	.	2
			b1402	Dividing attention	.	.	.	1
			b1403	Sharing attention	.	.	.	1
		b144		Memory functions	.	.	2	1
			b1441	Long-term memory	.	.	.	1
			b1442	Retrieval of memory	.	.	.	1
			b1448	Memory functions, other specified	.	.	.	3
		b147		Psychomotor functions	6	1	1	2
			b1470	Psychomotor control	.	.	2	3
		b152		Emotional functions	32	15	35	22
			b1521	Regulation of emotion	.	.	3	3
			b1522	Range of emotion	.	.	2	17
			b1528	Emotional functions, other specified	.	.	.	2
		b156		Perceptual functions	13	3	3	3
			b1560	Auditory perception	4	2	2	12
			b1561	Visual perception	4	3	1	3
			b1562	Olfactory perception	.	.	.	1
			b1564	Tactile perception	24	9	.	13
			b1565	Visuospatial perception	.	.	1	.
		b160		Thought functions	.	.	1	.
			b1600	Pace of thought	.	.	2	.
			b1601	Form of thought	.	.	.	1
			b1602	Content of thought	.	.	.	1
			b1603	Control of thought	.	.	.	1
		b164		Higher-level cognitive functions	38	17	1	9
			b1640	Abstraction	.	.	1	.
			b1641	Organization and planning	.	.	1	1
			b1642	Time management	.	.	1	2
			b1644	Insight	.	.	1	1
		b167		Mental functions of language	10	3	1	4
			b1670 (b16702)	Reception of language (Reception of sign language)	.	.	1	5
			b1671	Expression of language	4	3	2	4
		b180		Experience of self and time functions	17	6	3	.
			b1800	Experience of self	5	1	4	.
			b1802	Experience of time	9	1	2	2
Aggregated total (b1)					343	129	153	245
	b2	Sensory functions and pain			19	4	.	.
		b210		Seeing functions	50	22	12	31
			b2100	Visual acuity functions	.	.	.	15
			b2101	Visual field functions	.	.	4	1
			b2102	Quality of vision (Light sensitivity, Colour vision, Contrast sensitivity	.	.	6	5
		b220		Sensations associated with the eye and adjoining structures	.	.	.	2
		b230		Hearing functions	48	.	19	27
			b2300	Sound detection	.	21	1	1
			b2301	Sound discrimination	.	.	1	1
			b2302	Localization of sound source	.	.	.	5
			b2303	Lateralization of sound	.	.	.	5
			b2304	Speech discrimination	.	.	2	6
		b235		Vestibular functions	10	3	3	3
			b2350	Vestibular function of position	.	.	.	1
			b2351	Vestibular function of balance	11	3	6	8
			b2352	Vestibular function of determination of movement	.	.	2	2
			b2400	Ringing in ears or tinnitus	.	.	.	2
			b2401	Dizziness	.	.	.	1
			b2402	Sensation of falling	.	.	2	.
			b2408	Sensations associated with hearing and vestibular function, other specified	.	.	.	4
		b249		Hearing and vestibular functions, other specified and unspecified	.	.	3	1
		b250		Taste function	5	3	.	.
		b255		Smell function	6	6	.	1
		b260		Proprioceptive function	15	1	1	.
		b265		Touch function	16	16	1	8
		b270		Sensory functions related to temperature and other stimuli	.	.	1	1
			b2701	Sensitivity to vibration	.	.	.	2
			b2702	Sensitivity to pressure	.	.	.	3
			b2703	Sensitivity to a noxious stimulus	.	.	2	.
		b279		Additional sensory functions, other specified and unspecified	.	.	.	1
		b280		Sensation of pain	.	.	4	.
			b2800	Generalized pain	.	.	1	.
			b2801 (b28010, b28013, b28014, b28015, b28016, b28018)	Pain in body part (Pain in head and neck, Pain in back, Pain in upper limb, Pain in lower limb, Pain in joints, Other specified pain in body part)	.	.	9	6
		b289		Sensation of pain, other specified and unspecified	.	.	1	.
Aggregated total (b2)					180	79	80	142
	b3	Voice and speech functions			2	3	.	.
			b3100	Production of voice	.	.	.	1
			b3101	Quality of voice	.	.	.	1
		b320		Articulation functions	.	.	.	1
			b3302	Speed of speech	.	.	.	2
			b3303	Melody of speech	.	.	.	1
			b3308	Fluency and rhythm of speech functions, other specified	.	.	.	1
		b340		Alternative vocalization functions	.	.	1	.
			b3400	Production of tones	.	.	.	1
Aggregated total (b3)					2	3	1	8
	b4	Functions of the cardiovascular, haematological, immunological and respiratory systems			..	..	..	..
		b440		Respiration function	.	.	.	1
			b4550	General physical endurance	.	.	1	.
			b4552	Fatiguability	8	1	23	5
Aggregated total (b4)					8	1	24	6
	b5	Functions of the digestive, metabolic and endocrine systems			..	..	..	..
		b510		Ingestion functions	.	.	.	2
		b515		Digestive functions	.	.	.	1
		b520		Defecation functions	.	.	.	2
		b530		Weight maintenance functions	.	.	.	4
		b555		Endocrine gland functions	.	.	.	2
Aggregated total (b5)					0	0	0	11
	b6	Genitourinary and reproductive functions
			b6202	Urinary continence	.	.	.	2
			b6400	Functions of sexual arousal phase	.	.	.	1
			b6500	Regularity of menstrual cycle	.	.	.	1
			b6502	Extent of menstrual bleeding	.	.	.	1
			b6508	Menstruation functions, other specified	.	.	.	1
Aggregated total (b6)					0	0	0	6
	b7	Neuromusculoskeletal and movement-related functions			11	2	2	.
			b7151	Stability of several joints	.	.	.	1
		b730		Muscle power functions	.	.	1	.
			b7306	Power of all muscles of the body	.	.	.	5
		b750		Motor reflex functions	6	6	.	.
			b7508	Motor reflex functions, other specified	.	.	.	1
		b755		Involuntary movement reaction functions	.	.	2	.
			b7600	Control of simple voluntary movements				2
			b7601	Control of complex voluntary movements	.	.	1	.
			b7603	Supportive functions of arm or leg	.	.	1	.
			b7652	Tics and mannerisms	.	.	.	1
			b7653	Stereotypies and motor perseveration	.	.	.	1
		b770		Gait pattern functions	.	.	2	1
			b7800	Sensation of muscle stiffness	.	.	2	.
Aggregated total (b7)					17	8	11	12

Comparing geographic regions

Next, we compared the frequency distribution of unique categories of the GN with the GS within each ICF component, across the chapters at level 1 (d1 through d9 for activities and participation, and e1 through e5 for environmental factors). The analysis for aggregated frequencies was conducted for the survey data, and then for the qualitative interviews. For the survey data, the distribution of category frequencies did not statistically differ from expected values across the nine chapters for activities and participation between the GN and GS, χ² (df = 8) = 6.52, p > 0.05. Similarly, there were no deviations across the five chapters of environmental factors, χ² (df = 4) = 5.13, p > 0.05. These results may indicate that perspectives of professionals on functioning are independent of variables related to geography or resource levels.

For the qualitative interviews however, the analyses indicated a statistical deviation for activities and participation, χ² (df = 8) = 63.93, p < 0.01, whereby the two highest contributing category frequencies were found in chapters d7 (interpersonal interactions and relationships) and d9 (community, social and civic life). In the GN, d7 categories were used less frequently, whereas d9 categories were mentioned more often, and the reverse was the case for the GS. This effect was largely driven by an emphasis in the GS on level 2 and 3 categories under d760 (family relationships), and high frequency of the categories for d9205 (socializing) and d940 (human rights) in the GN. For the environmental factors, the analysis also indicated a statistically significant deviation, χ² (df = 4) = 26.63, p < 0.01, whereby the chapters contributing the most to this χ² were e3 (support and relationships), e5 (services, systems and policies) and e2 (natural environment and human-made changes to the environment). In the GN, the highest frequency was e5800 (Health services), compared to e5550 (Associations and organizational services) being used most in the GS. This difference may reflect variations in how services are provided and funded across different regions. In addition, priorities in the GS included e310 (immediate family), e320 (friends) as well as e325 (acquaintances, peers, colleagues, neighbours and community members), which could reflect the collectivistic cultures that are more often found in the GS. Finally, e298 (Natural environment and human made changes to the environment, other specified) was more frequently used in the GN, potentially indicating the expectations on, and efforts made by high-resources governments to create adaptations for the purpose of making the environment accessible to persons with sensory difficulties.

Comparing data sources

The final set of analyses focused on comparing aggregated category frequencies within each of the two geographic regions, by comparing data from the survey with data from the qualitative interviews. Focusing on data from the GN, the analysis of frequencies across the chapters of environmental factors indicated a statistically significant deviation, χ² (df = 4) = 81.14, p < 0.01. The most highly contributing chapters were e3 (support and relationships) and e4 (attitudes), whereby e310 (immediate family), 315 (extended family) and 320 (friends) were more frequently used in the coding of survey data compared to the qualitative interviews. The reverse was the case for categories referring to the individual attitudes of e410 (family members), e425 (acquaintances and peers), e450 (health professionals), e455 (strangers) and e460 (societal attitudes) categories, representing the importance of attitudes when linking data provided by persons with lived experience. When analyzing activities and participation categories, the distribution also differed statistically from expected values, χ² (df = 8) = 24.01, p < 0.01, whereby d6 (domestic life) was coded more often as relevant in data from the qualitative interviews and was less often mentioned within survey response. This effect was mainly based on d630 (preparing meals), d650 (doing housework) and d660 (assisting others) being mentioned more frequently by persons with lived experience.

Focusing on data from the GS, frequency analysis across the chapters of environmental factors also indicated a statistically significant deviation, χ² (df = 4) = 56.13, p < 0.01; the most contributing chapter was limited to e4 (attitudes), whereby attitudes of e410 (immediate family members), e425 (acquaintances, peers, colleagues, neighbours and community members) and e460 (societal attitudes in general) were mentioned more frequently by individuals with lived experience, compared to survey data from experts. When analyzing activities and participation categories within the GS data, the distribution also differed statistically from expected values, χ² (df = 8) = 50.34, p < 0.01, whereby d9 (community, social and civic life) was coded more often as relevant in data from the survey response, driven by d9205 (Socializing) and d940 (Human rights), and was less often mentioned within the qualitative interviews. Additionally, d2 (General tasks and demands) was coded more frequently in the survey than would be expected by chance, specifically category d230 (Carrying out daily routines), which is a common rehabilitation goal.

Discussion

The purpose of our study was to explore the presence of differences at both the component and the chapter level in the distribution of aggregated frequencies of unique categories in data collected from the GN versus the GS during the development of ICF Core Sets for deafblindness. The first step, the analysis at the component level, did not detect any differences in the proportional distribution of data from experts in the field; while we did detect differences among the proportion of categories used in linking the data provided by individuals with lived experience of deafblindness, their interpretation was not informative at this level. We speculate that the identified differences in environmental factors between the GN and GS may reflect broader socioeconomic structures, cultural values, and resource availability in these regions. Particularly from the perspective of lived experience, this standpoint connects the findings back to the ICF framework and underscores the importance of including lived experience from different regions of the world. In high-resource, individualistic societies such as in the GN, healthcare systems and governmental policies are generally well-funded with great availability of assistive technologies, specialized professionals and support services. In low-resource, collectivist societies that can be found in the GS, assistive technologies and specialized healthcare professionals are often hard to access, underfunded or simply not available, making family, friends, and informal associations and organizations the primary sources of support. To further elucidate potential differences, we explored the distribution of categories at the chapter level instead, which allowed us to explore the contribution of specific categories to the patterns that emerged.

The comparison of the survey data provided by experts from the GS and GN did not yield any statistically significant results whereas the data from persons with lived experience showed several differences. Experts typically support individuals with deafblindness in specific areas of their lives that correspond to their professional expertise, rather than in a holistic manner. For example, while holistic education is a currently growing movement where teachers integrate the psychosocial well-being of their students into their pedagogical approaches [17], this remains an evolving trend that may not be fully implemented in all education systems. Orientation and mobility specialists are tasked with focusing on the daily navigation and mobility of their clients, not directly responsible for other aspects of their health [25]. Physicians often do not adopt a holistic approach to their practice, as their focus is primarily on the biomedical model of patient health rather than the biopsychosocial model [18]. In contrast, individuals with lived experience provide a comprehensive firsthand account of their interactions with the environment across all aspects of their lives [9], which may explain the differences in the information they provide. Experts working in health-related fields may have framed their responses around the clinical and functioning aspects of deafblindness, and may simply lack the personal insight, while access to health and social services and assistive technology also vary significantly across different regions of the world [9].

In comparison, at the chapter level the qualitative interviews revealed how deafblindness impacts daily experiences, specifically where interpersonal interactions and relationships, as well as community, social and civic life are concerned. The comparison of the qualitative interviews pointed at several differences in the topics that were primarily discussed by individuals living with deafblindness. There was a high frequency of categories related to the importance of family and community. Under environmental factors, e310 (immediate family) was mentioned most often, followed by e320 (friends), while the most frequently identified categories for activities and participation were d7601 (child-parent relationship), d7701 (spousal relationship) and d760 (family relationship). This information aligns well with what is known about the role of family and community in disability care in the GS where low-resources regions of the world are concerned. Often, most of the care is provided by individuals close to the person with a disability, not only because other resources are lacking, but also because religious and cultural reasons may influence the perception of the family being responsible [24].

In comparison, individuals in the GN primarily discussed the importance of social and political aspects of living with deafblindness, potentially reflecting the importance of (existing or lacking) policies (d9205 Human rights, e298 Natural environment and human made changes to the environment, other specified) [6]. Such policies provide and finance access to much-needed services (e5800 Health Services), and the desire for increased social inclusion of individuals living with disabilities in societies that promote legislation of social equity [32]. This need is echoed in the GS, however, is expressed in the frequency of category e5550 (Associations and organizational services), given that most services in the GS are organized and provided through non-governmental organizations [7].

In the GN, categories within the activities and participation component related to d6 (domestic life) were frequently identified in the qualitative interviews but not in the expert survey. This finding is somewhat unexpected given the wide range of standardized tools already available to professionals for assessing activities of daily, particularly in the GN where professional and health service resources are generally assumed to be more effective and accessible [20]. This discrepancy may suggest that while professionals have access to validated instruments for assessing domestic life and daily activities, these tools may not fully capture the lived experiences of individuals with deafblindness. This finding potentially highlights a gap between what is clinically relevant to the professional versus what is subjectively meaningful to the person with deafblindness. In the GS, categories within the activities and participation component, specifically those related to d9 (community, social and civic life) and d2 (general tasks and demands) were prominently identified in the expert survey responses compared to the qualitative interviews. One possible explanation is the interdisciplinarity of the experts who responded to the survey, which may have reflected a broader biopsychosocial perspective on the health of individuals with deafblindness. This would include an emphasis on the psychosocial dimension of health, including social participation [12]. Furthermore, given the recruitment process thought global deafblindness advocacy organizations for the expert survey, some of the responding experts were likely engaged in policy and advocacy work for people with deafblindness, which may explain why the category of d940 (human rights) significantly emerged in their responses. By contrast, human rights as a category may be less tangible in the daily lives of individuals living with deafblindness and therefore, less reported.

The similarity of the frequency of unique categories between healthcare professionals from the GN and GS, might indicate the presence of a common professional lens under which experts view the lived experience of deafblindness, regardless of a country’s economic status. Existing literature suggests that experts’ perspective focuses on disability and is thereby limited within the health worker-patient relationship [2, 10, 17], given that individuals with lived experience focus on their own experience of functioning. The scarcity of the nonclinical dimension to health professionals’ training, and the emphasis of the medical model of disability may lead to the oversight of social factors contributing to the lived experience of barriers and facilitators to functioning instead [9, 18, 25]. Our findings further demonstrate the importance of the ICF framework, which considers functioning as the outcome of intricate interactions between the individuals’ health conditions and contextual factors [18], [34]. Finally, our data highlight how the identified regional and experiential differences can inform more contextually valid Core Set adaptations or validation processes. The utility of future Core Sets will likely increase if development teams increase their efforts to include data that span as many regions as possible, representing more diverse perspectives and needs.

We recognize some limitations within this project, including the absence of a comprehensive analysis of personal factors that can play a role in the comparison between the GN and GS, or even within regions of similar resource availabilities. Specifically, cultural variables such as language, beliefs, social practices, age, race, socioeconomic status, political beliefs, and lifestyle were not systematically recorded as they all go beyond the mandate of the ICF coding system and the development of Core Sets. Given the requirements for participation, it is likely that our participants in both studies over-represent individuals with higher education, more resources, and/or the motivation to advocate for persons living with disabilities and may therefore not fully represent the global population of individuals living with deafblindness and the professionals that serve them. Furthermore, we want to acknowledge that the division of our data sources into the GN versus the GS is somewhat simplistic and does not recognize multiple factors that influence health systems, beyond geography or financial resources. Finally, we recognize that data on body functions and body structures are not included in the analyses at the chapter level, given data distribution limitations. Their absence limits comprehensiveness of the results and should be explored in more detail in future studies.

Conclusion

Our findings suggest that differences in activity and participation among people with deafblindness vary across regions due to environmental influences such as socioeconomic conditions, cultural norms, and access to resources. These contrasts—where high-income countries tend to prioritize formal services and accessibility, while lower-income regions emphasize family and community support—indicate that geographic region itself functions as a significant environmental determinant. The lack of corresponding variation in expert-reported data implies that professional perspectives may not fully capture the lived environmental context. For the development of ICF Core Sets, this highlights the importance of including data derived from lived experience to achieve a more complete and contextually valid understanding of human functioning worldwide. While the generalizability of ICF Core Sets depends on globally representative data, such representation is not always feasible or prioritized. When both Global North and Global South data are available, examining regional differences can yield valuable insights into the diverse realities of functioning and disability.

Author contributions

WW and SG obtained funding for the study. SD, MS, and XYL conducted the data analyses, and drafted the first version of the manuscript under the supervision of WW. WW and SG revised the manuscript. All authors read and approved the final manuscript.

Funding

The studies reported here were funded through the Canadian Hearing Services, Deafblind International, DeafBlind Ontario Foundation and the Fonds de recherche du Québec Vision Science Research Network.

Data availability

The data that support the findings of this study are available through the corresponding author but are not publicly available. Data are however available from the authors upon reasonable request and with ethics approval though the Université de Montréal.

Declarations

Ethics approval and consent to participate

Ethical approval was obtained from the Institutional Review Boards of the Université de Montréal (CERC # 2022–1710, CERC 2023–4150, respectively). The multi-site qualitative study was also approved by the institutional review boards of the Centre de recherche interdisciplinaire en réadaptation du Montréal métropolitain (MP-50–2023-1749) in Canada, the Instituto del Salud Carlos III (#CEI PI 44_2021-v3) in Spain, and the University of Melbourne (#2023–25708-42888–3) in Australia. All participants provided informed consent as part of their participation.

Consent for publication

Not applicable.

Competing interests

The authors declare no competing interests.