An International Clinical Study of Ability and Disability in Autism Spectrum Disorder Using the WHO-ICF Framework
Journal of Autism and Developmental Disorders
An International Clinical Study of Ability and Disability in Autism Spectrum Disorder Using the WHO-ICF Framework
0 Soheil Mahdi
1 Department of Pediatrics, University of Alberta , Edmonton , Canada
This is the fourth international preparatory study designed to develop International Classification of Functioning, Disability and Health (ICF, and Children and Youth version, ICF-CY) Core Sets for Autism Spectrum Disorder (ASD). Examine functioning of individuals diagnosed with ASD as documented by the ICF-CY in a variety of clinical settings. A cross-sectional study was conducted, involving 11 units from 10 countries. Clinical investigators assessed functioning of 122 individuals with ASD using the ICF-CY checklist. In total, 139 ICF-CY categories were identified: 64 activities and participation, 40 body functions and 35 environmental factors. The study results reinforce the heterogeneity of ASD, as evidenced by the many functional and contextual domains impacting on ASD from a clinical perspective.
ASD; Neurodevelopmental disorder; Functioning; Assessment; ICD; DSM; Clinical study
Autism spectrum disorder (ASD) is a neurodevelopmental
condition with an estimated worldwide prevalence of 1–2%
(Baxter et al. 2015; CDC 2016; Idring et al. 2015)
characterized by persistent difficulties in social communication and
interaction, alongside restricted, repetitive behavior patterns
and interests (APA 2013). The symptoms cause adverse
functional outcomes in school (Levy and Perry 2011), work
(Howlin et al. 2013)
, social relationships
(Schmidt et al.
, domestic life
(Fortuna et al. 2015; Matson et al. 2009)
(Borremans et al. 2010; Du et al. 2015)
is also associated with an increased risk for other
neurodevelopmental and psychiatric conditions
(Pan 2014; Simonoff
et al. 2008)
, alterations in physical health
(Cashin et al.
2016; McElhanon et al. 2014)
, premature mortality
(Hirvikoski et al. 2016)
and lower life satisfaction
(Jonsson et al.
Extended author information available on the last page of the article
2017; van Heijst and Geurts 2015)
. Even though ASD is
primarily defined by challenges in various aspects of daily life,
it has also been reported to entail specific strengths, such as
attention to detail
(Baron-Cohen et al. 2009; de Schipper
et al. 2016)
, enhanced visuo-spatial skills
(Happé and Frith
(de Schipper et al. 2016)
Schipper et al. 2016)
. Furthermore, environmental factors
such as higher socio-economic background, parental
commitment, and provision of evidence-based treatments, have
found to facilitate the functional outcome of individuals with
ASD regarding social relationships as well as school and
(Delobel-Ayoub et al. 2015; Durkin
et al. 2010; Kirby et al. 2016; Rai et al. 2012)
. The research
findings here suggest that individual adaptive profile and
composition of abilities and disabilities in ASD may vary
substantially depending on developmental level, personal
characteristics, access to service and other factors.
Therefore, internationally accepted, standardized classification
tools for individual assessment of functioning in
individuals with ASD are desirable in clinical, research and
educational settings. The International Classification of
Functioning, Disability and Health (ICF) may serve as an effective
framework for developing such tools. Officially endorsed by
the World Health Organization in 2001, the ICF provides
a comprehensive, internationally accepted nomenclature to
describe health-related functioning in different conditions
and condition groups, promoting an etiological-neutral
perspective on disability (WHO 2001). In 2007, a child and
youth version of the ICF (i.e., ICF-CY) was developed,
specifically designed to capture functional abilities and
disabilities in developing individuals by adding and expanding
on the descriptions of existing ICF categories (WHO 2007).
The ICF-CY is grounded on an interactive bio-psycho-social
model of functioning (Fig. 1), which operationalizes
functioning beyond medical or biological conception, taking into
account other critical influences, such as the extended
environment and a multitude of contextual factors (WHO 2001,
2007). Each component of ICF-CY comprises
hierarchically structured categories that systematize various aspects
of health-related functioning (Fig. 2).
The ICF-CY includes all ICF categories, plus additional
ones specific to children and youth, making up 1685
categories in total (531 body functions, 329 body structures, 552
activities and participation categories, and 273 environmental
factors) (WHO 2007). By providing a standard language for
describing health and health-related states, the ICF-CY
enables users to record useful profiles of individuals’ functioning
across the lifespan for various purposes, ranging from
diagnostic and treatment purposes (
Escorpizo et al. 2013
to policy-making and raising public awareness of conditions
(WHO 2007). However, using all categories from the ICF-CY
to describe a specific health condition is unlikely to be
meaningful, given that it will be time-consuming and often
essentially undoable in clinical practice, as many categories would
be irrelevant to specific conditions. To address this issue, the
development of ICF Core Sets was initiated with the aim to
allow user-friendly and effective descriptions of health-related
functioning by generating shortlists of categories that are
most relevant to specific health conditions. The development
of ICF-CY “Core Sets” follows a rigorous scientific process,
established and monitored by the WHO and the ICF Research
(Selb et al. 2015a)
, involving a wide range of
professionals and stakeholders across all of the WHO-regions. The
first phase of the project comprises four preparatory studies,
each aiming to capture general and unique features of
functioning and contextual factors specific to a certain health condition.
The preparatory studies include a literature review (“research
perspective”), an expert survey (“expert perspective”), a
qualitative study (“client and close social environment
perspective”), and a clinical study (“clinical perspective”). The present
clinical study is therefore part of a superordinate project that
will result in the development of standardized ICF Core Sets
for ASD. As part of this project, ICF Core Sets are also being
developed for attention deficit-hyperactivity disorder (ADHD),
with the protocol and results reported in separate pu
(Bölte et al. 2014
; de Schipper et al. 2015). Once the
preparatory studies have been completed, the results will be presented
at an international consensus conference. At this conference,
a group of ASD experts will review the findings from the
preparatory studies and decide on which ICF-CY categories to
include in the first official versions of the ICF Core Sets for
The objective of this study was to capture aspects of
functioning and contextual factors pertaining to individuals
with ASD as assessed by the ICF-CY in a clinical practice
setting. For this purpose, an international cross-sectional
multicenter study was conducted, involving clinicians and
clinical researchers evaluating the functional level of
children, adolescents and adults with ASD, as well as rating
environmental barriers and facilitators.
(i.e., physical, social and attitudinal environment). ICF-CY
framework also includes personal factors that are inherent to the individual
but not part of the individual’s primary health condition, such as
gender, race/ethnicity, educational level and coping strategies. However,
personal factors are not classified in the ICF-CY due to their large
social and cultural variability (WHO 2001, 2007)
Fig. 2 Each ICF-CY component
is described and structured in
four different levels of depth.
The first level, referred to as
“chapters”, provide a general
overview of the areas of
functioning and environment that are
covered by the nomenclature.
The chapters, in turn, consist
of more specific categories of
functioning and environment
that are hierarchically
structured with up to three levels of
increasing detail, as
demonstrated by the following body
functions component example
b1 Mental Functions
functions of language
b1670 Reception of
b16700 Reception of
The study was approved by the Regional Ethics Review
Board in Stockholm and by the Local Ethics Review Boards
at each of the other participating sites. Prior to study
participation, informed written consent or assent was obtained
from the diagnosed individuals and/or caregivers depending
on age and cognitive and communication level. The consent
form assured voluntarily study participation and
confidentiality of the participants. An international cross-sectional,
multi-center study design, as recommended by the WHO
and ICF Research Branch
(Selb et al. 2015a)
, was applied for
this purpose, involving 11 clinical units from 10 countries
across 4 WHO regions: Argentina (The Americas), Brazil
(The Americas), Denmark (Europe), Germany (Europe),
Greece (Europe), Italy (Europe), Japan (Western Pacific),
Portugal (Europe), Saudi Arabia (Eastern Mediterranean)
and Sweden (Europe). This composition of country
representation was chosen for two primary reasons: (i) to meet
the basic requirements of an international sample, and (ii) to
enable future in-depth comparisons of cross-cultural
perceptions of ASD, as these have shown to influence assessment
and treatment of ASD
(Burkett et al. 2015; Ratto et al. 2015)
Participating sites were specialized in the clinical
management of neurodevelopmental disorders.
Ratings were made based on information from medical
records, medical history taking, neuropsychological testing
and standardized clinical instrument scores (e.g., Wechsler
Intelligence Scale for Children and Adults, Autism
Diagnostic Observation Schedule, Child Behavior Checklist,
Autism Diagnostic Interview-Revised, etc.), clinical
observations and interviews with the participant and/or caregivers
depending on age and developmental level of the rated case.
The minimum dataset that was required for an individual
to be included in this study was data from medical records
and clinical observation. Clinicians and clinical researchers
examined the medical information available at the respective
site for each participant and extracted relevant information
on socio-demography, co-morbidity and ASD-related
functioning aspects. Co-morbidity was systematically assessed
at all study sites by checking medical records. The
investigators then proceeded to interview the participant and/or
caregivers to rate the remaining categories of the ICF-CY
checklist. Interviews varied in length from 40 to 120 min.
Telephone interviews were occasionally used as an option
to accommodate logistical challenges, but also to comply
with some participants’ wishes to be interviewed via the
phone due to ASD-related difficulties in face-to-face social
interaction and communication.
In total, N = 126 participants fulfilled criteria for
participation and consented to take part in the study between March
and August 2016. Inclusion criteria were a primary clinical
diagnosis of ASD or a specified ASD diagnosis (autism,
Asperger syndrome, atypical autism, pervasive
developmental disorder not otherwise specified) along with any given
common co-morbidity (if applicable) according to local or
national guidelines and the diagnostic criteria of the ICD-10,
DSM-IV/-TR or DSM-5 and/or receiving treatment for ASD.
Participants were excluded from the study if the primary
diagnosis was unclear or if the caregiver or the individual
diagnosed with ASD could not communicate in the language
of the country where the recruitment took place.
Recruitment of participants was made at the respective clinical unit
facilitated by the clinical investigators in charge. Nearly
half of the adults (n = 18) and some preschool aged children
(n = 8) were, however, recruited via local and national
interest organizations for ASD. For most of these cases, access
to medical records was limited and the rating of functioning
level was primarily based on interview information.
Following the steps of previous ICF clinical studies
(Finger et al.
2011; Schiariti and Mâsse 2015)
, this study aimed to enroll
at least 100 participants.
The ICF Checklist 2.1a version is a rating tool aimed to elicit
and record information on the functioning and environment
of an individual by using selected categories from the ICF
(WHO 2003). The checklist consists of 123 second-level
categories from the 4 ICF components (31 body functions,
12 body structures, 48 activities and participation, 32
environmental factors). In addition, the checklist also includes
diagnostic information, which enables users to study the
relationship between a health condition and associated
functioning problems. The categories in the checklist are usually
rated by using ICF qualifiers, a five-point scale that defines
severity of functional impairment by looking at how often a
specific problem is present in an individual’s daily life. The
more often a specific problem is experienced, the larger the
impact. The validity of the ICF checklist has been explored
in previous studies
(Ewert et al. 2004; Kohler et al. 2011;
Okochi et al. 2005)
. The feasibility of the ICF checklist has
also been shown in patients diagnosed with different kinds
of chronic conditions (e.g., diabetes mellitus, osteoarthritis,
ischemic heart disease, depressive disorder, etc.).
For the current study, a tailored version of the WHO ICF
Checklist version 2.1a was used to rate the functional level
of individuals with ASD (see Supplementary Material) and
environmental barriers and facilitators. The checklist was
divided into four parts. Part 1 contained the inclusion criteria
of the study, part 2 included questions related to the
sociodemographic background of the diagnosed individual, part 3
consisted of ratings of 161 second-level ICF-CY categories,
and part 4 aimed to explore personal factors. To increase
the specificity of the checklist content to individuals with
ASD, 38 second-level ICF-CY categories were added in the
checklist (17 body functions, 17 activities and participation
categories, 3 environmental factors, and 1 body structure)
based on results from our previous 3 preparatory studies:
the literature review
(Schipper et al. 2015, the expert survey
Schipper et al. 2016 and the qualitative study Mahdi et al.
. The 161 ICF-CY categories were distributed among
all 4 ICF-CY components in the checklist and contained 65
activities and participation categories, 48 body functions, 35
environmental factors and 13 body structures.
An adapted version of the numeric rating scale (NRS)
was used to rate each ICF-CY category in the checklist.
(McCaffery and Beebe 1989)
, validated and
commonly used to assess pain intensity
et al. 2011)
, utilizes an 11-point scale, with 0
representing “no”, 1–3 “mild”, 4–6 “moderate” and 7–10 “severe”
(McCaffery and Beebe 1989)
the current study, functional impairment and strengths
were rated according to the NRS, following the same
metrics as stated above. The main reason for using the NRS in
this study was because of its relative simplicity and ease of
administration and scoring
(Ferreira-Valente et al. 2011)
Contrary to ICF qualifiers, which define severity of
functional impact by looking at how frequently a specific
problem is experienced in daily life, the NRS does not offer
a restricted definition. Instead, it enables investigators to
explore other factors that may affect an individual’s
functional level, such as degree and duration of impairment.
ICF qualifiers have also been reported to be difficult to
interpret by specific stakeholders, such as parents
et al. 2013)
. The NRS was also used to rate the categories
in the environmental factors component, but with 0
representing “no barrier or facilitator”, + 10 “complete
facilitator” and − 10 “complete barrier”. For all the components
in the checklist, additional scoring options of “Not
applicable” and “Not specified” were added. “Not applicable”
was used if a specific ICF-CY category was not applicable
to the individual (e.g., asking children about university
or college studies), while the “Not specified” option was
used if there was not sufficient information to rate the
specific category. An option to capture strengths in ASD was
also included. Strengths were defined as specific abilities
that individuals with ASD were better at, compared to the
average population. Information that indicated strengths
in clinical observations, medical records or psychological
test results were used to rate strengths. To minimize the
possibility of over or underestimation of strengths (or
difficulties) in interviews, the investigators were instructed
to ask participants for clarifications and examples.
Specific functioning categories that were not included in the
checklist, but deemed important to ASD, were also
documented and rated according to the NRS scale. An empty
page was added in the checklist for the investigators to
document any personal factors that were considered (either
by the diagnosed individual or caregiver) to impact daily
life functioning of individuals with ASD. Personal
factors (e.g., gender, race, education level, specific life
habits, etc.) were not rated, but documented descriptively in
interviews with the participant and/or caregiver.
Any ICF-CY category that was rated as 2 or more in at least
10% of the cases was included as candidate category for the
core set development. Although a scoring of “1” would be
enough to classify a specific aspect of functioning or
environmental factor as “mildly impaired/barrier/facilitator”, a
more conservative cut-off was chosen to avoid margins of
error (e.g., a specific problem might exist in daily life, but
not be significantly impairing enough to affect functioning
level). The choice of a 10% cut-off was based on results from
previous ICF clinical studies
(e.g., Vierhoff et al. 2015)
The same cut-off was also applied to ratings that indicated
above-average skills (strengths). Absolute (n) and relative
(%) frequencies of difficulties and strengths were reported.
Scorings that indicated “Not applicable” or “Not
specified” were excluded from the frequency analyses. The
participants’ socio-demographic background was summarized
using descriptive statistics. Personal factors were analyzed
exploratory by summarizing recurring themes.
Prior to study participation, the lead investigator at each
participating study site was required to take part in a
webbased ICF self-learning course (http://icf.ideaday.de/). The
course included an introduction to the ICF, its rationale and
application areas. The aim of the course was to help the
investigators understand the ICF model and classification
terms that are used in the nomenclature. Another aim was
to get the investigators to learn how to apply and use the ICF
in practice. After completing the course, the investigators
received examples of questions that they could use for the
interviews with the participants. To get acquainted with the
content of the ICF-CY checklist, each second-level ICF-CY
category was provided with clear definitions and examples.
Skype-meetings were arranged to discuss specific ICF-CY
categories that were unclear. The checklist was translated
into the language of each participating country, with the
exception of Denmark, which used an English translation
of the checklist. The study coordinator had regular contact
with the study sites, monitoring the progress and providing
material for quality management and comparability, such as
sending interview experiences from other study sites,
discussing ratings of ICF-CY categories.
Of the 126 individuals who were eligible for participation,
122 completed the study. Attrition was due to not showing
up for assessment (n = 3), or decline of participation
without provision of a reason after initial written consent (n = 1).
Table 1 shows the number of participants by country. Table 2
summarizes the socio-demographics of the participants
included in the final analysis with respect to age, gender,
marital status, education background, working status and
living situation. Forty-five participants (37%) were diagnosed
with ASD using DSM-5 criteria. Among the individuals who
were diagnosed according to DSM-IV(-TR) or ICD-10
criteria, Asperger syndrome was diagnosed in 40 (33%) cases,
followed by classic autism/autistic disorder (n = 26, 21%)
and atypical autism/pervasive developmental disorder not
otherwise specified (n = 11, 9%). The majority of the
participants (n = 94, 77%) had at least one additional diagnosis.
The most frequently reported co-morbidities were ADHD
(n = 28, 23%), intellectual disability (n = 19, 16%), depression
(n = 10, 8%), specific developmental disorder of motor
function (n = 8, 7%) and generalized anxiety disorder (n = 5, 4%).
ICF‑CY Category Ratings
In total, 139 of 161 ICF-CY categories assessed met the
cut-off in at least 10% of the participants. Data saturation
aOther marital status includes dating, live-apart, etc.
bOne missing data for education level
cOther education level includes daycare, pre-school and folk high
dOther living situation includes residential care living, living with a
showed that no candidate category would
have been lost if data only were analyzed from Europe.
There were, however, some candidate categories that would
not have been covered in the non-European study sites. For
example, 3 candidate categories (2%) were missing in the
study sample that came from the Americas, while 15 (11%)
were missing in Eastern Mediterranean and 48 (34%) in
Western Pacific. The 139 candidate ICF-CY categories were
distributed across 3 ICF-CY components: 64 categories in
the activities and participation component, 40 body
functions and 35 environmental factors. No body structure
categories reached the cut-off. Table 3 shows the second-level
categories identified in the activities and participation
component, along with their absolute and relative frequencies.
The categories were spread across all of the nine chapters
in this component (Table 3), i.e., d1 learning and applying
knowledge (k = 14), d4 mobility (k = 8), d5 self-care (k = 8),
d7 interpersonal interactions and relationships (k = 7), d8
major life areas (k = 7), d3 communication (k = 6), d2
general demands and tasks (k = 5), d9 community, social and
civic life (k = 5) and d6 domestic life (k = 4). The three most
frequently identified ICF-CY categories in this component
were d720 complex interpersonal interactions (n = 106,
86%), d710 basic interpersonal interactions (n = 104, 85%)
and d240 handling stress and other psychological demands
(n = 101, 82%).
Frequencies of the second-level categories identified in
the body functions component are listed in Table 4. The
categories were identified in seven of the eight chapters in
this component, i.e., b1 mental functions (k = 18), b2
sensory functions and pain (k = 8), b7 neuromusculoskeletal
and movement-related functions (k = 5), b3 voice and speech
functions (k = 3), b5 functions of the digestive, metabolic
and endocrine systems (k = 3), b6 genitourinary and
reproductive functions (k = 2) and b4 functions of the
cardiovascular, haematological, immunological and respiratory
systems (k = 1). The three most identified ICF-CY categories
were b122 global psychosocial functions (n = 108, 88%),
b125 dispositions and intra-personal functions (n = 106,
86%) and b140 attention functions (n = 105, 86%).
Table 5 shows the frequencies of second-level categories
that were identified in the environmental factors component.
The categories in this component were identified in all five
chapters, i.e., e5 services, systems and policies (k = 9), e3
support and relationships (k = 8), e4 attitudes (k = 8), e1
products and technology (k = 7) and e2 natural environment
and human-made changes to environment (k = 3). The three
most frequently identified second-level categories were e310
immediate family (n = 103, 84%), e410 individual attitudes
of immediate family members (n = 93, 76%) and e355 health
professionals (n = 87, 71%).
When analyzing ASD-related strengths, 3 ICF-CY
categories met the cut-off of 2 in at least 10% of the participants.
These included b144 memory functions (n = 20, 16%), d161
directing attention (n = 14, 11%) and b140 attention
functions (n = 13, 10%).
This international cross-sectional clinical study aimed to
investigate functioning and contextual factors of
individuals diagnosed with ASD using the ICF-CY framework. To
This study yielded a large number and variety of
categories across 3 components and 21 ICF-CY chapters.
Although the study findings suggest impairments in
aNumber of cases where the specific ICF-CY category was rated to be significantly affected by ASD
The 122 cases yielded a total of 148 personal factors that
were considered to either have a supportive or hampering
impact on daily life functioning. The study sample showed a
broad variation of personal factors. For this reason, personal
factors were analyzed exploratively in order to investigate
the data for any specific recurring themes. Examples of
supportive personal factors included high IQ, acceptance towards
own diagnosis and specific interests (e.g., art, sports). Having
high IQ was mentioned to facilitate individuals in generating
coping strategies to manage challenging or stressful life
situations, while acceptance towards own diagnosis enabled
individuals to seek knowledge and resources to understand their
condition better, and thus adapt to their environment. Specific
interests (e.g., art, sports) were reported to facilitate coming
into contact with other people and improve their social
interaction skills. Past traumatic life events (e.g., getting bullied
at school) were mentioned as a hampering personal factor, as
it affected the individual’s self-esteem and self-worth.
Having caregivers with psychiatric disorders was also reported
to negatively impact individual functioning, as it increased
level of stress in daily life. Increased level of stress was in
turn mentioned to exacerbate ASD symptoms. Perfectionism
was another hampering personal factor that was mentioned
to make it difficult to engage and initiate tasks and activities.
achieve an international sample, participants with ASD
were recruited from 11 clinical units from 10 countries
and 4 WHO-regions. Not surprisingly, large number and
broad variation of activities and participation categories
were captured in this study, covering all nine chapters,
ranging from difficulties with communication and social
interaction to limitations in mobility, work, self-care and
participation in civic life (including political and
citizenship life). Although a rich variety of mental functions were
captured in this study, other aspects of the body were also
identified to be impacted by ASD, such as motor
coordination deficits, hypersensitivity issues, gastrointestinal
problems and voice and speech disfluency. Genitourinary
and immunological functions were also considered to be
affected by ASD. Environmental factors varied from
support and attitudes of key individuals in life to provision of
services and products and technology in daily living.
Physical aspects of the environment, such as sound, climate,
and light were also covered in this study. Strengths were
scarcely reported in this study, but some recurring themes
included memory (i.e., visuo-spatial long term-memory)
and attention (i.e., hyper-focusing on tasks). Broad
variation of personal factors was mentioned to affect functional
level in ASD, including supportive factors such as high IQ
and acceptance towards own diagnosis, as well as
hampering factors, such as past traumatic life events and having
family member with psychiatric disorder.
Ratings of ICF‑CY Categories
aNumber of cases where the specific ICF-CY category was rated to be significantly affected by ASD
different cognitive functions, other aspects of the body
were also found to be altered in ASD, such as motor
(Fournier et al. 2010)
blems (McElhanon et al. 2014
), voice and speech
(Scaler Scott et al. 2014)
, and hypersensitivity
(Marco et al. 2011)
. The same is true for
immunological and genitourinary pro
blems (Byers and Nichols
; Lyall et al. 2015). The results here underpin the
importance of conducting multidisciplinary assessments
in ASD to enable better treatment plans and prognosis by
aNumber of cases where the specific ICF-CY category was rated to be significantly relevant to ASD-related functioning
capturing all aspects of the body, including physical
functions. The functional characteristics of ASD are further
demonstrated by the fact that categories were identified
from all nine chapters in the activities and participation
component, corroborating previous research findings on
difficulties in communication skills, social interaction,
self-care, domestic life, and conductance of general tasks
(Borremans et al. 2010; Fortuna et al. 2015;
Matson et al. 2009; Schmidt et al. 2015)
. We also
consistently identified several functional aspects of ASD that
have not been covered extensively by previous research,
particularly regarding community and civic life,
including participation in political and citizenship activities.
The limitations detected were related to negative societal
attitudes about the capacity of individuals with ASD to
raise public awareness and actively engage in
self-advocacy. Participants with ASD reported that they were not
given a fair chance to engage in the public discourse on
ASD. The latter might indicate violations of rights of
individuals with disabilities to enjoy active participation in
political life as committed in the UNICEF Convention on
the Rights of Persons with Disabilities (CRPD). The need
to make political participation more accessible to
individuals with disabilities has previously been emphasized
(Priestley et al. 2016)
. As the understanding of
neurodevelopmental disorders is shifting with research advances
challenging traditional notions of ASD, the voices of
diagnosed individuals are essential to the public discourse on
(Wright et al. 2014)
. Another finding that deepen the
current understanding of ASD was mobility, more
specifically the usage of public motorized transportation, such as
bus, train and metro. Research has shown that individuals
with ASD face difficulties when using public
transportation due to the absence of transportation options, lack
of familiarity with public transportation, and cost factors
(Lubin and Feeley 2016)
. However, we found that coping
with sensory stimuli from the environment (e.g., noises,
quick movements, strong scents) and stress caused by
crowding during rush hour are experienced as the major
challenges of public transport mobility. In general, we
confirmed and identified a broad array of environmental
factors being decisive for functioning in ASD. These
environmental factors generate information on how individual
functioning might be improved without changing the
individual, but by using enhancing environmental facilitators
and reducing barriers. Surprisingly, however, the role of
environmental factors for functioning has largely been
ignored in the diagnostic process of ASD, as evidenced
by the fact that golden standard scales that are used to
diagnose individuals with ASD do not sufficiently take
into account environmental factors (Castro et al. 2013).
Even more remarkably, they are underutilized in
individual-based special education programs that aim to promote
inclusive school curricula for individuals with ASD
(Castro et al. 2012)
. The bio-psycho-social model of the
ICFCY can address this issue by generating comprehensive
tools which professionals can use to explore environmental
factors in-depth and as such facilitate interventions that
meet the demands of individuals with ASD (WHO 2007).
The ICF-CY stresses the responsibility of stakeholders to
take an active role in modifying the environment to fit the
needs of individuals with disabilities. The emphasis on
environmental influences can provide the basis for
interventions that are more inclusive and less stigmatizing for
diagnosed individuals and their caregivers. Some issues,
such as those concerning mobility (transportation) may for
instance be easily addressed by offering alternatives (e.g.,
taxi, other time slots to avoid rush hours) or compensation
(e.g., earplugs, assistance) that will allow individuals to
attend to their daily errands and hobbies. Environmental
factors can either functionally be perceived as a barrier or
facilitator by the individual. For example, peer attitudes
(i.e., e425 individual attitudes of acquaintances, peers,
colleagues, neighbors and community members) may either
be inclusive and lead to deeper social bonds or lead to
discriminatory practices that cause social exclusion. The
present study found individual support and attitudes to be
essential to health-related functioning in ASD, which is
in line with previous studies that have shown individual
support and attitudes to influence school inclusion
and Humphrey 2010)
and successful work employment
(Parr and Hunter 2014)
. Besides individual support and
attitudes, large number of products and technology were
considered relevant to the daily living of individuals with
ASD, which is consistent with previous research findings,
where technological aids have been used to improve
communication skills in individuals with ASD
(Ganz et al.
. Additionally, different types of services were
identified to impact functioning in ASD, including services
offered at health care, education, work and social settings.
The findings here reinforce previous research findings,
which suggest services to be provided at different levels
and settings in order to optimize ASD outcome in daily
(Fein et al. 2017; Fleury et al. 2014; van Schalkwyk
and Volkmar 2017)
. To improve outcome, the ICF-CY can
jointly be used with the International Statistical
Classification of Diseases–Tenth Revision (ICD-10) (WHO 1992)
by complementing information on diseases, symptoms or
complaints with data on how environmental factors
influence daily life participation and execution of tasks (WHO
2007). These can also guide ICF-CY assessments
recommended for ASD in ICD-11 (http://apps.who.int/classifica
To date, this is the first international clinical study that
investigated ASD-related strengths using the ICF-CY framework.
Strengths reported here included memory and attention, which
interestingly, were also commonly identified to be strengths
in our previous expert survey of ASD
(Schipper et al. 2016)
Seriously taking into account strengths in ASD can be
beneficial to enhance the functional outcomes of individuals with
ASD. For example, attention to detail and intense focus have
previously been found to increase work output among
individuals with ASD
(Smith et al. 1995)
. Their focus combined
with their willingness to engage in repetitive and monotonous
tasks may benefit employers, as these types of tasks are often
disliked by others. Thus, they may provide valuable
assistance to companies and organizations, while at the same time
maintaining a more permanent position and become
wellintegrated in workplaces. Notably, several studies have found
supervisors to rate their employee with ASD highly on a range
of important job skills, suggesting that individuals with ASD
can be successful in competitive, entry-level employment
(Hillier et al. 2007)
. Exploring strengths can also help to
balance-out deficit and resource-oriented views of ASD by
facilitating interventions that are less stigmatizing and more
focused on reinforcing already existing individual strengths.
The ICF-CY can facilitate these types of interventions and
strength assessments by not only capturing functional
disabilities or limitations, but also individual strengths and abilities
This study faced some methodological issues that need to be
considered in order to fully evaluate its validity. First, even
though the assessed clinical sample involved cases from
10 different countries, the WHO-regions South East Asia
(e.g., India) and Africa were, unfortunately, not covered. In
addition, regarding the Western Pacific and The Americas,
only the Far East and South America were covered, limiting
potential inter-continental generalization. Second, a large
portion of the study sample came from Europe, limiting
cross-cultural comparisons and drawing of definite
conclusions about ASD-related functioning from a global
perspective. Although it is recommended by the WHO and ICF
(Selb et al. 2015a)
to involve international
stakeholders, it does not explicitly take into account
exploration of cultural differences. Saturation analyses showed
that all candidate categories were captured in study sites
representing the WHO-region Europe. In other words, no
candidate category would have been lost, if only data from
Europe would have been analyzed. To ensure that the
ICFCY categories are universally representative, there is a need
for cultural comparison studies that will explore this issue
more extensively. Culture can play an important role in how
quickly individuals with ASD get assessed and treated
(Burkett et al. 2015; Ratto et al. 2015)
. For this reason, there are
future plans on combining data from all preparatory
investigations to explore cultural effects on ASD functioning
more comprehensively with additional descriptive analyses.
Indeed, conducting cross-cultural comparisons in the future
may also add substantial value to the understanding of
functioning from a global perspective
(de Vries and Bölte 2016)
since most knowledge and science of ASD originates from
high-income countries, despite the fact that most people with
ASD live in low to middle-income countries (Durkin et al.
2015). Nevertheless, the objective of this study was not to
explore cultural influences on ASD-related functioning, but
identify the most informative ICF-CY categories for ASD
independent of culture from a clinical perspective. Another
study limitation is that for some adult and preschool
participants with ASD, there was no access to medical records, and
thus ICF-CY assessment was primarily based on interview
data. It is desirable in future studies to involve larger
numbers of units being specialized in younger pediatric
individuals and older adults diagnosed with ASD, as this study
did not include large numbers of individuals with ASD in
these age ranges. Furthermore, for some children and
adolescents, interviews were only conducted with immediate
family members. While proxy interviews are common in
psychiatry in these age ranges, additional first-hand
perspective interviews add substantial value. On the other hand,
there are some challenges with including young
individuals with disabilities. First, young individuals might lack the
insight, communication skills or understanding to provide
(Jonsson et al. 2017)
. Second, children
with developmental disabilities may experience
difficulties with memory and recall, making it difficult for them to
engage and fully respond to the interview questions
et al. 2009)
. Third, for children with mental health problems,
disorder-specific symptoms and impairments may also
hamper them from offering their own assessment
et al. 2010)
. For example, a child with ASD may experience
difficulties with reporting on social relationships due to their
limitations in verbal communication. Another study
limitation is related to the lack of cases involving individuals with
co-morbid intellectual disability, which potentially may have
caused a biased representation of categories. However, given
the large number and broad variation of candidate categories
that were identified in this study, we expect the results to
have covered the functional outcome of individuals from
the entire autism spectrum. Further, gender and age group
differences were not taken into account, partly because of
the uneven representation of females and preschoolers with
ASD, but also due to many confounder factors (e.g.,
culture, co-morbidity, ASD presentation, information sources)
that might potentially cause biased results. A final limitation
is that this study did not investigate inter-rater reliability
between the investigators, mainly due to its international
character with different languages used in the clinical work
with patients at the respective sites. For compensation, the
investigators were strictly encouraged to seek consensus
ratings within their clinical teams pertaining to the cases.
This clinical cross-sectional study sought to capture the
entire spectrum of functioning in ASD from a clinical
perspective, not only exploring disabilities, but also abilities
and strengths, using the ICF-CY framework. In addition,
environmental barriers and facilitators to individual
functioning were comprehensively examined. The results from
the current study are a step towards providing the scientific
basis for developing ICF Core Sets for ASD, from which
user-friendly tools can be derived and standardized for
multi-purpose usage, ranging from preclinical and clinical
research, educational and clinical practice to policy-making
and service reimbursement models. These tools will
facilitate in-depth assessments that enable diverse range of
functional profiles to be captured, while at the same examine
environmental facilitators and barriers to individual
functioning across countries and WHO-regions. An integral part
of the diagnostic process in the upcoming ICD-11 will be the
usage of ICF-CY categories to assess the functional impact
of a health condition
(Selb et al. 2015b)
. The ICF Core Sets
for ASD will provide stakeholders with shortlists of
categories that are pertinent to ASD, thus complementing
diagnostic information from golden standard scales and clinical
observations with data on functional impact and
environmental facilitators and barriers. The international framework
of the ICF-CY also creates future possibilities to conduct
cross-cultural comparisons, potentially adding substantial
knowledge about daily life functioning and environment of
those living with ASD in low to middle income countries.
The data from the current study will along with results from
the other preparatory studies provide the scientific basis for
the decision-making process at the consensus conference,
where the first version of the official ICF Core Sets for ASD
will be determined.
Acknowledgments The development of ICF Core Sets for ASD is a
cooperative effort between the ICF Research Branch, a cooperation
partner within the WHO Collaboration Centre for the Family of
International Classifications in Germany (at DIMDI), the International
Society for Autism Research (INSAR), and the Center of
Neurodevelopmental Disorders at the Karolinska Institutet (KIND) in
Sweden. Guidance on this Project is provided by the Steering
Committee, a group of key opinion leaders in the field of ASD from all six
WHO-regions. This study also acknowledges the assistance of
clinical researchers and clinicians who were involved in recruiting, rating
and analyzing the clinical cases. These include Afroditi Korogiannaki
(Theotokos Foundation, Greece), Dr. Alexia Rattazzi (PANAACEA,
Argentina), Ann-Janet Hansen (Aalborg University Hospital,
Psychiatry, Denmark), Chrysi Kotretsou (Theotokos Foundation, Greece),
Daniela Bordini (TEAMM Clinic, Department of Psychiatry, Federal
University of São Paulo, Brazil), Keiko Kawashima (Department of
Clinical Psychology, Taisho University, Japan), John Hasslinger, Philip
Ivers-Ohlsson, Christer Classon, and Micaela Meregalli (all KIND,
Karolinska Institutet & Stockholm läns landsting, Sweden), Dr. Nadia
Ronzano (University of Cagliari), Dr. Roberta Romaniello (University
of Cagliari) and Satomi Suzuki (Department of Clinical Psychology,
Taisho University, Japan).
Funding The development of ICF Core Sets for ASD is supported by
the Swedish Research Council in partnership with FAS (now renamed
FORTE), FORMAS and VINNOVA (trans-disciplinary research
programmes on child and youth mental health, Grant Nr. 259-2012-24).
Author Contribution SM prepared the study material, contacted the
study sites, collected data (from Sweden), performed the data analysis,
and had a major part in drafting the manuscript and interpreting the
data. KA, OA, VA, SC, JCD, MK, AK, AL, MBL, GR, TU and NW
collected data from their respective study sites and contributed to
critically review the manuscript. MS, MG, PdV and LZ played a part in
preparing the study design and critically reviewing the manuscript.
SB is the Principal Investigator, contributing to the study design and
coordinating it, critically reviewing the manuscript, and interpreting the
study results. All authors revised the manuscript critically and approved
the final version.
Compliance with Ethical Standards
Conflict of interest Soheil Mahdi, Katja Albertowski, Omar
Almodayfer, Vaia Arsenopoulou, Sara Carucci, José Carlos Dias,
Mohammad Khalil, Ane Knüppel, Anika Langmann, Marlene B. Lauritsen,
Graccielle R. Cunha, Tokio Uchiyama, Nicole Wolff, Melissa Selb,
Mats Granlund, Petrus J. de Vries, Lonnie Zwaigenbaum, and Sven
Bölte declare no conflict of interest related to this work. Sara Carucci
discloses that she in the last three years have collaborated within
projects from the European Union (7th Framework Program), has received
travel support from Shire Pharmaceutical Company; she collaborated
as Sub-investigator in sponsored clinical trials by Shire
Pharmaceutical Company and Lundbeck. Petrus J. de Vries discloses that he has
received grants and funds from Novartis, as part of clinical trials of Mtor
inhibitors for Tuberous Sclerosis Complex. Sven Bölte discloses that
he has in the last 5 years acted as an Author, Consultant or Lecturer for
Shire, Medice, Roche, Eli Lilly, Prima Psychiatry, GLGroup, System
Analytic, Kompetento, Expo Medica, and Prophase. He receives
royalties for text books and diagnostic tools from Huber/Hogrefe,
Kohlhammer and UTB.
Ethical Approval All procedures performed in this study with the
human participants were in accordance with the Ethical Standards of
the Institutional and/or National Research Committee and with the
1964 Helsinki Declaration and its later amendments or comparable
ethical standards. Ethical permission for this study was obtained from
the Regional Ethical Review Board in Stockholm, Sweden, and by the
Local Ethics Review Boards at each of the other participating sites.
Informed Consent Informed consent (in written form) was obtained
from each participant prior to study participation.
Open Access This article is distributed under the terms of the
Creative Commons Attribution 4.0 International License (http://creativeco
mmons.org/licenses/by/4.0/), which permits unrestricted use,
distribution, and reproduction in any medium, provided you give appropriate
credit to the original author(s) and the source, provide a link to the
Creative Commons license, and indicate if changes were made.
Soheil Mahdi1,2 · Katja Albertowski3 · Omar Almodayfer4 · Vaia Arsenopoulou5 · Sara Carucci6 ·
José Carlos Dias7 · Mohammad Khalil8 · Ane Knüppel9 · Anika Langmann10 · Marlene Briciet Lauritsen11 ·
Graccielle Rodrigues da Cunha12 · Tokio Uchiyama13 · Nicole Wolff3 · Melissa Selb14,15 · Mats Granlund16 ·
Petrus J. de Vries17 · Lonnie Zwaigenbaum18 · Sven Bölte1,2,19
Aalborg University Hospital, Clinical Institute, Aalborg,
TEAMM Clinic, Department of Psychiatry, Federal
University of São Paulo (UNIFESP), São Paulo, Brazil
Child and Adolescent Psychiatry, Stockholm County
Council, Stockholm, Sweden
Center of Neurodevelopmental Disorders at Karolinska
Institutet (KIND), Division of Neuropsychiatry, Department
of Women’s and Children’s Health, Karolinska Institutet,
113 30 Stockholm, Sweden
Center for Psychiatry Research, Stockholm County Council,
Experimental Developmental Psychopathology, Department
of Child and Adolescent Psychiatry, Faculty of Medicine
of the TU Dresden, Dresden, Germany
Mental Health Department, KAMC-R, MNGHA, Riyadh,
Theotokos Foundation, Athens, Greece
Child & Adolescent Neuropsychiatric Unit, Department
of Biomedical Science, University of Cagliari & “A. Cao”
Microcitemico Paediatric Hospital, Cagliari, Italy
Childhood and Adolescence Psychiatry Department, Oporto
Hospital Centre, Porto, Portugal
Human Development Center, Riyadh, Saudi Arabia
Aalborg University Hospital Psychiatry, Aalborg, Denmark
Department of Child and Adolescent Psychiatry,
Psychosomatics and Psychotherapy, University
Hospital of Marburg & Institute of Clinical Psychology,
Philipps-University Marburg, Marburg, Germany
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13 Japan Centre for Applied Autism Research, Department of Clinical Psychology, Taisho University, Tokyo, Japan 14 ICF Research Branch, A Cooperation Partner Within the WHO Collaborating Centre for the Family of International Classifications in Germany (at DIMDI), Nottwil , Switzerland