Autism spectrum disorder in architecture perspective: a review of the literature and bibliometric assessment of research indexed in Web of Science

Theoretical models of autism

Many human-environment interaction research conducted by environmental psychologists have focused on the environment's psychological factors rather than the physical setting. This section will clarify the relationship between autism and the environment.

1- Human ecosystem (HES)

In 1992, Guerin defined the Human ecosystem (HES) theory model in a learning environment to understand autistic behavior. The variables in this progress are related to the specific model components:

Some researchers regarding the Nature of autism are convinced that autism is a pandemic of modern culture, with environmental factors at the roots such as pollution; researchers found early-life exposure to air pollution may be a risk factor for autism. (Naviaux, 2012).

2- Performance prediction model (PPM)

The performance prediction model (PPM) describes the transactions between the users and their physical environment through the behavior. Also, understand how the physical environment affects user variables by observing behavior. In addition, clarify the interaction between the three components to lead to universal design principles. Even though this model is not explicitly created for ASD children, the research can be applied to users with different personal characteristics or functional abilities. This model consists of three main components (user variables, behavior, and environment). The variables in this progress are related to these specific components:

This model is used as a guide for the designer in designing different types of the physical environment for different users because it helps to categorize the users according to their characteristics, which are:

The characteristics of autism are varied in intensity, degree, and amount and manifest differently from person to person and over time. The common characteristics associated with ASD are loosely based on the DSM-5, common features of ASD, and PMM on ASD.

There is limited research on how environments may affect behavior and be designed to meet the needs of those with ASD. Also, there is a lack of information on the experience of spaces and perceptions by people with autism. Only two research have been found namely 'MEDIATE – a responsive environment designed for children with autism (Gumtau et al., 2005) and 'Could light colour and source change mood in children with autism? (Hernandez Rivera, 2020).

3- Theoretical underpinnings of design

Interior designers concentrate on the design of the interior environment with the requirements of the person who will inhabit the space as the driving force behind all design decisions. Human factors, lighting, occupant wellbeing and performance, post-occupancy evaluation, research, theories about the relationship between human behavior and the https://discovery.ucl.ac.uk/id/eprint/10108977/7/Hernandez%20Rivera_10108977_Thesis_redacted.pdf designed environment, and universal design are among the ten knowledge areas covered by the 'Human Environment Needs: Research and Application' (HEN) category.

Experts on ASD consider the first six years of school, from preschool to sixth grade, important in reaching children and laying the groundwork for lifelong learning and general wellbeing. Even when daily activities are meticulously organized, classrooms attended by children with ASD or other children are highly dynamic, unpredictable environments. Because of this instability, examining the architecture of classroom space in schools where children with ASD attend from preschool to sixth grade is difficult. However, the framework identified by (Guerin, 1992), which recognized the interaction of the human organism (HO), the BTE, the natural environment (NE), and the behavioral environment (BHE).

Autism spectrum disorder (ASD) is a complicated neurological disorder that, until now, has been inscrutable. The population of individuals on the spectrum worldwide is increasing due to the increased awareness. As their numbers grow, professionals in many fields started studying their ASD cases to provide them with a better life (Hauptman et al., 2019). Individuals on the spectrum are part of a growing population usually ignored in design despite the current tendency to create designs that focus on persons with special needs. There are binding recommendations and laws on designing buildings that respect physical disabilities, and the field is rich in design applications for physical needs (Sánchez et al., 2011). By contrast, there is utter indifference toward the person with mental health disabilities, even with guidelines for inclusion of children with physical impairment are used and successful, the inclusion of children with mental disabilities lags much behind (Bilbo et al., 2015) in their research mentioned that "the environment plays a role in human behavior" that greatly influenced the practice of interior architects designing people centers design. ASD children have sensory processing difficulties, which create challenges in understanding the surrounding environment, thus affecting their behaviors negatively (Sánchez et al., 2011). The built environment can cause extra confusion, which negatively impacts children with ASD due to the challenging developmental disorder of the ASD. Architects and interior architects are responsible for providing an inclusive built environment to improve the quality of life, especially for people with special needs (Kopec, 2012), yet it is still relatively unnoticed by architects and designers as it's still excluded from building codes or design guidelines. Environmental and behavioral research has profoundly influenced the practice of interior architecture as it's vital to explore the environmental design for autism.

A vast amount of literature has been published on autism in medical and psychological journals over the years. However, few studies from an architectural perspective have been published even though the role of the sensory environment in autistic behavior has been an issue of debate since Leo Kanner first defined the disorder in 1943 (Kanner, 1943). Recently, architects have become interested in finding out about the relationship between environment and autistic behavior to provide a suitable environment and support wellbeing.

Few interior designers and architects have yet started to define codes and guidelines such as Autism Planning and Design Guidelines 1.0 by Knowlton School of Architecture (2018) as a design solution for ASD to build autism-friendly surroundings that support users with ASD and prepare them to face other environments. The designer's approach usually compares children with ASD and without through their behaviors to find the differences in their needs in the environment (Delmolino & Harris, 2012). Environmental and behavioral research has profoundly influenced architecture, and there is a growing need and trend toward user-centered and evidence-based design research to create an environment where people with ASD can thrive.

Few scientometric studies have been done to cover the knowledge gap in the ASD research, in that the authors considered examining the topic generally, such as Ozgur & Balci (2022). They found that 'studies on autism have increased significantly in recent years. While approximately 150 studies were published annually in the early 80s, around 6000 studies were published in 2020. In this study, 59653 publications were retrieved, 63.69% of which were journal articles. The remaining publications were reviews, meeting abstracts, editorial materials, proceedings papers, etc. The primary language was English (96.70%) for the retrieved articles. Other languages like Spanish, French, German, Portuguese, Russian, Turkish, etc., were also encountered.

Sweileh et al. (2016) studied growth of ASD research from 2005 to 2014 and found a total of 18,490 articles were retrieved. The Journal of Autism and Developmental Disorders, with 48,416 citations and an average of 23.59 citations per article, was identified as the most prolific journal. The United States (US) (n = 8594; 46.48 %), the United Kingdom (n = 2430; 13.14 %) and Canada (n = 1077; 5.8 %) have been most productive countries. King's College London (UK) was found on the top of the list for producing literature and receiving citations. 50% of the highly cited articles were in molecular genetics, and the papers with more than 50 citations were published mainly by authors from USA, UK, and Canada.

The above general studies conclude that most literature is based on medical, biotechnology, and psychological perspectives. Most funding agencies are identified as medical institutions, and the US is the most contributing country to generating the literature. Most ASD research in article form and double and triple authorship has more consideration. The citation rate shows an increase in the trend, and the growth in ASD research literature in terms of medical and psychological are noted as a steady increase and are higher in this decade.

However, the development of ASD literature in the architectural field has not been found. Therefore, based on the scientometric analysis, the present study considers estimating and identifying the gaps in the available literature on ASD from the architectural perspective compared to the literature available from the other perspectives, such as medical and psychological.

Annual research growth and citation's structure in autism spectrum disorder during 1992–2021

The first research paper on autism was recorded in 1992 with 382 citations (no publication indexed in 1993, 1995, 1996, 1997, and 2003), similar results reported by (Kumar et al., 2021). Though the research output gradually increases, but shallow up until 2012. The autism research increased markedly after 2013, noticeably more than 50 papers appeared every year after 2013. The year 2019 was the most successful in term of the number of the article (NP=101), followed by the year 2016 and 2017, in which the second highest number of research papers published, coincidently the year 2018 and 2020 have equal number published articles (NP=84) and the year 2021 have 35 papers with 19 citations. The highest number of citations received in 2014 (TC=6634) for 53 publications, followed by the year 2011 (TC=4078) for 31 papers and the year 2010 (TC=3108, TP=34) (Table 1).

The authors have scanned all these documents to pinpoint the exact number of research papers purely on architectural design perspective and found a quite low number also, some of it belongs to art and design, these numbers represent the actual gap in the literature, which authors intended to explore and found that gap is quite huge. See (Table 1).

The first paper on ASD research based on a purely architectural design perspective was published in 2004 and then in 2008. These papers remain unrecognized since they didn't receive a single citation. After a gap of 5 years, another research published under the title "Autism and Architecture" by Segado VF and Segado TA in 2013 received 2 citations; then, in 2015, two research papers were published, again without citations. In 2016 three research papers were published, namely "Interaction Design in the Built Environment: Designing for the Universal User" with 2 citations, "Designed by the pupils, for the pupils: An autism-friendly school" with 7 citations, and "Autism-Friendly Architecture from the outside in and the inside out An explorative study based on autobiographies of autistic people" with 8 citations. In 2017 only one research published under the name "Toward an autism-friendly home environment" by Nagib W and Williams A received 11 citations. A single research in 2018 as, "Sensory Spaces: Sensory Learning - An experimental approach to educating future designers to design autism schools," by Love JS, published in ARCHNET-IJAR, received only 2 citations. Three research papers were published in 2019 under the title Quality of the built environment from the point of view of people with autism spectrum disorder", "The impact of color and light on children with autism in interior spaces from an architectural point of view," and "Studio teaching experiments- spatial transitioning for autism schools" begged 0, 1,1 citations respectively. During pandemic 2020, only one research was published and didn't receive citations, and in 2021 (continuing years) didn't notice any research. Therefore, only 16 ASD research papers were purely related to architectural design from 812 documents noted from 1992 to 2021, with as many as 11 citations. These number of documents and citations reveal that these research areas are not very popular amongst the researchers. Please refer to the recent growth in general ASD research (Ozgur & Balci, 2022), as mentioned in the literature review.

Type of research papers

The journal articles (NP=537) were the most preferred form, which agrees with (Rahaman et al., 2021b). The review found a second preferred form (NP=142), followed by proceedings papers (NP=71) and then meeting abstract (NP=17). Other documents were minor in the list, published only three papers each. On the other hand, the articles also received the highest number of total cations (24922), followed by review (TC=8916) (Table 2). The research was purely based on an architectural perspective, mostly published as journal articles (13) and then as proceeding papers (3) out of 16. Please refer to (Table 1) for the total number of pure architectural design research.

Productive organization

It is evident that the top ten organizational productivity ranges between 25 to 42 publications (Table 3). The University of Toronto is the leading organization in autism research (NP=42), followed by Vanderbilt University (NP=37), University of California, Los Angeles (NP=35), Yale University (NP=33), and Massachusetts General Hospital (NP=30). Harvard Medical School (NP=25) identified as the minor producer of research in the top ten list. Interestingly, most of the listed organization are in the USA (9 organizations), and one organization from Canada. Stanford University was the most cited organization (TC=6686) for 28 publications, followed by Yale University (TC=6059) for 33 research in autism.

Productive country

Moreover, it is found that the top eight countries produced over 50 research papers (Table 4). Only two countries have over 100 articles on autism. The USA had outstanding research output in autism with 433 publications and 27124 citations, followed by the UK (118 publications, 7569 citations), Canada (79 publications, 6816 citations), China (72 publications, 3339 citations), and France (60 publications, 3304 citations). This result parallels the previous scientometric analyses on ASD research, which says that the USA is highly active in producing ASD literature.

The analyses reveal that half of the research in autism contributed by the USA that received the highest number of citations (TC=27124) for 433 publications, followed by the UK with 7569 citations with 118 publications, and Canada with 6816 citations and 79 publications. Australia managed minimum citation (TC=2048) in the list with 46 publications.

The relevant sources in ASD

All the top ten sources have more than 12 publications; coincidentally, six sources (American Journal of Human Genetics, American Journal of Medical Genetics Part B-Neuropsychiatric Genetics, Biological Psychiatry, Molecular Autism, Molecular Psychiatry, Neuron) produced 12 publications each. Scientific Reports (Nature Publishing Group) was considered the most relevant source with 14 publications and 203 citations, followed by Nature Neuroscience (Nature Publishing Group) with 14 publications and 1986 citations and Human Molecular Genetics and Plos One with 13 publications each and 1015 and 371 citations, respectively. The analysis reveals that most of the sources belongs to the Q1 category (eight sources), and two in Q2 category. The highest impact factor journal in the list was Nature Neuroscience (JIF=20.07), followed by Neuron (JIF=14.41) and Molecular Psychiatry (JIF=12.38) (Table 5). These results also revealed the gap in the development of the ASD research literature in terms of architectural design perspective. The top ten journals are again from genetic, molecular biology, and biological psychiatry; this top ten listing lags the source in the areas of architecture or architectural design. Hence, the authors have further explored the sources in which the 16 research papers purely on architectural design have been published. They found very few but popular sources in the field, namely, Archnet-IJAR International Journal of Architectural Research, International Journal of Arts and Technology, Housing Studies, Journal of Housing and the Built Environment, Journal of Intellectual Disability Research, Journal of Policy and Practice in Intellectual Disabilities, Advances in Human Factors, Sustainable Urban Planning, and Infrastructure.

Prolific authors

This analysis reveals that the article range of authors varied between nine and 12. Five authors (Devlin B, Geschwind DH, Scherer SW, State MW, and Wang Y) emerged as the most prolific authors with 13 publications each, 4383, 3409, 3338, 3662, and 333 citations, respectively. Buxbaum JD (Icahn School of Medicine at Mount Sinai) found as the second highest prolific author with 13 publications and 2970 citations, followed by Bourgeron T, Eichler EE, and Li Y with 11 publications and 2142, 1944, and 568 citations, respectively. Casanova MF (University of South Carolina School of Medicine) noted as the least contributed authors in the top ten list with nine publications and 361 citations. Devlin B (Mount Sinai School of Medicine) was the most cited author with 4383 citations for 13 publications, followed by Geschwind DH with 3409 citations for 13 publications, and Wang Y (Carnegie Mellon University) managed only 333 citations for 13 publications. The table also shows that the most prolific authors belong from the USA (7 authors), followed by Canada, France, and China. (Table 6). It is also revealed that most of the authors belong to medicine and psychology; the authors from the field of architecture are missing from the top 10 list. There are 24 authors found contributing to ASD research in the field of architectural design, amongst them Tufvesson C; Tufvesson J, and Nagib W; Williams A contributing one paper and begged 11 citations, followed by Kinnaer M; Baumers S; Heylighen A (NP=1, TC=8), Mcallister K; Sloan S (NP=1, TC=7). The other authors with one paper received two citations are Segado Vazquez F; Segado Torres A; Dalton C; and Love JS. Shareef SS; Farivarsadri G received one citation for one paper, and the other nine authors didn't receive a citation.

The pattern of authorship

The Figure 2 illustrated the pattern of authorship in autism literature. It was clear from the figure that the authorship pattern ranged from single to two hundred and forty-seven. The analysis reveals that collaborative research is more prominent among the research of autism over the study period. The top six authorship patterns produced over 50 publications in the field. Three authorship patterns (NP=123) contributed a maximum article in autism, followed by two authorship (NP=120), four authorship (NP=93), five authorship (NP=79), single authorship (NP=61), and six authorship (NP=56). The authorship of 27, 36, 38, 39, 40, 42, 46, 56, 58, 65, 67, 73, 86, 88, 118, 125, 146, and 247 each contributed only single publications in autism. The results also showed that two authorship patterns received the highest number of citations (TC=4775), followed by five authorship (TC=3296) and Three authorship (TC=3071). Rahaman conducted a similar type of authorship pattern analysis (Rahaman et al., 2021a).

Figure 2. Pattern of authorship in autism.

Mapping co-occurrence of all keywords (author and indexed)

Figure 3 shows analysis of all keywords used in autism research from 1992–to 2021. The results showed that 3848 keywords appeared in autism research. To map the co-occurrence of all the keywords, minimum of 15 occurrences of keywords were considered for analysis. Out of 3848 keywords, only 79 keywords met the thresholds, and all 79 selected keywords are clustered in Figure 3 with 1737 links and total link strength (5557). The size of the ball indicates a strong network of keywords, with each color representing a distinct cluster.

Figure 3. Keyword analysis using Vosviewer.

Cluster 1 comprises 31 keywords (abnormalities, activation, adolescents, adults, architecture Asperger-syndrome, autism, autism spectrum disorder, autism spectrum disorders, behavior, brain, childhood, children, classification, connectivity, cortex, diagnostic interview, fMRI, functional connectivity, high-functioning autism, human cerebral-cortex, meta-analysis, networks, organization, patterns, pervasive developmental disorders, sleep, spectrum disorder, spectrum disorders, white-matter, and young-children).

Cluster 2 has 22 keywords (association, bipolar disorder, copy number variation, disorder, genes, genetic architecture, genetics, genome-wide association, heritability, identification, individuals, linkage, mutations, phenotype, prevalence, psychiatric-disorders, reveals, risk, schizophrenia, spectrum, susceptibility, and variants).

Cluster 3 includes 19 keywords (brain-development, copy number variants, copy-number variation, de-novo mutations, disease, disorders, epilepsy, evolution, expression, gene, intellectual disability, mechanisms, mental-retardation, network, neurodevelopmental disorders, neurons, prefrontal cortex, protein, and structural variation).

Cluster 4 has seven keywords (fragile x syndrome, fragile-x-syndrome, gene-expression, mental-retardation protein, mouse model, rett-syndrome, and synaptic plasticity).

The top ten keywords were autism (frequency=257), architecture (165), autism spectrum disorder (127), children (123), schizophrenia (92), autism spectrum disorders (91), de-novo mutations (86), Risk (73), brain (59) and expression (freq.=55) had weighty number of occurrence with strong total link strength.

Each cluster is based on the theme, which shows the various aspect of the subject and its development. The themes special for architecture or design or built environment are missing to track the development of the subject.

The authors have found a few trendy keywords are missing here, such as acoustics, acoustical control, spatial sequencing, escape spaces, compartmentalization, natural light, fluorescent light, snoezelen, sensory environment, multisensory, neutral sensory, hypersensitive, hyposensitive, sensory trigger, sensory zoning, stimulus level, overstimulating, transition, transition spaces, safety, audio, auditory, auditory processing, distraction, interactive, tactile, tactile sense, altered senses.

Thematic map by title

Figure 4 shows four alternative typologies of themes that can be visualized using a thematic map. The thematic parameter is considered the title selected for the field, the minimum number of words selected is 80, and Unigram is selected for the graph.

Figure 4. Thematic map by title analysis.

The basic theme: Autism spectrum which represented by cluster 1 (autism, spectrum, disorder, children, brain, network, functional, connectivity, based, analysis, sleep, neural, developmental, learning, networks, structural, reveals, system, approach, design, matter, review, robot, resting, control, developing and white).

The motor theme: architecture human in cluster 2 (architecture, human, gene, syndrome, social, development, cortical, protein, autistic, model, synaptic, fragile, neuronal, cognitive, ASD, altered, behavior, mental, mice, role, cortex, expression, function, visual, cell, mouse, processing, and activity.

Niche theme: genetic disorder placed in cluster 3 (disorders, genetic, variants, risk, schizophrenia, neurodevelopmental, genes, psychiatric, rare, common, de, genetics, novo, genomic, related, mutations, copy, disease, mechanisms, and sequencing).

Emerging or declining theme: study genome represented by cluster 4 (study, genome, association, wide and evidence).

Most cited research papers in autism

The top ten papers (Table 7) have more than 300 citations, published between 2007 and2015. "Large-scale brain networks and psychopathology: a unifying triple network model" (2011) by Menon V, published in Trends Cogn Sci was the topmost cited paper (1425 citations) (Menon, 2011), followed by "Synaptic, transcriptional and chromatin genes disrupted in autism" (2014) by De Rubeis S, appeared in "Nature" (1220 citations) (De Rubeis et al., 2014), "The contribution of de novo coding mutations to autism spectrum disorder" (2014) by Iossifov I, published in Nature (1118 citations) (Iossifov et al., 2014), "Mapping autism risk loci using genetic linkage and chromosomal rearrangements" (2007) by Szatmari (999 citations) (Szatmari et al., 2007). "Dendritic spine pathology in neuropsychiatric disorders" (2011) by Penzes (838 citations) (Penzes et al., 2011), and "A genome-wide scan for common alleles affecting risk for autism" was the least cited paper among the top ten (393 citations) (Anney et al., 2010). It was noticeable that half of the top ten cited papers were published by Nature Publishing Group. The article entitled "Synaptic, transcriptional and chromatin genes disrupted in autism" (De Rubeis et al., 2014) has the highest total citations per year (152.50).

The papers that are well received in architecture or architectural design are not listed here due to a lack of citations than the papers in the other fields; hence, the ASD research in the given fields is less prevalent. The most cited papers in the architectural field are: ' The building process as a tool towards an all-inclusive school. A Swedish example focusing on children with defined concentration difficulties such as ADHD, Autism, and Down's Syndrome (2009) and 'Toward an Autism-friendly home environment' (2017) received 11 citations each. 'Autism-friendly architecture from the outside in and the inside out: An explorative study based on autobiographies of Autistic people' (2016) received eight citations, and 'Designed by the pupils, for the pupils: An Autism-friendly school' (2016) got seven citations.

Most Cited references in autism research

Table 8 explained the most top ten cited references in autism research. It is clear from the table that all listed references received more than 50 citations. Article entitled "Insights into Autism Spectrum Disorder Genomic Architecture and Biology from 71 Risk Loci" (2015) by Sanders SJ, appeared in 'Neuron' was the most cited (TC=92) reference in autism research (Sanders et al., 2015), followed by an article named 'Synaptic, transcriptional and chromatin genes disrupted in autism (2014) by De Rubeis S with 91 citations (De Rubeis et al., 2014), 'and 'The contribution of de novo coding mutations to autism spectrum disorder' (2014) by Lossifov I with 91 citations and appeared in the journal Nature (Iossifov et al., 2014). The cited references 'De novo gene disruptions in children on the autistic spectrum (2012) by Iossifov I published in 'NEURON' was the most diminutive receiver of citation with 61 TC (Iossifov et al., 2012). However, the top ten listed references belong to the biotechnology, genetic architecture, and medicinal aspects; the gap identified here is the lack of ASD study on architectural in terms of designer perspective.

Highly influential funding agencies

There are only four funding agencies from the top 10 list which funded more than 100 research papers (Table 9). National Institutes of Health renowned as leading funding agency (313 publications, 23087 citations), followed by the United States Department of Human Health Services (313 publications, 22759 citations), the National Institute of Mental Health (182 publications, 16164 citations), European Commission (111 publications, 8476 citations), and National Institute of Child Health Human Development (66 publications, 7927 citations). The Wellcome Trust appeared as the least influential funding agency among the top ten (36 publications, 3959 citations). The USA was dominant in the top ten list (six funding agencies), followed by the UK (three funding agencies) and one agency from the EU.

It is to be noted that all funding agencies belong to the health and medicine except one that is the 'UK Research Innovation,' which is a good sign for the researcher belonging to the field of innovation, architecture, design, and creativity to apply for a funded research/projects.

Country collaboration in autism

The most dominant country collaborations were the USA and United Kingdom (51 publications), followed by the USA and Canada (43 publications), the USA and China (38 publications), the USA and Italy (26 publications), and the USA and the Netherlands (26 publications). The USA with Sweden collaboration (19 publications) was listed at the bottom of the top ten list. It was interesting to show that the USA collaborated with nine countries (the UK, Canada, China, Italy, the Netherlands, Germany, France, Australia, and Sweden). The UK followed this with two countries (the USA and Canada). (Figure 5).

Figure 5. International collaboration map.

Underlying data

Zenodo: Underlying data for 'autism spectrum disorder in architecture perspective: A review of the literature and bibliometric assessment of research indexed in Web of Science'. https://doi.org/10.5281/zenodo.5080242

Data are available under the terms of the Creative Commons Attribution 4.0 International license (CC-BY 4.0).